Blue-white Rigel is Orion’s brightest star

The constellation Orion the Hunter, showing Rigel at the bottom right.

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Rigel is one of several brilliant stars that grace our night sky this time of the year. It’s also the brightest star in one of the most beloved of constellations, Orion the Hunter. Rigel appears blue-white to the eye. It’s a stunning contrast to red Betelgeuse, Orion’s second-brightest star. Classified as a blue supergiant, Rigel is in the latter stages of its stellar lifetime and will someday explode as a supernova. Hidden in Rigel’s brilliance are at least three other fainter companion stars that can only be detected using large telescopes.

How to find Rigel

At magnitude 0.13, Rigel is the 7th-brightest star in the night sky. It appears at a lower corner (or upper corner as seen from the Southern Hemisphere) of Orion the Hunter, one of the sky’s best-known constellations. It’s easy to spot because of its brightness and because of its distinctive blue-white color.

You can catch Orion in the east before dawn during the late Northern Hemisphere summer. It’ll emerge in the evening sky during the Northern Hemisphere’s late autumn. Then Orion shines prominently in the sky on northern winter (southern summer) evenings. By early March, as soon as the sun sets, Orion is at its highest in the sky. By early May, as seen from around the globe, Orion sets before the sky has a chance to get really dark.

Look for Orion

To find Rigel, first look for its constellation, Orion. You’ll notice three stars in a short, straight line. These stars mark Orion’s Belt. An imaginary line in the sky, heading generally southward – that’s at a right or 90-degree angle from Orion’s Belt – takes you to Rigel. (If you instead draw in the other direction, you’d come to Betelgeuse, with its distinctive reddish tinge.)

Do not confuse Rigel with Sirius, which is farther to the east and farther south. Sirius is similar in appearance, but significantly brighter than Rigel.

View at EarthSky Community Photos. | Here’s a closer look at the constellation Orion. Rigel appears as the bright star on the right with reddish Betelgeuse opposite it on the far left. Amr Elsayed in Fayoum, Egypt, captured this image of the night sky on December 6, 2024. Thanks, Amr!

A map of Orion the Hunter, showing the location of Rigel. Image via IAU/ Sky & Telescope magazine/ Wikimedia Commons.

The science of Rigel

We couldn’t live as close to Rigel as we do to our sun. That’s because its surface temperature is much hotter, about 21,000 degrees Fahrenheit (11,600 degrees Celsius) in contrast to about 10,000 F (5,500 C) for the sun.

Counting all its radiation (not just visible light, but infrared, ultraviolet and so on), it emits about 120,000 times more energy than the sun. Astronomers calculate this luminosity based on a distance of 860 light-years, a distance derived from data collected by the Hipparcos space telescope. With such enormous energy, you might not be surprised to find that Rigel has only 21 times more mass, and is more than 70 times the diameter of our sun.

The blue-white star Rigel in the constellation Orion the Hunter. Image via Fred Espenak/ astropixels.com. Used with permission.

Rigel is a blue supergiant star, designated as type B8Ia. According to stellar evolution theory, it is a massive star entering the latter part of its life, having exhausted most of the hydrogen fuel in its core. It’s also a variable star that shows slight irregular fluctuations in brightness. Someday, it will explode as a supernova.

Yet Rigel is not one of the galaxy’s largest stars, as the video below – from the European Southern Observatory – shows.

A little-known fact about Rigel: it is the largest star in a multiple star system. There is a close companion about 400 times fainter. That “companion” is actually two stars that can only be resolved by large telescopes. And one of those two companion stars is what’s known as a spectroscopic binary: two stars so close they can be distinguished as two distinct entities only via spectroscopic observations.

In other words, the Rigel system has four known stars!

History and mythology

Historically, the brightest star in a constellation receives the designation Alpha, the second-brightest is Beta, and so on. This system isn’t used for Orion’s stars, however. Instead, the red star Betelgeuse is Alpha Orionis, and Rigel is Beta. But Rigel is the brightest star in Orion.

This deviation from standard stellar designations might be because Betelgeuse is a variable star and has been known to at least approach Rigel in brilliance. The German astronomer Johann Bayer applied the designation Beta Orionis to Rigel in the early 1600s. He sought to systematize stellar naming conventions. It’s possible Betelgeuse was brighter around this time. Nowadays, Rigel outshines Betelgeuse.

A depiction of Orion from Mercator‘s celestial globe, from the Harvard Map Collection. Rigel is labeled at its left foot. Gerardus Mercator was a 16th century geographer, cosmographer and cartographer from Rupelmonde, County of Flanders in modern-day Belgium. Image via Gerard Mercator/ Wikimedia Commons.

The name Rigel comes from an Arabic phrase frequently translated as “The left foot of the central one.” Although Orion was depicted as a giant or warrior in many cultures, in the original Arabic it might have been a reference to a black sheep with a white spot or spots. Thus in the original form, Rigel might have designated the left foot of a sheep! Now, however, many people know it as the left foot of Orion the Hunter.

Aurvandill’s big toe

The mythology related to Rigel is sparse and unclear. Perhaps the most interesting connection is in Norse mythology, which sometimes identified Orion with Aurvandill (also Orwandil, Earendel and others). According to some, Aurvandill was traveling with his companion, the god Thor, when his big toe froze in an unfortunate river-crossing incident. Thor broke off the frozen digit and threw it into the sky, where it became the star we see as Rigel. In some variations, Aurvandill’s other big toe became faint Alcor in Ursa Major.

Rigel’s position is RA: 05h 14m 32.3s, Dec: -08° 12′ 05.9”.

Bottom line: Rigel, the brightest star in the constellation Orion the Hunter, shines a brilliant bluish-white color. It’s much hotter and more massive than our sun, and someday, it will explode as a supernova.

The post Blue-white Rigel is Orion’s brightest star first appeared on EarthSky.

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The constellation Orion the Hunter, showing Rigel at the bottom right.

EarthSky’s 2026 lunar calendar is available now. Get yours today! Makes a great gift.

Rigel is one of several brilliant stars that grace our night sky this time of the year. It’s also the brightest star in one of the most beloved of constellations, Orion the Hunter. Rigel appears blue-white to the eye. It’s a stunning contrast to red Betelgeuse, Orion’s second-brightest star. Classified as a blue supergiant, Rigel is in the latter stages of its stellar lifetime and will someday explode as a supernova. Hidden in Rigel’s brilliance are at least three other fainter companion stars that can only be detected using large telescopes.

How to find Rigel

At magnitude 0.13, Rigel is the 7th-brightest star in the night sky. It appears at a lower corner (or upper corner as seen from the Southern Hemisphere) of Orion the Hunter, one of the sky’s best-known constellations. It’s easy to spot because of its brightness and because of its distinctive blue-white color.

You can catch Orion in the east before dawn during the late Northern Hemisphere summer. It’ll emerge in the evening sky during the Northern Hemisphere’s late autumn. Then Orion shines prominently in the sky on northern winter (southern summer) evenings. By early March, as soon as the sun sets, Orion is at its highest in the sky. By early May, as seen from around the globe, Orion sets before the sky has a chance to get really dark.

Look for Orion

To find Rigel, first look for its constellation, Orion. You’ll notice three stars in a short, straight line. These stars mark Orion’s Belt. An imaginary line in the sky, heading generally southward – that’s at a right or 90-degree angle from Orion’s Belt – takes you to Rigel. (If you instead draw in the other direction, you’d come to Betelgeuse, with its distinctive reddish tinge.)

Do not confuse Rigel with Sirius, which is farther to the east and farther south. Sirius is similar in appearance, but significantly brighter than Rigel.

View at EarthSky Community Photos. | Here’s a closer look at the constellation Orion. Rigel appears as the bright star on the right with reddish Betelgeuse opposite it on the far left. Amr Elsayed in Fayoum, Egypt, captured this image of the night sky on December 6, 2024. Thanks, Amr!

