EarthSky https://earthsky.org Updates on your cosmos and world Sun, 31 May 2026 13:49:53 +0000 en-US hourly 1 https://wordpress.org/?v=6.9.4 Could aliens visit Earth? Here are some challenges https://earthsky.org/space/could-aliens-visit-earth-challenges-of-interstellar-spaceflight/ https://earthsky.org/space/could-aliens-visit-earth-challenges-of-interstellar-spaceflight/#respond Sun, 31 May 2026 12:00:06 +0000 https://earthsky.org/?p=547528 Scientists say it’s unlikely aliens visit Earth anytime soon, because interstellar travel faces huge barriers of distance, energy and time.

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]]> Classic-looking gray alien with a big bald head and large eyes, pointing a finger.
Could aliens visit Earth? Here are some of the challenges of traversing the almost inconceivably vast distances in our Milky Way galaxy. Image via Shutterstock.
  • Interstellar travel requires enormous amounts of energy, shielding from radiation and ways to sustain life for generations.
  • While there are a number of options for propulsion systems, they all have drawbacks. For example, for rocket fuel, you need fuel to transport your fuel!
  • Scientists say advanced propulsion concepts may help someday, but the possibility of aliens visiting Earth seems highly unlikely.

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This article was originally published in The Conversation. Edits by EarthSky.

By Kai James, Georgia Institute of Technology

Could aliens visit Earth?

On May 22, 2026, the Pentagon released a 2nd batch of previously classified photos and videos showing what appear to be unexplained flying objects. These file dumps were the culmination of a process that was set in motion back in July 2023, when a group of government whistleblowers testified before Congress that the U.S. government was secretly in possession of extraterrestrial spacecraft and suspected alien body parts.

That congressional hearing marked the beginning of a cultural shift in which UFO reports are increasingly treated as a matter for serious discussion, both within the government and the scientific community.

A grainy photo of a dark, blurry object in the sky.
The Pentagon released over 200 previously classified UFO files in May 2026. Image via Department of Defense.

But is this newfound legitimacy deserved? As an aerospace scientist who studies aircraft and spacecraft design, I approach this question using math, physics and the principles of engineering. To assess the plausibility of alien visitors, it’s necessary to understand the obstacles that an extraterrestrial vessel would need to overcome to reach Earth.

The tyranny of distance

There is no evidence of intelligent alien life in our solar system. So any extraterrestrial visitors would likely have to come from another star system within our Milky Way galaxy.

Proxima Centauri, the star closest to our sun, is located 4.25 light-years (about 25 trillion miles or 40 trillion kilometers) away.

For perspective, if Earth were the size of a pea, the distance to Proxima Centauri would roughly equal the distance between New York and Sydney, Australia.

Even the stars closest to Earth are incredibly far away.

Since scientists think only a fraction of stars host intelligent life, the nearest alien civilization – if one exists – is surely much farther away than Proxima.

A need for speed

Given the scale of interstellar distances, it’s inevitable that any alien voyage to Earth would span many years and possibly several centuries. But as the time spent in transit increases, so does the risk of catastrophic accidents or system malfunctions that could jeopardize the mission. So it’s important to avoid an overly lengthy journey by traveling as fast as possible.

No object can reach or exceed the speed of light, roughly 186,000 miles per second (300,000 km/s). But well before approaching that threshold, engineering constraints begin to assert themselves. Limited fuel availability and the potential for structural damage will restrict the spacecraft’s peak velocity.

There is no universally accepted upper limit on interstellar flight speeds. But studies tend to converge around 19,000 miles per second (30,000 km/s) – 10% of the speed of light – as a realistic cruise velocity. At this speed, a journey of 10 light-years will take approximately 100 years to complete.

Aliens visit Earth: A field of a myriad tiny, distant galaxies and one bright star at upper left with spikes.
The universe is vast and teeming with stars. But if intelligent life exists, could aliens visit Earth? An aerospace engineer details the challenges of interstellar spaceflight. Image via NASA/ ESA/ CSA/ STScI/ Rohan Naidu (MIT). Image processing: Joseph DePasquale (STScI).

Fueling the dream

Finding a way to accelerate the ship to its target cruise speed is the central challenge facing any would-be alien explorers.

Interstellar space is unforgivingly vast, but the emptiness has some advantages. The lack of atmosphere means there is no aerodynamic drag. So when the ship reaches its cruise speed, it can shut down its propulsion system and coast toward the final destination. Unfortunately, the lack of atmosphere also means there is nothing to slow the ship down prior to arrival. So ideally, the propulsion system would be used for both acceleration at the start of the trip and deceleration at the end.

Laser propulsion

One of the more exotic propulsion strategies employs high-powered laser beams to push the ship through space. The beam is projected from a stationary array near the travelers’ home planet and directed toward a thin reflective sail attached to the ship. The beam’s photons exert radiation pressure on the sail, propelling the ship forward.

This approach has a major advantage in that it requires no onboard fuel. But the amount of energy and infrastructure needed to operate the laser would be staggering. Also, beamed propulsion provides no mechanism for deceleration. At best, this method could be deployed as part of a hybrid strategy that uses a separate system for deceleration.

Rocket propulsion

A more practical approach is to use rocket propulsion. Rockets generate propulsive force, also known as thrust, by expelling high-velocity exhaust in a rearward stream. By reversing the direction of the exhaust, rockets can also slow the ship down.

Their main disadvantage is that rockets must carry their own fuel in addition to carrying the passengers, the habitat and other life-sustaining systems. The extra load necessitates even more fuel. In other words, you need fuel to transport your fuel. The result is a costly snowball effect that can cause the total fuel requirement to balloon to absurd proportions.

Rocket propulsion can be divided into three broad categories.

  • Chemical propulsion uses chemical reactions – typically combustion – to extract energy from the bonds between atoms. All human space missions thus far have used chemical propulsion. The problem with this method is that it accesses only a tiny fraction of the energy contained within the fuel. Downside: Using chemical propulsion to achieve a cruise velocity of 19,000 miles per second (30,000 km/s) would require more fuel than all the mass in the observable universe.

  • Antimatter propulsion is theoretically the most efficient option. When antimatter comes into contact with ordinary matter, the two undergo mutual annihilation and 100% of their combined mass converts into energy. This makes it possible to achieve the same cruise velocity – 1/10 the speed of light – with fuel accounting for less than 1/4 of the ship’s total mass. This is science fiction-level fuel efficiency, which makes antimatter an attractive option for interstellar propulsion. Downside: Antimatter is extremely unstable and difficult to make. To date, particle physicists have produced less than 20 billionths of a gram of antimatter. Moreover, these particles had lifespans lasting only fractions of a second and a price tag in the hundreds of millions of dollars.

  • Nuclear fusion offers a more viable alternative to antimatter. This approach harvests energy stored inside the nucleus of an atom using the same process that powers the sun. With current technology, fusion engines remain aspirational. But they could, in theory, produce 10 million times more energy per kilogram than chemical rockets. Downside: A fusion-powered ship with a cruise velocity of 19,000 miles per second (30,000 km/s) would require fuel equivalent to 150 times the mass of the ship itself.

A cylindrical spacecraft with a large silver module at one end orbiting Earth.
NASA has been working to develop nuclear propulsion. This artist’s impression shows what a nuclear-powered rocket could look like. Image via John Frassanito & Associates/ Wikipedia.

A delicate balancing act

These numbers assume that our extraterrestrial visitors have figured out how to efficiently convert the energy released by their reactor – whether nuclear fusion or antimatter – into thrust.

Just as importantly, they must be able to create optimized fuel tank structures that are ultra lightweight yet highly secure. Designing the structure of the ship, from the fuel tanks to the hull, would be one of the biggest engineering challenges of the entire mission.

Interstellar space contains a sparse smattering of hydrogen atoms and microscopic grains of cosmic dust. At 19,000 miles per second (30,000 km/s), dust particles would smash into the ship’s hull with the energy of a .22-caliber bullet. The bombardment of hydrogen atoms would produce a violent cascade of radiation that could erode even the most resilient engineering materials.

Surviving the onslaught would require no less than a flying fortress with complex magnetic shielding. This would increase the total mass of the ship, which further drives up the demand for fuel.

This example is just one of the hundreds of delicate design trade-offs that would plague any interstellar vessel. Each individual design requirement acts as a filter, reducing the number of feasible solutions.

No simple solution

Finding a single system that simultaneously satisfies all the requirements is analogous to shopping for a car online. With each new filter you apply – four-wheel drive, black exterior, less than five years old – the number of available options dwindles.

When design requirements are in tension with one another – for example, requiring a structure that is lightweight but also supremely durable – the number of feasible solutions can drop to zero.

No single law of physics prohibits an interstellar voyage. But the combined effects of hundreds of extreme, often conflicting engineering requirements may render it physically infeasible.

It’s also possible that alien civilizations have discovered novel technologies that outperform anything currently known to humans. But like the examples discussed here, any such technology will inevitably encounter its own engineering hurdles.

The trillion-dollar question

Ultimately, engineering challenges are just some of the many barriers to interstellar travel. Any prospective alien visitors must also have sufficient cognitive ability, technological maturity, physical resources, collective desire and proximity to Earth.

That said, if the stars were to align and an alien vessel made it to Earth intact, it would trigger a torrent of burning questions: Where are they from? What do they want? What are they made of?

But the question that would go furthest in shedding light on the deeper mysteries of the universe is, “How on Earth did they get here?”The Conversation

Kai James, Professor of Aerospace Engineering, Georgia Institute of Technology

This article is republished from The Conversation under a Creative Commons license. Read the original article.

Bottom line: Scientists say it’s unlikely aliens visit Earth anytime soon, because interstellar travel faces huge barriers of distance, energy and time.

Read more: Pentagon UFO files released: Views from the moon and more

Read more: 2nd batch of Pentagon UAP files: Over 50 videos to watch

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]]> https://earthsky.org/space/could-aliens-visit-earth-challenges-of-interstellar-spaceflight/feed/ 0 BOOM over Massachusetts and U.S. East probably a meteor https://earthsky.org/earth/boom-over-massachusetts-and-u-s-east-probably-a-meteor/ https://earthsky.org/earth/boom-over-massachusetts-and-u-s-east-probably-a-meteor/#respond Sun, 31 May 2026 11:55:09 +0000 https://earthsky.org/?p=547802 Many reported a streak across the daytime sky and a boom over Massachusetts and surrounding areas in the US East, probably a meteor.

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]]> Bright white fireball, with large brilliant head and a glowing tail, streaking across a blue sky.
Daytime fireballs are extremely rare to see across a single human lifetime. But they happen unseen, frequently, over Earth as a whole. Here’s one from Macon, Georgia, in 2005. And there are many reports of a big double BOOM over Massachusetts and the U.S. East on May 30, 2026. Image by Josh Grant/ WMAZ on X.

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Flash and boom over Massachusetts

Many in the U.S. East – particularly around Massachusetts – reported a bright daytime meteor streaking across the sky at around 2:07 p.m. EDT (18:07 UTC) yesterday afternoon (May 30, 2026). And eyewitnesses also reported hearing a big double BOOM. The reports came in to the American Meteor Society’s report a fireball page. Meanwhile, NOAA’s GOES-19 satellite recorded a flash over that part of the North American continent. NASA also chimed in on X, calling the event a “meteor,” and suggesting:

The meteor appears to have fragmented at an altitude of 40 miles (64 km) over northeast Massachusetts and southeast New Hampshire. The energy released at breakup is estimated to be equivalent to about 300 tons of TNT, which accounts for the loud noise.

Experts later suggested the object was traveling at a speed of 75,000 mph (121,000 kph).

Boom probably a meteor: Partial map of U.S. east, with icons of human beings indicating where the reports were made.
Reports to the American Meteor Society (AMS) of a loud boom, probably a meteor from space, over Massachusetts and parts of the U.S. East around 18:07 UTC (2:07 p.m. EDT) on Saturday, May 30. Image via AMS.

Eyewitness reports

Eyewitnesses noted on the AMS events page that the meteor looked like a shooting star in the daytime sky.

A witness in Hudson Falls, New York, explicitly reported that the fireball was:

… very easily visible in full sunlight.

Another in Stowe, Vermont, stated that:

… the ‘falling fire’ stood out clearly against the bright sky.

While many caught a glimpse of it, an even greater number of people on the ground reported hearing a massive double boom and feeling buildings shake around 2:07 p.m. EDT (18:07 UTC).

Weather satellite photo with a large green flash in the midst of white clouds.
NOAA’s GOES-19 satellite recorded a flash over that part of the North American continent at around 2:07 EDT (18:07 UTC) on Saturday, May 30, 2026. Image via NOAA.

How often does this happen?

Exact statistics on daytime meteors – over Earth as a whole – are hard to come by. The vast majority would go unnoticed in the bright sunlight. But scientists and meteor organizations still have a clear estimate of how often they should happen.

According to data from the American Meteor Society (AMS) and planetary scientists:

  • A lot of space debris strikes Earth’s atmopshere daily. Astronomers estimate that roughly 100 to 150 tons of space debris hits Earth’s atmosphere every single day. Most of this is dust or tiny pebbles. But larger chunks capable of producing a bright “fireball” (objects ranging from the size of a softball to a small car) hit the atmosphere about 500,000 times per year. As a further example, in 2014, the Nuclear Test Ban Treaty Organization reported 26 atom-bomb-scale impacts to our atmosphere over a 14-year period. This organization operates a network of sensors, monitoring Earth continually for the infrasound signature of nuclear detonations.
  • Still, daytime reports are rare. Bright sunlight can mask even bright incoming fireballs. Plus, most fall over the ocean or over other uninhabited areas (deserts, ice caps, forests). Finally, most people don’t simply don’t look up much.
  • Estimated global visibility. According to the American Meteor Society, a daytime fireball bright enough to easily break through full sunlight and be noticed by casual observers on the ground only happens over any given localized, populated area once every few years.

