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.

Heads up! Lunar eclipse coming

Get pointers on viewing the August 27-28 nearly total lunar eclipse from EarthSky’s Deborah Byrd. Watch in the player above, or on YouTube. Prefer to read? Read about the August 27-28 lunar eclipse here.

Details here: Deep partial lunar eclipse of the August 27-28 Sturgeon Moon

Mercury will soon go behind the sun

Late August morning planets: Saturn, Mars, Jupiter

August 29 and 30 evenings: Moon near Saturn

September 1 evening: Moon near Saturn

September morning planets: Northern Hemisphere view

September 2 and 3 evenings: Moon near Pleiades

Read more: The Pleiades – or 7 Sisters – known around the world

September 4: Watch for the 3rd quarter moon

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

September 5 morning: Moon visits Mars and a pair of bright stars

Read more: Capella is one of the sky’s brightest stars

September 6 and 7 mornings: Moon near Jupiter, Mars and a trio of bright stars

Read more: Castor – the twin star – is 6 stars in one

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.

September 8 and 9 mornings: Moon near Jupiter

Watch for the zodiacal light

September 11: New moon

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

September 13 and 14 evenings: Moon visits Venus

September 15 evening: Moon near Venus and Antares

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

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.

September 16 and 17 evenings: Moon near Antares

September 18: 1st quarter moon

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

September 18: Venus reaches greatest brilliancy

September 18 and 19 evenings: Moon near Teapot

Read more: Teapot of Sagittarius points to Milky Way center

Late September evening planets: Northern Hemisphere view

September 23: September equinox

Full Harvest Moon September 26

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.

September 28 evening: Moon near Pleiades

September 29 and 30 evenings: Moon near Pleiades

August evening planet

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

August morning planets

September evening planets

September morning planets

August stars

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

Have fun exploring the sky!

New to stargazing? Read more: Planisphere: Your friend to find stars and constellations

September stars

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

Have fun exploring the sky!

New to stargazing? Read more: Planisphere: Your friend to find stars and constellations

Sky dome map for visible planets and night sky

Read more: Guy Ottewell explains sky dome maps

Heliocentric solar system visible planets and more

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.

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

Bottom line: Visible planets and night sky guide: Love eclipses? Don’t miss these tips for making the most of the upcoming lunar eclipse!

The post Visible planets and night sky guide for August and September first appeared on EarthSky.

Sun news August 24: Quiet sun, but fast solar winds to come

(11 UTC August 23 – 11 UTC August 24)

Today’s top story: With the Earth-facing solar disk currently quiet, forecasters are looking ahead to a likely round of fast solar wind later this week. The solar wind is streaming from an area of low density in the sun’s outer atmosphere known as a coronal hole, and it should start reaching Earth late on August 26 or, more likely, on August 27. That could open the door for auroras across northerly latitudes, including northern Scotland.

Past 24 hours on the sun

Flare activity: Solar activity remained at low levels. The sun fired 8 C-class flares and 2 B-class events during the period.

• Strongest flare: C3.5 from AR4513 at 22:03 UTC on August 23.
• Lead flare producer: AR4513 was responsible for 7 of the 10 flares tracked over the period.

Sunspot regions: The Earth-facing solar disk displayed four numbered active regions over the past day.

• AR4513 (beta-gamma) remained the most significant region on the disk, and was the source of nearly all the flaring.
• AR4517 (beta) grew in both its leader and trailer spots. Still, it kept a relatively simple magnetic structure.
• AR4508 and AR4514 rotated across the western horizon during the period. AR4514 produced two minor C-class flares before departing the visible disk.
• The remaining two smaller regions on the disk were magnetically simple. Neither showed significant activity.

Blasts from the sun? Observers spotted no Earth-directed coronal mass ejections in available coronagraph imagery during the period.

Past 24 hours in space weather

Solar wind: Speeds declined through the period, dropping to a slow background level.

Bt, Bz and magnetic coupling: The interplanetary magnetic field (IMF) stayed weak. The Bz component varied weakly, with no significant or sustained southward intervals. That is unfavorable for aurora production.

Earth’s magnetic field: The field was quiet throughout the entire period, with Kp values of just 1-2. Aurora sightings stayed confined to the far northern auroral zone: Iceland, northern Scandinavia, northern Alaska, and Canada.

What’s ahead? Sun-Earth forecast

Flare activity forecast: Forecasters expect low levels to continue over August 24-26. Even so, a chance (45%) for M-class flares remains, along with a slight chance (5%) for an X-class event (R3 or greater).