A map of Orion the Hunter, showing the location of Rigel. Image via IAU/ Sky & Telescope magazine/ Wikimedia Commons.

The science of Rigel

We couldn’t live as close to Rigel as we do to our sun. That’s because its surface temperature is much hotter, about 21,000 degrees Fahrenheit (11,600 degrees Celsius) in contrast to about 10,000 F (5,500 C) for the sun.

Counting all its radiation (not just visible light, but infrared, ultraviolet and so on), it emits about 120,000 times more energy than the sun. Astronomers calculate this luminosity based on a distance of 860 light-years, a distance derived from data collected by the Hipparcos space telescope. With such enormous energy, you might not be surprised to find that Rigel has only 21 times more mass, and is more than 70 times the diameter of our sun.

The blue-white star Rigel in the constellation Orion the Hunter. Image via Fred Espenak/ astropixels.com. Used with permission.

Rigel is a blue supergiant star, designated as type B8Ia. According to stellar evolution theory, it is a massive star entering the latter part of its life, having exhausted most of the hydrogen fuel in its core. It’s also a variable star that shows slight irregular fluctuations in brightness. Someday, it will explode as a supernova.

Yet Rigel is not one of the galaxy’s largest stars, as the video below – from the European Southern Observatory – shows.

A little-known fact about Rigel: it is the largest star in a multiple star system. There is a close companion about 400 times fainter. That “companion” is actually two stars that can only be resolved by large telescopes. And one of those two companion stars is what’s known as a spectroscopic binary: two stars so close they can be distinguished as two distinct entities only via spectroscopic observations.

In other words, the Rigel system has four known stars!

History and mythology

Historically, the brightest star in a constellation receives the designation Alpha, the second-brightest is Beta, and so on. This system isn’t used for Orion’s stars, however. Instead, the red star Betelgeuse is Alpha Orionis, and Rigel is Beta. But Rigel is the brightest star in Orion.

This deviation from standard stellar designations might be because Betelgeuse is a variable star and has been known to at least approach Rigel in brilliance. The German astronomer Johann Bayer applied the designation Beta Orionis to Rigel in the early 1600s. He sought to systematize stellar naming conventions. It’s possible Betelgeuse was brighter around this time. Nowadays, Rigel outshines Betelgeuse.

A depiction of Orion from Mercator‘s celestial globe, from the Harvard Map Collection. Rigel is labeled at its left foot. Gerardus Mercator was a 16th century geographer, cosmographer and cartographer from Rupelmonde, County of Flanders in modern-day Belgium. Image via Gerard Mercator/ Wikimedia Commons.

The name Rigel comes from an Arabic phrase frequently translated as “The left foot of the central one.” Although Orion was depicted as a giant or warrior in many cultures, in the original Arabic it might have been a reference to a black sheep with a white spot or spots. Thus in the original form, Rigel might have designated the left foot of a sheep! Now, however, many people know it as the left foot of Orion the Hunter.

Aurvandill’s big toe

The mythology related to Rigel is sparse and unclear. Perhaps the most interesting connection is in Norse mythology, which sometimes identified Orion with Aurvandill (also Orwandil, Earendel and others). According to some, Aurvandill was traveling with his companion, the god Thor, when his big toe froze in an unfortunate river-crossing incident. Thor broke off the frozen digit and threw it into the sky, where it became the star we see as Rigel. In some variations, Aurvandill’s other big toe became faint Alcor in Ursa Major.

Rigel’s position is RA: 05h 14m 32.3s, Dec: -08° 12′ 05.9”.

Bottom line: Rigel, the brightest star in the constellation Orion the Hunter, shines a brilliant bluish-white color. It’s much hotter and more massive than our sun, and someday, it will explode as a supernova.

The post Blue-white Rigel is Orion’s brightest star first appeared on EarthSky.

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Meet the Winter Circle, aka the Winter Hexagon

The Winter Circle (or Winter Hexagon) isn’t a constellation. It’s an asterism, or noticeable pattern of stars. It’s made up of 6 bright stars in the winter evening sky for the Northern Hemisphere (and summer sky for the Southern Hemisphere). The Winter Circle covers a large portion of the sky. And once you can find these 6 bright stars, you can use them to trace out their constellations. Plus, in 2026, the bright planet Jupiter is joining them in the evening sky and it’s brighter than all the stars. Chart via EarthSky.

2026 lunar calendars on sale now. Makes a great gift! Check it out here.

The Winter Circle or Winter Hexagon

The Winter Circle (or Hexagon) is a large circular pattern, made of some of the brightest stars in the Northern Hemisphere’s winter sky (or the Southern Hemisphere’s summer sky). It isn’t a constellation. It’s an asterism, or prominent group of stars that form a noticeable pattern. In addition, the Winter Circle has a smaller asterism inside it, called the Winter Triangle.

Plus, in early 2026, the planet Jupiter will lie near the Winter Circle.

Meet the Winter Circle

Strictly speaking, you’ll see this circular pattern of 1st-magnitude stars – the brightest stars in our sky – from six different constellations. These are Rigel in Orion the Hunter, Aldebaran in Taurus the Bull, Capella in Auriga the Charioteer, Pollux (and its forever companion Castor) in Gemini the Twins, Procyon in Canis Minor the Lesser Dog and Sirius in Canis Major the Greater Dog. Also, an additional 1st-magnitude star, Betelgeuse in Orion the Hunter, lies toward the center of the Circle.

The Circle is big

The Winter Circle is big! To get an idea of the it’s humongous size, the span from the southernmost star, Sirius, to the northernmost star, Capella, covers about 1/3 of the dome of the sky.

The late evening sky on November 24, 2025, taken with an allsky camera. The Winter Hexagon takes up a large portion of the sky. Image via WyoAstro observatory.

When is the Winter Circle (or Hexagon) visible?

So, like all stars, those in the Winter Circle rise and set some four minutes earlier with each passing night. Indeed, by late January, the Winter Circle will have risen high enough above the northeastern horizon so it’s visible by about 7 p.m. local time. Then, if you look around midnight, the Winter Circle will be high above the southern horizon. And later, after about 3 a.m. local time, it sinks toward the southwestern horizon, with some of it setting in the west before sunrise.

Then, in late February and early March, the Winter Circle is in your southern sky at nightfall and early evening.

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

Finding the Winter Circle

First, to find the Winter Circle (or Hexagon), find the easily recognizable constellation of Orion the Hunter. Indeed, its three belt stars give it away. Then, look for the bright bluish star to the lower right. This star is Rigel, the southwest corner of the Winter Circle and the first of the six stars in the Circle. By the way, Rigel is the brightest star in Orion and the seventh brightest star in the night sky.

Now, draw a line through Orion’s Belt stars upward to find Aldebaran, the ruddy eye of Taurus the Bull. Aldebaran is the second star in the Circle and the brightest star in Taurus. As a matter of fact, Aldebaran is the fourteenth brightest star in the sky.

Next, continue upward in a counterclockwise direction to find the next bright star, Capella in Auriga the Charioteer. Capella is the third star on our journey and the northernmost point of the Winter Circle. In fact, Capella is the sixth brightest star in the heavens.

View at EarthSky Community Photos. | Amit Raka in India 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!

Completing the Circle

Then, as we start to wind down the other side of the Circle, we run into two bright stars. Those are the twins stars in Gemini the Twins. Pollux, the brighter of the two, is our fourth corner in the Circle. And you’ll notice its “twin,” Castor, is just a bit fainter. Pollux is the sky’s 17th brightest star, and Castor is the 24th.

Our second-to-last stop around the Winter Circle is the bright star below the twins stars, Procyon. Procyon is the brightest star in Canis Minor the Lesser Dog, and, in fact, is one of only two named stars in the constellation. For such a “minor” constellation, Procyon shines brilliantly as the seventh brightest star in the sky.

