Do the planets revolve around the sun? Not exactly

Do the planets revolve around the sun? Sort of. Our solar system moves around a common center of mass, called a barycenter. And right now, that barycenter isn’t even inside the sun! The barycenter of the solar system will return to being inside the sun in early 2027. Image via NASA.

Do the planets revolve around the sun?

What if I told you that the planets don’t revolve around the sun? At least, not exactly. You were probably taught in grade school that Earth and the other planets do revolve around the sun. And generally speaking, it’s true, or not far from being true. But, strictly speaking, the physics of the situation is slightly different. The planets and the sun revolve around a common center of mass. This location or point is called the barycenter. Because the sun is so much more massive than the planets, the center of mass between them is often a point inside the sun’s giant ball of gas. But not always!

Right now, the solar system’s barycenter is outside the sun’s surface. And, because of the constantly changing location of the planets, the barycenter won’t return to being inside the sun until late January or early February 2027.

And most of that shifting is thanks to Jupiter. The sun contains about 99.86% of the solar system’s mass. Jupiter contains about 0.1%. That might sound tiny. But Jupiter is massive enough – and at just the right distance from the sun – to tug the solar system’s center of mass substantially outside the sun’s surface.

But this isn’t unusual. In fact, the solar system’s barycenter (or common center of mass) spends roughly 60% (or more) of its time outside the sun and only about 40% (or less) of its time inside!

The laws of physics dictate that the planets and sun revolve around a common center of mass, called barycenter. Archimedes in ancient Greece was the first to formalize this idea. The word barycenter comes from a combination of two Ancient Greek roots: barys meaning “heavy” or “weight” and kentron meaning “center.” Literally translated, barycenter means the “center of weight” or “center of gravity.” Image via NASA.

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The location of the planets

So, where are the planets currently in relation to the sun? In the two diagrams below, we’ve zoomed out so you can see the location of where the largest gas giant planets are currently orbiting. The first diagram is the location of the planets in late August 2026. The second diagram shows where the planets will be in relation to each other and the sun on February 7, 2027.

At the moment (late August 2026), the largest, outer planets are mostly clustered to one side of the sun. This is what moves the common center of mass for the solar system – the barycenter – to the outside of the sun. The barycenter will move to be inside the sun in early 2027. Image via InTheSky.org. Used with permission.

By February 7, 2027, you can start to see how Jupiter is separating from the other giant planets. It’s moving toward the opposite side of the sun. Jupiter’s movement is what’s pulling the barycenter back within the sun’s surface. Image via InTheSky.org. Used with permission.

Other planetary systems

Not just our sun and planets, but all stars and their planets move around a barycenter … a common center of mass for that system as a whole. If you looked from afar, you’d see a distant star with planets appear to “wobble” for this reason. Detecting that wobble is one of the tried-and-true way astronomers look for and find planets orbiting around farflung stars.

The wobble method is also called the radial velocity method. Radial velocity refers to the speed at which a star moves directly toward or away from an observer on Earth along our line of sight.

The wobble that astronomers see in systems like this is revealed through an analysis of the star’s spectrum, the rainbow array of its light broken into colors. As the star – orbiting with its companion planet – slightly moves toward us, we see its light waves compress toward shorter, bluer wavelengths. As the star slightly moves away, its light waves stretch toward longer, redder wavelengths.

This is the classic Doppler shift that also occurs with sound. It’s what causes the siren of an approaching ambulance to sound higher in pitch than when the same ambulance is moving away. And, clearly, with stars, it works best for systems that are aligned edge-on to us! If we’re looking at a system face-on, we can’t detect the shift.

Plus, the wobble method works best for massive planets close to their stars. Earth-mass planets are much harder to detect because their weaker gravitational tug produces a much smaller wobble in the star.

This is an exaggerated demonstration of how a star and planet orbit a common center of mass, or barycenter, which causes the star to appear to wobble. This is a technique astronomers use to find exoplanets, that is, planets around distant stars. Image via NASA.

This shows the side view of how a star can wobble when it and its planet orbit a common center of mass. Image via NASA.

Bottom line: Do the planets revolve around the sun? Not exactly. The sun and planets orbit a common center of mass (or barycenter), which, right now, is outside the sun. This will change in 2027, when Jupiter’s gravity will pull the barycenter back within the sun.

The post Do the planets revolve around the sun? Not exactly first appeared on EarthSky.

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Do the planets revolve around the sun? Sort of. Our solar system moves around a common center of mass, called a barycenter. And right now, that barycenter isn’t even inside the sun! The barycenter of the solar system will return to being inside the sun in early 2027. Image via NASA.

Do the planets revolve around the sun?

What if I told you that the planets don’t revolve around the sun? At least, not exactly. You were probably taught in grade school that Earth and the other planets do revolve around the sun. And generally speaking, it’s true, or not far from being true. But, strictly speaking, the physics of the situation is slightly different. The planets and the sun revolve around a common center of mass. This location or point is called the barycenter. Because the sun is so much more massive than the planets, the center of mass between them is often a point inside the sun’s giant ball of gas. But not always!

Right now, the solar system’s barycenter is outside the sun’s surface. And, because of the constantly changing location of the planets, the barycenter won’t return to being inside the sun until late January or early February 2027.

And most of that shifting is thanks to Jupiter. The sun contains about 99.86% of the solar system’s mass. Jupiter contains about 0.1%. That might sound tiny. But Jupiter is massive enough – and at just the right distance from the sun – to tug the solar system’s center of mass substantially outside the sun’s surface.

But this isn’t unusual. In fact, the solar system’s barycenter (or common center of mass) spends roughly 60% (or more) of its time outside the sun and only about 40% (or less) of its time inside!

The laws of physics dictate that the planets and sun revolve around a common center of mass, called barycenter. Archimedes in ancient Greece was the first to formalize this idea. The word barycenter comes from a combination of two Ancient Greek roots: barys meaning “heavy” or “weight” and kentron meaning “center.” Literally translated, barycenter means the “center of weight” or “center of gravity.” Image via NASA.

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

The location of the planets

So, where are the planets currently in relation to the sun? In the two diagrams below, we’ve zoomed out so you can see the location of where the largest gas giant planets are currently orbiting. The first diagram is the location of the planets in late August 2026. The second diagram shows where the planets will be in relation to each other and the sun on February 7, 2027.

At the moment (late August 2026), the largest, outer planets are mostly clustered to one side of the sun. This is what moves the common center of mass for the solar system – the barycenter – to the outside of the sun. The barycenter will move to be inside the sun in early 2027. Image via InTheSky.org. Used with permission.

By February 7, 2027, you can start to see how Jupiter is separating from the other giant planets. It’s moving toward the opposite side of the sun. Jupiter’s movement is what’s pulling the barycenter back within the sun’s surface. Image via InTheSky.org. Used with permission.

Other planetary systems

Not just our sun and planets, but all stars and their planets move around a barycenter … a common center of mass for that system as a whole. If you looked from afar, you’d see a distant star with planets appear to “wobble” for this reason. Detecting that wobble is one of the tried-and-true way astronomers look for and find planets orbiting around farflung stars.

The wobble method is also called the radial velocity method. Radial velocity refers to the speed at which a star moves directly toward or away from an observer on Earth along our line of sight.