Bottom line: Many reports a fiery streak in the daytime sky and a boom, probably a meteor, over the U.S. East.

Did you see the fireball? Report it here

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]]> https://earthsky.org/earth/boom-over-massachusetts-and-u-s-east-probably-a-meteor/feed/ 0 Visible planets and night sky guide for May and June https://earthsky.org/astronomy-essentials/visible-planets-tonight-mars-jupiter-venus-saturn-mercury/ https://earthsky.org/astronomy-essentials/visible-planets-tonight-mars-jupiter-venus-saturn-mercury/#comments Sun, 31 May 2026 11:35:08 +0000 https://earthsky.org/?p=85647 Visible planets and night sky guide. The full-appearing Blue Moon is still in the sky tonight. Watch a video about it with EarthSky's Deborah Byrd.

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May 31 all night … still a Blue Moon


What’s a Blue Moon? What’s a micromoon? Tonight’s moon is still full, so it’s both a Blue (in name) and also small (in a far part of its orbit). The crest of this 2nd full moon for May fell at 8:45 UTC on May 31. That’s 3:45 a.m. CDT. So – for the Americas, Europe and Africa – the fullest moon fell the night of May 30. But across the International Dateline – in Australia, New Zealand and Asia – the fullest moon comes on the night of May 31. EarthSky’s Deborah Byrd talks about the May 30-31 Blue Moon and micromoon. Watch the video here, or on Youtube.

Sky chart: The white, round full moon near a red star, along the slanted green line of the ecliptic.
The crest of this 2nd full moon for May fell at 8:45 UTC on May 31. That’s 3:45 a.m. CDT. So – for the Americas, Europe and Africa – the fullest moon fell the night of May 30. But across the International Dateline – in Australia, New Zealand and Asia – the fullest moon comes on the night of May 31. For all of us, the waning Blue Moon will appear round and full tonight as well. It’ll lie near the bright red star Antares, Heart of the Scorpion. This full moon is the 2nd full moon of May: a Blue Moon. And it’s a micromoon: 2026’s smallest, dimmest and most distant full moon, 252,360 miles (406,135 km) away. Chart via EarthSky.

These charts are mostly set for mid-latitudes in the Northern Hemisphere. To see a precise view – and time – from your location, try Stellarium Online.

Video: Wow! Watch Venus, Jupiter and Mercury now


Join EarthSky’s Deborah Byrd and find out about the upcoming, super-spectacular Venus-Jupiter conjunction. Watch in the player above, or on YouTube.

June evenings: Charts for Venus, Jupiter and Mercury

A starred dot, Venus, is below a large dot, Jupiter. Below them is a smaller dot, Mercury. They all lie above a wavy line, the horizon.
Venus, Jupiter and Mercury on June 1. Watch for them in the west shortly after sunset. Chart via EarthSky.
A starred dot, Venus, lies below a large dot, Jupiter. Below them is a smaller dot, Mercury. They all lie above a wavy line, the horizon.
Venus, Jupiter and Mercury on June 3. Watch for them in the west shortly after sunset. Chart via EarthSky.
A starred dot, Venus, lies near but below a large dot, Jupiter. Below them is a smaller dot, Mercury. They all lie above a wavy line, the horizon.
Venus, Jupiter and Mercury on June 5. Getting close! Watch for them in the west shortly after sunset. Chart via EarthSky.
Shortly after sunset, brilliant Venus lies next to bright Jupiter, while Mercury is much closer to the horizon on the evening of June 7.
Venus, Jupiter and Mercury on June 7. Super close now! don’t miss them in the west shortly after sunset. Chart via EarthSky.
A starred dot, Venus, is next to a large dot, Jupiter. Below them is a smaller dot, Mercury. They all lie above a wavy line, the horizon.
Shortly after sunset on June 8, brilliant Venus will appear next to bright Jupiter. They’ll be a spectacular sight and only 3-full-moon widths apart! Your little pinky held at arm’s length will fit between them. Meanwhile, little Mercury will lie below them in the evening twilight. Chart via EarthSky.
A starred dot, Venus, is immediately above a large dot, Jupiter. Below them is a smaller dot, Mercury. They all lie above a wavy line, the horizon.
Shortly after sunset on June 9, brilliant Venus will still be near bright Jupiter, forming a dazzling duo that evening. At this point, the conjunction is over, and Venus has begun its ascent away from Jupiter. Venus will get higher in the west after sunset over the coming weeks. Meanwhile, Jupiter will head toward Mercury and the sunset. It’ll disappear into the sunset glare by July. Chart via EarthSky.

Our charts are mostly set for mid-latitudes in the Northern Hemisphere. To see a precise view – and time – from your location, try Stellarium Online.

June 10 before dawn: Daytime Arietids

Star chart: Cassiopiea, Aries, and Capella with radial lines from a point in the sky.
Most meteor showers are easy to observe. Just find a dark sky and look up! But what about meteor showers that happen in the daytime, when the sun is up? The Arietids are sometimes said to be the most active daytime meteor shower. In 2026, their predicted peak will be around the morning of June 10. You might catch some Arietids in the dark hour before dawn. Chart via EarthSky.

Read more: Arietids, most active daytime meteor shower

June 10 and 11 mornings: Moon near Saturn

A crescent shape, the moon, lies above a dot, Saturn. The following morning,the crescent shape has moved left of the dot. They are all above a wavy line, the horizon.
On the mornings of June 10 and 11, the waning crescent moon will shine near Saturn. Look for them a few hours before sunrise. Chart via EarthSky.

Our charts are mostly set for mid-latitudes in the Northern Hemisphere. To see a precise view – and time – from your location, try Stellarium Online.

June 15: New supermoon

sun news
This GOES-19 CORR1 coronagraph from November 18-19, 2025 (designed to show coronal mass ejections from the sun), captured a fun view of the new moon, which would normally not be visible from Earth during this phase. The moment of new moon will fall at 2:54 UTC on June 15, 2026. That’s 9:54 p.m. CDT on June 14. In fact, this is the 3rd of 5 new supermoons in a row. And it’s the closest new supermoon of 2026. It’ll be 221,966 miles (357,221 km) away. Compare that with the average moon distance of 238,900 miles (384,472 km). New moons rise and set with the sun. Nights around the new moon are perfect for stargazing. See EarthSky’s best places to stargaze. Images via NOAA/ GOES.

Want more? Here are 4 keys to understanding the moon’s phases.

June 15: Mercury at greatest elongation from the sun

A starred dot, Venus, shines above a large dot, Jupiter. Between them and the wavy line of the horizon is a small dot, Mercury.
From the Northern Hemisphere, shortly after sunset, Mercury will lie below the much brighter planets Venus and Jupiter, low in the West. It’ll reach its greatest elongation from the sun at 20 UTC on June 15. At that time, Mercury will be 25 degrees from the sun in our sky. Mercury will slip away before the end of the month. Chart via EarthSky.
A starred dot, Venus, shines above a large dot, Jupiter. Between them and the wavy line of the horizon is a . small dot, Mercury.
From the Southern Hemisphere, shortly after sunset, Mercury will lie below the much brighter planets Venus and Jupiter, low in the West. It’ll reach its greatest elongation from the sun at 20 UTC on June 15. At that time, Mercury will be 25 degrees from the sun in our sky. Mercury will slip away before the end of the month. Chart via EarthSky.

June 16 after sunset: Moon, Venus, Jupiter and Mercury

A starred dot, Venus, lies above a dot, Jupiter, which lies above a small dot, Mercury. A crescent shape, the moon, is between the dot and small dot. They all lie above a wavy line, the horizon.
On the evening of June 16, shortly after sunset, check out the pretty waxing crescent moon. It’ll hang low in the western sky after sunset. And it’ll be near the brilliant planet Venus and the bright planet Jupiter, and close to the elusive planet Mercury. Look for them about 35 minutes after sunset. Chart via EarthSky.

Our charts are mostly set for mid-latitudes in the Northern Hemisphere. To see a precise view – and time – from your location, try Stellarium Online.

June 17 after sunset: Spectacular! Moon, Venus, Jupiter and Mercury

A crescent shape, the moon, is next to a starred dot, Venus. Below them is a large dot, Jupiter, and below that is a small dot, Mercury. They all lie above a wavy line, the horizon.
On the evening of June 17, about 40 minutes after sunset, check out the pretty waxing crescent moon. It’ll be close to the brilliant planet Venus and near the bright planet Jupiter. Plus the planet Mercury is nearby. Also look for the glow of earthshine on the unlit portion of the moon. That’s light reflected off Earth. Chart via EarthSky.

Read more: Earthshine is a lovely glow on the unlit portion of the moon

Our charts are mostly set for mid-latitudes in the Northern Hemisphere. To see a precise view – and time – from your location, try Stellarium Online.

June 18 and 19 evenings: Moon, Venus and Regulus

A crescent shape, the moon, passes a dot, the star Regulus, on June 18 and 19. A starred dot, Venus, is to their lower right.
On the evenings of June 18 and 19, the waxing crescent moon will be near brilliant Venus and Regulus, the brightest star in Leo the Lion. Regulus is the bright dot at the bottom of a backward question-mark pattern of stars known as the Sickle. They’ll set around midnight. Chart via EarthSky.

Read more: Leo the Lion and its easy-to-see backward question mark

June 21: 1st quarter moon

Moon, half illuminated.
View at EarthSky Community Photos. | Lorraine Boyd captured this view from New York on November 9, 2024. She wrote: “Peeking through tree limbs at the first quarter moon (50% illumination), just after sunset.” Thank you, Lorraine. This month’s moment of 1st quarter moon will fall at 21:55 UTC on June 21, 2026. That’s 4:55 p.m. CDT. A 1st quarter moon rises around noon your local time and sets around midnight. Watch for a 1st quarter moon high in the sky at sundown.

Want more? Here are 4 keys to understanding the moon’s phases.

June Solstice

June solstice: Four black and white images of half-Earth from space, 2 upright and 2 tilted.
Satellite views of Earth on the solstices and equinoxes. From left to right, a June solstice, a September equinox, a December solstice and a March equinox. To understand these images, look at the poles. Notice that at the June solstice, the North Pole is in sunlight. At the December solstice, the South Pole is in sunlight. In 2026, the June solstice moment will fall at 8:25 UTC on June 21 (3:25 a.m. CDT). Read more about these images, which are via Robert Simmon (Sigma Space Corporation)/ NASA.

June 22 and 23 evenings: Moon and Spica

A hemisphere, the moon, passes a dot, the star Spica.
On the evenings of June 22 and 23, the waxing gibbous moon will be near Spica, the brightest star in Virgo the Maiden. You can also catch them until after midnight. Chart via EarthSky.

Read more: Virgo the Maiden represents a harvest goddess

Our charts are mostly set for mid-latitudes in the Northern Hemisphere. To see a precise view – and time – from your location, try Stellarium Online.

June 26 and 27 evenings: Moon near Antares

An almost full disk, the moon, is next to a dot, the star Antares. On the next evening, an almost full disk, the moon, is to the left of the dot.
As darkness falls on June 26 and 27, the bright waxing gibbous moon will shine near Antares. Antares is the brightest star in Scorpius the Scorpion. Chart via EarthSky.

Read more: Massive ruby red Antares is the Scorpion’s Heart

June 28 evening: Moon near Teapot

A fat hemisphere, the moon, approaches eight dots, representing the stars of the Teapot asterism. They are above the wavy line of the horizon.
On the evening of June 28, the bright waxing gibbous moon will hang near the stars of the asterism of Sagittarius called the Teapot. Chart via EarthSky.

Read more: Teapot of Sagittarius points to Milky Way center

June 29: Full Strawberry Moon

A disk, the full moon, lies among eight dots, representing the stars of the Teapot asterism. They are above the wavy line of the horizon.
At sunset on June 29, the full Strawberry Moon will rise in the east near the asterism of Sagittarius called the Teapot. Though the moon will be so bright that it will drown out the Teapot’s stars. The crest of the full moon falls at 23:57 UTC on June 29. That’s 6:57 p.m. CDT. Plus it’s the last of 3 full micromoons – or most distant full moons – in a row in 2026. It’ll be 251,811 miles (405,251 km) away. The average moon distance is 238,900 miles (384,472 km) away. Chart via EarthSky.

June 30 evening: Moon near Teapot

A fat hemisphere, the moon, lies left of eight dots, representing the stars of the Teapot asterism. They are above the wavy line of the horizon.
On the evening of June 30, the bright waning gibbous moon will hang near the stars of the asterism of Sagittarius called the Teapot. Look for them about an hour after sunset. They’ll be visible all night. Chart via EarthSky.

Read more: Sagittarius the Archer and its famous Teapot

Our charts are mostly set for mid-latitudes in the Northern Hemisphere. To see a precise view – and time – from your location, try Stellarium Online.