Finally, we come down to the southernmost star in the Winter Circle and the brightest of them all: Sirius in Canis Major the Greater Dog. Sirius is the brightest star in the Winter Circle and in the entire night sky. In fact, only the moon and some planets can outshine Sirius.

Finding the Winter Triangle

Then after you’ve found the Winter Circle, look inside it to find another asterism. That’s the Winter Triangle. First, take the last two stars of the Circle, Sirius and Procyon, then head toward the center of the Circle. That’s where you’ll find reddish star Betelgeuse, marking the shoulder of Orion. Betelgeuse makes the third corner of the Winter Triangle. Betelgeuse is the 10th brightest star in the sky and second brightest star in Orion.

Procyon, Sirius and Betelgeuse are easy to find on winter and spring evenings. Plus they form a large pattern of 3 bright stars, known as the Winter Triangle. Chart via EarthSky.

View at EarthSky Community Photos. | Cecille Kennedy in Depoe Bay, Oregon, captured this image on February 23, 2023, and wrote: “Orion appears as a beautiful giant hunter in the night sky. Orion continues to march westward and, in a few months, will disappear from the northern sky, lost in the glare of the sun. The Winter Triangle consisting of the stars Sirius, Procyon and Betelgeuse was also highly visible, as well as the Pleiades, Aldebaran of constellation Taurus and Elnath of constellation Auriga. It was a rare beautiful night for stargazing!” Thank you, Cecille!

The Circle contains areas of the Milky Way

Then for a bonus, on a dark and clear moonless night, you can see the soft-glowing river of stars that we call the Milky Way meandering right through the center of the Winter Circle.

Bottom line: The Winter Circle, aka the Winter Hexagon, is a giant shape made from some of the brightest stars in the sky, including Rigel, Aldebaran, Capella, Pollux, Procyon and Sirius. And in early January 2026 Jupiter is near the Winter Circle.

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The post Meet the Winter Circle, aka the Winter Hexagon first appeared on EarthSky.

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The Winter Circle (or Winter Hexagon) isn’t a constellation. It’s an asterism, or noticeable pattern of stars. It’s made up of 6 bright stars in the winter evening sky for the Northern Hemisphere (and summer sky for the Southern Hemisphere). The Winter Circle covers a large portion of the sky. And once you can find these 6 bright stars, you can use them to trace out their constellations. Plus, in 2026, the bright planet Jupiter is joining them in the evening sky and it’s brighter than all the stars. Chart via EarthSky.

2026 lunar calendars on sale now. Makes a great gift! Check it out here.

The Winter Circle or Winter Hexagon

The Winter Circle (or Hexagon) is a large circular pattern, made of some of the brightest stars in the Northern Hemisphere’s winter sky (or the Southern Hemisphere’s summer sky). It isn’t a constellation. It’s an asterism, or prominent group of stars that form a noticeable pattern. In addition, the Winter Circle has a smaller asterism inside it, called the Winter Triangle.

Plus, in early 2026, the planet Jupiter will lie near the Winter Circle.

Meet the Winter Circle

Strictly speaking, you’ll see this circular pattern of 1st-magnitude stars – the brightest stars in our sky – from six different constellations. These are Rigel in Orion the Hunter, Aldebaran in Taurus the Bull, Capella in Auriga the Charioteer, Pollux (and its forever companion Castor) in Gemini the Twins, Procyon in Canis Minor the Lesser Dog and Sirius in Canis Major the Greater Dog. Also, an additional 1st-magnitude star, Betelgeuse in Orion the Hunter, lies toward the center of the Circle.

The Circle is big

The Winter Circle is big! To get an idea of the it’s humongous size, the span from the southernmost star, Sirius, to the northernmost star, Capella, covers about 1/3 of the dome of the sky.

The late evening sky on November 24, 2025, taken with an allsky camera. The Winter Hexagon takes up a large portion of the sky. Image via WyoAstro observatory.

When is the Winter Circle (or Hexagon) visible?

So, like all stars, those in the Winter Circle rise and set some four minutes earlier with each passing night. Indeed, by late January, the Winter Circle will have risen high enough above the northeastern horizon so it’s visible by about 7 p.m. local time. Then, if you look around midnight, the Winter Circle will be high above the southern horizon. And later, after about 3 a.m. local time, it sinks toward the southwestern horizon, with some of it setting in the west before sunrise.

Then, in late February and early March, the Winter Circle is in your southern sky at nightfall and early evening.

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

Finding the Winter Circle

First, to find the Winter Circle (or Hexagon), find the easily recognizable constellation of Orion the Hunter. Indeed, its three belt stars give it away. Then, look for the bright bluish star to the lower right. This star is Rigel, the southwest corner of the Winter Circle and the first of the six stars in the Circle. By the way, Rigel is the brightest star in Orion and the seventh brightest star in the night sky.

Now, draw a line through Orion’s Belt stars upward to find Aldebaran, the ruddy eye of Taurus the Bull. Aldebaran is the second star in the Circle and the brightest star in Taurus. As a matter of fact, Aldebaran is the fourteenth brightest star in the sky.

Next, continue upward in a counterclockwise direction to find the next bright star, Capella in Auriga the Charioteer. Capella is the third star on our journey and the northernmost point of the Winter Circle. In fact, Capella is the sixth brightest star in the heavens.

View at EarthSky Community Photos. | Amit Raka in India 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!

Completing the Circle

Then, as we start to wind down the other side of the Circle, we run into two bright stars. Those are the twins stars in Gemini the Twins. Pollux, the brighter of the two, is our fourth corner in the Circle. And you’ll notice its “twin,” Castor, is just a bit fainter. Pollux is the sky’s 17th brightest star, and Castor is the 24th.

Our second-to-last stop around the Winter Circle is the bright star below the twins stars, Procyon. Procyon is the brightest star in Canis Minor the Lesser Dog, and, in fact, is one of only two named stars in the constellation. For such a “minor” constellation, Procyon shines brilliantly as the seventh brightest star in the sky.

Finally, we come down to the southernmost star in the Winter Circle and the brightest of them all: Sirius in Canis Major the Greater Dog. Sirius is the brightest star in the Winter Circle and in the entire night sky. In fact, only the moon and some planets can outshine Sirius.

Finding the Winter Triangle

Then after you’ve found the Winter Circle, look inside it to find another asterism. That’s the Winter Triangle. First, take the last two stars of the Circle, Sirius and Procyon, then head toward the center of the Circle. That’s where you’ll find reddish star Betelgeuse, marking the shoulder of Orion. Betelgeuse makes the third corner of the Winter Triangle. Betelgeuse is the 10th brightest star in the sky and second brightest star in Orion.

Procyon, Sirius and Betelgeuse are easy to find on winter and spring evenings. Plus they form a large pattern of 3 bright stars, known as the Winter Triangle. Chart via EarthSky.

View at EarthSky Community Photos. | Cecille Kennedy in Depoe Bay, Oregon, captured this image on February 23, 2023, and wrote: “Orion appears as a beautiful giant hunter in the night sky. Orion continues to march westward and, in a few months, will disappear from the northern sky, lost in the glare of the sun. The Winter Triangle consisting of the stars Sirius, Procyon and Betelgeuse was also highly visible, as well as the Pleiades, Aldebaran of constellation Taurus and Elnath of constellation Auriga. It was a rare beautiful night for stargazing!” Thank you, Cecille!

The Circle contains areas of the Milky Way

Then for a bonus, on a dark and clear moonless night, you can see the soft-glowing river of stars that we call the Milky Way meandering right through the center of the Winter Circle.

Bottom line: The Winter Circle, aka the Winter Hexagon, is a giant shape made from some of the brightest stars in the sky, including Rigel, Aldebaran, Capella, Pollux, Procyon and Sirius. And in early January 2026 Jupiter is near the Winter Circle.