Geomagnetic activity forecast:

• August 24: Quiet conditions are expected (Kp 0-2). Background solar wind will prevail with no significant drivers. Aurora sightings are unlikely outside the far northern auroral zone.
• August 25: Quiet conditions should continue (Kp 0-2). The slow ambient solar wind regime persists, and forecasters anticipate no CME arrivals. Aurora sightings remain unlikely at mid-latitudes.
• August 26: Mostly quiet conditions are expected through much of the day. Then a coronal hole high-speed stream may arrive late, lifting activity to unsettled-to-active levels (Kp 3-4). The chance of G1 (minor) storm intervals (Kp 5) increases as the fast wind arrives. If the stream arrives on schedule, aurora may become visible from Seattle, Minneapolis, Edinburgh, and the Scottish Highlands.
• August 27 (extended outlook): The coronal hole stream is more likely to peak on this day, and solar wind speeds should increase to elevated levels. Forecasters expect unsettled-to-active conditions (Kp 3-4), with a chance of G1 (minor) storm intervals (Kp 5). Aurora watchers across northern Europe, northern Canada and the northern tier of the United States should stay alert for possible displays.

The sun in recent days

Sun images from our community

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

Bottom line: Sun news August 24, 2026: A quiet sun, but fast solar wind from a coronal hole will arrive later this week, potentially bringing auroras to Seattle and Scotland!

Submit your photos here.

View community photos here.

The post Sun news: Quiet sun, but fast solar winds to come first appeared on EarthSky.

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Dwarf planet Pluto

On August 24, 2006, the International Astronomical Union (IAU) announced it had re-classified Pluto as a dwarf planet. Moreover, it declared that Pluto was “not a planet.”

From 1930 until that day, Pluto had been considered a planet, and the outermost world of the solar system. As technology advanced, though, astronomers began to see fainter and fainter objects in our neighborhood. That led them to recognize Pluto as only the largest of many small bodies in the outer solar system. So is Pluto a planet or not?

Today, Pluto is known as a dwarf planet, and Neptune – 8th world from the sun – is considered the outermost of our solar system’s classical planets. It all came about because the IAU formulated and pushed through a new definition of what it means to be a planet.

But some astronomers, and a small segment of the public, are still angry about it.

Why? And what would happen if Pluto were re-classified as a planet today? The video below, produced by EarthSky’s Deborah Byrd, has part of the answer.

Why did Pluto change status?

Prior to 2006, astronomers hadn’t gotten around to establishing clear standards for categorizing a solar system “planet” versus a “dwarf planet.”

They began to see a need when many small bodies – such as Haumea and Makemake – began to be discovered in the outer solar system. Eris, also considered a dwarf planet, has even more mass than Pluto (though it’s not quite as large). So if Pluto is a planet, why shouldn’t Eris be granted planet status as well? That was the question the IAU asked itself, which led to its formation of a Planet Definition Committee and ultimately the 2006 decision.

The committee had a few possible roads to travel down. One would be to choose a size or mass limit that would make Pluto remain a planet. That would mean that Eris and Ceres – the largest body in the inner solar system’s asteroid belt – would become planets, too. And today we know there would be perhaps hundreds of small bodies large enough to call “planets” if we followed this path. This solution – favored by most of the original IAU committee members – looked as if it might be implemented for a while.

Another option for the IAU might have been to define the concept of a planet without any specific logic: Earth is a planet, Pluto is a planet, but Eris is not just because. But would that have been very scientific?

New planetary classifications

On August 24, 2006, the IAU announced its solution. It decided to create a scientific definition of what it means to be a planet. And that definition excluded Pluto from major planet status. Here’s the definition:

A planet is a celestial body that
(a) is in orbit around the sun,
(b) has sufficient mass for its self-gravity to overcome rigid body forces so that it assumes a hydrostatic equilibrium (nearly round) shape, and
(c) has cleared the neighborhood around its orbit.

It’s “c” that causes Pluto to fail as a planet, according to the IAU. For an object to be a major planet, according to this definition, it must be the dominant gravitational object in its orbit. It must either sling other objects away or merge with them.

Pluto is only 0.07 times the mass of the objects in its orbit. Meanwhile, Earth is 1.7 million times the mass of the objects in its orbit.

Still, today, there are astronomers on Team Planet-Pluto who will declare:

But Earth has not cleared its orbit either.

Pluto hasn’t cleared its neighborhood

On that fateful day – August 24, 2006 – the IAU also created a new category of celestial objects for Pluto and all Pluto-like objects:

A “dwarf planet” is a celestial body that
(a) is in orbit around the sun,
(b) has sufficient mass for its self-gravity to overcome rigid body forces so that it assumes a hydrostatic equilibrium (nearly round) shape,
(c) has not cleared the neighborhood around its orbit, and
(d) is not a satellite.

How many dwarf planets are there? According to this page by planetary astronomer Mike Brown of CalTech, as of November 25, 2025, there are:

10 objects which are nearly certainly dwarf planets,
27 objects which are highly likely to be dwarf planets,
68 objects which are likely to be dwarf planets,
130 objects which are probably dwarf planets, and
741 objects which are possibly dwarf planets.

Hundreds of dwarf planets?

Astronomers believe there may be hundreds more undiscovered dwarf planets in the Kuiper Belt of the outer solar system. There may be up to 10,000 in the region beyond.