June evening planets

Sphere chart showing a large dot, Venus, above the western horizon. Immediately next to it is a smaller dot, Jupiter. A smaller dot, Mercury, lies just above the western horizon.
Here’s an all-sky chart – centered around June 8 – showing brilliant Venus shining in the west about 60 minutes after sunset with bright Jupiter lying next to it. Much closer to the western horizon is the fainter Mercury. Note that these planets lie along the path the sun travels in the sky (the green line on our chart). Chart via EarthSky.
Two charts. In the first, a starred dot, Venus, is above a dot, Jupiter. Below the dot is a small dot, Mercury. They are all above a wavy line, the horizon. On the second chart, the starred dot, Venus, and the dot, Jupiter, move apart. The small dot, Mercury, drops much closer to a wavy line, the horizon.
In the 2nd half of June, Venus and Jupiter will move away from each other with Jupiter slowly approaching the horizon. The much fainter Mercury will lie below Jupiter. As the month proceeds, Mercury moves closer to the horizon and becomes even fainter and more difficult to spot. Chart via EarthSky.

June morning planets: Northern Hemisphere

Sphere chart showing a dot, Saturn, above the eastern rim. Immediately below it is another dot, Mars.
Here’s an all-sky chart showing the 2 planets in the eastern sky shortly before sunrise in June. The brightest and highest planet is Saturn. Closer to the horizon is Mars. As the month proceeds, Saturn pulls farther away from the slowly ascending Mars. Note that these planets lie along the path the sun travels in the sky (the green line on our chart). Chart via EarthSky.
Two charts: In the first, a dot, Mars, is above a wavy line, the horizon. In the second, a dot, Mars, lies higher than before, and next to five small dots, the Pleiades star cluster.
In the first half of June, Mars sits low in the bright eastern twilight shortly before sunrise. In the second half of June, it rises higher and moves near the delicate Pleiades star cluster. Chart via EarthSky.
Chart showing a dot representing Saturn above a wavy line, the horizon.
In June, Saturn will lie in the east as morning twilight begins. Chart via EarthSky.

June stars

If you’re out stargazing on any June evening, look for these stars and constellations overhead in the sky.

Boötes the Herdsman

Kite shaped group of stars making up Boötes the Herdsman.
Almost overhead on June evenings is bright orange Arcturus. It’s in the constellation Boötes the Herdsman. Boötes has the shape of a kite, and Arcturus is at the point where you’d attach a tail. You can’t miss its distinctive shape. Chart via EarthSky.

The Big Dipper and Little Dipper

The Big and Little Dipper with arrow showing how 2 stars from the Big Dipper point to Polaris.
Ursa Major the Great Bear is home to the Big Dipper. The Big Dipper is an asterism – a well-known group of stars – not an official constellation. You’ll find the Big Dipper high overhead from mid-northern latitudes in June evening skies. You can use the 2 outer stars in the Big Dipper’s bowl – sometimes called the Pointers – to find Polaris, the North Star. It is the end star in the handle of the Little Dipper. Chart via EarthSky.

Hercules the Hero and the Hercules Cluster

Star chart of man-shaped constellation with bent arms and legs.
Hercules is a faint constellation. But its midsection contains the easy-to-see Keystone asterism. You can find Hercules between the bright stars Vega in Lyra the Harp and Arcturus in Boötes the Herdsman. And once you find the Keystone, you can easily locate M13, the Hercules cluster. Chart via EarthSky.

Have fun exploring the sky!

Our charts are mostly set for the northern half of Earth. To see a precise view – and time – from your location, try Stellarium Online.

May stars

If you’re out stargazing on any May evening, look for these stars and constellations overhead in the sky.

Pointer stars of the Big Dipper pointing to Leo the Lion.
On May evenings, the Big Dipper is high overhead in the sky. The Big Dipper is an asterism – a well know pattern of stars – in the constellation of Ursa Major the Great Bear. It’s handy to locate the North Star, Polaris. And you can use the Big Dipper to locate Leo the Lion. Draw an imaginary line southward from the pointer stars in the Big Dipper – the 2 outer stars in the Dipper’s bowl – to point toward Leo the Lion. The brightest star in Leo is Regulus.
Star chart: Lines and dots outlining animal-shaped Leo, with star Regulus at bottom right.
On May evenings, near your zenith – overhead in the sky – you’ll see Leo the Lion. There are 2 main shapes that make up Leo. First are the stars that form a backward question mark representing Leo’s head. This is also known as the Sickle. The bright star Regulus is the period at the bottom of the backward question mark. The second shape is the triangle that represents the Lion’s hindquarters. Scan Leo with even a medium-sized telescope and you’ll spy some of the dozens of galaxies in this region of the sky. Chart via EarthSky.
A triangle inside a triangle showing the two versions of the Spring Triangle asterism. On is Regulus, Arcturus and Spica. The other is Denebola, Arcturus and Spica.
The Spring Triangle is an asterism with 3 bright stars at its corners: Arcturus, Spica and Regulus. All 3 stars are in different constellations. Regulus is in Leo the Lion. Arcturus is in Boötes the Herdsman. And Spica is in Virgo the Maiden. But some stargazers see a smaller triangle of stars. This trio of stars consists of Arcturus, Spica and Denebola, a star in Leo. Image via EarthSky.

May evening planets

A starred dot, Venus, and a dot, Jupiter, slowly move closer to each other. They are both above a wavy line, the horizon.
Brilliant Venus lies above the western horizon as darkness falls. Bright Jupiter shines higher in the sky. Throughout the month, the 2 planets will move closer to each other. They will have a spectacular close encounter around June 8. They’ll be about 9 degrees apart at the end of May. And both of them will set before midnight by month’s end. Chart via EarthSky.
A dot, Jupiter, is below two smaller dots, the stars Castor and Pollux.
As darkness falls, Jupiter will shine brightly high in the western sky. And it’ll be near the twin stars of Gemini, Castor (the slightly dimmer one) and Pollux (the slightly brighter one). The moon and Jupiter will make a lovely pair on May 20. Jupiter and Venus will be inching closer to each other all month and will make a spectacular pair in the evening sky around June 8. Jupiter will set around midnight by month’s end. Chart via EarthSky.
Chart showing a dot, Mercury, above a wavy line, the horizon. A large starred dot, Venus, is to its upper left. Another dot, Jupiter, is farther to the upper left.
For viewers in the Northern Hemisphere, on the last few days of May, little Mercury will appear in the bright evening twilight low above the western horizon. Brilliant Venus and bright Jupiter will shine nearby. Mercury will reach its greatest distance from the sun on June 15. Chart via EarthSky.
Chart showing a dot, Mercury, above a wavy line, the horizon. A large starred dot, Venus, is to its upper right. Another dot, Jupiter, is farther to the upper right.
For viewers in the Southern Hemisphere, on the last few days of May, little Mercury will appear in the bright evening twilight low above the western horizon. Brilliant Venus and bright Jupiter will shine nearby. Mercury will reach its greatest distance from the sun on June 15. Chart via EarthSky.

May morning planets

Two charts: In the first, a dot, Saturn, is above another dot, Mars. They are both above a wavy line, the horizon. In the second, a dot, Saturn, has moved higher and away from the other dot, Mars. Again, they are both above a wavy line, the horizon.
In the first half of May, Saturn will sit low in the bright eastern twilight shortly before sunrise. And, nearby and closer to the horizon, look for the dimmer planet Mars. In the second half of May, Saturn will pull away from Mars, and Mars will slowly climb higher behind it. Chart via EarthSky.

Sky dome map for visible planets and night sky

Circle constellations, planets, the moon, the Milky Way and celestial lines.
Here is the sky dome view for May 2026. It shows what is above the horizon at mid-evening for mid-northern latitudes. The view may vary depending on your location. Image via Guy Ottewell’s 2026 Astronomical Calendar.
Circle constellations, planets, the moon, the Milky Way and celestial lines.
Here is the sky dome view for June 2026. It shows what is above the horizon at mid-evening for mid-northern latitudes. The view may vary depending on your location. Image via Guy Ottewell’s 2026 Astronomical Calendar.

Read more: Guy Ottewell explains sky dome maps

Heliocentric solar system visible planets and more

Visible planets: Circle with sun at center, planets around, and zodiac names on outer edge.
Heliocentric view of solar system, May 2026. Chart via Guy Ottewell’s 2026 Astronomical Calendar. Used with permission. Plus Guy Ottewell explains heliocentric charts here.
Circle with sun at center, planets around, and zodiac names on outer edge.
Heliocentric view of solar system, June 2026. Chart via Guy Ottewell’s 2026 Astronomical Calendar. Used with permission. Plus Guy Ottewell explains heliocentric charts here.

Read more: Guy Ottewell explains heliocentric charts.

Some resources to enjoy

For more videos of great night sky events, visit EarthSky’s YouTube page.

Don’t miss anything. Subscribe to daily emails from EarthSky. It’s free!

Visit EarthSky’s Best Places to Stargaze to find a dark-sky location near you.

Post your own night sky photos at EarthSky Community Photos.

See the indispensable Observer’s Handbook, from the Royal Astronomical Society of Canada.

Visit Stellarium-Web.org for precise views from your location.

Almanac: Bright visible planets (rise and set times for your location).

Visit TheSkyLive for precise views from your location.

Bottom line: Visible planets and night sky guide. The Blue Moon’s still in the sky tonight. Watch a video about it with EarthSky’s Deborah Byrd.

The post Visible planets and night sky guide for May and June first appeared on EarthSky.

]]> https://earthsky.org/astronomy-essentials/visible-planets-tonight-mars-jupiter-venus-saturn-mercury/feed/ 1126 Can a single season have only 2 full moons? https://earthsky.org/astronomy-essentials/blue-moon-seasonal-definition-possible-2-full-moons-one-season/ https://earthsky.org/astronomy-essentials/blue-moon-seasonal-definition-possible-2-full-moons-one-season/#comments Sun, 31 May 2026 11:30:32 +0000 https://earthsky.org/?p=178280 We know it's possible to squeeze 4 full moons into a single season. But can a season have just 2 full moons? Turns out it can, but it is rare.

The post Can a single season have only 2 full moons? first appeared on EarthSky.

]]> 2 full moons:A bright white full moon in a dark blue dusk sky.
View at EarthSky Community Photos. | Stephane Picard in Quispamsis, New Brunswick, Canada, captured the full moon on the morning of December 5, 2025. Stephane wrote: “This morning’s December supermoon is appropriately called the Cold Moon, as our region will hit almost -30 Celsius (about -22 Fahrenheit). With nearly a foot (30 cm) of snow, it lit up the night over our bright snow base.” Thank you, Stephane! Is it possible to have only 2 full moons in a season? Read more below.

Don’t miss the next unmissable night sky event. Sign up for EarthSky’s free newsletter and get daily night sky updates!

Longtime EarthSky writer – our own beloved Bruce McClure – loved cycles! Here’s one involving the moon …

2 full moons only in a season

A “season” to astronomers is the three-month period between a solstice and an equinox, or an equinox and a solstice. We have a full moon about once a month. So do we ever have a season with just two full moons?

The answer is, yes, it’s possible. But it’s extremely rare! It last happened between the December 1961 solstice and the March 1962 equinox. A full moon fell shortly before the December solstice in 1961 and after the March equinox in 1962, leaving only enough room for two full moons during that season.

Only two full moons occurred in the northern winter (southern summer) of 1961-1962:

Full moon: Dec. 22, 1961 (00:42 UTC)
Solstice: Dec. 22, 1961 (02:19 UT)
Full moon: Jan. 20, 1962
Full moon: Feb. 19, 1962
Equinox: Mar. 21, 1962 (02:30 UTC)
Full moon: Mar. 21, 1962 (07:55 UT)

When will it happen again? Not in the 21st century (2001-2100), 22nd century (2101-2200) or 23rd century (2201-2300). To find out when the next season of two full moons will happen, keep reading.

When’s the next time?

When is the next season with only two full moons? It took some legwork to find out this answer. I finally directed a query to obliquity.com. And, much to my delight, I received an immediate response from David Harper. He wrote in an email to EarthSky:

It’s a very rare phenomenon indeed. Between 1962 and 3000, it happens only four more times, in the winters of 2314/5, 2333/4, 2686/7 and 2705/6. In each case – as in 1961/2 – there is a full moon less than five hours before the December solstice, and there are four full moons in both the preceding autumn and following spring.

I find it interesting that two lunar cycles seem to be at work when it comes to realigning two full moons with the winter season: the long-period lunar cycle of 372 years and the 19-year Metonic cycle.

As you might have noticed, a two-full-moon season is only possible around the December solstice, which corresponds to the northern winter and southern summer. This is the shortest season of the year, lasting about 89 days. Northern spring (southern autumn) lasts for nearly 93 days, northern summer (southern winter) lasts for nearly 94 days, and northern autumn (southern spring) 90 days.

For a winter season to have only two full moons, the December full moon has to occur just before the December solstice.

Also, the full moons from December until March must closely coincide with lunar apogee – the moon’s farthest point from Earth in its monthly orbit. When full moons happen appreciably close to apogee, the time period between successive full moons is longer than average. The shorter season plus longer lunations (lunar months) conspire to give an extremely rare two-full-moon season.

An alternative to “Blue Moon”?

Since the saying once in a Blue Moon is supposed to indicate something exceedingly rare, or something that almost never happens, I propose that we consider calling the second of a season’s two full moons a Blue Moon!

By the way, why is the third of four full moons in a season the Blue Moon? Why not the fourth one? It’s because each month’s full moons already carry their own names.

Although fewer than 10% of the seasons harbor four full moons, the occurrence isn’t all that uncommon. A four-full-moon season happens seven times in 19 years. Or another way of looking at it, a total of 37 four-full-moon seasons take place in the 21st century (2001-2100).