Enjoying EarthSky? Sign up for our free daily newsletter today!

The post Meet the Winter Circle, aka the Winter Hexagon first appeared on EarthSky.

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Earth’s ice ages shaped by tiny tugs from Mars

NASA’s Curiosity rover captured this image showing Earth as a tiny dot of light seen from the surface of Mars. Our planet Earth shines more brightly than any star in the Martian night sky. But can Mars affect Earth’s climate? Scientists from UC Riverside are saying that tiny tugs on Earth from Mars have had a big effect on Earth’s ice ages. Wow! Image via NASA.

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Earth’s ice ages shaped by tiny tugs from Mars

You wouldn’t think that Mars could have an influence on Earth’s ice ages. Mars is only half the size of Earth. It has just 1/10 of Earth’s mass. Plus, depending on where they are in orbit around the sun, the two worlds can be separated by tens to hundreds of millions of miles. Still, scientists at the University of California Riverside said on January 12, 2026, that small gravitational tugs from Mars help shape the cycles that drive long-term climate patterns on Earth.

Scientists had long thought Mars’ gravitational pull was too weak to impact Earth’s climate. But some recent studies have suggested otherwise. So Stephen Kane, a professor of planetary astrophysics at UC Riverside, decided to run some computer models to see for himself. Kane said:

I knew Mars had some effect on Earth, but I assumed it was tiny. I’d thought its gravitational influence would be too small to easily observe within Earth’s geologic history. I kind of set out to check my own assumptions.

Kane and colleagues published their study in the peer-reviewed journal Publications of the Astronomical Society of the Pacific on December 18, 2025.

The cycles that shape our climate

How much solar energy Earth receives is what determines our climate. And there are three cycles, called Milankovitch cycles, that affect how much radiation Earth receives from the sun. These cycles are based on orbital mechanics. NASA describes the three Milankovitch cycles as:

eccentricity, or the shape of Earth’s orbit
obliquity, or the angle Earth’s axis is tilted with respect to Earth’s orbital plane
precession, or the direction Earth’s axis of rotation is pointed

Kane created computer simulations of how these cycles change over tens of thousands to millions of years. He ran the simulations showing the whole solar system, and then played with the size of Mars, increasing it and decreasing it, including removing it altogether. And for two of the cycles, the team found that removing Mars made the two cycles vanish.

Earth’s orbit around the sun, in contrast to the orbit of Mars. Image via NASA/ UC Riverside.

Mars’ impact on our climate

The two cycles that Mars’ presence impacts are Earth’s eccentricity and obliquity. These two characteristics influence how much sunlight different areas of Earth get.

Let’s take a closer look at how Mars influences the tilt (obliquity) of Earth. Currently, Earth has a tilt from straight up and down of about 23.5 degrees. Kane said:

As the mass of Mars was increased in our simulations, the rate of change in Earth’s tilt goes down. So increasing the mass of Mars has a kind of stabilizing effect on our tilt.

In other words, if Mars were larger, it would dramatically change the pattern of ice sheet growth and retreat on Earth.

Mars’ pull on Earth’s eccentricity – or how circular or stretched out our orbit is around the sun – has an impact, too. In a grand cycle that lasts 2.4 million years, Mars’ gravitational pull slightly shifts Earth’s path around the sun.

During ice ages, the poles remain covered with ice, and glaciers can cover vast areas of Earth. Image via Parveen/ Pexels.

Earth’s ice ages

Earth has survived at least five major ice ages. In fact, we’re in one now. An ice age is when there are permanent ice sheets at the poles. And sometimes during the ice ages, glaciers can advance and cover much of the globe. It was only about 11,000 years ago that the last major ice sheet – the Wisconsin glaciation – retreated after covering much of North America.

The Milankovitch cycles have helped to bring about and also end these different ice ages. And now we know that Mars plays a role in these cycles as well. Kane mused:

Without Mars, Earth’s orbit would be missing major climate cycles. What would humans and other animals even look like if Mars weren’t there?

Impacts on other solar systems

The computer simulations suggest that life on distant worlds could even be influenced by small, outer, lifeless planets. Kane said:

When I look at other planetary systems and find an Earth-sized planet in the habitable zone, the planets further out in the system could have an effect on that Earth-like planet’s climate.

Our solar system and neighboring planets have even more of an impact on our lives than we might have first thought.

Bottom line: Computer simulations show the presence of Mars affects the cycles that cause Earth’s ice ages and climate changes.

Source: The Dependence of Earth Milankovitch Cycles on Martian Mass

Via UC Riverside

Read more: Gravity between Mars and Earth drives climate and currents

The post Earth’s ice ages shaped by tiny tugs from Mars first appeared on EarthSky.

from EarthSky https://ift.tt/KOT14Gv

NASA’s Curiosity rover captured this image showing Earth as a tiny dot of light seen from the surface of Mars. Our planet Earth shines more brightly than any star in the Martian night sky. But can Mars affect Earth’s climate? Scientists from UC Riverside are saying that tiny tugs on Earth from Mars have had a big effect on Earth’s ice ages. Wow! Image via NASA.

EarthSky’s 2026 lunar calendar shows the moon phase for every day of the year. Get yours today!

Earth’s ice ages shaped by tiny tugs from Mars

You wouldn’t think that Mars could have an influence on Earth’s ice ages. Mars is only half the size of Earth. It has just 1/10 of Earth’s mass. Plus, depending on where they are in orbit around the sun, the two worlds can be separated by tens to hundreds of millions of miles. Still, scientists at the University of California Riverside said on January 12, 2026, that small gravitational tugs from Mars help shape the cycles that drive long-term climate patterns on Earth.

Scientists had long thought Mars’ gravitational pull was too weak to impact Earth’s climate. But some recent studies have suggested otherwise. So Stephen Kane, a professor of planetary astrophysics at UC Riverside, decided to run some computer models to see for himself. Kane said:

I knew Mars had some effect on Earth, but I assumed it was tiny. I’d thought its gravitational influence would be too small to easily observe within Earth’s geologic history. I kind of set out to check my own assumptions.

Kane and colleagues published their study in the peer-reviewed journal Publications of the Astronomical Society of the Pacific on December 18, 2025.

The cycles that shape our climate

How much solar energy Earth receives is what determines our climate. And there are three cycles, called Milankovitch cycles, that affect how much radiation Earth receives from the sun. These cycles are based on orbital mechanics. NASA describes the three Milankovitch cycles as:

eccentricity, or the shape of Earth’s orbit
obliquity, or the angle Earth’s axis is tilted with respect to Earth’s orbital plane
precession, or the direction Earth’s axis of rotation is pointed

Kane created computer simulations of how these cycles change over tens of thousands to millions of years. He ran the simulations showing the whole solar system, and then played with the size of Mars, increasing it and decreasing it, including removing it altogether. And for two of the cycles, the team found that removing Mars made the two cycles vanish.

Earth’s orbit around the sun, in contrast to the orbit of Mars. Image via NASA/ UC Riverside.

Mars’ impact on our climate

The two cycles that Mars’ presence impacts are Earth’s eccentricity and obliquity. These two characteristics influence how much sunlight different areas of Earth get.

Let’s take a closer look at how Mars influences the tilt (obliquity) of Earth. Currently, Earth has a tilt from straight up and down of about 23.5 degrees. Kane said:

As the mass of Mars was increased in our simulations, the rate of change in Earth’s tilt goes down. So increasing the mass of Mars has a kind of stabilizing effect on our tilt.

In other words, if Mars were larger, it would dramatically change the pattern of ice sheet growth and retreat on Earth.

Mars’ pull on Earth’s eccentricity – or how circular or stretched out our orbit is around the sun – has an impact, too. In a grand cycle that lasts 2.4 million years, Mars’ gravitational pull slightly shifts Earth’s path around the sun.