The wobble that astronomers see in systems like this is revealed through an analysis of the star’s spectrum, the rainbow array of its light broken into colors. As the star – orbiting with its companion planet – slightly moves toward us, we see its light waves compress toward shorter, bluer wavelengths. As the star slightly moves away, its light waves stretch toward longer, redder wavelengths.

This is the classic Doppler shift that also occurs with sound. It’s what causes the siren of an approaching ambulance to sound higher in pitch than when the same ambulance is moving away. And, clearly, with stars, it works best for systems that are aligned edge-on to us! If we’re looking at a system face-on, we can’t detect the shift.

Plus, the wobble method works best for massive planets close to their stars. Earth-mass planets are much harder to detect because their weaker gravitational tug produces a much smaller wobble in the star.

This is an exaggerated demonstration of how a star and planet orbit a common center of mass, or barycenter, which causes the star to appear to wobble. This is a technique astronomers use to find exoplanets, that is, planets around distant stars. Image via NASA.

This shows the side view of how a star can wobble when it and its planet orbit a common center of mass. Image via NASA.

Bottom line: Do the planets revolve around the sun? Not exactly. The sun and planets orbit a common center of mass (or barycenter), which, right now, is outside the sun. This will change in 2027, when Jupiter’s gravity will pull the barycenter back within the sun.

The post Do the planets revolve around the sun? Not exactly first appeared on EarthSky.

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Do you love twilight? The 3 stages explained

View at EarthSky Community Photos. | Soumyadeep Mukherjee shared this composite image from photos taken at Singalila National Park in India in 2024. The bright object is Venus! Soumyadeep wrote: “There are some images, which, after you create, make you happy. This is one of them.” Thank you, Soumyadeep!

Twilight is that magical time of day when a glow pervades the air, even though the sun is below the horizon. Earth’s atmosphere scatters the sun’s rays to create the colors of twilight. On worlds with no atmospheres, such as the moon, the sky falls instantly dark after the sun sets.

And, if you could see twilight from outer space, you’d find that it isn’t marked by a sharp boundary on Earth’s surface. Instead, the shadow line on Earth – sometimes called the terminator line – is spread over a fairly wide area on the surface and shows the gradual transition to darkness we all experience as night falls.

Astronomers – those experts on nighttime – recognize three stages of twilight. Keep reading or watch a video to hear about the intricacies of civil, nautical and astronomical twilight, below.

Stage 1: Civil twilight

Let’s consider the stages of twilight as occurring after sunset. Keep in mind that they would reverse their order at sunrise. Civil twilight begins the moment the sun slips below the horizon. The official definition of civil twilight is the time from when the sun disappears until the sun’s center is 6 degrees below the horizon. A measurement of 6 degrees of sky is a bit more than three fingers held at arm’s length.

During civil twilight, there’s enough light to see, but people turn on their lights to drive a car, and the streetlights are starting to come on. The brightest planets appear during civil twilight.

For mid latitudes, civil twilight lasts a bit longer in summer and winter and is a bit shorter in spring and fall. In spring and fall, the sun rises and sets more directly in the east and west. Therefore, it makes a straighter path downward (or upward), reaching the 6 degree mark in a shorter period of time. In summer and winter, the sun arcs across the sky, cutting across the horizon at an angle. This angle is more pronounced in summer, which is why civil twilight lasts the longest in summer. Civil twilight in mid latitudes can last, on average, 1/2 hour.

Compare this to tropical regions. At the equator, the length of civil twilight hardly varies. The sun around the equator makes a path across the sky that cuts cleanly down toward the horizon at sunset in a nearly perpendicular fashion. Therefore, the sun and its rays disappear faster, giving equatorial regions a shorter twilight than higher latitudes. Near the poles, twilight times last much longer.

The 3 types of twilight. Image via TWCarlson/ Wikimedia Commons.

Stage 2: Nautical twilight

In the evening, nautical twilight takes over where civil twilight ends. The definition of nautical twilight is the time period when the center of the sun is 6 degrees below the horizon to 12 degrees below the horizon. You can remember the name “nautical” because it ends when the distant line between sea and sky is no longer distinguishable. Also, more bright stars appear during this time, which was important in the early days of navigation. When nautical twilight began, sailors could use the stars as directional cues.

During nautical twilight, terrestrial objects are visible, but you need artificial lights to carry on outdoor activities.

For polar regions, the summer sun does not get more than 12 degrees below the horizon. Therefore, these regions have nautical twilight all night long, never reaching astronomical twilight or total darkness. For mid latitudes, nautical twilight can last from about 1/2 hour in spring, winter and fall, to about 45 minutes in summer.

Stage 3: Astronomical twilight

The darkest twilight stage is astronomical twilight. The definition of astronomical twilight is the period of time when the center of the sun is 12 degrees below the horizon to 18 degrees below the horizon. You probably don’t even notice any illumination left in the sky at this time.

For stargazers, this is the time when fainter stars, clusters and other sky objects appear and become good observing targets.

In mid latitudes, astronomical twilight can last about 1/2 hour from fall through spring but up to an hour in summer. Astronomical twilight begins about an hour to 1 1/2 hours after sunset for mid latitudes. So, as a rule of thumb, if you’d like to observe something in the night sky that isn’t particularly bright, you should wait about 90 minutes after sunset before you start observing.

Twilight photo gallery

Twilight on Earth, viewed from space. Astronauts aboard the International Space Station captured this photo – a single digital frame – in June 2001. On the right, you see Earth illuminated by the sun. On the left, it’s nighttime. Between, washed in subtle colors, is the realm of twilight. Image via ISS Expedition 2 Crew/ Gateway to Astronaut Photography of Earth/ NASA.

View at EarthSky Community Photos. | Marcy Curran in Cheyenne, Wyoming, shared this image of the moon, brilliant Venus, bright Jupiter, shy Mercury and the stars Castor and Pollux on the morning of August 20, 2025. She wrote: “When you’re awake at 5 a.m. why not go check out the morning sky?” Thank you, Marcy!

View at EarthSky Community Photos. | John Ashley of Amado, Arizona, caputured this image on July 6, 2024, and wrote: “A 1% crescent moon sets through twilight haze beyond the large telescopes (left horizon) at Kitt Peak National Observatory (43 miles from the camera) just after sunset on Saturday, July 7, 2024.” Thank you, John!

Bottom line: Twilight is that magical time between sunlight and darkness. Astronomers, experts on nighttime, recognize three stages of twilight.

The post Do you love twilight? The 3 stages explained first appeared on EarthSky.

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View at EarthSky Community Photos. | Soumyadeep Mukherjee shared this composite image from photos taken at Singalila National Park in India in 2024. The bright object is Venus! Soumyadeep wrote: “There are some images, which, after you create, make you happy. This is one of them.” Thank you, Soumyadeep!

Twilight is that magical time of day when a glow pervades the air, even though the sun is below the horizon. Earth’s atmosphere scatters the sun’s rays to create the colors of twilight. On worlds with no atmospheres, such as the moon, the sky falls instantly dark after the sun sets.