Diagram of Earth's orbit showing one side closer to the sun (periapsis) than the other (apoapsis).
Northern Hemisphere winter (Southern Hemisphere summer) is the shortest season. That’s when Earth travels fastest in its orbit because it is always closest to the sun during that season. We’re about 3 million miles (5 million km) closer to the sun in early January than in early July. Image via Wikimedia Commons.

Bottom line: A season with only two full moons is truly rare. It last happened during the Northern Hemisphere winter of 1961/1962 and won’t happen again until 2314/2315.

How often do we have a seasonal Blue Moon?

Can you tell me the full moon names?

The post Can a single season have only 2 full moons? first appeared on EarthSky.

]]> https://earthsky.org/astronomy-essentials/blue-moon-seasonal-definition-possible-2-full-moons-one-season/feed/ 2 Deneb is an incredibly distant star. But how do we know? https://earthsky.org/tonight/deneb-how-do-astronomers-know-distances-to-stars/ https://earthsky.org/tonight/deneb-how-do-astronomers-know-distances-to-stars/#comments Sun, 31 May 2026 11:30:01 +0000 https://208.96.63.114/?p=3229 The star Deneb - part of the Summer Triangle - is one of the most distant stars you can see with your eye alone. But why don't we know its distance precisely?

The post Deneb is an incredibly distant star. But how do we know? first appeared on EarthSky.

]]> Chart showing groups of stars of varying colors and sizes.
View larger. | This is the famous Hertzsprung-Russell diagram. It shows the luminosities of stars. Luminosity describes a star’s absolute, intrinsic power output. See Deneb at the top of the diagram? It’s an absolute monster of a star, one of the most luminous (powerful) stars known, shining some 200,000 times brighter than our sun. Image via ESO/ Wikimedia Commons.

How far away is Deneb?

The star Deneb – in the constellation Cygnus the Swan – is one of the most luminous stars we know. It shines some 200,000 times more brightly than our sun! To put that in perspective: if our sun were a standard 100-watt lightbulb, Deneb would be a blinding 20-million-watt beacon. Yet it is only the 19th-brightest star in our sky. That means, as you look at the bright star Deneb, you must be gazing across a great expanse of space.

The distance to Deneb remains uncertain. Current estimates place it from about 1,600 to 2,600 light-years away. Either way, Deneb is one of the most distant stars we can see with the eye alone. It’s definitely the most distant bright star we can see.

But distance estimates vary for this star. And they vary a lot! Why?

The answer offers a glimpse into the process of science, and the way that astronomers use advancing technologies to try to improve on previous discoveries.

Science news, night sky events and beautiful photos, all in one place. Click here to subscribe to our free daily newsletter.

Tiny dot (the sun) next to part of a huge circle (Deneb).
Deneb (bottom half of frame) is somewhere around 200 times wider in diameter than our sun. Image via Wikimedia Commons.

Measuring Deneb’s distance

Scientists have obtained estimates for Deneb’s distance through a variety of methods. Some of these methods involve theoretical models related to the way stars evolve. Some assume Deneb’s membership in Cygnus OB7, a star-forming complex within our Milky Way galaxy.

ESA’s Earth-orbiting Hipparcos Space Astrometry Mission provided the most significant modern measurement of Deneb’s distance in the 1990s. Early analyses of the astrometric data Hipparcos gathered on the star indicated a distance of somewhere around 2,600 light-years. That’s the figure you still see most often today.

But, since then, various groups of astronomers have re-analyzed Hipparcos data. This is because computer power, which gets stronger with each passing year, helps to improve techniques for analysis. For example, the peer-reviewed journal Astronomy and Astrophysics published a study in 2009 using a newer method of analysis [Editor’s note: if you click into that study, skip to the last page for Deneb].

This new analysis showed a distance to Deneb that’s roughly half the widely accepted value. The study suggests 1,548 light-years as the distance, with a range between 1,336 and 1,841 light-years. That’s a big ballpark figure.

So is Deneb 1,600 light-years away or 2,600 light-years away? The fact is, we don’t know. Either way, it’s still one of the most distant stars we see with the unaided eye. And it’s the most distant 1st-magnitude – or bright – star.

Complex diagram: lines from Earth in its orbit to a nearby star appearing in 2 places.
Astronomers use the parallax method to measure distances to nearby stars. That method is akin to holding up a finger, and closing first one eye, then the other. When you do that, you see your finger appear to shift relative to the background. Likewise, using the parallax method, scientists can measure a shift in a nearby star’s apparent position, from one side of Earth’s orbit around the sun to the other. But this technique doesn’t work for Deneb; it’s too far away for accurate parallax measurements from Earth’s surface. Image via ESA/ NASA/ A. Feild (STSci).

Why does Deneb’s distance matter?

Distance matters because it can give us other measurements, too. If astronomers don’t know exactly how far away Deneb is, they can’t get accurate numbers of its size, mass and energy output.

ESA had a 2nd and more wonderful astrometric satellite – the magnificent Gaia space observatory – that was in a distant orbit similar to that of the James Webb Space Telescope. Gaia launched on December 19, 2013. Its five-year nominal mission ended in July 2019. However, the mission was extended to December 31, 2025, and Gaia was officially powered down in March 2025. Gaia’s goal was to measure the positions and distances of stars with more precision than ever before. And it exceeded expectations. We really can’t say enough about the incredible things learned about our Milky Way galaxy via Gaia. Click here for a few of Gaia’s discoveries.

But Gaia’s 1st data release, in 2016, didn’t include a new estimate for Deneb’s distance. And Gaia’s 2nd data release, in 2018, didn’t include one either. How about the 3rd data release? Nope, not there either. The 4th data release is currently slated for release no earlier than mid-2026.

Deneb was too bright for Gaia

Gaia produced data on some 2 billion sources (stars and other objects) in our Milky Way galaxy. But it couldn’t image Deneb, the 19th brightest star in our sky. That’s because the telescope wasn’t able to measure the distance to bright stars. They would have saturated its sensor, making measurements impossible. Gaia’s brightest possible star was magnitude 1.71. Deneb is brighter, at magnitude 1.25. Note that the lower the number, the brighter the star.

And it’s not that they didn’t try. In 2018, the Gaia team posted an employment opportunity specifically asking for someone to find a way to image bright stars with Gaia. But, last we heard, that position hadn’t been filled.

When Gaia was launched, its team was working on the problem of imaging bright stars. Paper after paper after poster addressed the problem of Gaia not being able to image bright stars.

So, how far away is Deneb? If it is part of the Cygnus OB7 group, then it’s as far away as that group: about 2,050 light-years. But the center of that group is 5.2 degrees to the northeast of Deneb, so Deneb might not be a part of it.

Interestingly, in 1838, the first star for which the distance was calculated was 61 Cygni, which lies less than 8 degrees southeast of Deneb.

How to see Deneb

From the Northern Hemisphere, Deneb can be seen easily as part of the beautiful Summer Triangle, an asterism. This noticeable star pattern – visible in the evening in the northern summer months of June, July and August – consists of three bright stars in three different constellations. Want to see them? Read more about Deneb and find charts.

From the Southern Hemisphere, if you’re at 45 degrees south latitude or farther south, you won’t see Deneb. It’s a far northern star and won’t rise above your horizon. And, even from 30 or 35 degrees south latitude, Deneb won’t get very high in your sky. It’ll appear only about 10-15 degrees above your northern horizon, or roughly the width of your fist held at arm’s length. But Deneb is a bright star. So if conditions are good – and if you can catch it at the right time – you can see it surprisingly well from parts of the Southern Hemisphere. The best evening views are around August and September. You need a flat horizon, dark skies, clear air, and little to no city glow to the north. Plus, you’ll still see Deneb with Vega and Altair, in the famous Summer Triangle pattern. But it won’t be summer for you. And, from 35 degrees south latitude, the whole pattern will appear low and somewhat sideways in the northern sky. Deneb will be the closest of these three stars to your northern horizon.

For an exact view from your latitude, try Stellarium.

Deneb: 3 lines and 3 dots for Deneb, Vega and Altair create a triangle. Words
Here’s Deneb in the Summer Triangle asterism – or star pattern – as seen from the Northern Hemisphere. Southern Hemisphere chart coming soon! Chart via EarthSky.

Bottom line: The star Deneb – part of the famous Summer Triangle – is one of the most distant stars you can see with your eye alone. But we don’t yet know its precise distance.

Read more: Delta Cephei helps measure cosmic distances

The post Deneb is an incredibly distant star. But how do we know? first appeared on EarthSky.

]]> https://earthsky.org/tonight/deneb-how-do-astronomers-know-distances-to-stars/feed/ 6 How cities can change the weather during storms https://earthsky.org/earth/how-cities-can-change-the-weather-storms-flooding/ https://earthsky.org/earth/how-cities-can-change-the-weather-storms-flooding/#respond Sun, 31 May 2026 11:23:01 +0000 https://earthsky.org/?p=547416 Researchers looked at 22 years of data to discover how cities can change the weather. Certain storms intensify over cities, leading to more urban flooding.

The post How cities can change the weather during storms first appeared on EarthSky.

]]> Cities can change the weather: Vertical lightning bolt strikes water between 2 large cities glittering with lights at night.
View at EarthSky Community Photos. | Alexander Krivenyshev of WorldTimeZone.com captured this stormy shot on July 14, 2023. Alexander wrote: “Lightning bolt strikes the Hudson River between lower Manhattan and Jersey City.” Thank you, Alexander! A new study shows how cities can change the weather and provides particular insight into when urban flooding can happen.

Science news, night sky events and beautiful photos, all in one place. Click here to subscribe to our free daily newsletter.

Cities can change the weather

It’s a hot, steamy day, and you see a pop-up thunderstorm darken the sky to your west as a low grumble of thunder shudders the ground. Whether you’re watching from the countryside or a cement-and-steel city can determine what will happen next. Researchers from Texas A&M University said on May 20, 2026, that certain types of storms can intensify over cities. They looked at more than 40,000 storms over 22 years in Texas to discover that certain storms, such as isolated thunderstorm cells, can grow stronger and drop more rain over urban areas.

The researchers pored over data of storms that hit Houston, Dallas-Fort Worth, Austin and San Antonio between 1995 and 2017. While other studies have looked at regional rainfall, this team of researchers zeroed in on the rainfall resulting from different types of storms that hit cities. Co-author John Nielsen-Gammon of Texas A&M University said:

Different storms are driven by different physical processes. Once you separate storms by type, the patterns became much clearer.

The researchers published their study in the peer-reviewed journal Nature on May 20, 2026.

Storms that boost rainfall

Urban flooding is a significant problem in cities. Cities largely consist of buildings and concrete without many places for rainwater to naturally soak into the ground. And storms that hit quickly with heavy rainfall can overwhelm a city’s stormwater system. As a result, streets can flood, endangering drivers and pedestrians. Plus, homes and businesses can incur expensive flood damage. So discovering which storms increase rainfall was particularly important to the researchers.

Two of the categories of storms the researchers looked at – single-cell thunderstorms and larger isolated storms – showed intensification and heavier rainfall when encountering a city. Looking at the radar data, the researchers found single-cell thunderstorms in particular grew taller and more intense over cities. The urban heat island effect – where cities trap heat and are warmer than the surrounding landscape – can cause updrafts that feed storms. In the four Texas cities studied, these small storms occurred 7 to 31% more often than over nearby rural land.

This was especially true at night, when rural areas cooled but the cities retained their heat. Nielsen-Gammon said:

Urban areas hold heat after sunset. That retained warmth can continue to fuel storms overnight, when similar storms over rural areas are more likely to weaken.

View from above of someone with an umbrella wading through high water at night under a streetlight.
A person navigates a flooded city street at night. Image via Rafael Titoneli/ Pexels.

Storms that weaken over cities

But not all storms intensify when they reach a city. For example, storms along a cold front can weaken as they drift over urban heat islands. These types of storms form because of the temperature difference between the advancing cold air and the warm air already present. The study found that storms associated with cold fronts declined about 16 to 28% in their rainfall intensity compared with nearby rural areas. Although, as the storm first hits the city, it can sometimes briefly intensify as the temperature difference becomes sharper. But then it would diminish as the warmth of the city and buildings disrupt the air flow.

Nielsen-Gammon explained:

Cold front rainfall is driven by sharp temperature and wind differences. As they move into the warmer and more turbulent urban environment, those contrasts can weaken, reducing rainfall intensity.

A man with gray hair and beard wearing a gray suit with mauve shirt.
John Nielsen-Gammon of Texas A&M University was a co-author of the new study. Image via Texas A&M University.

Other storms and the urban environment

Cities had less of an effect on the other two categories of storms the researchers studied: warm front storms and tropical storms. The main difference the researchers found was that for tropical storms, such as hurricanes, the heavy rain formed lower in the atmosphere over cities. So that could have an impact on flooding. But Nielsen-Gammon said:

These larger systems are driven mainly by ocean heat and larger-scale wind patterns. Urban effects don’t disappear, but they’re secondary compared to those factors.

Animated radar image of a rotating hurricane in false color hitting Texas.
In 2017, Hurricane Harvey caused flooding in Texas and Louisiana and resulted in the deaths of more than 100 people. Image via NOAA/ Wikimedia Commons.