During ice ages, the poles remain covered with ice, and glaciers can cover vast areas of Earth. Image via Parveen/ Pexels.

Earth’s ice ages

Earth has survived at least five major ice ages. In fact, we’re in one now. An ice age is when there are permanent ice sheets at the poles. And sometimes during the ice ages, glaciers can advance and cover much of the globe. It was only about 11,000 years ago that the last major ice sheet – the Wisconsin glaciation – retreated after covering much of North America.

The Milankovitch cycles have helped to bring about and also end these different ice ages. And now we know that Mars plays a role in these cycles as well. Kane mused:

Without Mars, Earth’s orbit would be missing major climate cycles. What would humans and other animals even look like if Mars weren’t there?

Impacts on other solar systems

The computer simulations suggest that life on distant worlds could even be influenced by small, outer, lifeless planets. Kane said:

When I look at other planetary systems and find an Earth-sized planet in the habitable zone, the planets further out in the system could have an effect on that Earth-like planet’s climate.

Our solar system and neighboring planets have even more of an impact on our lives than we might have first thought.

Bottom line: Computer simulations show the presence of Mars affects the cycles that cause Earth’s ice ages and climate changes.

Source: The Dependence of Earth Milankovitch Cycles on Martian Mass

Via UC Riverside

Read more: Gravity between Mars and Earth drives climate and currents

The post Earth’s ice ages shaped by tiny tugs from Mars first appeared on EarthSky.

from EarthSky https://ift.tt/KOT14Gv

Top 10 brightest objects in our solar system

Top 10 brightest objects in our solar system

There are at least 10 natural objects in our solar system – our neighborhood of space – that are, in theory, visible to the unaided eye. Most of these objects are easy to see! But a few aren’t.

So what are these objects, the brightest natural objects in our solar system? Note that we’re not counting transient objects, such as very bright meteors. And we’re not counting human-made objects, such as satellites and the International Space Station.

Keep reading to find out which are the top 10 brightest natural solar system objects, in order from brightest to dimmest. You can see the first seven objects on this list easily, using just your eyes, even from cities and suburbs. The last few items are fainter and more challenging … but still among our solar system’s brightest objects.

View at EarthSky Community Photos. | Prateek Pandey captured this sunset view in Pachmari, Madhya Pradesh, India, on January 3, 2025. Beautiful! The sun is #1 on our list for brightest objects in our solar system. Remember, even when the sun is low in the sky like this, its brightness is so great that it can permanently damage your eyes. Never look at it directly!

#1. Brightest object in our solar system: The sun

No surprise here. You mustn’t ever look at the sun without protective filters. Gazing at the sun directly without special filters can cause permanent blindness. Don’t do it!

How bright is the sun? Astronomers speak of an object’s brightness by its magnitude. The brightest objects have negative magnitudes. And the sun shines at magnitude -26.7!

Read about the magnitude scale here.

Read: Top 7 tips for observing the sun safely

Read the sun news: Daily updates

#2. The moon

To the eye alone, there’s nothing more beautiful than a bright moon shining in a dark night sky, casting its light and creating moon shadows in the landscape all around you. The moon is our sky’s 2nd-brightest object.

On the other hand, if you’re a deep-sky observer – interested in distant, faint star clusters, nebulae and galaxies – the moon is bright enough to ruin your night vision. If you get a chance to use a telescope, let the moon be your last stop of the night.

So how bright is the moon? Its brightness varies, depending on its phase. At its full phase, when it’s the brightest, it tops out at magnitude -12.7. In a crescent phase, it shines at only about magnitude -6.

Pick up EarthSky’s moon phases calendar for 2026 to keep track of the moon’s nightly show.

View at EarthSky Community Photos. | Stephane Picard in Quispamsis, New Brunswick, Canada, captured the full moon on the morning of December 5, 2025. Stephane wrote: “This morning’s December supermoon is appropriately called the Cold Moon, as our region will hit almost -30 Celsius (about -22 Fahrenheit). With nearly a foot (30 cm) of snow, it lit up the night over our bright snow base.” Thank you, Stephane!

#3. Venus

Venus is the closest planet to Earth, one step inward in orbit around the sun. And it’s also our sky’s brightest planet and 3rd-brightest object, after the sun and moon. As with all other solar system objects, Venus varies in brightness depending on where Earth and Venus are in their orbits with respect to each other. Also, as a planet orbiting inward from Earth, Venus shows phases! The planet is brightest when it’s in a slim crescent phase. So the next greatest brilliancy for Venus is coming around September 18, 2026! Wait. What? It’s brighter in our sky when in a slimmer phase? Yup!

So how bright is Venus? It can shine as brightly as magnitude -4.7. That’s bright enough to be seen in daylight!

Why is Venus so bright? The answer isn’t just it’s nearness. It’s also its thick, reflective clouds.

Venus is too close to the sun to see in January 2026, but will emerge in the evening sky late February or early March. Find Venus’ current location in EarthSky’s night sky guide.

View at EarthSky Community Photos. | Soumyadeep Mukherje shared this composite image from photos he took at Singalila National Park in India. Soumyadeep wrote: “There are some images, which, after you create, make you happy. This is one of them. The image shows Venus in the varying backgrounds of twilight colors. As twilight progresses, the background stars, the Sagittarius arm and nebulae are slowly revealed. The change in colors and background within the same twilight period ranged around 26 minutes during this period and latitude.” Thank you, Soumyadeep!

#4. Mars

The red planet is the 2nd-closest to Earth, after Venus. And, yes, it’s the 4th-brightest object in our night sky … sometimes. Every two years, Earth flies between the sun and Mars. That’s when Mars reaches opposition to the sun, appearing opposite the sun in Earth’s sky. And it’s when Earth and Mars are closest for that two-year period. And that’s when Mars can outshine Jupiter, becoming our sky’s 4th-brightest object.

When is that once-in-two-years opportunity here? The red planet will have an opposition on February 20, 2027.

How bright can Mars get at its brightest? Magnitude -2.9.

By the way, this 2027 opposition won’t see Mars at its absolute brightest. It won’t outshine Jupiter in 2027. But it’ll still be very bright and very red in color. It’ll be close to the brightness of Sirius, our sky’s brightest star.

In between its times of great brightness – in other words, most of the time – Mars is faint. Read about Mars’ changing brightness here.

And find Mars’ location for each month in EarthSky’s night sky guide.

View at EarthSky Community Photos. | B Martin in Riverside, California, captured this image of red Mars on December 15, 2024, just 1 month before Earth goes between the red planet and the sun, bringing Mars closest for this 2-year period. B wrote: “Mars was around maybe 45 degrees up. I saw it in live view, I knew it was a banger … Bonus, you can see the shadow of the cloud of the ribbon white long cloud stream on the lower left. The shadow is in the direction hugging the right of the cloud. The shadow is dark brown in color as it casts on the Martian sand.” Thank you for sharing, B!

#5. Jupiter

Because Jupiter is the largest planet in our solar system, some mistakenly believe it’s the brightest planet. But not so. It’s the 3rd-brightest planet and 5th-brightest solar system object. Jupiter’s greater distance from us lets Venus and Mars, our neighbors, shine more brightly.

But – unlike Mars – Jupiter is always bright. It’s nearly as bright as Mars’s peak of -2.9, and always brighter than Sirius, the sky’s brightest star.

How bright is Jupiter? At its maximum, it shines at magnitude -2.8. And it’s at its brightest for 2026 in January. Come to know Jupiter, and you’ll enjoy seeing its bright face in your sky for much of every year.

Find Jupiter’s location for each month of the year in EarthSky’s night sky guide.