And, if you could see twilight from outer space, you’d find that it isn’t marked by a sharp boundary on Earth’s surface. Instead, the shadow line on Earth – sometimes called the terminator line – is spread over a fairly wide area on the surface and shows the gradual transition to darkness we all experience as night falls.

Astronomers – those experts on nighttime – recognize three stages of twilight. Keep reading or watch a video to hear about the intricacies of civil, nautical and astronomical twilight, below.

Stage 1: Civil twilight

Let’s consider the stages of twilight as occurring after sunset. Keep in mind that they would reverse their order at sunrise. Civil twilight begins the moment the sun slips below the horizon. The official definition of civil twilight is the time from when the sun disappears until the sun’s center is 6 degrees below the horizon. A measurement of 6 degrees of sky is a bit more than three fingers held at arm’s length.

During civil twilight, there’s enough light to see, but people turn on their lights to drive a car, and the streetlights are starting to come on. The brightest planets appear during civil twilight.

For mid latitudes, civil twilight lasts a bit longer in summer and winter and is a bit shorter in spring and fall. In spring and fall, the sun rises and sets more directly in the east and west. Therefore, it makes a straighter path downward (or upward), reaching the 6 degree mark in a shorter period of time. In summer and winter, the sun arcs across the sky, cutting across the horizon at an angle. This angle is more pronounced in summer, which is why civil twilight lasts the longest in summer. Civil twilight in mid latitudes can last, on average, 1/2 hour.

Compare this to tropical regions. At the equator, the length of civil twilight hardly varies. The sun around the equator makes a path across the sky that cuts cleanly down toward the horizon at sunset in a nearly perpendicular fashion. Therefore, the sun and its rays disappear faster, giving equatorial regions a shorter twilight than higher latitudes. Near the poles, twilight times last much longer.

The 3 types of twilight. Image via TWCarlson/ Wikimedia Commons.

Stage 2: Nautical twilight

In the evening, nautical twilight takes over where civil twilight ends. The definition of nautical twilight is the time period when the center of the sun is 6 degrees below the horizon to 12 degrees below the horizon. You can remember the name “nautical” because it ends when the distant line between sea and sky is no longer distinguishable. Also, more bright stars appear during this time, which was important in the early days of navigation. When nautical twilight began, sailors could use the stars as directional cues.

During nautical twilight, terrestrial objects are visible, but you need artificial lights to carry on outdoor activities.

For polar regions, the summer sun does not get more than 12 degrees below the horizon. Therefore, these regions have nautical twilight all night long, never reaching astronomical twilight or total darkness. For mid latitudes, nautical twilight can last from about 1/2 hour in spring, winter and fall, to about 45 minutes in summer.

Stage 3: Astronomical twilight

The darkest twilight stage is astronomical twilight. The definition of astronomical twilight is the period of time when the center of the sun is 12 degrees below the horizon to 18 degrees below the horizon. You probably don’t even notice any illumination left in the sky at this time.

For stargazers, this is the time when fainter stars, clusters and other sky objects appear and become good observing targets.

In mid latitudes, astronomical twilight can last about 1/2 hour from fall through spring but up to an hour in summer. Astronomical twilight begins about an hour to 1 1/2 hours after sunset for mid latitudes. So, as a rule of thumb, if you’d like to observe something in the night sky that isn’t particularly bright, you should wait about 90 minutes after sunset before you start observing.

Twilight photo gallery

Twilight on Earth, viewed from space. Astronauts aboard the International Space Station captured this photo – a single digital frame – in June 2001. On the right, you see Earth illuminated by the sun. On the left, it’s nighttime. Between, washed in subtle colors, is the realm of twilight. Image via ISS Expedition 2 Crew/ Gateway to Astronaut Photography of Earth/ NASA.

View at EarthSky Community Photos. | Marcy Curran in Cheyenne, Wyoming, shared this image of the moon, brilliant Venus, bright Jupiter, shy Mercury and the stars Castor and Pollux on the morning of August 20, 2025. She wrote: “When you’re awake at 5 a.m. why not go check out the morning sky?” Thank you, Marcy!

View at EarthSky Community Photos. | John Ashley of Amado, Arizona, caputured this image on July 6, 2024, and wrote: “A 1% crescent moon sets through twilight haze beyond the large telescopes (left horizon) at Kitt Peak National Observatory (43 miles from the camera) just after sunset on Saturday, July 7, 2024.” Thank you, John!

Bottom line: Twilight is that magical time between sunlight and darkness. Astronomers, experts on nighttime, recognize three stages of twilight.

The post Do you love twilight? The 3 stages explained first appeared on EarthSky.

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Telescopium the Telescope is below the Teapot

To see the constellation Telescopium from the Northern Hemisphere, being farther south is better. Look right after sunset and enjoy it for a few hours before it disappears in the horizon. From the Southern Hemisphere, this constellation is high in the sky all night. This chart shows the view from Houston, Texas, or around 30 degrees north latitude. Chart via EarthSky.

If you live toward the south in the Northern Hemisphere, you have a window in late summer and early fall (winter and spring in the Southern Hemisphere) when you can spot the diminutive constellation of Telescopium. Location alone is not enough, however. You’ll also want dark skies. Even the brightest star in Telescopium is rather dim: magnitude 3.51 Alpha Telescopii. Perhaps Telescopium is a fitting name, because to view anything in this constellation you’ll benefit from a telescope.

Nicolas Louis de Lacaille visited the Southern Hemisphere in the 18th century. He gave names to 14 new constellations. He named Telescopium in honor of the scientific instrument he used.

How to find Telescopium

Technically, most locations in the United States and others around 40 degrees North latitude will have the main stars in the constellation rise above their horizon. But, when you consider buildings along the southern horizon, light pollution and the dim stars of the constellation, your best bet is to be further south.

With this in mind, look right after sunset and find the Telescope by first finding brighter constellations above it. The Teapot of Sagittarius and the curving tail of Scorpius the Scorpion are the perfect places to start. If, however, the Scorpion is dragging its tail along the horizon from your point of view, you’re out of luck.

Also, if you look below the half of the Teapot that is closest to Scorpius, past the arcing curve of Corona Australis, you may spot two rather dim stars. One is on top of the other. These two stars are all that make up the shape of Telescopium the Telescope.

Telescopium lies close to Corona Australis and Sagittarius the Archer. Image via Wikimedia Commons (public domain).

Stars in the Telescope

The brightest star in Telescopium is Alpha Telescopii at magnitude 3.51. It lies 278 light-years away.

Its second brightest star is just 3 degrees to the south: 4.09 Zeta Telescopii. It lies 127 light-years away.

Then, less than a degree to the southeast of Alpha is the double star Delta 1 and Delta 2 Telescopii. The brighter member, Delta 1, lies 795.5 light-years away and shines at magnitude 4.92. Delta 2, conversely, lies 1,116.9 light-years away and shines at magnitude 5.07. The pair lies less than 10 arcminutes apart.

The stars of Telescopium. Image via IAU/ Sky & Telescope/ Wikipedia (CC BY 3.0).

The black hole that wasn’t

In 2020, the European Southern Observatory announced the discovery of the closest black hole to Earth, 1,000 light-years away, in a corner of Telescopium. However, a study released in 2022 found it was simply a binary star system and did not contain a black hole.

Bottom line: Telescopium the Telescope is a constellation that appears best in southern skies.