More about the Kuiper Belt: https://t.co/qNCG1GvgeP https://t.co/kPGvZtR4IY pic.twitter.com/FYX5Cv2PDD

— NASA Solar System (@NASASolarSystem) February 20, 2024

Not a new idea

By the way, it’s not common knowledge that many astronomers started out being quite careful about their use of the word “planet” with respect to Pluto. In 1932, for example, only two years after American astronomer Clyde Tombaugh discovered Pluto, another astronomer, Armin Otto Leuschner, wrote in a journal article:

You may observe that with extreme conservatism I am still referring to Pluto as an object rather than as a planet. There is every probability that it is a planet, as is now universally concluded, from available material … So far only an upper limit for the mass of Pluto … has been established, and such a mass is believed from gravitational considerations to be too small to affect the motions of Uranus and Neptune sufficiently … There is also a remote chance that later investigations will render its mass comparable to that of comets.

So is Pluto a planet or not?

Recall why astronomers began searching for Pluto in the first place. They expected to find an object large enough to gravitationally disturb the orbit of Neptune. But that’s not Pluto, it’s not large enough to disturb Neptune. Pluto was found by accident.

If Pluto had been discovered a decade or so later, when Edgeworth began speculating about the existence of what we now call the Kuiper Belt – a belt of small Pluto-like objects in the outer solar system – Pluto itself might have never been awarded the status of planet. As explained in the videos at the top of this article, if Pluto were classified as a planet today, our solar system would now contain not just eight or nine, but dozens of “planets.”

Eventually, we are expected to find hundreds of objects that would need to be classified as planets, if the Team Planet-Pluto wins the argument about Pluto’s planet status.

The search for Planet 9

And that’s why astronomer Michael Brown does not believe Pluto should be called a planet. Brown studies the dynamics of our solar system. He perceives it as eight classical planets – Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, Neptune – and two large “belts” of objects: the asteroid belt between Mars and Jupiter and the Kuiper Belt in the outer solar system.

The first eight classical planets formed in a process involving smaller objects sticking together to make larger objects, that eventually became large enough to have enough self-gravity to pull themselves into the shapes of balls.

Did the smaller bodies in the asteroid belt and Kuiper Belt form this way? Perhaps. Pluto, for example, is round. But perhaps not. The formation of the bodies in the asteroid belt and Kuiper Belt might have been different: less complex. Brown thinks we can understand the solar system better if we categorize those objects in a way different from the eight classical planets.

Whatever happens, whether Pluto ultimately re-gained its planet status or not, the de-classification of Pluto has been eye-opening! And if Pluto is not the ninth planet, could there actually be a ninth planet waiting to be discovered?

Bottom line: August 24 is the anniversary of Pluto’s demotion to dwarf planet status. The International Astronomical Union demoted Pluto largely because it is has not “cleared the neighborhood around its orbit.”

Read more about Pluto here

The IAU talks about its decision to demote Pluto here

Read more: Pluto’s atmosphere is thinning toward a collapse

Read more: Pluto terrain in rainbow colors

The post Pluto demoted to dwarf planet 20 years ago today first appeared on EarthSky.

• New Horizons observed Pluto’s atmosphere in 2015 as “thin.” The spacecraft found a mostly nitrogen atmosphere for this dwarf planet.
• And now we know the atmospheric pressure on Pluto decreased by 16% between mid-2021 and July 2023.
• How do we know? Scientists detected the change while watching Pluto pass in front of distant stars, during what are called “occultations.”

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

Pluto’s atmosphere is thinning

A team of scientists led by Amanda Sickafoose at the Planetary Science Institute in Tucson, Arizona, says that Pluto’s atmospheric pressure decreased by 16% between mid-2021 and July 2023. The researchers detected the change by observing Pluto occult – or pass in front of – distant stars. The team might have even detected the first signs of Pluto’s coming atmospheric collapse.

Only one spacecraft from Earth has ever visited Pluto. That was New Horizons in 2015. It found that Pluto has an extremely thin, but hazy, atmosphere made mostly of nitrogen. But we knew before New Horizons that Pluto’s atmosphere should thicken and thin in a 248-year cycle, as this tiny outer world – with its greatly elongated orbit – moves closer to and then farther from the sun.

Pluto came closest to the sun on September 5, 1989. Now it is moving away from the sun, heading out to a colder part of the solar system. We know its atmosphere will thin out and freeze onto its surface.

Pluto won’t turn back towards the sun until the year 2114. Until then, there’s lots of time for scientists to study this little world in the colder part of its orbit.

The researchers published their peer-reviewed findings in The Planetary Science Journal on July 31, 2026.

Measuring Pluto’s thinning atmosphere

The new study examined how Pluto’s atmosphere has changed between 2021 and 2023. New Horizons’ flyby of Pluto was in 2015. The researchers found that between the flyby and into 2021, Pluto’s atmospheric pressure remained constant. No thinning yet.

But then something changed. Between mid-2021 and July 2023, the atmospheric pressure decreased by 16%.

Occultations provide clues

How did the researchers measure the atmosphere? They can do so when Pluto occults – passes in front of – a distant star. By measuring how the starlight changes, the researchers can get clues about Pluto’s atmosphere.