View at EarthSky Community Photos. | Here’s why Jupiter is bright now. It was at its opposition – when Earth flew between it and the sun – on January 10, 2026, and therefore brightest in our sky. So, it’s reflecting more sunlight in our direction now. Nishat Khan in Vaughan, Ontario, shared this comparison image of Jupiter from September 16 with one taken on December 14, 2024. Nishat wrote: “Comparing 2 images of Jupiter taken 3 months apart. It was about 40 arcseconds in the September image; while it is bigger, around 48 arcseconds, in the image taken around opposition time in December. Both images are taken with the exact same setup. September image shows the moon Io as well.” Thank you, Nishat!

#6. Mercury

Surprise! The rarely-seen planet Mercury shines more brightly than Saturn at its best. Mercury can also shine more brightly than Sirius, the sky’s brightest star. It’s the 6th-brightest natural solar system object in our night sky. So why is Mercury often called elusive?

It’s because Mercury is our solar system’s innermost planet. So it always stays near the sun in our sky. You can see it only shortly before sunrise or shortly after sunset. It never gets very high in the night sky. And so we often see it set against bright twilight and not in a nice dark sky. The twilight dims Mercury’s glory.

Still, Mercury’s brightness will surprise you! It can reach -1.9 magnitude. That’s in contrast to Sirius at magnitude -1.3.

Mercury comes and goes in our sky rapidly and switches back and forth between the morning and evening sky. To see if Mercury is visible now, check EarthSky’s night sky guide.

#7. Saturn

The ringed planet Saturn is stunning in a telescope, and it’s also an easy catch without optical aid. With the eye alone, you won’t see its rings. But you will see Saturn’s golden color and steady light. Saturn outshines most stars and is on a par with most of the brightest stars. Plus – because it orbits our sun beyond Earth’s orbit – casual observers can spot it more often than Mercury. Saturn is often around deep into the night, when its brightness contrasts with the depths of a dark night sky.

Saturn shines magnitude +0.7. Notice we just slipped over into positive magnitudes? From here on out, the bigger the number, the dimmer the object.

Read about the magnitude scale here.

View at EarthSky Community Photos. | Tameem Altameemi in Dubai, UAE, took this image of the 5 visible planets and the moon on December 25, 2022. Tameem wrote: “A wonderful celestial scene, 5 planets of the solar system that can be seen with the unaided eye with the 7.6% waxing crescent moon, after sunset. The planets in order from bottom right are Venus, Mercury, Saturn, Jupiter and Mars.” Thank you, Tameem!

#8. Jupiter’s moon Ganymede

If you ever look up at night, you’ve probably seen all the objects mentioned so far without optical aid, knowingly or not. But only a few have seen Jupiter’s largest moon, Ganymede, without optical aid. Still, Ganymede is relatively bright, in contrast to most moons of the outer planets, or to the million tiny bodies (asteroids and the like) that orbit our sun.

Ganymede shines at approximately +4.6 magnitude. Lots of stars in the night sky have this same brightness. So Ganymede is about as bright of some of the faintest of our night sky’s stars.

Binoculars will – at times – let you spot Ganymede circling Jupiter. This large Jovian moon takes about seven Earth-days to complete an orbit around Jupiter (in contrast to the other Galilean moons, which take varying amounts of time, Io nearly two days, Europa about four days, Callisto 17 days).

There are four of these Galilean moons orbiting Jupiter, with Ganymede the brightest.

View at EarthSky Community Photos. | Nanci McCraine at Finger Lakes, New York, took this photo on September 30, 2023, and wrote: “I noticed craggy edges around Jupiter. Zooming in, I spotted this line of 4 straight lights across the planet that I assume are satellites.” That is correct! Binoculars or a small telescope will show Jupiter’s moons.

#9. Asteroid Vesta

Here’s an object that’s not a planet or moon. It’s an asteroid, the 4th asteroid ever discovered and 10th-brightest natural solar system object: Vesta. It’s the only asteroid to make our list of brightest solar system objects. Vesta is the 2nd-largest asteroid after Ceres. Vesta can reach magnitude 5.1 when at opposition; in other words, when it’s opposite the sun from Earth (when Earth is passing between Vesta and the sun). That’ll happen next around October 13, 2026.

Around the time of Vesta’s opposition, Earth sweeps more or less between Vesta and the sun, bringing the asteroid closest to us for the year. Because Vesta doesn’t have a bright nearby locator, as Ganymede and Io have with Jupiter, you can see this object only by watching over several nights in a row. You can draw Vesta’s star field, and note which dim “star” in the area appears to move slowly in front of the fixed star background. Visit In-The-Sky.org for more.

#10. Planet Uranus

Finally! Many know that planet Uranus is theoretically visible to the unaided eye. The 7th planet from the sun appears at magnitude 5.6 at its best. That’s barely within unaided eye visibility.

Uranus is most easily picked up with the unaided eye after first pinning down its location with binoculars or a telescope. It has a disk instead of a pinpoint image through an optical device and may even appear faintly bluish green.

It’s particularly easy to find when it pairs up closely with objects easier to locate, such as Mars. And it’s best around its time of opposition, that is, when Earth is passing between Uranus and the sun, bringing Uranus opposite the sun in our sky and closest to Earth for that year. The next opposition of Uranus will be November 25, 2026.

View at EarthSky Community Photos. | Nancy Ricigliano in Long Island, New York, captured this image on November 13, 2023, and wrote: “When I found out Uranus was at opposition, I figured I would give it a try. I was able to capture it in an eyepiece but had a difficult time finding it with my camera. It took me about an hour but I finally found it and was thrilled to capture this planet that is the 7th planet from the sun. Most of the planet is made of water, ammonia, and methane in a supercritical phase of matter, which in astronomy is called ‘ice’ or volatiles. The ice giant is surrounded by 13 faint rings and 27 small moons as it rotates at a nearly 90-degree angle from the plane of its orbit. This unique tilt makes Uranus appear to spin sideways, orbiting the sun like a rolling ball.” Thank you!

Bottom line: Here are the top 10 brightest natural solar system objects, in order from brightest to dimmest. If you’ve seen every one of these objects, with or without optical aid, congrats!

The post Top 10 brightest objects in our solar system first appeared on EarthSky.

from EarthSky https://ift.tt/SBFvO0J

Top 10 brightest objects in our solar system

There are at least 10 natural objects in our solar system – our neighborhood of space – that are, in theory, visible to the unaided eye. Most of these objects are easy to see! But a few aren’t.

So what are these objects, the brightest natural objects in our solar system? Note that we’re not counting transient objects, such as very bright meteors. And we’re not counting human-made objects, such as satellites and the International Space Station.

Keep reading to find out which are the top 10 brightest natural solar system objects, in order from brightest to dimmest. You can see the first seven objects on this list easily, using just your eyes, even from cities and suburbs. The last few items are fainter and more challenging … but still among our solar system’s brightest objects.

View at EarthSky Community Photos. | Prateek Pandey captured this sunset view in Pachmari, Madhya Pradesh, India, on January 3, 2025. Beautiful! The sun is #1 on our list for brightest objects in our solar system. Remember, even when the sun is low in the sky like this, its brightness is so great that it can permanently damage your eyes. Never look at it directly!

#1. Brightest object in our solar system: The sun

No surprise here. You mustn’t ever look at the sun without protective filters. Gazing at the sun directly without special filters can cause permanent blindness. Don’t do it!

How bright is the sun? Astronomers speak of an object’s brightness by its magnitude. The brightest objects have negative magnitudes. And the sun shines at magnitude -26.7!

Read about the magnitude scale here.

Read: Top 7 tips for observing the sun safely

Read the sun news: Daily updates

#2. The moon

To the eye alone, there’s nothing more beautiful than a bright moon shining in a dark night sky, casting its light and creating moon shadows in the landscape all around you. The moon is our sky’s 2nd-brightest object.