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To see the constellation Telescopium from the Northern Hemisphere, being farther south is better. Look right after sunset and enjoy it for a few hours before it disappears in the horizon. From the Southern Hemisphere, this constellation is high in the sky all night. This chart shows the view from Houston, Texas, or around 30 degrees north latitude. Chart via EarthSky.

If you live toward the south in the Northern Hemisphere, you have a window in late summer and early fall (winter and spring in the Southern Hemisphere) when you can spot the diminutive constellation of Telescopium. Location alone is not enough, however. You’ll also want dark skies. Even the brightest star in Telescopium is rather dim: magnitude 3.51 Alpha Telescopii. Perhaps Telescopium is a fitting name, because to view anything in this constellation you’ll benefit from a telescope.

Nicolas Louis de Lacaille visited the Southern Hemisphere in the 18th century. He gave names to 14 new constellations. He named Telescopium in honor of the scientific instrument he used.

How to find Telescopium

Technically, most locations in the United States and others around 40 degrees North latitude will have the main stars in the constellation rise above their horizon. But, when you consider buildings along the southern horizon, light pollution and the dim stars of the constellation, your best bet is to be further south.

With this in mind, look right after sunset and find the Telescope by first finding brighter constellations above it. The Teapot of Sagittarius and the curving tail of Scorpius the Scorpion are the perfect places to start. If, however, the Scorpion is dragging its tail along the horizon from your point of view, you’re out of luck.

Also, if you look below the half of the Teapot that is closest to Scorpius, past the arcing curve of Corona Australis, you may spot two rather dim stars. One is on top of the other. These two stars are all that make up the shape of Telescopium the Telescope.

Telescopium lies close to Corona Australis and Sagittarius the Archer. Image via Wikimedia Commons (public domain).

Stars in the Telescope

The brightest star in Telescopium is Alpha Telescopii at magnitude 3.51. It lies 278 light-years away.

Its second brightest star is just 3 degrees to the south: 4.09 Zeta Telescopii. It lies 127 light-years away.

Then, less than a degree to the southeast of Alpha is the double star Delta 1 and Delta 2 Telescopii. The brighter member, Delta 1, lies 795.5 light-years away and shines at magnitude 4.92. Delta 2, conversely, lies 1,116.9 light-years away and shines at magnitude 5.07. The pair lies less than 10 arcminutes apart.

The stars of Telescopium. Image via IAU/ Sky & Telescope/ Wikipedia (CC BY 3.0).

The black hole that wasn’t

In 2020, the European Southern Observatory announced the discovery of the closest black hole to Earth, 1,000 light-years away, in a corner of Telescopium. However, a study released in 2022 found it was simply a binary star system and did not contain a black hole.

Bottom line: Telescopium the Telescope is a constellation that appears best in southern skies.

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Huge rift valleys on Venus hint at a still-living planet

View larger/full image. | Some of the huge rift valleys on Venus as seen by NASA’s Magellan spacecraft. NASA released this radar image on June 4, 1998. It is color-coded to show different elevations. Image via NASA/ JPL/ USGS/ ETH Zurich.

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• Is Venus dead geologically? Or is it still active? New evidence from ETH Zurich suggests that Venus is still active.
• Recent analysis of huge rift valleys show that they formed more recently than previously thought.
• This means that they could still be active today. This is in addition to other evidence for currently active volcanoes on Venus.

Is Venus dead?

Scientists once thought Venus was geologically dead. But growing evidence of active volcanoes suggests the planet might still be rumbling beneath its thick haze and clouds. On July 24, 2026, researchers at ETH Zurich in Switzerland said the planet’s huge rift valleys might have been active more recently than thought … and perhaps still are active.

Rift valleys are low areas that form when Earth’s tectonic plates pull apart. This creates a sunken floor called a graben with steep walls on the sides. One example on Earth is the East African Rift.

The researchers published their peer-reviewed findings in Nature Geoscience on July 24, 2026.

Article: Rifts on Venus are still, or were recently, active and may have undergone faster extension than usually assumed, potentially because of mantle plume activityhttps://t.co/gSkCUQ2RLB

— Nature Geoscience (@NatureGeosci) July 24, 2026

The Devana Chasma rift valley on Venus, as seen by the Magellan spacecraft. The Theia Mons volcano is at the lower left. Image via JPL/ NASA/ Wikimedia Commons (Public Domain).

New 3D models of rift valleys on Venus

Xi Yang, the paper’s lead author, conducted the research as part of his master’s studies under Taras Gerya, professor of geodynamics at ETH Zurich.

The research team created a new computer model to simulate rift valleys on Venus. The high-resolution 3D simulations are the first of their kind. They can simulate known rift valleys on Venus in great detail. Earlier models were simpler and were mostly 2D.

The simulations revealed broad ridges called rift flanks. They form along the edges of rift valleys. This happens when the rift valleys are still relatively young geologically and are still moving or have stopped moving only recently. The analysis also suggests that the rifts widen faster than scientists previously thought, at a rate of about 3–10 centimeters (1–4 inches) per year.

The results are further evidence that Venus is still tectonically active beneath the surface. The study did not directly measure the valleys moving. Instead, the researchers inferred recent activity from their shapes. Gerya said:

The results help us to better assess the tectonic activity on Venus.

The study found that the rift flanks eventually flatten after movement ends. The older the rift system, the flatter and narrower its flanks become. Crustal relaxation causes the flanks to subside. On Earth, though, erosion is usually responsible.

View larger. | Artist’s illustration of Quetzalpetlatl Corona, one of hundreds of coronae – large tectonic and volcanic feature – on Venus. They are thought to be locations where plumes of hot, buoyant material from the planet’s mantle rise to the surface. Image via NASA/ JPL-Caltech/ Peter Rubin.

Taras Gerya at ETH Zurich in Switzerland led the new study about rift valleys on Venus. Image via ETH Zurich.

Active volcanoes and lava tubes on Venus

There has also been growing evidence in recent years that Venus’ volcanoes are still active. Much of this evidence has come from re-analysis of old data from NASA’s Magellan mission.

In addition, scientists have found evidence for lava tubes on Venus. One lava tube announced earlier this year is wider and taller than any on Earth.

Scientists will now be able to use the data from the study to pinpoint the likely most active regions on Venus. And future missions, such as the European Space Agency’s EnVision (2031), NASA’s VERITAS (2031) and DAVINCI (early 2030s), ISRO’s Venus Orbiter Mission (2028) and Rocket Lab/MIT’s Venus Life Finder (TBD), could then focus on these areas.

Taken together, these discoveries show that Venus has been a geologically very active planet, and still is. What else will we learn from future missions?

Bottom line: A new study of huge rift valleys on Venus shows that they are likely younger than previously thought and might still be geologically active today.

Source: Recent active rifting on Venus revealed by wide rift flank uplifts

Via ETH Zurich

Read more:

Active tectonics on Venus? Old data reveal new clues

Have Venus volcanoes been caught in the act?

New evidence of lava tube on Venus found in old radar data

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View larger/full image. | Some of the huge rift valleys on Venus as seen by NASA’s Magellan spacecraft. NASA released this radar image on June 4, 1998. It is color-coded to show different elevations. Image via NASA/ JPL/ USGS/ ETH Zurich.