Even though Pluto is extremely far away from us, it casts its shadow on Earth during an occultation. Scientists in different parts of the world create maps of the shadow’s path across Earth.

Sickafoose and her colleagues have observed 10 such occultations since 2017. The researchers could confirm their observations from multiple locations on Earth. Sickafoose said:

We often prefer to observe predicted occultations that have shadow paths over large observatories because that equipment and data have proven successful. Then, we try to improve those datasets by collaborating with local observers in the shadow paths.

Brightness of a star

Pluto is extremely faint of course, since it is incredibly far away. This is why the brightness of the background star is so important. Scientists use various telescopes to measure the brightness of the star before, during and after the occultation.

Despite the faintness of Pluto, its thin, hazy atmosphere bends the star’s light enough to be detectable from Earth. Sickafoose said:

I’m constantly amazed at how the simple technique of watching starlight dim and reappear allows us to study a thin atmosphere – a few millionths of the Earth’s – on a world two-thirds the size of our moon and 30 times farther from the sun.

Sickafoose concluded:

We’re at a particularly interesting point for Pluto. Our work suggests that the atmosphere has recently started decreasing in pressure. I am hopeful that we’ll be able to get more data in the next years to decades to specifically confirm or refute this trend.

New Horizons sees Pluto’s hazy atmosphere

NASA’s New Horizons spacecraft saw Pluto’s hazy atmosphere up close when it flew past the dwarf planet on July 14, 2015. You can clearly see the haze layers in the images the probe sent back to Earth. And the famous “blue ring”, at the top of this post, is particularly amazing. It shows Pluto backlit by the sun, with its atmosphere appearing a bright blue ring in the blackness of space.

Last month, another study found that Pluto and Saturn’s moon Titan both have the same mysterious molecule on their surfaces. And scientists don’t know what it is yet. Interesting!

Bottom line: Scientists detected that Pluto’s atmosphere is thinning as it moves farther away from the sun in its orbit. Is its atmospheric collapse already happening?

Source: Changes in Pluto’s Atmosphere Based on Stellar Occultation Data from 2017 to 2023

Via Planetary Science Institute

Read more: Titan and Pluto share same mysterious molecule: What is it?

Read more: Will Pluto become a planet again? The ongoing debate

The post Pluto’s atmosphere is thinning toward a collapse first appeared on EarthSky.

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1st photo of Earth from the moon

On August 23, 1966, Lunar Orbiter 1 took the 1st-ever photo of the Earth from the moon. It shows half of Earth, shot with 1960s technology, seen from the moon’s distance of 236,000 miles (380,000 km). And in the image, you can see the Earth from Istanbul to Cape Town with areas east shrouded in night. The image isn’t very detailed. But it’s mind-boggling to think about. What a contrast with NASA’s recent Artemis 2 mission that sent astronauts to orbit the moon for the first time in over 50 years! See Artemis 2 images here.

Lunar Orbiter 1 was one of five Lunar Orbiters that NASA sent to the moon in the 1960s. The Lunar Orbiter’s priority was to take photographs of the moon. That’s because NASA was preparing for the first manned Apollo mission, which came three years later. Read about the Lunar Orbiter missions, 1966-1967.

As you can see, the photo taken in 1966 reveals no detail on Earth’s surface.

But, surely, this photo stunned those on Earth who finally saw our home planet from the moon.

Years later, a digitally enhanced version

Then, in 2008, NASA released a newly restored version of the original 1966 image of Earth. NASA used refurbished machinery and modern digital technology. Consequently, the new image is higher resolution than what was possible when it was originally taken. Wow! What a difference.

The impressive restored image of the Earth from the moon is below.

Bottom line: As NASA plans to land astronauts on the moon with the Artemis IV mission in 2028, it’s fun to see this 1st-ever photo of Earth from the moon, taken on August 23, 1966.

NASA releases 12,000 Artemis pics! See our faves here

The post 1st photo of Earth from the moon 60 years ago first appeared on EarthSky.

If you’re outside on an August or September evening, you can glimpse the zodiacal constellation Sagittarius the Archer. From our northerly latitudes, it never climbs high in the sky. Yet when you’re looking toward Sagittarius, you’re looking in the direction of one of the most wondrous places we can imagine: the center of our own Milky Way galaxy.

Plus, Sagittarius is fairly easy to spot if you have a dark sky. Its brightest stars form an asterism in the distinctive shape of a Teapot.

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How to find Sagittarius

You’ll want a dark, rural location to see and enjoy Sagittarius. In August or September, when you’re outside camping or ending a picnic on a summer evening – any place away from light pollution – simply look up. You’ll notice the starlit band of the Milky Way. It’ll appear as a hazy band stretching all the way across the sky. The haze is really countless stars.

From the Northern Hemisphere, the starlit trail of the Milky Way seems to bulge just before it reaches the southern horizon (from the Southern Hemipshere, this bulge is high in the sky). This bulge marks the approximate location of the Milky Way’s center.