Knowing how cities can change the weather can help us prepare

The researchers said that urban planners need to factor in storms of short duration and high intensity. Previous plans for drainage systems and flood controls relied on averaged rainfall statistics. Nielsen-Gammon said:

If you design only for region-wide averages, you can underestimate the kinds of rainfall that actually cause the most damage. Understanding which storms cities amplify helps planners target the real risks. Asking whether cities get more or less rain is the wrong question. The right question is which storms are affected, because that’s what determines the risk people actually face on the ground.

Bottom line: Researchers have looked at 22 years of data to discover how cities can change the weather. Certain types of storms intensify over cities, leading to more urban flooding.

Source: Divergent urban storm response to convective, frontal and tropical systems

Via Texas A&M University

Read more: Cumulonimbus clouds bring thunderstorms: How to spot them

The post How cities can change the weather during storms first appeared on EarthSky.

]]> https://earthsky.org/earth/how-cities-can-change-the-weather-storms-flooding/feed/ 0 Sun news: Solar wind surges, brings aurora to high latitudes https://earthsky.org/sun/sun-news-activity-solar-flare-cme-aurora-updates/ Sun, 31 May 2026 09:30:53 +0000 https://earthsky.org/?p=387071 Sun news for May 31, 2026: Solar wind surges past 550 km/s! Kp hits 4. G1 storm chance today. Glancing CMEs may add fuel. Aurora watchers, stay alert!

The post Sun news: Solar wind surges, brings aurora to high latitudes first appeared on EarthSky.

]]>
Sun news for May 31, 2026. Speaking of auroras, they’re not just an earthly phenomenon! This video from NASA’s Hubble Space Telescope captures stunning auroral displays on Jupiter, the largest planet in our solar system. The view opens with the full disk of Jupiter before zooming into the north pole, where brilliant ultraviolet auroras dance above the cloud tops. The solar wind, the same stream of charged particles from the sun that drives auroras here on Earth. Video via NASA/ESA Hubble Space Telescope.

Sun news May 31: Solar wind surges, brings aurora to high latitudes

Today’s top story: Earth’s magnetic field stirred to active levels overnight. A stream of fast solar wind from a coronal hole poured in. The activity fell just short of G1 (minor) geomagnetic storm thresholds. But aurora watchers in Anchorage, Reykjavik, and northern Scandinavia might have caught faint displays during dark windows. Forecasters see a chance for isolated G1 storm periods today. The coronal hole stream persists. And possible glancing coronal mass ejection (CME) influences from earlier this week might arrive. That keeps conditions mildly unsettled into early June. Share your aurora photos with us!

Past 24 hours of sun news

(11 UTC May 30 – 11 UTC May 31)

Flare activity

Over the past day, solar activity held at low levels. In total, the sun fired 12 C-class flares.

  • Strongest flare: C4.8 from AR4446 (S17W16), peaking at 11:45 UTC on May 30. As a C-class event, it produced no radio blackout. A faint, narrow CME was observed in association but should have a negligible Earth impact.
  • Lead flare producer: AR4446 topped the list. It fired 5 of the 12 flares, including both events above C3.0. Meanwhile, AR4452 and AR4449 each contributed 2 flares. And AR4455 and AR4453 each added one.

Sunspot regions: key players

The Earth-facing solar disk showed 9 numbered active regions. Most were magnetically simple and relatively stable.

Blasts from the sun?

A halo coronal mass ejection (CME) appeared in GOES CCOR-1 imagery at approximately 9:15 UTC on May 30. It lifted off from the north limb at a projected speed of roughly 550 km/s. But forecasters assessed it as originating from the far side. No Earth impact is expected from this event. No significant Earth-directed CMEs were identified during the period.

Past 24 hours in space weather

Solar wind

Solar wind speeds surged during the past day, with coronal hole high-speed stream driving the increase. Speeds climbed from just below 400 km/s early in the period to near 550 km/s by the end. They peaked at 576 km/s after 18 UTC on May 30. That pushed the Kp index to 4. Meanwhile, Earth’s magnetic field also strengthened, with the total interplanetary magnetic field (IMF) increasing to 10–11 nT (moderate levels).

Bz and magnetic coupling

The Bz component underwent several sustained southward dips. It reached -7 to -10 nT early in the period and again later. Each southward plunge opened the door for geomagnetic coupling and auroral activity. As always, a southward Bz favors aurora displays at high latitudes.

Earth’s magnetic field

Over the past day, Earth’s magnetic field ranged from quiet to active levels. The Kp index sat at 1–3 for most of the period. But it reached Kp 4 (active) during the 18:00–0:00 UTC window spanning May 30–31. Conditions stayed just below G1 (minor) geomagnetic storm thresholds. Close, but not quite.

What’s ahead? Sun–Earth forecast

Flare activity forecast

Forecasters expect low to moderate levels through June 2. C-class flares are very likely. And a chance (40%) exists for isolated M-class (R1–R2) flares. AR4452, with its beta-gamma configuration, remains the most likely source before it rotates beyond the west limb.

AR4455 and the newly emerged AR4457 also bear watching as they evolve. X-class flares are unlikely (5%) given the current magnetic setups on the disk.

Geomagnetic activity forecast

  • May 31: Expect unsettled-to-active conditions (Kp 3–4) as the negative-polarity coronal hole stream continues. A chance for isolated G1 (minor) geomagnetic storm periods exists. That chance increases if glancing influences from the slow CMEs of May 27–28 arrive. Aurora may reach Anchorage, Reykjavik, and northern Scandinavia. But limited hours of darkness in the Northern Hemisphere at this time of year will reduce visibility.
  • June 1: Expect quiet-to-active conditions as the coronal hole stream wanes. Possible glancing CME influences could sustain isolated unsettled-to-active periods (Kp 3–4) early in the day. Conditions should trend quieter through the second half.
  • June 2: Expect mostly quiet conditions (Kp 1–2) as ambient solar wind returns. No significant geomagnetic activity is anticipated.
The sun, seen as a large yellow sphere with dark spots, each labeled.
This image shows sun activity – with the most active regions labeled – as of 4 UTC on May 31, 2026. Original image, without labels, via NASA SDO. Courtesy of NASA/SDO and the AIA, EVE, and HMI science teams, with labeling by EarthSky. Armando Caussade posted today’s sun. Why are east and west on the sun reversed?

Sun news May 30: Blast from sun might brush past Earth today

Our star hurled several blobs of stuff – solar plasma and magnetic fields – into space this week. It launched these coronal mass ejections (CMEs) on May 26 and 27. The blobs might reach Earth later today and tomorrow. If they deliver a glancing blow, they could disturb Earth’s magnetic field. What does that mean for aurora watchers? Forecasters expect unsettled-to-active conditions with the Kp index reaching 4. But a G1 (minor) geomagnetic storm level of Kp 5 is not ruled out. Auroral displays are possible tonight and tomorrow at high latitudes. Clear skies! And please share your aurora photos with us!

Past 24 hours of sun news

(11 UTC May 29 – 11 UTC May 30)

Flare activity

Solar activity dropped back to low levels over the past day. The long-awaited newcomer AR4455 lost its gamma configuration. It keeps flaring, but only faint C-class events. In total, it fired 7 C-class (common) flares.

  • Strongest flare: C4.0 from AR4449 in the southwest, peaking at 7:47 UTC on May 30.
  • Lead flare producer: AR4455 keeps flaring. Once again, it topped the list. It fired 4 of the 7 flares. Meanwhile, AR4449 contributed 2 C-class flares. The remaining flare came from elsewhere on the disk.

Sunspot regions

Currently, the Earth-facing solar disk shows 7 numbered active regions. Notably, only one sunspot region retains its beta-gamma configuration: AR4452. Both AR4455 (now beta) and AR4446 (now beta) lost their gamma components. The remaining 4 regions carry simpler alpha or beta configurations. They appear stable or in decay.

Blasts from the sun?

Several faint eruptions were observed in the southeast earlier this week. At least two were strong enough for SOHO LASCO C2 and GOES SUVI to register. The first occurred at 23:00 UTC on May 27. A second followed at 9:38 UTC on May 28. Modeling and analysis of these events continue. The CMEs from May 26 and 27 might deliver a glancing blow later today or tomorrow. No other Earth-directed CMEs appeared during the period.

Past 24 hours in space weather

Solar wind

Solar wind speeds held at moderate to moderate-high levels during the period. The coronal hole high-speed stream continued driving the elevated speeds. But by 11 UTC on May 30, speeds dropped back to moderate levels. Meanwhile, the total interplanetary magnetic field (IMF) showed a slight increase to moderate levels.

Bz and magnetic coupling

The Bz component pointed strongly southward from late May 29 through early this morning. That opened the door for geomagnetic coupling. But at 3 UTC on May 30, the Bz shifted northward. At the time of this writing, it still points north. As always, south is the orientation most favorable for auroral displays.

Earth’s magnetic field

Over the past day, Earth’s magnetic field has held at unsettled-to-active levels. Solar wind from the coronal hole continued reaching us and producing enhancements. Specifically, the Kp 4 threshold was reached at 19:49 UTC on May 29. Currently, Kp sits at level 3.

  • May 30: Expect quiet-to-unsettled conditions (Kp 2–3) as the coronal hole high-speed stream starts to wane. But late today, enhancements are possible with the arrival of a glancing blow from CMEs hurled into space on May 26 and 27.
  • May 31: Active conditions anticipated as the CME material arrives and delivers a glancing blow. G1 (minor) geomagnetic storm enhancements are possible. Aurora watchers at high latitudes should stay alert!
  • June 1: Expect conditions to return to quiet levels as the CME effects start to wane.
    • Sun news for May 30, 2026. This video from NOAA’s GOES-19 SUVI in the 304-angstrom channel captures AR4455 doing what it does best: flaring. The newcomer lost its gamma configuration and now carries a simpler beta setup. Its flares have dropped to faint C-class levels. But don’t let that fool you. AR4455 still packs a punch. Watch as this eruption hurls plasma outward into space. Video via NOAA/GOES.
    Sun news for May 30, 2026. This image shows the WSA-ENLIL solar wind prediction model from NOAA’s Space Weather Prediction Center. The model maps the solar wind environment between the sun and Earth, tracking coronal mass ejections (CMEs) as they travel through interplanetary space. Flare activity on the Earth-facing disk dropped back to low levels this period. But the sun hurled several blobs of solar stuff into space earlier this week. The ENLIL model tracks those CMEs and estimates when and where they will arrive. Earth appears as a small dot along its orbit. Watch for the enhanced density features sweeping outward from the sun. The CMEs launched on May 26 and 27 may deliver a glancing blow late today or tomorrow. Image via NOAA/SWPC.

    Sun news May 29: BAM! M flare from newcomer AR4455

    Today’s top story: The long-awaited newcomer has delivered! AR4455, the fiery region we have been watching approach from the northeast, fired an M1.2 flare at 7:04 UTC on May 29. The blast triggered an R1 (minor) radio blackout that affected an area over India. It’s a promising start for this sunspot group, which had already become the leading flare producer on the solar disk while still rotating into view yesterday. Now fully visible, AR4455 has revealed itself to have a promising beta-gamma magnetic complexity. That makes it one of three beta-gamma regions currently on the disk, alongside AR4446 and AR4452. Three beta-gamma regions at once is noteworthy. The more magnetic complexity on the disk, the greater the chances for stronger flares. Let’s see what else these regions have in store!

    Past 24 hours of sun news

    (11 UTC May 28 – 11 UTC May 29)

    Flare activity

    Over the past day, solar activity jumped to moderate levels with an isolated M-class flare. In total, the sun fired 7 flares: 1 M-class (moderate) and 6 C-class (common).

    • Strongest flare: M1.2 from AR4455 in the northeast, peaking at 7:04 UTC on May 29. It triggered an R1 (minor) radio blackout over India.
    • Lead flare producer: AR4455 once again topped the list. It fired 5 of the 7 flares, including the M1.2. The remaining 2 flares came from other regions on the disk.

    Sunspot regions

    The Earth-facing solar disk shows 8 numbered active regions. Notably, three sunspot regions carry beta-gamma configurations. AR4455 (beta-gamma) is the newcomer to watch. Now fully in view, it is already the top flare producer. And its beta-gamma complexity gives it the potential for M-class or even stronger flares. AR4446 (beta-gamma) continues holding its complexity. It remains a candidate for stronger activity. AR4452 (beta-gamma) rounds out the trio of complex regions. The remaining 5 regions carry simpler alpha or beta configurations. They appear stable or in decay.

    Blasts from the sun?

    Several faint eruptions were observed in the southeast. At least two were strong enough for SOHO LASCO C2 and GOES SUVI to observe. The first occurred at 23:00 UTC on May 27. A second followed at 9:38 UTC on May 28. Modeling and analysis of these events is ongoing. No other Earth-directed coronal mass ejections (CMEs) appeared during the period.

    Past 24 hours in space weather

    Solar wind

    Solar wind speeds climbed to moderate-high levels late on May 28. The increase was driven by coronal hole high-speed stream influence. But this morning, speeds dropped back to moderate levels. Meanwhile, the total interplanetary magnetic field (IMF) stayed weak, with only a slight increase.

    Bz and magnetic coupling

    The Bz component pointed strongly southward through most of the period. Only a few northward peaks occurred. At the time of this writing, it still points south. That is the orientation most favorable for auroral displays.

    Earth’s magnetic field

    Over the past day, Earth’s magnetic field has jumped to unsettled-to-active levels, reaching just below Kp level 4. Currently, it sits at Kp level 3.

    Sun news for May 29, 2026. This video from NASA’s Solar Dynamics Observatory (SDO) captures an M1.2 flare from newcomer sunspot region AR4455, which peaked at 7:04 UTC on May 29. Video via NASA/SDO.