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• Is Venus dead geologically? Or is it still active? New evidence from ETH Zurich suggests that Venus is still active.
• Recent analysis of huge rift valleys show that they formed more recently than previously thought.
• This means that they could still be active today. This is in addition to other evidence for currently active volcanoes on Venus.

Is Venus dead?

Scientists once thought Venus was geologically dead. But growing evidence of active volcanoes suggests the planet might still be rumbling beneath its thick haze and clouds. On July 24, 2026, researchers at ETH Zurich in Switzerland said the planet’s huge rift valleys might have been active more recently than thought … and perhaps still are active.

Rift valleys are low areas that form when Earth’s tectonic plates pull apart. This creates a sunken floor called a graben with steep walls on the sides. One example on Earth is the East African Rift.

The researchers published their peer-reviewed findings in Nature Geoscience on July 24, 2026.

Article: Rifts on Venus are still, or were recently, active and may have undergone faster extension than usually assumed, potentially because of mantle plume activityhttps://t.co/gSkCUQ2RLB

— Nature Geoscience (@NatureGeosci) July 24, 2026

The Devana Chasma rift valley on Venus, as seen by the Magellan spacecraft. The Theia Mons volcano is at the lower left. Image via JPL/ NASA/ Wikimedia Commons (Public Domain).

New 3D models of rift valleys on Venus

Xi Yang, the paper’s lead author, conducted the research as part of his master’s studies under Taras Gerya, professor of geodynamics at ETH Zurich.

The research team created a new computer model to simulate rift valleys on Venus. The high-resolution 3D simulations are the first of their kind. They can simulate known rift valleys on Venus in great detail. Earlier models were simpler and were mostly 2D.

The simulations revealed broad ridges called rift flanks. They form along the edges of rift valleys. This happens when the rift valleys are still relatively young geologically and are still moving or have stopped moving only recently. The analysis also suggests that the rifts widen faster than scientists previously thought, at a rate of about 3–10 centimeters (1–4 inches) per year.

The results are further evidence that Venus is still tectonically active beneath the surface. The study did not directly measure the valleys moving. Instead, the researchers inferred recent activity from their shapes. Gerya said:

The results help us to better assess the tectonic activity on Venus.

The study found that the rift flanks eventually flatten after movement ends. The older the rift system, the flatter and narrower its flanks become. Crustal relaxation causes the flanks to subside. On Earth, though, erosion is usually responsible.

View larger. | Artist’s illustration of Quetzalpetlatl Corona, one of hundreds of coronae – large tectonic and volcanic feature – on Venus. They are thought to be locations where plumes of hot, buoyant material from the planet’s mantle rise to the surface. Image via NASA/ JPL-Caltech/ Peter Rubin.

Taras Gerya at ETH Zurich in Switzerland led the new study about rift valleys on Venus. Image via ETH Zurich.

Active volcanoes and lava tubes on Venus

There has also been growing evidence in recent years that Venus’ volcanoes are still active. Much of this evidence has come from re-analysis of old data from NASA’s Magellan mission.

In addition, scientists have found evidence for lava tubes on Venus. One lava tube announced earlier this year is wider and taller than any on Earth.

Scientists will now be able to use the data from the study to pinpoint the likely most active regions on Venus. And future missions, such as the European Space Agency’s EnVision (2031), NASA’s VERITAS (2031) and DAVINCI (early 2030s), ISRO’s Venus Orbiter Mission (2028) and Rocket Lab/MIT’s Venus Life Finder (TBD), could then focus on these areas.

Taken together, these discoveries show that Venus has been a geologically very active planet, and still is. What else will we learn from future missions?

Bottom line: A new study of huge rift valleys on Venus shows that they are likely younger than previously thought and might still be geologically active today.

Source: Recent active rifting on Venus revealed by wide rift flank uplifts

Via ETH Zurich

Read more:

Active tectonics on Venus? Old data reveal new clues

Have Venus volcanoes been caught in the act?

New evidence of lava tube on Venus found in old radar data

The post Huge rift valleys on Venus hint at a still-living planet first appeared on EarthSky.

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The Wild Duck cluster, M11, a lovely open cluster in Scutum

This is the open star cluster M11, imaged by the European Southern Observatory’s 2.2-meter telescope at the La Silla Observatory in Chile. Image via ESO. Used with permission.

The Wild Duck cluster, also known as Messier 11 or M11, is a distant open star cluster. That is, a loosely bound collection of stars that were born from the same gas cloud.

The Wild Duck cluster lies in the direction of the constellation Scutum the Shield. Its distance of 6,120 light-years means it’s quite faint. So, you’ll need binoculars or a telescope to see it. Here’s how.

How to find the Wild Duck cluster

To find M11, first locate the bright star Altair in the sky. It is the brightest star in the constellation Aquila the Eagle, and the second brightest star in the Summer Triangle. Altair is flanked on each side by the two moderately bright stars Tarazed and Alshain.

A star map showing Aquila and Scutum. Altair is a bright star, easily identifiable in the sky because it’s part of the Summer Triangle. Image via Roberto Mura/ Wikimedia Commons.

From Altair, following the chart below, you can star-hop toward the Wild Duck cluster. Delta Aquilae is your first hop, about 8 degrees from Altair. (For reference, the width of four fingers held at arm’s length is about 8 degrees in the sky.)

Then, using binoculars, keep going downward a bit more than twice the Altair-Delta Aquilae distance, until you see a semicircle of stars that pretty much fills your binocular field. The Wild Duck cluster pops out as a hazy star-like object just beneath this semicircle star pattern.

Aquila the Eagle is home to the star Altair, which is one of the corners of the Summer Triangle. In addition, you can also use Aquila to starhop your way to the Wild Duck cluster in Scutum. Image via EarthSky.

When to look

Tthe Wild Duck cluster appears best when it’s relatively high in the southern sky. In the Northern Hemisphere, that’s in the wee hours before sunrise in spring, late night in early summer, and mid-evening in late summer and early fall.

View at EarthSky Community Photos. | David Hoskin in Halifax, Nova Scotia, Canada, captured this telescopic view of open cluster Messier 11 on July 25, 2022. He wrote: “The Wild Duck cluster (Messier 11) is an open star cluster located in the constellation Scutum. Its name comes from the cluster’s rough V-shape. The Wild Duck cluster is densely populated, containing over 2,900 stars. It is 6,200 light-years from Earth.” Thank you, David!

The science of M11

M11 is an open star cluster like the Pleiades and the Hyades, but it’s much farther away. The Pleiades cluster lies 444 light-years away and the Hyades cluster is just 153 light-years away. Compare those to the Wild Duck cluster, which sits about 6,120 light-years away.

Basically, an open star cluster is a group of stars that formed from the same giant cloud of mostly molecular hydrogen. These gas and dust clouds are nebulae that contain stellar nurseries. Initially, the young stars are loosely bound together by gravity, and they eventually disperse over time.

With about 3,000 stars, M11 is one of the most massive open star clusters known. The hottest, bluest stars congregate at the center. Scientists think the cluster formed between 250 to 316 million years ago. Astronomers refer to it as a metal-rich cluster because a nearby supernova likely seeded its molecular cloud with heavier elements, or more metallic elements in the language of astronomers.