Here’s another way to find Sagittarius. If you’re familiar with the Summer Triangle asterism, draw an imaginary line from the star Deneb and through the star Altair to locate Sagittarius near the horizon. At mid-northern latitudes, the Summer Triangle hangs high in the south to overhead on late summer and autumn evenings.

Deep-sky wonders in the Archer

So Sagittarius points to the heart of our Milky Way galaxy. But we can’t see all the way to the center. Why not? Because it’s so far away, 26,000 light-years. And because of the huge plethora of stars, star clusters, nebulae and dust that block our view.

On the other hand, the stars, star clusters, nebulae and dust are themselves worth viewing! And you don’t need to know what you’re seeing to enjoy them. Just take binoculars with you, next time you know you’ll have access to a dark sky on an August or September evening. Look up! And aim your binoculars along the starry path of the Milky Way.

Here are some deep-sky treasures in Sagittarius: Sagittarius Star Cloud (Messier 24), globular cluster Messier 22, Lagoon Nebula (Messier 8), Trifid Nebula (Messier 20) and Omega Nebula (Messier 17).

Sharp-eyed people can even see these deep-sky objects with the unaided eye. Binoculars let you see them better. And a small telescope would give you a beautiful view.

Modern stargazers have difficulty making out the Centaur in Sagittarius. But the Teapot is easy to see, once you learn to look for it. Find the Teapot, and it’ll help you on your star-hopping adventures to deep-sky marvels.

Photos of the Teapot

The Teapot is the central region of Sagittarius. Once you’ve learned to trace the Teapot’s shape in the sky, it’ll become easier to spot. Check out the photos below to learn its shape and then try to spot it yourself.

The stars of Sagittarius

The brightest star in Sagittarius is the star marking the bottom right corner of the teapot, Kaus Australis. Also known as Epsilon Sagittarii, this magnitude 1.8 star lies 143 light-years away.

The next brightest star is at the opposite end of the teapot, the top star in the handle, Nunki. Also known as Sigma Sagittarii, this 2.1-magnitude star shines from a distance of 228 light-years.

Most of the other stars in Sagittarius are of 2nd and 3rd magnitude. The star marking the top of the teapot’s lid is Kaus Borealis, a magnitude 2.82 star lying 77 light-years away. The stars marking the top of the spout are Alnasl, which marks the tip of the spout at magnitude 2.98 and is 96 light-years away, and Kaus Media, which marks the spout’s connection to the pot at magnitude 2.72 and is 306 light-years away. The star at the bottom of the handle where it connects to the pot is Ascella, a magnitude 2.60 star lying 89 light-years away.

Sagittarius in mythology

The constellations Sagittarius and Centaurus are both supposed to represent a centaur, a creature with the upper torso of a man and the body and legs of a horse. Historically, centaurs might have really been like cowboys, using horses to round up cattle in ancient Greece.

According to Greek myth, the centaurs were the offspring of Ixion and the cloud nymph Nephele. Apparently, Sagittarius’ drawn-out bow and arrow originated from the Mesopotamian archer god. So this constellation might not have always represented the centaur Chiron.

It’s said that the Greeks associated Sagittarius with Crotus the satyr, another type of monstrosity, a man with horse ears and tail and goat legs. Quite possibly, the Romans first identified the constellation Sagittarius with Chiron, the wise and kindly centaur.

Here’s something that distinguishes Sagittarius the Archer from the other 13 constellations of the zodiac. The sun shines in front of this constellation on the December 21 solstice.

Also, the ecliptic – the sun’s yearly pathway in front of the backdrop stars – intersects the galactic equator in Sagittarius.

The constellation versus the sign

In our modern times, the sun passes in front of the constellation Sagittarius from about December 18 to January 20. These dates are off by about a month from what you read on the horoscope page. The sun moves through the sign Sagittarius from about November 21 to December 21.

Yes, there is a difference between an astronomical constellation and an astrological sign! Keep in mind that we’re talking about the constellation Sagittarius in this article. The horoscope is referring to the sign Sagittarius.

By definition, the sun enters the sign Sagittarius whenever the sun is precisely 30 degrees west of the December solstice point. Then, on the December solstice, the sun enters the sign Capricorn.

While the signs remain fixed relative to the solstices and equinoxes, the solstices and equinox points move 30 degrees westward in front of the constellations – or backdrop stars – in about 2,160 years.

The constellation boundaries were formally defined by the International Astronomical Union (IAU) in 1930. Based on the present IAU boundaries, the December solstice point moved into the constellation Sagittarius in the year 131 BCE and will move into the constellation Ophiuchus in 2269 CE.

Bottom line: Look for the constellation Sagittarius on an August or September evening. The brightest stars in Sagittarius form the distinctive shape of a teapot. And the spout of the Teapot points to the center of the Milky Way galaxy.

Teapot of Sagittarius points to the Milky Way’s center

The post Sagittarius the Archer is home to deep-sky wonders first appeared on EarthSky.