    Sun news May 28: Exciting sunspot region finally arrives

    A long-awaited sunspot region has finally come into view on the northeast solar horizon. Now officially numbered AR4455, all signs indicate this is the sunspot region that’s been erupting powerfully from the far side in recent days. It seems pretty large, but we still need to wait until it rotates farther into view to analyze it properly from Earth. It’s been producing jets and prominences all day, and has already fired more flares than any other region over the past 24 hours. Let’s see what else AR4455 has in store!

    Past 24 hours of sun news

    (11 UTC May 27 – 11 UTC May 28)

    Flare activity

    Solar activity has been low, with only faint C-class and B-class flares over the past 24 hours. We saw a total of 6 Cs and 1 B flare.

    • Strongest flare: C3.4 from AR4451 in the southeast at 12:16 UTC on May 27.
    • Lead flare producer: Active region AR4455 in the northeast was at the top of list. It fired 5 of the 7 flares.

    Sunspot regions

    The Earth-facing solar disk shows 11 numbered active regions. Three newcomer sunspot regions received an official number: AR4453 near the northwest horizon, AR4454 in the southeast and AR4455 in the northeast. AR4455 seems to be the one that’s been flaring from the far side. It seems pretty large, but we still need to wait for it to rotate more into view for a better analysis. For now, it shows a beta configuration. AR4446 keeps its beta-gamma configuration, the most complex on the solar disk currently. The rest of the sunspot region on the Earth-viewed solar disk show either alpha or beta configurations.

    Blasts from the sun?

    A partial halo CME registered by LASCO C2 at 22:30 UTC on May 26 may give us at Earth a glancing blow on May 31. No other Earth-directed CMEs appeared during the period.

    Past 24 hours in space weather

    Solar wind

    Solar wind speeds averaged at moderate levels throughout the period. Meanwhile, the total interplanetary magnetic field (IMF) stayed weak with a slight increase.

    Bz and magnetic coupling

    The Bz component kept shifting between north and south through the period. At the time of this writing, it points southward. Southward is the orientation most favorable for auroral displays.

    Earth’s magnetic field

    Over the past day, Earth’s magnetic field jumped to unsettled with some quiet periods (Kp 1-3). Currently, Earth’s magnetic field sits at Kp level 2.

    Sun news.
    Sun news for May 27, 2026. A long-awaited active region has finally made its appearance on the northeast solar horizon. It’s been flaring all day, producing prominences and fiery jets like this one. Image via NOAA.

    Sun news May 27: Almost-M flare from promising sunspot region

    A C9.7 flare from sunspot region AR4446 brought activity tantalizingly close to moderate levels yesterday. The almost-M flare was fired at 12:38 UTC on May 26. And its producer, AR446, is evolving. It gained a gamma component over the past day, bringing it up to a beta-gamma magnetic complexity. That makes it the most complex sunspot region on the Earth-viewed disk right now. And the more complex a region is, the greater its potential for stronger flares. Let’s see what AR4446 has in store!

    Past 24 hours of sun news

    (11 UTC May 26 – 11 UTC May 27)

    Flare activity

    Over the past day, solar activity held at low levels. But the C9.7 from AR4446 nearly pushed conditions to moderate. In total, the sun sparked 7 C-class flares.

    • Strongest flare: C9.7 from AR4446 in the southeast at 12:38 UTC on May 26. Just a whisker below M-class territory.
    • Lead flare producer: The incoming northeast newcomer, still unnumbered, once again topped the list. It fired 5 of the 7 flares. Meanwhile, AR4446 contributed the remaining 2 C-class flares. Notably, those two were the strongest of the period.

    Sunspot regions

    Currently, the Earth-facing solar disk shows 10 numbered active regions. And a region that emerged from seemingly nowhere in the northwest quadrant received an official number: AR4452. AR4446 (beta-gamma) is the star of the show. It developed a gamma component during this period. It now carries the strongest magnetic complexity on the disk. As a result, it tops the watch list for stronger flare production.

    Blasts from the sun?

    Forecasters analyzed the C9.7 event. They determined that any coronal mass ejection (CME) produced during the flare was too narrow or faint to track. No Earth-directed CMEs appeared during the period.

    Past 24 hours in space weather

    Solar wind

    Solar wind speeds sat at moderate levels by the end of the period. A momentary jump to moderate-high levels occurred at 19 UTC on May 26. Meanwhile, the total interplanetary magnetic field (IMF) stayed weak.

    Bz and magnetic coupling

    The Bz component kept shifting between north and south through the period. At the time of this writing, it points northward. That orientation is not favorable for auroral displays. But that could change as the coronal hole stream arrives.

    Earth’s magnetic field

    Over the past day, Earth’s magnetic field ranged from unsettled to quiet (Kp 1–3). No geomagnetic storm conditions occurred. Currently, Earth’s magnetic field sits at Kp level 1.

    Sun news May 26: Far-side eruption hints at incoming action

    Though the Earth-facing sun is currently quiet, action is on the way! A dramatic eruption over the solar horizon around 22 UTC last night suggests that volatile sunspot regions are on the sun’s far side. The eruption launched a coronal mass ejection (CME) into space, but this burst of sun-stuff is heading far to the north of Earth. Meanwhile, an active region just rotating into view in the east fired 6 of the past day’s 12 C (common) flares. The volume of activity from this sunspot group hints at a potent region, with some of its magnetic complexity likely still hidden from view. Experts expect some active far-side regions to start rotating into view from the east in the coming days. Stay tuned!

    Past 24 hours of sun news

    (11 UTC May 25 – 11 UTC May 26)

    Flare activity

    Over the past day, solar activity continued at low levels. In total, the sun sparked 12 C-class flares.

    • Strongest flare: C4.6 from an as-yet-unnumbered incoming region in the northeast at 22:42 UTC on May 25.
    • Lead flare producer: The incoming northeast newcomer topped the list. It fired 6 of the 12 flares, including the C4.6 peak event. Meanwhile, AR4451 contributed 3 C-class flares.

    Sunspot regions: key players

    The Earth-facing solar disk shows 9 numbered active regions. Notably, four newcomers received official numbers during the period: AR4448, AR4449, AR4450 and AR4451.

    AR4447 (beta) underwent notable growth. It consolidated both its leading and trailing poles. As a result, it remains the region of greatest interest on the disk.

    AR4446 (alpha) was resolved into two distinct groups as it rotated further into view. The second component received the new designation AR4449 (beta).

    AR4451 (beta) received its official number this period. Despite its small size and simple setup, it fired 3 C-class flares.

    Sunspot regions: supporting cast

    AR4448 (beta) and AR4445 (beta) both showed some growth during the period. The remaining regions appear stable or in decay. All sunspot regions carry simple alpha or beta configurations. No delta structures are present on the disk.

    Blasts from the sun?

    No Earth-directed coronal mass ejections (CMEs) appeared during the period.

    A partial halo CME showed up in SOHO LASCO C3 imagery in the northwest at 22:12 UTC on May 25. Forecasters confirmed it is not heading toward Earth. It aimed far to the north. And a second CME lifted off from the northeast limb at 7:12 UTC on May 25. It is also not expected to reach us.

    Past 24 hours in space weather

    Solar wind

    Solar wind speeds increased to moderate levels throughout the period. Meanwhile, the total interplanetary magnetic field stayed weak.

    Bz and auroras

    The Bz component pointed mostly southward late on May 25, with sustained intervals. As a result, conditions briefly favored auroral displays late that evening. But at 0:00 UTC on May 26, the Bz shifted northward. It stayed there through the rest of the period.

    Earth’s magnetic field

    Over the past day, Earth’s magnetic field ranged from unsettled to quiet (Kp 1–3). No geomagnetic storm conditions occurred. Currently, Earth’s magnetic field sits at Kp level 1.

    Sun news for May 26, 2026. This video from the CCOR-1 coronagraph aboard NOAA’s GOES-19 spacecraft captures the magnificent coronal mass ejection (CME) hurled into space by an unseen far-side sunspot late on May 25. The far side of the sun is where the action is right now. Stay tuned! Video via NOAA/ GOES.
    Sun news for May 26, 2026. This video from NOAA’s GOES-19 satellite shows dramatic far-side eruptions from late on May 25. The images have been inverted to negative, swapping bright and dark features. This technique makes it much easier to spot faint activity against the solar disk and along the limb (edge). Video via NOAA/ GOES.

    Sun news May 25: Coronal hole’s fast winds could disturb the peace

    After an impressive burst of 18 flares in the previous day, the sun has calmed over the past 24 hours. We observed just 6 C-flares (common), while solar wind speeds remained sluggish. But change is on the way. A stream of high-speed solar wind from a coronal hole should arrive late on May 26 into May 27, potentially unsettling our magnetic field to G1 (minor) geomagnetic storm levels. Stay tuned!

    Past 24 hours of sun news

    (11 UTC May 24 – 11 UTC May 25)

    Flare activity

    Over the past day, solar activity held at low to moderate levels. In total, the sun fired 6 C-class flares.

    • Strongest flare: C3.7 from AR4447 at 0:51 UTC on May 25.
    • Lead flare producer: AR4447 topped the list. It fired 4 of the 6 flares, including the C3.7 peak event. Meanwhile, AR4441 contributed the remaining 2 C-class flares.

    Sunspot regions

    The Earth-facing solar disk currently shows 9 numbered active regions.

    Blasts from the sun?

    No Earth-directed coronal mass ejections (CMEs) appeared during the period.

    Past 24 hours in space weather

    Solar wind

    Solar wind conditions stayed slow and near background levels throughout the period. Meanwhile, the total interplanetary magnetic field was weak.

    Bz and magnetic coupling

    The Bz component fluctuated mildly north and south. No sustained southward intervals developed. As a result, conditions were unfavorable for auroras.

    Earth’s magnetic field

    Over the past day, Earth’s magnetic field stayed quiet (Kp 0–2). No geomagnetic storm conditions occurred.

    Sun news for May 25, 2026. This video from NASA’s Scientific Visualization Studio highlights stunning imagery captured by NASA’s Parker Solar Probe during its record-breaking pass by the sun in 2024. The spacecraft flew just 3.8 million miles (6.1 million km) from the solar surface on December 24, 2024. This video shows a coronal mass ejection (CME) at first, but the rest of the imagery shows just how interesting the solar wind can be. A fresh burst of fast solar wind could unsettle Earth’s magnetic field in the current days, possibly triggering auroras at high latitudes. Video via NASA/ SVS.

    Sun news May 24: New region arrives, fires 16 flares!

    Newcomer AR4446 announced its arrival on the sun’s east limb with a bang. This freshly numbered region fired off 16 C-class flares in just 24 hours! The strongest was a C5.6 at 21:57 UTC on May 23. None of these flares triggered radio blackouts. But the sheer volume of activity hints at a complex region still partially hidden behind the solar limb. And, veteran AR4441 made some noise too. Now approaching the west limb, it launched a long-duration C2.8 flare at 19:54 UTC on May 23. That blast produced a Type II radio burst with an estimated shock speed of 932 km/s. That speed signals a coronal mass ejection (CME) was likely produced. But with the source on the western limb, no Earth-directed CMEs were identified. On the space weather front, the solar wind remained sleepy. Speeds averaged near 330 km/s under background conditions. Earth’s magnetic field stayed quiet. Looking ahead, the arrival of AR4446 on the visible disk could bring a step-up in activity. Forecasters see a chance for isolated M-class flares over the coming days. Also, active regions behind the east limb fired C-class flares, suggesting more activity may emerge soon. Stay tuned!

    Past 24 hours of sun news

    (11 UTC May 23 – 11 UTC May 24)

    Flare activity

    Over the past day, solar activity held at low to moderate levels. In total, the sun fired 18 C-class flares. No M-class or X-class events occurred.

    • Strongest flare: C5.6 from AR4446 (S08E89) at 21:57 UTC on May 23. Other notable events included a C4.8 at 23:43 UTC, a C3.7 at 2:33 UTC, and a C3.5 at 0:48 UTC, all from AR4446. In addition, AR4441 fired a long-duration C2.8 at 19:54 UTC on May 23, accompanied by a Type II radio burst (shock speed ~932 km/s).
    • Lead flare producer: AR4446 dominated the period. It fired 16 of the 18 flares, including the C5.6 peak event. Meanwhile, AR4441 contributed the remaining 2 flares.

    Sunspot regions

    The Earth-facing solar disk showed a modest number of active regions. Two stand out.

    AR4446 (beta) received its official number this period. It emerged from behind the east limb and immediately became the most active region on the disk with 16 C-class flares. Its position near the limb suggests more complexity may be revealed as it rotates further into view.

    AR4441 is nearing the west limb. It continued producing occasional C-class flares, including the long-duration C2.8 event with the Type II radio burst. However, its geoeffective potential is fading as it rotates toward the far side.

    Blasts from the sun?

    No Earth-directed coronal mass ejections (CMEs) appeared during the period. Several CMEs showed up in coronagraph imagery. But the analysis pointed to source locations on the solar limb or the far side. The Type II radio burst from AR4441’s C2.8 flare (shock speed ~932 km/s) suggests a CME was produced. Even so, with the source at W71 on the western limb, any ejecta would be aimed well away from Earth.

    Past 24 hours in space weather

    Solar wind

    Solar wind conditions reflected a quiet, near-background regime. Speeds averaged roughly 330 km/s with no notable increases. Meanwhile, the total interplanetary magnetic field (IMF) held steady near 3 nT, quite weak.