The history of the Wild Duck cluster

In 1733, English naturalist William Derham was able to resolve the Wild Duck cluster as individual stars through a telescope. Not long after, in 1764, French astronomer Charles Messier added it to his famous catalog. Originally, M11 got its unusual name of the Wild Duck cluster from Admiral William Henry Smyth. While observing the cluster through a telescope in 1835, Smyth noted a V-shaped pattern of its brightest stars that reminded him of the flight formation of wild ducks.

The Wild Duck cluster is positioned at RA: 18h 51m 5s; Dec: -6° 16′ 12″.

View larger. | The Hubble Space Telescope’s Wide Field Camera 3 took this image of a section of the Wild Duck cluster. Image via P. Dobbie et al./ NASA/ ESA Hubble. Used with permission.

Bottom line: The Wild Duck cluster, also known as M11, is an open star cluster in the constellation Scutum that appears best through binoculars or a telescope.

The post The Wild Duck cluster, M11, a lovely open cluster in Scutum first appeared on EarthSky.

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This is the open star cluster M11, imaged by the European Southern Observatory’s 2.2-meter telescope at the La Silla Observatory in Chile. Image via ESO. Used with permission.

The Wild Duck cluster, also known as Messier 11 or M11, is a distant open star cluster. That is, a loosely bound collection of stars that were born from the same gas cloud.

The Wild Duck cluster lies in the direction of the constellation Scutum the Shield. Its distance of 6,120 light-years means it’s quite faint. So, you’ll need binoculars or a telescope to see it. Here’s how.

How to find the Wild Duck cluster

To find M11, first locate the bright star Altair in the sky. It is the brightest star in the constellation Aquila the Eagle, and the second brightest star in the Summer Triangle. Altair is flanked on each side by the two moderately bright stars Tarazed and Alshain.

A star map showing Aquila and Scutum. Altair is a bright star, easily identifiable in the sky because it’s part of the Summer Triangle. Image via Roberto Mura/ Wikimedia Commons.

From Altair, following the chart below, you can star-hop toward the Wild Duck cluster. Delta Aquilae is your first hop, about 8 degrees from Altair. (For reference, the width of four fingers held at arm’s length is about 8 degrees in the sky.)

Then, using binoculars, keep going downward a bit more than twice the Altair-Delta Aquilae distance, until you see a semicircle of stars that pretty much fills your binocular field. The Wild Duck cluster pops out as a hazy star-like object just beneath this semicircle star pattern.

Aquila the Eagle is home to the star Altair, which is one of the corners of the Summer Triangle. In addition, you can also use Aquila to starhop your way to the Wild Duck cluster in Scutum. Image via EarthSky.

When to look

Tthe Wild Duck cluster appears best when it’s relatively high in the southern sky. In the Northern Hemisphere, that’s in the wee hours before sunrise in spring, late night in early summer, and mid-evening in late summer and early fall.

View at EarthSky Community Photos. | David Hoskin in Halifax, Nova Scotia, Canada, captured this telescopic view of open cluster Messier 11 on July 25, 2022. He wrote: “The Wild Duck cluster (Messier 11) is an open star cluster located in the constellation Scutum. Its name comes from the cluster’s rough V-shape. The Wild Duck cluster is densely populated, containing over 2,900 stars. It is 6,200 light-years from Earth.” Thank you, David!

The science of M11

M11 is an open star cluster like the Pleiades and the Hyades, but it’s much farther away. The Pleiades cluster lies 444 light-years away and the Hyades cluster is just 153 light-years away. Compare those to the Wild Duck cluster, which sits about 6,120 light-years away.

Basically, an open star cluster is a group of stars that formed from the same giant cloud of mostly molecular hydrogen. These gas and dust clouds are nebulae that contain stellar nurseries. Initially, the young stars are loosely bound together by gravity, and they eventually disperse over time.

With about 3,000 stars, M11 is one of the most massive open star clusters known. The hottest, bluest stars congregate at the center. Scientists think the cluster formed between 250 to 316 million years ago. Astronomers refer to it as a metal-rich cluster because a nearby supernova likely seeded its molecular cloud with heavier elements, or more metallic elements in the language of astronomers.

The history of the Wild Duck cluster

In 1733, English naturalist William Derham was able to resolve the Wild Duck cluster as individual stars through a telescope. Not long after, in 1764, French astronomer Charles Messier added it to his famous catalog. Originally, M11 got its unusual name of the Wild Duck cluster from Admiral William Henry Smyth. While observing the cluster through a telescope in 1835, Smyth noted a V-shaped pattern of its brightest stars that reminded him of the flight formation of wild ducks.

The Wild Duck cluster is positioned at RA: 18h 51m 5s; Dec: -6° 16′ 12″.

View larger. | The Hubble Space Telescope’s Wide Field Camera 3 took this image of a section of the Wild Duck cluster. Image via P. Dobbie et al./ NASA/ ESA Hubble. Used with permission.

Bottom line: The Wild Duck cluster, also known as M11, is an open star cluster in the constellation Scutum that appears best through binoculars or a telescope.

The post The Wild Duck cluster, M11, a lovely open cluster in Scutum first appeared on EarthSky.

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Fastest star in the galaxy could unlock black hole secrets

This video shows the fastest star in the galaxy, S301, as it orbits the supermassive black hole at the center of the Milky Way galaxy. When closest to the black hole (named Sagittarius A*), the star moves at more than 8% the speed of light. Astronomers are hoping to see the influence of the warped space-time around the black hole on the star’s orbit. This would reveal, for the 1st time, the spin of the black hole. Video via ESO.

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Fastest star in the galaxy could unlock black hole secrets

Astronomers have discovered the fastest star in the Milky Way galaxy. They call it S301, and it moves at more than 8% the speed of light, or 56 million miles per hour (25,000 km/s), as it orbits the central supermassive black hole in our galaxy.

But the real triumph in discovering this star, the European Southern Observatory said on August 19, 2026, is that it can unlock the mystery of our central black hole’s spin.

S301 is the closest star to the Milky Way’s black hole that astronomers have yet discovered. It lies just 12 Earth-sun distances (12 AU) from the mammoth gravity well. Co-author Reinhard Genzel of the Max Planck Institute for Extraterrestrial Physics in Germany said:

Decades carefully tracking stars orbiting our galaxy’s central black hole, Sagittarius A*, have led to this breakthrough discovery of a very promising star. Because it orbits so close to Sagittarius A*, S301 opens a new window to the fundamental properties of spacetime in this extreme black-hole environment.

The researchers published their peer-reviewed study on August 19, 2026, in the journal Nature.

Speeding through a warped space-time environment

S301 has an elliptical (oval-shaped) orbit, so it’s not always 12 AU from our supermassive black hole, Sagittarius A*. That is the closest it gets in its orbit. But the orbit is speedy, whipping around the black hole once every 8.7 years.

Astronomers have already found data from the Very Large Telescope Interferometer to reveal one orbit of the swift star around the black hole. They hope to get even better data for a second orbit once the Extremely Large Telescope comes online around 2030.

S301 gets so close to Sagittarius A* in its orbit that astronomers think it could be affected by the rotating black hole. This rotation is something astronomers have been itching to measure.