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3 supermassive black holes in a single galaxy

Scientists think most large galaxies have supermassive black holes at their hearts. And, earlier this year, astronomers from the Max Planck Institute for Radio Astronomy said they’ve detected the first pair of supermassive black holes at the center of a galaxy … two monster black holes so close they could merge. Now, on August 12, 2026, astronomers from the Max Planck Institute for Extraterrestrial Physics announced that – for the first time – they’ve detected three supermassive black holes in one galaxy.

Two of these black hole triplets lie near one another and the center of their galaxy. They are only 620 light-years apart. One of these two is the most massive of the three at 80 million solar masses (a single solar mass is a unit of measurement in astronomy). The other central black hole is the least massive with just 600,000 solar masses. The third black hole looms on the galaxy’s outskirts, about 5,500 light-years from the center, with 2 million times the mass of our sun.

The galactic home of these three black holes is called J0148-4214. It lies 12.5 billion light-years away from us, in the very early universe. So we’re seeing it as it appeared about 1.2 billion years after the Big Bang, the initiation of our universe.

The researchers published their peer-reviewed study in the journal Astronomy & Astrophysics on August 12, 2026.

Black holes in the early universe

These early-universe black holes are hungry! All three are actively accreting, or consuming nearby material in a disk. That’s unlike the supermassive black hole at the center of our own Milky Way galaxy, and other galaxies near us in space. Their older supermassive black holes appear more quiescent.

So the researchers say these early active black holes can provide insight into how our universe grew into what we see today.

Hannah Übler of the Max Planck Institute for Extraterrestrial Physics led the new triple-black-hole study. Übler said:

This is the first evidence of three active black holes in a single galaxy in the distant universe.

It suggests that processes in the early universe were efficient at bringing massive black holes together, setting the stage for the massive black hole mergers we expect to detect with future gravitational wave observatories.

Scientists have long thought that black hole mergers in the early universe are what allowed supermassive black holes to grow so big so quickly. And now, finding three supermassive black holes in one galaxy strengthens that theory.

Seeing the 3 supermassive black holes

So these three black holes have 80 million, 2 million and 6 thousand times the mass of our sun. And while you might think the most massive of the three is the greediest gobbler of nearby gas and dust, analysis suggests that the smallest of the black holes is actually accreting (gaining material) at the fastest rate. In fact, the hungry little black hole is:

… exceeding the maximum accretion rate predicted by basic theories of black hole growth (the Eddington limit).

So … another mystery!

How did the scientists spot these three black holes? They used the Webb space telescope’s NIRSpec instrument to examine the galaxy’s spectral signature. This breakdown in the wavelengths of light allowed them to see hydrogen moving at high velocities. Without this tool, the scientists would not have been able to see the black holes as separate objects. So they likely would only have identified one black hole in the galaxy.

A merger in the making

The data from Webb allowed the scientists to identify three black holes and discover their masses. Co-author Giovanni Mazzolari of MPE said:

The JWST data allowed us not only to identify the three black holes, but also to estimate their masses, accretion rates, and the stellar mass of the galaxy. We find a total stellar mass of about 1.3 billion suns, and the black holes represent a significant fraction of that.

And the scientists say the central two black holes are on a collision course. They expect them to merge within the next few hundred million years. Co-author Roberto Maiolino of the University of Cambridge said:

These results are extremely exciting. They suggest that black hole merging may be an additional, fast route for their rapid growth in the early universe.

What about the third black hole? Astronomers have two scenarios. It could someday merge with the central black holes. Or it could have already been kicked out of the inner circle during a previous merger of black holes.

Bottom line: For the first time, astronomers have discovered three supermassive black holes in a single galaxy in the early universe. The two central black holes may merge in a few hundred million years.

Source: BlackTHUNDER: Evidence of three massive black holes in a z ? 5 galaxy

Via MPE

The post A first! 3 supermassive black holes discovered in 1 galaxy first appeared on EarthSky.

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Neptune’s rings confirmed August 22, 1989

By the late 1980s, astronomers suspected that there are rings around Neptune, our solar system’s outermost major planet. After all, the next planet inward, Uranus, has rings (found in 1977). So does Jupiter (found in 1979) and Saturn (first glimpsed through early telescopes in the 1600s).

Then, watching from Earth in 1984, astronomers recorded extra blinks before and after Neptune passed in front of a distant star. That added to the evidence that Neptune had at least a partial ring system. But it was NASA’s Voyager 2 spacecraft that provided the first photographic proof of the existence of Neptune’s rings on August 22, 1989.

At the time, the spacecraft was a few days out from its closest encounter with the planet on August 25, 1989. As Neptune began looming large in Voyager’s cameras, the spacecraft photographed a faint but continuous ring system encircling the planet. The images of Neptune’s rings confirmed astronomers’ long-held suspicions.

Names for Neptunian rings

Today, Voyager 2 remains the only earthly spacecraft to have encountered Neptune. But since Voyager’s 1989 flyby, the Hubble Space Telescope, the James Webb Space Telescope, and Earth-based telescopes have imaged the two brightest rings of Neptune. Astronomers named those two Neptunian rings Adams and Le Verrier. They’re named for John Couch Adams and Urbain Jean Joseph Le Verrier, whose independent calculations helped find Neptune’s position in the sky – and thus led to its discovery – in 1846.