    Bz and magnetic coupling

    The Bz component fluctuated gently between roughly -4 and +4 nT. No sustained southward orientation developed. As a result, these calm conditions offered no fuel for geomagnetic disturbances or aurora enhancement.

    Earth’s magnetic field

    Over the past day, Earth’s magnetic field stayed quiet (Kp 1–2). No geomagnetic storm conditions occurred. Conditions settled quickly after a brief period of unsettled weather just before our reporting window.

    The sun in recent days

    The sun, seen as a large yellow sphere with dark spots, each labeled.
    This image shows sun activity – with the most active regions labeled – as of 7 UTC on May 30, 2026. Image via NASA/ SDO.
    The sun, seen as a large yellow sphere with dark spots, each labeled.
    This image shows sun activity – with the most active regions labeled – as of 6 UTC on May 29, 2026. Image via NASA/ SDO.
    The sun, seen as a large yellow sphere with dark spots, each labeled.
    This image shows sun activity – with the most active regions labeled – as of 5 UTC on May 28, 2026. Image via NASA/ SDO.

    Earlier sun images

    The sun, seen as a large yellow sphere with dark spots, each labeled.
    This image shows sun activity – with the most active regions labeled – as of 2 UTC on May 27, 2026. Image via NASA/ SDO.
    The sun, seen as a large yellow sphere with dark spots, each labeled.
    This image shows sun activity – with the most active regions labeled – as of 6 UTC on May 26, 2026. Image via NASA/ SDO.
    The sun, seen as a large yellow sphere with dark spots, each labeled.
    This image shows sun activity – with the most active regions labeled – as of 7 UTC on May 25, 2026. Image via NASA/ SDO.
    The sun, seen as a large yellow sphere with dark spots, each labeled.
    This image shows sun activity – with the most active regions labeled – as of 7 UTC on May 24, 2026. Image via NASA/ SDO.

    Sun images from our community

    The sun, seen as a large white sphere with small dark spots.
    View at EarthSky Community Photos. | Patricio León in Santiago, Chile, captured this filtered image on May 30, 2026. Patricio wrote: “Sunspots, flare level and auroral activity continue stable. The big cores of AR4446 and AR4455 are barely detectable with unaided protected eye. Good seeing conditions.” Thank you, Patricio!
    The sun, seen as six spheres in different bright colors.
    View at EarthSky Community Photos. | Mario Rana in Hampton, Virginia, captured these filtered images on May 30, 2026. Mario wrote: “The sun in hydrogen-alpha, helium D3, sodium D2, magnesium (b1), and calcium-K.” Thank you, Mario!
    The sun, seen as a green sectional sphere with dark spots, each labeled.
    View at EarthSky Community Photos. | Victor Rogus in Sedona, Arizona, captured this filtered image on May 30, 2026. Victor wrote: “Through clear skies this morning we see sunspots AR4446 and AR4452 still have ‘beta-gamma’ magnetic fields that harbor energy for M-class solar flares. There are at least 11 numbered sunspots on the solar disk at the moment.” Thank you, Victor!

    More sun images from our community

    The sun, seen as a large gray sphere with small dark spots.
    View at EarthSky Community Photos. | David Hawkes in South Yorkshire, United Kingdom, captured this filtered image on May 30, 2026. David wrote: “Great solar imaging conditions. Solar regions AR4455 in the east and AR4446 in the southwest dominate the solar landscape.” Thank you, David!
    The sun, seen as a large yellow sphere with a mottled surface.
    View at EarthSky Community Photos. | Jim Militello in Tucson, Arizona, captured this filtered image on May 29, 2026. Jim wrote: “Hydrogen-alpha image of the sun showing sunspot active regions, filaments and some nice prominences.” Thank you, Jim!
    The sun, seen as four gray spheres.
    View at EarthSky Community Photos. | Eliot Herman in Tucson, Arizona, captured these filtered images in calcium-K during 4 days from May 23, 2026 to May 30, 2026. Thank you, Eliot!
    The sun, seen as two spheres in different bright colors.
    View at EarthSky Community Photos. | Anthony Faulkner in Tucson, Arizona, captured these filtered images of the sun on May 25, 2026. Anthony wrote: “Our sun in broadband white light (left) and calcium K (right). Sunspot AR4446 is emerging from the eastern limb while sunspots AR4444 and AR4447 lead the chase westward.” Thank you, Anthony!

    We sometimes feature sun images obtained using hydrogen-alpha filters. Read why.

    Bottom line: Sun news for May 31, 2026: Solar wind surges past 550 km/s! Kp hits 4. G1 storm chance today. Glancing CMEs may add fuel. Aurora watchers, stay alert!

    Submit your photos here.

    View community photos here.

    The post Sun news: Solar wind surges, brings aurora to high latitudes first appeared on EarthSky.

    ]]>         Blue Origin mega-rocket explodes on launch pad https://earthsky.org/human-world/blue-origin-mega-rocket-explodes-on-launch-pad/ https://earthsky.org/human-world/blue-origin-mega-rocket-explodes-on-launch-pad/#respond Fri, 29 May 2026 12:00:45 +0000 https://earthsky.org/?p=547590 Blue Origin experienced a setback late Thursday when its New Glenn mega-rocket exploded. The launch pad was also destroyed.

    The post Blue Origin mega-rocket explodes on launch pad first appeared on EarthSky.

    ]]>     Blue Origin explosion: Huge explosion with glowing clouds of gas and glowing trails of things being thrown out of it.
    The Blue Origin mega-rocket explosion took place at 9 p.m. EDT on Thursday, May 28, 2026. Image via SpaceFlight Now.

    Jeff Bezos’ space company Blue Origin experienced a major setback late Thursday when its New Glenn mega-rocket exploded during testing at a launch site in Cape Canaveral, Florida. It was one of the largest rocket explosions in U.S. history. Blue Origin later confirmed the explosion, as did Jeff Bezos, who said in a statement:

    All personnel are accounted for and safe. It’s too early to know the root cause, but we’re already working to find it. Very rough day, but we’ll rebuild whatever needs rebuilding and get back to flying.

    The explosion happened at approximately 9 p.m. EDT on the night of May 28, 2026 (1 UTC on May 29). At 9:31 p.m. EDT, Blue Origin released this official statement:

    We experienced an anomaly during today’s hotfire test. All personnel have been accounted for. We will provide updates as we learn more.

    What sort of rocket was it?

    The Blue Origin rocket is one of the largest operational or near-operational rockets on Earth. It belonged to the class of Heavy Lift Launch Vehicles (HLLVs). These rockets are about 98 meters (322 feet) tall, or roughly the height of a 32-story building.

    NASA had just announced earlier this week that Blue Origin would play a major role in carrying payloads to the moon for its planned moon base. And this is the rocket design that will play a role in those moon missions.

    This Blue Origin rocket is designed to carry up to 45 metric tons (nearly 100,000 pounds) of cargo to low Earth orbit (LEO) in its fully reusable configuration. That’s roughly equivalent to launching three fully loaded commercial school buses into space at the exact same time.

    The Blue Origin explosion came during testing

    Blue Origin was performing a test ahead of an anticipated launch of the new rocket in the coming weeks. The coming launch was supposed to carry Amazon Leo internet satellites to space.

    So the rocket was likely fully fueled, contributing to what is one of the largest rocket explosions in U.S. history and the worst failure in Blue Origin’s existence, according to media sources.

    Before this, Blue Origin’s most notable inflight “anomaly” happened with an uncrewed New Shepard suborbital mission (NS-23) in 2022. Its capsule escape system safely triggered, but the booster hit the ground and was destroyed. And, before last night’s explosion, the company had never lost a massive, orbital-class vehicle like the New Glenn, let alone experienced a catastrophic pad explosion of this magnitude.

    While the explosion caused significant damage to Launch Complex 36, Amazon luckily confirmed that the 48 Amazon Leo (formerly called Project Kuiper) internet satellites scheduled for the upcoming flight were not yet loaded onto the rocket during the test. So they are safe.

    Science news, night sky events and beautiful photos, all in one place. Click here to subscribe to our free daily newsletter.
     

    What sort of test was it?

    During the test, the rocket’s engines were ignited at full thrust while the vehicle was securely clamped down to the launchpad. That is what is known as a static fire test (also called a static hotfire test). It’s a common pre-launch procedure in aerospace engineering.

    The primary goal is to test the rocket’s propulsion system and overall readiness under flight-like conditions without actually letting it lift off.

    Likely next steps for Blue Origin?

    Now, Blue Origin is likely to shift from preparation to investigation and recovery. New Glenn is central to both commercial contracts and NASA’s lunar timeline. So the company faces intense pressure.

    Their next steps probably include:

    • A “root cause” investigation. Before any rocket can clear for flight, Blue Origin — coordinating with Space Launch Delta 45 and the Federal Aviation Administration (FAA) — must determine exactly what triggered the anomaly.
    • Rebuilding Launch Complex 36 at Cape Canaveral. The explosion of a 98-meter mega-rocket completely loaded with liquefied natural gas and liquid oxygen inflicts severe damage on pad infrastructure. Blue Origin will need to clear the debris and rebuild the heavily damaged launch mount, umbilical towers, fuel lines, and electrical systems. Jeff Bezos acknowledged the scale of this task in his statement, when he said, “We’ll rebuild whatever needs rebuilding and get back to flying.”
    • Rescheduling the flight profile. The destroyed rocket was supposed to launch 48 of Amazon’s controversial Amazon Leo internet satellites. While those satellites are safe because they hadn’t been integrated onto the rocket yet, Blue Origin will have to manufacture a brand-new New Glenn first stage and reschedule the flight.
    • Mitigating delays for NASA’s moon missions. This failure heavily impacts NASA’s upcoming lunar schedule.

    Bottom line: Blue Origin experienced a setback late Thursday when its New Glenn mega-rocket exploded during testing at a launch site in Cape Canaveral, Florida.

    The post Blue Origin mega-rocket explodes on launch pad first appeared on EarthSky.

    ]]>     https://earthsky.org/human-world/blue-origin-mega-rocket-explodes-on-launch-pad/feed/ 0     Arcturus, brightest star of the northern sky https://earthsky.org/brightest-stars/bright-orange-arcturus-use-the-big-dipper-to-find-it/ https://earthsky.org/brightest-stars/bright-orange-arcturus-use-the-big-dipper-to-find-it/#comments Fri, 29 May 2026 10:12:32 +0000 https://208.96.63.114/?p=3924 Arcturus is the brightest star in the northern half of the sky. It's easy to find in spring in the Northern Hemisphere near the handle of the Big Dipper.

    The post Arcturus, brightest star of the northern sky first appeared on EarthSky.

    ]]>     Star chart: Big Dipper with long magenta arrows from its handle to stars Arcturus and Spica.
    The bright star Arcturus is easy to identify for those in the Northern Hemisphere. Just follow the arc in the handle of the Big Dipper. In other words, follow the arc to Arcturus. Image via EarthSky.

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    Follow the arc to Arcturus

    Arcturus is a red giant star. It’s about 25 times the size of our sun, and some 170 times more luminous. And considering the fact that it’s only 36.7 light-years away, it should be little surprise that Arcturus is the 4th-brightest star in Earth’s sky.

    And when it comes to stars in the northern half of the sky, Arcturus is the very brightest. It’s far enough north on the sky’s dome that – for Northern Hemisphere observers – it’s visible at some point in the night throughout most of the year.

    In the Northern Hemisphere, Arcturus is best viewed on spring or early summer evenings. There’s an easy mnemonic for finding it. Just remember the phrase follow the arc to Arcturus. You need to continue the arc of the Big Dipper’s handle on the sky until you reach a bright orange star. That will be Arcturus!

    Arcturus is the brightest star of a cone-shaped constellation called Boötes the Herdsman. It takes a lot of imagination to see a herdsman in these stars … but you might easily see a kite! See the chart below.

    Group of stars, long pointed oblong, with a bright star at its narrow end labeled Arcturus.
    Arcturus is in the constellation Boötes the Herdsman. Boötes has the shape of a kite, and Arcturus is at the point where you’d attach a tail. You can see it on spring evenings in the Northern Hemisphere.

    It’s the brightest star in the northern half of the sky

    When astronomers speak of the celestial sphere, they’re talking about the imaginary sphere of stars surrounding Earth.

    Imagine Earth’s equator projected onto the sky. A line drawn all the way around the sky – above Earth’s equator – is called the celestial equator. It divides the sky into northern and southern hemispheres, much as the earthly equator does for Earth.

    The three brightest stars of the sky – Sirius, Canopus and Alpha Centauri – are all south of this celestial equator.

    But Arcturus is north of the celestial equator. That makes it the brightest star in the northern part of the sky. But it’s only marginally brighter than the north celestial sphere’s 2nd-brightest star, blue-white Vega.

    By the way … did you know? Some people think Polaris, the North Star, is the brightest star. But it’s not. It’s about the 50th brightest star! It’s famous for being located near the celestial north pole. Read about Polaris here.

    Southern Hemisphere view of Arcturus

    Via Daniel Gaussen, Founder & Guide – Stargaze Mackenzie – New Zealand

    From southern latitudes, Arcturus still appears as a bright star. One Earth, one sky, after all. But the Northern Hemisphere’s follow the arc of the Big Dipper trick doesn’t apply. That’s because – from the Southern Hemisphere – the perspective on the sky is shifted. And so the Big Dipper sits low or is entirely out of view, below the northern horizon for much of the south.