On the other hand, if you’re a deep-sky observer – interested in distant, faint star clusters, nebulae and galaxies – the moon is bright enough to ruin your night vision. If you get a chance to use a telescope, let the moon be your last stop of the night.

So how bright is the moon? Its brightness varies, depending on its phase. At its full phase, when it’s the brightest, it tops out at magnitude -12.7. In a crescent phase, it shines at only about magnitude -6.

Pick up EarthSky’s moon phases calendar for 2026 to keep track of the moon’s nightly show.

View at EarthSky Community Photos. | Stephane Picard in Quispamsis, New Brunswick, Canada, captured the full moon on the morning of December 5, 2025. Stephane wrote: “This morning’s December supermoon is appropriately called the Cold Moon, as our region will hit almost -30 Celsius (about -22 Fahrenheit). With nearly a foot (30 cm) of snow, it lit up the night over our bright snow base.” Thank you, Stephane!

#3. Venus

Venus is the closest planet to Earth, one step inward in orbit around the sun. And it’s also our sky’s brightest planet and 3rd-brightest object, after the sun and moon. As with all other solar system objects, Venus varies in brightness depending on where Earth and Venus are in their orbits with respect to each other. Also, as a planet orbiting inward from Earth, Venus shows phases! The planet is brightest when it’s in a slim crescent phase. So the next greatest brilliancy for Venus is coming around September 18, 2026! Wait. What? It’s brighter in our sky when in a slimmer phase? Yup!

So how bright is Venus? It can shine as brightly as magnitude -4.7. That’s bright enough to be seen in daylight!

Why is Venus so bright? The answer isn’t just it’s nearness. It’s also its thick, reflective clouds.

Venus is too close to the sun to see in January 2026, but will emerge in the evening sky late February or early March. Find Venus’ current location in EarthSky’s night sky guide.

View at EarthSky Community Photos. | Soumyadeep Mukherje shared this composite image from photos he took at Singalila National Park in India. Soumyadeep wrote: “There are some images, which, after you create, make you happy. This is one of them. The image shows Venus in the varying backgrounds of twilight colors. As twilight progresses, the background stars, the Sagittarius arm and nebulae are slowly revealed. The change in colors and background within the same twilight period ranged around 26 minutes during this period and latitude.” Thank you, Soumyadeep!

#4. Mars

The red planet is the 2nd-closest to Earth, after Venus. And, yes, it’s the 4th-brightest object in our night sky … sometimes. Every two years, Earth flies between the sun and Mars. That’s when Mars reaches opposition to the sun, appearing opposite the sun in Earth’s sky. And it’s when Earth and Mars are closest for that two-year period. And that’s when Mars can outshine Jupiter, becoming our sky’s 4th-brightest object.

When is that once-in-two-years opportunity here? The red planet will have an opposition on February 20, 2027.

How bright can Mars get at its brightest? Magnitude -2.9.

By the way, this 2027 opposition won’t see Mars at its absolute brightest. It won’t outshine Jupiter in 2027. But it’ll still be very bright and very red in color. It’ll be close to the brightness of Sirius, our sky’s brightest star.

In between its times of great brightness – in other words, most of the time – Mars is faint. Read about Mars’ changing brightness here.

And find Mars’ location for each month in EarthSky’s night sky guide.

View at EarthSky Community Photos. | B Martin in Riverside, California, captured this image of red Mars on December 15, 2024, just 1 month before Earth goes between the red planet and the sun, bringing Mars closest for this 2-year period. B wrote: “Mars was around maybe 45 degrees up. I saw it in live view, I knew it was a banger … Bonus, you can see the shadow of the cloud of the ribbon white long cloud stream on the lower left. The shadow is in the direction hugging the right of the cloud. The shadow is dark brown in color as it casts on the Martian sand.” Thank you for sharing, B!

#5. Jupiter

Because Jupiter is the largest planet in our solar system, some mistakenly believe it’s the brightest planet. But not so. It’s the 3rd-brightest planet and 5th-brightest solar system object. Jupiter’s greater distance from us lets Venus and Mars, our neighbors, shine more brightly.

But – unlike Mars – Jupiter is always bright. It’s nearly as bright as Mars’s peak of -2.9, and always brighter than Sirius, the sky’s brightest star.

How bright is Jupiter? At its maximum, it shines at magnitude -2.8. And it’s at its brightest for 2026 in January. Come to know Jupiter, and you’ll enjoy seeing its bright face in your sky for much of every year.

Find Jupiter’s location for each month of the year in EarthSky’s night sky guide.

View at EarthSky Community Photos. | Here’s why Jupiter is bright now. It was at its opposition – when Earth flew between it and the sun – on January 10, 2026, and therefore brightest in our sky. So, it’s reflecting more sunlight in our direction now. Nishat Khan in Vaughan, Ontario, shared this comparison image of Jupiter from September 16 with one taken on December 14, 2024. Nishat wrote: “Comparing 2 images of Jupiter taken 3 months apart. It was about 40 arcseconds in the September image; while it is bigger, around 48 arcseconds, in the image taken around opposition time in December. Both images are taken with the exact same setup. September image shows the moon Io as well.” Thank you, Nishat!

#6. Mercury

Surprise! The rarely-seen planet Mercury shines more brightly than Saturn at its best. Mercury can also shine more brightly than Sirius, the sky’s brightest star. It’s the 6th-brightest natural solar system object in our night sky. So why is Mercury often called elusive?

It’s because Mercury is our solar system’s innermost planet. So it always stays near the sun in our sky. You can see it only shortly before sunrise or shortly after sunset. It never gets very high in the night sky. And so we often see it set against bright twilight and not in a nice dark sky. The twilight dims Mercury’s glory.

Still, Mercury’s brightness will surprise you! It can reach -1.9 magnitude. That’s in contrast to Sirius at magnitude -1.3.

Mercury comes and goes in our sky rapidly and switches back and forth between the morning and evening sky. To see if Mercury is visible now, check EarthSky’s night sky guide.

#7. Saturn

The ringed planet Saturn is stunning in a telescope, and it’s also an easy catch without optical aid. With the eye alone, you won’t see its rings. But you will see Saturn’s golden color and steady light. Saturn outshines most stars and is on a par with most of the brightest stars. Plus – because it orbits our sun beyond Earth’s orbit – casual observers can spot it more often than Mercury. Saturn is often around deep into the night, when its brightness contrasts with the depths of a dark night sky.

Saturn shines magnitude +0.7. Notice we just slipped over into positive magnitudes? From here on out, the bigger the number, the dimmer the object.

Read about the magnitude scale here.

View at EarthSky Community Photos. | Tameem Altameemi in Dubai, UAE, took this image of the 5 visible planets and the moon on December 25, 2022. Tameem wrote: “A wonderful celestial scene, 5 planets of the solar system that can be seen with the unaided eye with the 7.6% waxing crescent moon, after sunset. The planets in order from bottom right are Venus, Mercury, Saturn, Jupiter and Mars.” Thank you, Tameem!

#8. Jupiter’s moon Ganymede

If you ever look up at night, you’ve probably seen all the objects mentioned so far without optical aid, knowingly or not. But only a few have seen Jupiter’s largest moon, Ganymede, without optical aid. Still, Ganymede is relatively bright, in contrast to most moons of the outer planets, or to the million tiny bodies (asteroids and the like) that orbit our sun.

Ganymede shines at approximately +4.6 magnitude. Lots of stars in the night sky have this same brightness. So Ganymede is about as bright of some of the faintest of our night sky’s stars.

Binoculars will – at times – let you spot Ganymede circling Jupiter. This large Jovian moon takes about seven Earth-days to complete an orbit around Jupiter (in contrast to the other Galilean moons, which take varying amounts of time, Io nearly two days, Europa about four days, Callisto 17 days).

There are four of these Galilean moons orbiting Jupiter, with Ganymede the brightest.