There are also three more rings around Neptune: Galle, Lassell, Arago. So moving outward from near the planet, the main rings are Galle, Leverrier, Lassell, Arago, and Adams.

Peculiar ring arcs

Today, we know that Neptune has at least five main rings. Plus, it has four prominent ring arcs. The arcs are peculiar clumps of dust. Astronomers struggled to understand their existence, because the laws of motion predict these arcs should spread out into a uniform ring over short timescales. Scientists now believe the gravitational effects of Galatea, a moon just inward from the ring, confine the arcs.

Also, four of the prominent arcs have names. Astronomers call them Liberté (Liberty), Egalité (Equality), Fraternité (Fraternity), and Courage. They’re located in the outermost ring, Adams.

Bottom line: NASA’s Voyager 2 spacecraft confirmed the discovery of Neptune’s rings on August 22, 1989, when it took images of a faint, continuous ring system around the planet.

Read more: Webb sees Neptune’s rings and moons

The post Voyager 2 confirms Neptune’s rings on August 22 in 1989 first appeared on EarthSky.

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Come to know the Teapot of Sagittarius

Our Milky Way galaxy is a vast collection of hundreds of billions of stars. We’re not in the galaxy’s center, but instead about 2/3 of the way out from center, in one of the Milky Way’s spiral arms. And on August evenings, under a dark sky, all of us on Earth can gaze toward the galaxy’s center.

The band of the Milky Way gets broader and brighter in the direction of the center. And in that direction, you’ll find a famous asterism called the Teapot, in the constellation Sagittarius.

The Teapot’s pattern is distinctive. It’s easy to see it as an earthly teapot. You’ll find it southward on August evenings from the Northern Hemisphere, and overhead from the Southern Hemisphere.

Even if your sky isn’t dark, once you find the Teapot, you can use it to guide your mind’s eye to the star-rich center of our galaxy. A supermassive black hole lies at the galaxy’s heart, with some 4 million times the mass of our sun. It’s called Sagittarius A* (Sagittarius A-Star).

How to spot the Teapot

You’ll want a fairly dark sky to find the Teapot. A suburban sky will likely work, if you’re not standing under a streetlight. You can see the Teapot even if you can’t see the starry band of the Milky Way.

If you’re in the Northern Hemisphere, look southward on August evenings a couple of hours after sunset. If you’re in the Southern Hemisphere, look overhead.

The Teapot and Sagittarius are best viewed during the evening hours from about July to September.

Want a more exact location for Sagittarius? Try Stellarium, which will let you set a date and time from your exact location on the globe.

The Teapot looks like its name

The constellation Sagittarius is supposed to be a centaur, a mythical half man/half horse creature, carrying a bow and arrow. But good luck spotting the centaur in these stars!

On the other hand, the Teapot – unlike many star patterns – looks just like its namesake. That’s because the Teapot appears to have a handle, spout and lid, as any earthly teapot would. And just be sure to head to a dark sky for your best views of this Milky Way region.

Once you’ve found the Teapot, assuming you have a dark sky, you can see “steam” billowing out of the spout. Gaze into the midst of this “steam” – actually billions of stars – and you’ll be gazing toward the center of our Milky Way galaxy.

The Teapot is highest in the evening sky in August

Because the sun passes in front of Sagittarius from about December 18 to January 20, the Teapot isn’t visible then. However, about half a year later – on July 1 – the Teapot climbs to its highest point for the night around midnight (1 a.m. daylight saving time or DST), when it appears due south as seen from the Northern Hemisphere or due north as seen from the Southern Hemisphere. In August, the Teapot – and the Milky Way’s center – reach their highest points for the night during the evening hours.

By the way, another noteworthy point lies in the direction of the Teapot in space. It’s the point at which the sun shines on the December solstice around December 21 each year.

The center of our Milky Way

The center of our galaxy is some 26,000 light-years away. We can’t see directly into it, because this region is shrouded by dust and gas clouds. But studies by astronomers have shown that, when we look in this direction, we’re looking toward the supermassive black hole located at our galaxy’s heart. This black hole has some 4 million times our sun’s mass. It’s known as Sagittarius A*.

Now sweep the area around the Teapot with binoculars or a telescope. You’ll see many faint fuzzy objects pop into view. They’re star clusters and nebulae (gas clouds) located in the disk of our galaxy, in the direction of the galaxy’s center.

So, find the Teapot on a dark night – when the moon is out of the way – and enjoy all it has to offer.

Bottom line: As you gaze toward the famous Teapot asterism in the constellation Sagittarius, you’re looking toward the center of our Milky Way galaxy.

Read more: Milky Way’s black hole emits rapid-fire flickers and flares

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NASA is studying pyrocumulonimbus clouds by plane

NASA said on August 17, 2026, that researchers have been taking to the skies this summer to chase some of the wildest weather on Earth: fire-generated thunderstorms.