According to Einstein’s theory of general relativity, a massive object such as Sagittarius A* will warp the space-time around it. So, astronomers are hoping that when S301 is at its closest to the supermassive black hole, they’ll be able to detect the warp of space-time in the speedy star’s orbit. That would help them measure the spin of the black hole for the first time. Co-author Felix Mang of MPE said:

With this star we hope to measure, within the next 10 years, the spin of the black hole. That would be a dream come true.

These are images from the GRAVITY instrument at ESO’s Very Large Telescope Interferometer (VLTI). The bright dot near bottom left is the supermassive black hole at the center of our galaxy, Sagittarius A*. The other dots are stars circling the black hole. The solid line is the path S301 has already completed. And the dimmer, dashed line marks the path it will follow next. Image via ESO/ Gravity Collaboration.

How did the star get so close?

S301 is the closest star we know of to the Milky Way’s central black hole. Mang said:

What is special about this star is that it’s orbiting Sagittarius A* on a very tight orbit, taking just 8.7 years to complete it, and is approaching the black hole at a mere 12 times the distance of Earth to the sun. That is unprecedented.

So how did this star get so unprecedentedly close to the black hole? It couldn’t have formed there, because the gravitational tugs from the black hole wouldn’t have allowed any clouds of gas and dust to coalesce into stars. Therefore, astronomers think the star migrated there. They say it was likely after this star and its binary pair felt the tidal yank of the supermassive black hole. One got flung away from the black hole, while the other was pulled toward it.

That’s fortunate for us, because now – thanks to a speedy star with a short orbit – astronomers can continue to unlock the mysteries of Sagittarius A* and help bolster Einstein’s general theory of relativity. Co-author Juan Osorno of LIRA Observatoire de Paris–PSL, France, said:

For the first time, we would actually be able to measure very directly the spin of a massive black hole, which would be a key test of Einstein’s theory. Without this star, we would need to measure the motion of other stars for several more decades to get anywhere close to measuring the spin of the black hole.

Watch the black hole pull in the fastest star

This animation shows how the fastest known star – S301 – likely came to orbit the supermassive black hole so closely. Initially, the 2 stars orbit each other. But as they near the black hole, the tidal forces pull S301 in, while yeeting the other star into a new neighborhood. Video via ESO/ L. Calçada, M. Kornmesser.

Bottom line: Astronomers have discovered the fastest star in the galaxy. It’s orbiting the supermassive black hole at the center of our galaxy, and it could reveal the black hole’s spin.

Source: Discovery of a star sensitive to the spin of Sagittarius A*

Via ESO

Read more: Astronomers discover a black hole star, a new type of object

Read more: A first! 3 supermassive black holes discovered in 1 galaxy

The post Fastest star in the galaxy could unlock black hole secrets first appeared on EarthSky.

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This video shows the fastest star in the galaxy, S301, as it orbits the supermassive black hole at the center of the Milky Way galaxy. When closest to the black hole (named Sagittarius A*), the star moves at more than 8% the speed of light. Astronomers are hoping to see the influence of the warped space-time around the black hole on the star’s orbit. This would reveal, for the 1st time, the spin of the black hole. Video via ESO.

You deserve a daily dose of good news. For the latest in science and the night sky, click here to subscribe to our free daily newsletter.

Fastest star in the galaxy could unlock black hole secrets

Astronomers have discovered the fastest star in the Milky Way galaxy. They call it S301, and it moves at more than 8% the speed of light, or 56 million miles per hour (25,000 km/s), as it orbits the central supermassive black hole in our galaxy.

But the real triumph in discovering this star, the European Southern Observatory said on August 19, 2026, is that it can unlock the mystery of our central black hole’s spin.

S301 is the closest star to the Milky Way’s black hole that astronomers have yet discovered. It lies just 12 Earth-sun distances (12 AU) from the mammoth gravity well. Co-author Reinhard Genzel of the Max Planck Institute for Extraterrestrial Physics in Germany said:

Decades carefully tracking stars orbiting our galaxy’s central black hole, Sagittarius A*, have led to this breakthrough discovery of a very promising star. Because it orbits so close to Sagittarius A*, S301 opens a new window to the fundamental properties of spacetime in this extreme black-hole environment.

The researchers published their peer-reviewed study on August 19, 2026, in the journal Nature.

Speeding through a warped space-time environment

S301 has an elliptical (oval-shaped) orbit, so it’s not always 12 AU from our supermassive black hole, Sagittarius A*. That is the closest it gets in its orbit. But the orbit is speedy, whipping around the black hole once every 8.7 years.

Astronomers have already found data from the Very Large Telescope Interferometer to reveal one orbit of the swift star around the black hole. They hope to get even better data for a second orbit once the Extremely Large Telescope comes online around 2030.

S301 gets so close to Sagittarius A* in its orbit that astronomers think it could be affected by the rotating black hole. This rotation is something astronomers have been itching to measure.

According to Einstein’s theory of general relativity, a massive object such as Sagittarius A* will warp the space-time around it. So, astronomers are hoping that when S301 is at its closest to the supermassive black hole, they’ll be able to detect the warp of space-time in the speedy star’s orbit. That would help them measure the spin of the black hole for the first time. Co-author Felix Mang of MPE said:

With this star we hope to measure, within the next 10 years, the spin of the black hole. That would be a dream come true.

These are images from the GRAVITY instrument at ESO’s Very Large Telescope Interferometer (VLTI). The bright dot near bottom left is the supermassive black hole at the center of our galaxy, Sagittarius A*. The other dots are stars circling the black hole. The solid line is the path S301 has already completed. And the dimmer, dashed line marks the path it will follow next. Image via ESO/ Gravity Collaboration.

How did the star get so close?

S301 is the closest star we know of to the Milky Way’s central black hole. Mang said:

What is special about this star is that it’s orbiting Sagittarius A* on a very tight orbit, taking just 8.7 years to complete it, and is approaching the black hole at a mere 12 times the distance of Earth to the sun. That is unprecedented.

So how did this star get so unprecedentedly close to the black hole? It couldn’t have formed there, because the gravitational tugs from the black hole wouldn’t have allowed any clouds of gas and dust to coalesce into stars. Therefore, astronomers think the star migrated there. They say it was likely after this star and its binary pair felt the tidal yank of the supermassive black hole. One got flung away from the black hole, while the other was pulled toward it.

That’s fortunate for us, because now – thanks to a speedy star with a short orbit – astronomers can continue to unlock the mysteries of Sagittarius A* and help bolster Einstein’s general theory of relativity. Co-author Juan Osorno of LIRA Observatoire de Paris–PSL, France, said:

For the first time, we would actually be able to measure very directly the spin of a massive black hole, which would be a key test of Einstein’s theory. Without this star, we would need to measure the motion of other stars for several more decades to get anywhere close to measuring the spin of the black hole.

Watch the black hole pull in the fastest star

This animation shows how the fastest known star – S301 – likely came to orbit the supermassive black hole so closely. Initially, the 2 stars orbit each other. But as they near the black hole, the tidal forces pull S301 in, while yeeting the other star into a new neighborhood. Video via ESO/ L. Calçada, M. Kornmesser.