    Instead, to find Arcturus from the Southern Hemisphere, look northward on autumn evenings (April–June). Arcturus appears as a bright orange star, making a low arc across the northern sky, but standing out for its warm color.

    One reliable way to identify Arcturus from the Southern Hemisphere is by using another bright star, Spica, as a guide. Spica is a more southerly star than Arcturus. So it makes a wider arc across our northern sky. It appears generally “above” Arcturus (often to one side of it) as you stand facing north. From our part of the globe, Arcturus and Spica appear as two bright stars, forming a loose line across the northern sky. Arcturus is the brighter of the two and noticeably more orange. Spica is blue-white in color.

    It’s true Arcturus is the brightest star in the northern half of the sky. But Southern Hemisphere observers have a better view of the brightest stars overall. From the southern half of the globe, it’s possible to see all four of the brightest stars in the night sky – Sirius (brightest), Canopus (2nd-brightest), Alpha Centauri (3rd-brightest) and Arcturus — during the same season, spread across the sky.

    So we in this hemisphere can see with our own eyes what’s true in an absolute sense for all of Earth; Arcturus ranks as the 4th-brightest star in the sky.

    So be sure to look for Arcturus from the Southern Hemisphere. Though it never passes overhead from our latitudes, it is one of the most prominent stars of our northern sky.

    History and mythology of Boötes and Arcturus

    Arcturus’ constellation Boötes the Herdsman is sometimes pictured as guarding the Great Bear, or Ursa Major, which contains the Big Dipper asterism. We sometimes hear Arcturus called the Bear Guard.

    In China, Arcturus’ constellation is also called the Dragon.

    In some classical Greek stories, Boötes was Icarus, who flew too close to the sun.

    Because it passes directly over the Hawaiian islands, Arcturus – brightest light in Boötes – was a particularly important navigational star to the islands’ indigenous inhabitants and other Polynesians.

    The translation may be questioned, but Arcturus is among the few stars mentioned in the Bible. (“Which maketh Arcturus, Orion and Pleiades, and the chambers of the south” – Job 9:9, KJV, and “Canst thou bring forth Mazzaroth in his season? or canst thou guide Arcturus with his sons?” – Job 38:32, KJV.)

    Arcturus is so bright, it can be seen in daytime

    In 1635, less than three decades after the invention of the telescope, Jean-Baptiste Morin of France observed Arcturus in the daytime with a telescope.

    It was the first time that any star, besides the sun and a rare supernova, had been seen telescopically during daylight hours.

    You can also observe Arcturus with the unaided eye during the day. There’s an explanation on how to do it in this reprint of a science paper from 1911.

    1933 Century of Progress Exposition in Chicago

    One interesting story about Arcturus relates to the 1933 Century of Progress Exposition in Chicago. Its promoters wanted a flashy way to open the show. And somebody figured out that the light from Arcturus could start it.

    At 9:15 pm on May 27, 1933, four telescopes located in different observatories captured the light from the star and focused it into photoelectric cells. The photocells in turn worked as the switch that turned on the main spotlights to open the exhibition. It’s a good thing it wasn’t cloudy!

    How did this idea come about? There’d also been a World’s Fair in Chicago in 1893, 40 years earlier. And, at the time, astronomers thought that Arcturus was 40 light-years away. If so, that light left Arcturus at the end of the 1893 fair and traveled for 40 years through space, like an Olympic torch bearer, to open the 1933 show.

    It was a good idea. But today’s astronomers place the distance to Arcturus at just less than 37 light-years. Oh well. Progress!

    Gigantic star bigger than the orbit of Mars; very much smaller star and dot labeled sun.
    The red giant Arcturus is roughly 25 times the diameter of our sun. But it’s not the largest of the red giants, as this diagram shows. Image via Wikimedia Commons.

    Arcturus compared to our sun

    Arcturus is a more evolved star than our sun. Billions of years from now, our sun will be a red giant star, much as Arcturus is now.

    Arcturus’ diameter is roughly 25 times greater than our sun’s. Because of its larger size, it radiates more than 100 times the light of our sun, in visible light. If you consider infrared and other frequencies in the electromagnetic spectrum, Arcturus is about 200 times more powerful than our sun. But its mass is only slightly greater than the sun’s.

    The reddish or orange color of Arcturus signifies its temperature, which is about 7,300 degrees Fahrenheit (around 4,000 degrees Celsius). That makes it several thousand degrees cooler than the surface of our sun.

    Arcturus is flying southward

    Generally speaking, the stars are fixed. They are all moving through space, but we don’t see them move because they’re so far away. But Arcturus has a large proper motion, or sideways motion, on the dome of Earth’s sky. Among the 1st-magnitude (or bright) stars in our stellar neighborhood, only Alpha Centauri – our sun’s nearest neighbor among the stars – has a higher proper motion.

    And of course, the large proper motion of Alpha Centauri stems from the fact that it’s so close to us.

    But what does the proper motion of Arcturus tell us?

    It tells us that Arcturus is moving at a tremendous speed (76 miles/s or 122 km/s) relative to our solar system. Arcturus is thought to be an old star. It appears to be moving with a group of at least 52 other such stars, known as the Arcturus stream or Arcturus moving group.

    Scientists think these stars weren’t part of our Milky Way galaxy, originally. Instead, they might have come from a dwarf satellite galaxy that assimilated into the Milky Way.

    From the vantage point of Earth, Arcturus is rapidly moving in a southerly direction at a rate of 3.9 arcminutes per century. It’s now at about its closest point to Earth. As it moves away, it’ll someday vanish from visibility to the unaided eye.

    This will happen when it reaches the border of the southern constellations Carina and Vela … in about 150,000 years.

    The position of Arcturus is RA: 14h 15 m 39.7s, dec: +19° 10′ 56″

    Dark blue starry sky with houses and trees in foreground. The star Arcturus, Big Dipper, Little Dipper and Polaris are labeled.
    View at EarthSky Community Photos. | Cecille Kennedy captured this image on May 1, 2025, from Oregon and wrote: “The Big Dipper, Arcturus and Polaris, the North Star, shine brightly with the other stars in the still of the blue midnight. The 2 front stars of the Big Dipper are called Pointers because they point to Polaris, the North Star. Polaris is the brightest star in the Little Dipper and the closest bright star to the north celestial pole. When you are looking at Polaris, you are facing north. Arcturus is a 1st-magnitude star and stands right behind the Big Dipper. Arcturus is the brightest star of the constellation Boötes the Herdsman.” Thank you, Cecille!

    Bottom line: Arcturus is the brightest star in the northern half of the sky. It’s easy to find in spring in the Northern Hemisphere near the handle of the Big Dipper.

    The post Arcturus, brightest star of the northern sky first appeared on EarthSky.

    ]]>     https://earthsky.org/brightest-stars/bright-orange-arcturus-use-the-big-dipper-to-find-it/feed/ 63     The 1919 solar eclipse that proved Einstein right https://earthsky.org/human-world/may-29-1919-solar-eclipse-einstein-relativity/ https://earthsky.org/human-world/may-29-1919-solar-eclipse-einstein-relativity/#comments Fri, 29 May 2026 08:40:46 +0000 https://earthsky.org/?p=314102 During a May 29, 1919, solar eclipse, astronomers saw the sun bend starlight, proving Einstein's general relativity and catapulting him to rock star fame.

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    ]]>     1919 solar eclipse: Black disk, with streamers of white light coming off it all around, and some tiny white dots with tick marks.
    Einstein’s triumph. This early photograph shows a 1919 solar eclipse. See the tick marks around stars near the eclipsed sun? It was the precise measurement of the positions of these stars that proved the sun’s mass caused surrounding space to curve, bending starlight, in accordance with Einstein’s theory of general relativity. Image via Wikimedia Commons.

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    May 29, 1919, is the date of a solar eclipse that caused a revolution in human thought. The eclipse is famous for testing Albert Einstein’s theory of general relativity. Einstein was relatively unknown at the time. He had proposed general relativity in 1915, introducing a new way of thinking about gravity. Key to the theory was the transformative idea that mass causes space to curve.

    Scientists were intrigued. But no one had experimentally proven Einstein’s theory to be true.

    Then, on May 29, 1919, an expedition of English scientists – led by Sir Arthur Eddington – traveled to the island of Príncipe off the west coast of Africa to observe a total solar eclipse. If Einstein’s theory were correct, the light of stars should be bent while traveling the curved space near our sun. In other words, the sun’s gravity would cause the stars in the sun’s vicinity to appear displaced.

    An eclipse, where the moon blocks the sunlight enough for stars to be seen near the sun, was the perfect opportunity to test this wild-sounding theory.

    The scientists’ measurements during the eclipse showed that, astoundingly, Einstein’s predictions were correct. The locations of stars near the sun – made visible when the moon blocked the sun’s blazing light from view – appeared displaced.

    Light did have to travel to our eyes on the curved space around the sun. Gravity worked as Einstein said it did.

    From anonymity to stardom via a solar eclipse

    Later that year – on November 6, 1919, in London – England’s Astronomer Royal, Frank Dyson, who had organized the expedition, presented the results at a joint meeting of the Royal Astronomical Society and the Royal Society. Dyson said “there can be no doubt” that measurements made during the May 29, 1919, solar eclipse “confirm Einstein’s prediction.”

    As part of the celebration of the 100th anniversary of this legendary solar eclipse, Caltech physicist Sean Carroll explained to NBCNews in 2019:

    General relativity was the poster child for being a crazy, new, hard-to-understand theory, with dramatic implications for the nature of reality. And yet you could see [the results]; you could photograph it. So people got caught up in that excitement.

    And so Albert Einstein was catapulted to rock star fame, a status in popular culture he has retained ever since.

    Diagram of sun, star, Earth. Straight line from us to a star's apparent location and a bent line to its real location.
    During a solar eclipse, stars normally not visible in the glaring sunlight appear on the side of the sun and are displaced from the location they’d normally be in. Why? Because – just as Einstein’s theory said it should – light bends in the presence of mass, in this case the mass of a star, our sun. Rather than traveling in a straight path, the light of distant stars is forced to travel a curved path along the curved space near the sun. Note that the bending of starlight is exaggerated in this image. In reality, the stars are displaced by up to 1.75 arcseconds (about 0.0005 degrees). Image via NASA/ Goddard Space Flight Center/ DiscoverMagazine.com.

    A new perspective on gravity and the universe

    Einstein’s general theory of relativity underlies our most basic modern cosmology, our way of looking at the universe as a whole. Before Einstein, scientists relied on Isaac Newton’s theory of gravity. Newton’s way of looking at gravity is still valid and is still taught to physics students. But while Newton’s formulation of gravity is more of a special case under specific conditions, Einstein’s theory is a refinement of scientists’ understanding of gravity that covers the big picture … and what a mind-blowing big picture! Einstein proposed that mass causes space to curve.

    So, for example, although there appears to be a “force” (as described by Newton) that causes our Earth to be pulled towards the sun by gravity. That force can “simply” be described as Earth traveling in curved space around the sun, according to Einstein.

    Einstein’s general theory of relativity not only explains the motion of Earth and the other planets in our solar system. In our modern cosmology, it also describes extreme examples of curved space, such as around black holes. And it helps to describe the history and expansion of the universe as a whole.

    The solar eclipse was the first proof of many

    In the century and a bit since the 1919 total solar eclipse, Einstein’s relativity theory has been proven again and again, in many different ways. You might have seen the recent first-ever photo of a black hole? It also proved, once again, that Einstein was right.

    Read more: Black hole image confirms Einstein’s relativity theory

    Read more: Clocks, gravity and the limits of relativity

    Glowing, fuzzy orange donut with black center.
    This image captured people’s imaginations when it was released in 2019: the first-ever actual image of a giant black hole, in the center of galaxy M87. It also proves Einstein’s theory, which predicted the observations from M87 with unerring accuracy. Image via Event Horizon Telescope Collaboration.

    Now and then

    The Royal Astronomical Society (RAS) described modern-day practical applications of Einstein’s theory:

    The theory fundamentally changed our understanding of physics and astronomy, and underpins critical modern technologies such as the satellite-based Global Positioning System (GPS).

    The theory of relativity is essential for the correct operation of GPS systems, which in turn are relied on in many common applications including vehicle satellite navigation (SatNav) systems, weather forecasting, and disaster relief and emergency services. However, the world had to wait decades before the applications of such a blue skies result could be realized.

    Back in the day of the 1919 eclipse, Sir Arthur Eddington attended a dinner of the same organization – RAS – shortly after the successful expedition. He then showed his humorous side by reciting a verse he had written on the feat:

    Oh leave the wise our measures to collate
    One thing at least is certain, light has weight
    One thing is certain and the rest debate
    Light rays, when near the sun, do not go straight.

    Black and white photo of a man with pince-nez glasses.
    Sir Arthur Eddington led the expedition that provided the first proof of Einstein’s theory of general relativity. Image via Wikimedia Commons.
    A dark-haired young man with a mustache and a dignified expression, in a suit.
    Albert Einstein in 1912. Image via Wikimedia Commons.

    Bottom line: The solar eclipse of May 29, 1919, was the day astronomer Sir Arthur Eddington verified Einstein’s general theory of relativity, by observing how stars near the sun were displaced from their normal positions. This apparent change in position happens because, according to Einstein’s theory, the path of light is bent by gravity when it travels close to a massive object like our sun.

    Via RAS

    Via NBCNews

    And via DiscoverMagazine.com

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