These towering clouds, called pyrocumulonimbus clouds, form when intense wildfires send enormous amounts of heat upward. They can produce lightning, hail and heavy rain. Plus, they can carry smoke and gases high into the atmosphere. And those particles can reach the stratosphere, where they may linger for months or even years.

Besides satellite and ground-based observations, scientists are flying aircraft directly into the smoke plumes. As part of NASA’s INSPYRE mission, researchers are using NASA’s ER-2 aircraft and an NSF/NCAR Gulfstream V to sample the plumes. On August 3, the Gulfstream chased smoke from Utah’s Widemouth 2 fire, flying into a plume about 8 miles (12 km) above Earth’s surface. Instruments aboard the plane collected measurements at an altitude that forecasters aren’t normally able to include in their models.

Scientists hope to learn why some fires form pyrocumulonimbus clouds and others don’t. They also want to learn what types of vegetation are most likely to fuel these clouds or why some generate more lightning than others. The airborne measurements could help answer those questions and improve forecasts. Better forecasts could aid the battles against wildfires and accurately organize evacuations.

More about pyrocumulonimbus clouds

Cumulonimbus clouds are towering thunderheads that bring storms with lightning, thunder, heavy rain, hail and sometimes tornadoes. Pyro is a prefix meaning fire. And pyrocumulonimbus clouds are thunderheads that form due to fires.

When wildfires grow large and intense, they can create their own weather. The heat and smoke from fires can rise into the atmosphere like the updraft in a thunderstorm. As the hot air ascends, it carries smoke, ash and water vapor high into the atmosphere.

If conditions are right – especially if the atmosphere is unstable – the rising plume can grow into a towering thunderstorm cloud. These clouds look quite similar to cumulonimbus clouds that produce lightning and heavy rain, except for brownish colors at their base. But pyrocumulonimbus clouds are fueled by fire rather than typical atmospheric processes.

Some pyrocumulonimbus clouds can reach heights of 30,000 to 50,000 feet (9 to 15 km)! That’s far above the height most airplanes fly. They can punch through the troposphere (the layer of air closest to Earth where we live) to the stratosphere. They can also spread out into anvil-shaped tops.

And the higher these clouds reach, the more these fires can spread smoke. It’s partly thanks to pyrocumulonimbus clouds that the smoke from wildfires can travel thousands of miles away from the actual wildfire.

A storm born of fire

Pyrocumulonimbus clouds can start as pyrocumulus clouds. This smaller version of a fire-generated cloud will have a darker, brown-tinged base. Sometimes you can see the fire beneath it, but sometimes the fire is hidden by haze or the terrain.

But as the fire grows, so can the cloud. The hot fire heats the air above, and hot air rises. As the hot air rises, it cools and expands. Water vapor then condenses on the ash. These pyrocumulus clouds can keep growing and building until they reach the pryocumulonimbus stage, which can have all the hallmarks of a thunderstorm. So pyrocumulonimbus clouds can bring rain. But, unfortunately, by that time the cloud has often drifted downwind. So the rain typically falls outside the fire.

And there’s an especially pernicious aspect of pyrocumulonimbus clouds. They can create lightning and thus spark new areas of fire nearby. Plus, the storms can generate strong winds that make the fire situation worse.

In fact, if the conditions are right, the storms that occur with pyrocumulonimbus clouds can even generate a fire tornado. Also known as a fire whirl, fire swirl, fire devil, firenado or fire twister, a fire tornado is a whirlwind induced by a fire and often (at least partially) composed of flame or ash.

In 2018, a firefighter was tragically killed in California when the Carr fire spawned a fire tornado. Read about it here. Or watch incredible video of the fire tornado in the news report below.

Smoke in the upper atmosphere can last for months

In 2023, scientists with the National Oceanic and Atmospheric Administration (NOAA) released a study of pyrocumumlonimbus clouds’ effect on Earth’s atmosphere. The study showed that that smoke injected into the upper atmosphere via these clouds can stick around for months. A fire in 2017 in the Pacific Northwest put so much smoke into the atmosphere that remote sensing instruments around the globe monitored it for more than eight months.

Fires that year also forced black carbon and organic carbon into the lower stratosphere. This carbon affected our climate and temporarily cooled the planet.

Joshua Schwarz, a NOAA scientist, said in 2023:

These fire clouds are growing larger and more frequent.

Lead author Joe Katich, who now works for BAE Systems, said that same year:

Pyrocumulonimbus clouds contribute more to the stratospheric makeup than we thought. They act in different ways than we thought and stick around longer than we thought. This finding is important on its own. But it will also help us understand the long-term implications of solar geoengineering with aerosols. [Editor’s note: Geoengineering refers to a range of different activities that humans might undertake with the goal of cooling the Earth or removing certain gases from the atmosphere.]

Bottom line: This summer, NASA has been studying pyrocumulonimbus clouds, or fire-driven thunderstorms. Researchers are flying planes right into the smoke plumes to take samples.

Read more: Western US wildfires fewer, but more destructive

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The post Pyrocumulonimbus clouds are fire-generated thunderstorms first appeared on EarthSky.