Bottom line: Astronomers have discovered the fastest star in the galaxy. It’s orbiting the supermassive black hole at the center of our galaxy, and it could reveal the black hole’s spin.

Source: Discovery of a star sensitive to the spin of Sagittarius A*

Via ESO

Read more: Astronomers discover a black hole star, a new type of object

Read more: A first! 3 supermassive black holes discovered in 1 galaxy

The post Fastest star in the galaxy could unlock black hole secrets first appeared on EarthSky.

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The Winter Circle: Catch in the morning before dawn

Although it’s summer in the Northern Hemisphere, a clear sign of winter now looms large in the morning sky. Look for the Winter Circle before dawn in the sunrise direction. Chart via EarthSky.

Summer will soon be ending for us in the Northern Hemisphere. Although it’s still hot outside across much of northern Earth, our days are rapidly shortening now and our nights are getting longer. Meanwhile, a classic sign of winter looms large now in the predawn sky, as it does every year at this time.

The Winter Circle – also called the Winter Hexagon – is not a constellation. Instead, it’s an asterism, or recognizable pattern of stars. It consists of six stars in six different constellations. They are all associated with the winter sky for those in the Northern Hemisphere (summer sky for the Southern Hemisphere).

Winter Circle’s 6 (or 7) bright stars

Beloved constellation Orion the Hunter is in the southwest portion of the Winter Circle (lower right on our chart above). If you’ve never seen the Winter Circle but are acquainted with Orion, this constellation presents a great jumping off place for identifying these stars. And it presents a great size comparison too. Orion is big, but the Winter Circle is much bigger!

So look at our chart above and notice the star Rigel in Orion. Then start moving around the Circle clockwise. You’ll encounter Sirius in the constellation Canis Major the Greater Dog, Procyon in the constellation Canis Minor the Smaller Dog, Pollux (and Castor) in the constellation Gemini the Twins, Capella in the constellation Auriga the charioteer and Aldebaran in the constellation Taurus the Bull. Nearly all of the Winter Circle stars are 1st-magnitude stars. And that means they’re bright and easy to see.

The exception is the star Castor in Gemini. It’s not a 1st-magnitude star and not as bright as the other stars in the Winter Circle. But it’s pretty bright! In fact, it’s the sky’s brightest 2nd-magnitude star. If you include Castor as a Winter Circle star, then there are seven stars in the Circle.

When to see the Winter Circle

We don’t see the Winter Circle in June and July because it’s lost in the glare of the sun. However, in late August, the Winter Circle returns to the morning sky. And months from now, when we’re into the Northern Hemisphere’s winter, we’ll see the Winter Circle in the evening sky.

View at EarthSky Community Photos. | Amit Raka| submitted this image on January 25, 2025, and wrote: “We gazed upon a breathtaking celestial wonder: the Winter Circle, also known as the Winter Hexagon. This image showcases the brilliance of 6 of the brightest stars forming a giant hexagonal asterism in the winter night sky. The view was truly mesmerizing, leaving all in awe as they admired the countless stars and even spotted planets twinkling amidst the vast cosmic expanse.” Thank you, Amit!

View at EarthSky Community Photos. | Jose Zarcos Palma in Mina São Domingo, Mertola, Portugal, took this image of the winter hexagon on December 26, 2022. Jose wrote: “I planned this composition to catch the great Winter Circle in an early stage of its ascension. We can clearly see Sirius in Canis Major the Greater Dog near the chimney on the right side. It’s just below Orion the Hunter. On top of the image, the planet Mars is near Aldebaran in Taurus the Bull.” Thank you, Jose!

Bottom line: The Winter Circle – or Winter Hexagon – is back in the morning sky. Check it out before dawn. It’s made up of some of our brightest stars from several constellations.

Don’t miss the next unmissable night sky event. Sign up to our free newsletter for daily night sky updates, as well as the latest science news.

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Although it’s summer in the Northern Hemisphere, a clear sign of winter now looms large in the morning sky. Look for the Winter Circle before dawn in the sunrise direction. Chart via EarthSky.

Summer will soon be ending for us in the Northern Hemisphere. Although it’s still hot outside across much of northern Earth, our days are rapidly shortening now and our nights are getting longer. Meanwhile, a classic sign of winter looms large now in the predawn sky, as it does every year at this time.

The Winter Circle – also called the Winter Hexagon – is not a constellation. Instead, it’s an asterism, or recognizable pattern of stars. It consists of six stars in six different constellations. They are all associated with the winter sky for those in the Northern Hemisphere (summer sky for the Southern Hemisphere).

Winter Circle’s 6 (or 7) bright stars

Beloved constellation Orion the Hunter is in the southwest portion of the Winter Circle (lower right on our chart above). If you’ve never seen the Winter Circle but are acquainted with Orion, this constellation presents a great jumping off place for identifying these stars. And it presents a great size comparison too. Orion is big, but the Winter Circle is much bigger!

So look at our chart above and notice the star Rigel in Orion. Then start moving around the Circle clockwise. You’ll encounter Sirius in the constellation Canis Major the Greater Dog, Procyon in the constellation Canis Minor the Smaller Dog, Pollux (and Castor) in the constellation Gemini the Twins, Capella in the constellation Auriga the charioteer and Aldebaran in the constellation Taurus the Bull. Nearly all of the Winter Circle stars are 1st-magnitude stars. And that means they’re bright and easy to see.

The exception is the star Castor in Gemini. It’s not a 1st-magnitude star and not as bright as the other stars in the Winter Circle. But it’s pretty bright! In fact, it’s the sky’s brightest 2nd-magnitude star. If you include Castor as a Winter Circle star, then there are seven stars in the Circle.

When to see the Winter Circle

We don’t see the Winter Circle in June and July because it’s lost in the glare of the sun. However, in late August, the Winter Circle returns to the morning sky. And months from now, when we’re into the Northern Hemisphere’s winter, we’ll see the Winter Circle in the evening sky.

View at EarthSky Community Photos. | Amit Raka| submitted this image on January 25, 2025, and wrote: “We gazed upon a breathtaking celestial wonder: the Winter Circle, also known as the Winter Hexagon. This image showcases the brilliance of 6 of the brightest stars forming a giant hexagonal asterism in the winter night sky. The view was truly mesmerizing, leaving all in awe as they admired the countless stars and even spotted planets twinkling amidst the vast cosmic expanse.” Thank you, Amit!

View at EarthSky Community Photos. | Jose Zarcos Palma in Mina São Domingo, Mertola, Portugal, took this image of the winter hexagon on December 26, 2022. Jose wrote: “I planned this composition to catch the great Winter Circle in an early stage of its ascension. We can clearly see Sirius in Canis Major the Greater Dog near the chimney on the right side. It’s just below Orion the Hunter. On top of the image, the planet Mars is near Aldebaran in Taurus the Bull.” Thank you, Jose!

Bottom line: The Winter Circle – or Winter Hexagon – is back in the morning sky. Check it out before dawn. It’s made up of some of our brightest stars from several constellations.

Don’t miss the next unmissable night sky event. Sign up to our free newsletter for daily night sky updates, as well as the latest science news.

The post The Winter Circle: Catch in the morning before dawn first appeared on EarthSky.

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