View at EarthSky Community Photos. | Nanci McCraine at Finger Lakes, New York, took this photo on September 30, 2023, and wrote: “I noticed craggy edges around Jupiter. Zooming in, I spotted this line of 4 straight lights across the planet that I assume are satellites.” That is correct! Binoculars or a small telescope will show Jupiter’s moons.

#9. Asteroid Vesta

Here’s an object that’s not a planet or moon. It’s an asteroid, the 4th asteroid ever discovered and 10th-brightest natural solar system object: Vesta. It’s the only asteroid to make our list of brightest solar system objects. Vesta is the 2nd-largest asteroid after Ceres. Vesta can reach magnitude 5.1 when at opposition; in other words, when it’s opposite the sun from Earth (when Earth is passing between Vesta and the sun). That’ll happen next around October 13, 2026.

Around the time of Vesta’s opposition, Earth sweeps more or less between Vesta and the sun, bringing the asteroid closest to us for the year. Because Vesta doesn’t have a bright nearby locator, as Ganymede and Io have with Jupiter, you can see this object only by watching over several nights in a row. You can draw Vesta’s star field, and note which dim “star” in the area appears to move slowly in front of the fixed star background. Visit In-The-Sky.org for more.

#10. Planet Uranus

Finally! Many know that planet Uranus is theoretically visible to the unaided eye. The 7th planet from the sun appears at magnitude 5.6 at its best. That’s barely within unaided eye visibility.

Uranus is most easily picked up with the unaided eye after first pinning down its location with binoculars or a telescope. It has a disk instead of a pinpoint image through an optical device and may even appear faintly bluish green.

It’s particularly easy to find when it pairs up closely with objects easier to locate, such as Mars. And it’s best around its time of opposition, that is, when Earth is passing between Uranus and the sun, bringing Uranus opposite the sun in our sky and closest to Earth for that year. The next opposition of Uranus will be November 25, 2026.

View at EarthSky Community Photos. | Nancy Ricigliano in Long Island, New York, captured this image on November 13, 2023, and wrote: “When I found out Uranus was at opposition, I figured I would give it a try. I was able to capture it in an eyepiece but had a difficult time finding it with my camera. It took me about an hour but I finally found it and was thrilled to capture this planet that is the 7th planet from the sun. Most of the planet is made of water, ammonia, and methane in a supercritical phase of matter, which in astronomy is called ‘ice’ or volatiles. The ice giant is surrounded by 13 faint rings and 27 small moons as it rotates at a nearly 90-degree angle from the plane of its orbit. This unique tilt makes Uranus appear to spin sideways, orbiting the sun like a rolling ball.” Thank you!

Bottom line: Here are the top 10 brightest natural solar system objects, in order from brightest to dimmest. If you’ve seen every one of these objects, with or without optical aid, congrats!

The post Top 10 brightest objects in our solar system first appeared on EarthSky.

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Strange shock wave around dead star surprises astronomers

The inset image shows dead star RXJ0528+2838 creating a shock wave as it moves through space. A strong outflow expelled from a star is usually the cause of such a shock wave. However, in the case of RXJ0528+2838, astronomers discovered that the shock wave can’t be explained by any known mechanism. Image via ESO/ K. Ilkiewicz and S. Scaringi et al./ PanSTARRS.

ESO published this original story on January 12, 2026. Edits by EarthSky.

EarthSky’s 2026 lunar calendar is available now. Get yours today! Makes a great gift.

Strange shock wave around dead star surprises astronomers

Gas and dust in interstellar space can, under the right conditions, clash with a star’s surroundings and create a shock wave. Now, astronomers using the European Southern Observatory’s Very Large Telescope have imaged a beautiful shock wave around a dead star … and they can’t quite explain it.

According to all known mechanisms, the small, dead star – named RXJ0528+2838 – should not have such structure around it. This discovery, as enigmatic as it’s stunning, challenges our understanding of how dead stars interact with their surroundings.

Simone Scaringi, co-lead author of the new study, said:

We found something never seen before and, more importantly, entirely unexpected.

The researchers published their findings in the peer-reviewed journal Nature Astronomy on January 12, 2026.

Bow shock of a dead star

The star, RXJ0528+2838, is located 730 light-years away. And, like the sun and other stars, it rotates around our galaxy’s center. As it moves, it interacts with the gas that permeates the space between stars, creating a type of shock wave called a bow shock.

Noel Castro Segura, a collaborator in this study, described this as:

… a curved arc of material, similar to the wave that builds up in front of a ship.

Material outflowing from a central star usually creates these bow shocks. But in the case of RXJ0528+2838, none of the known mechanisms can fully explain the observations.

RXJ0528+2838 is a white dwarf – the left-over core of a dying low-mass star – and has a sun-like companion orbiting it. In such binary systems, the material from the companion star is transferred to the white dwarf, often forming a disk around it. While the disk fuels the dead star, some of the material also gets ejected into space, creating powerful outflows.

But RXJ0528+2838 shows no signs of a disk, making the origin of the outflow and resulting nebula around the star a mystery.

Scaringi said:

The surprise that a supposedly quiet, diskless system could drive such a spectacular nebula was one of those rare ‘wow’ moments.

Dead star discovery

The team first spotted a strange nebulosity around RXJ0528+2838 on images from the Isaac Newton Telescope in Spain. Noticing its unusual shape, they observed it in more detail with the MUSE instrument on ESO’s Very Large Telescope.

Krystian Ilkiewicz, study co-lead, said:

Observations with the ESO MUSE instrument allowed us to map the bow shock in detail and analyze its composition. This was crucial to confirm that the structure really originates from the binary system and not from an unrelated nebula or interstellar cloud.

An answer to the mystery?

The shape and size of the bow shock imply that the white dwarf has been expelling a powerful outflow for at least 1000 years. Scientists don’t know exactly how a dead star without a disk can power such a long-lasting outflow … but they do have a guess.

This white dwarf is known to host a strong magnetic field, which the MUSE data have confirmed. This field channels the material stolen from the companion star directly onto the white dwarf without forming a disk around it.

The results hint that the hidden energy source is this strong magnetic field. But this “mystery engine”, as Scaringi puts it, still needs to be investigated. The data show that the current magnetic field is only strong enough to power a bow shock lasting for a few hundred years. That means this only partly explains what the astronomers are seeing.

To better understand the nature of such diskless outflows, many more binary systems need to be studied. ESO’s upcoming Extremely Large Telescope (currently set to be operational in 2030) could be instrumental here, Scaringi foresees:

[It will help astronomers] to map more of these systems, as well as fainter ones and detect similar systems in detail, ultimately helping in understanding the mysterious energy source that remains unexplained.

Bottom line: Astronomers have spotted a beautiful shock wave around a dead star and can’t fully explain how it’s possible.

Source: A persistent bow shock in a diskless magnetized accreting white dwarf

Via ESO

Read more: Hungry white dwarf devours surprisingly icy Pluto-like world

The post Strange shock wave around dead star surprises astronomers first appeared on EarthSky.

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The inset image shows dead star RXJ0528+2838 creating a shock wave as it moves through space. A strong outflow expelled from a star is usually the cause of such a shock wave. However, in the case of RXJ0528+2838, astronomers discovered that the shock wave can’t be explained by any known mechanism. Image via ESO/ K. Ilkiewicz and S. Scaringi et al./ PanSTARRS.

ESO published this original story on January 12, 2026. Edits by EarthSky.

EarthSky’s 2026 lunar calendar is available now. Get yours today! Makes a great gift.

Strange shock wave around dead star surprises astronomers

Gas and dust in interstellar space can, under the right conditions, clash with a star’s surroundings and create a shock wave. Now, astronomers using the European Southern Observatory’s Very Large Telescope have imaged a beautiful shock wave around a dead star … and they can’t quite explain it.

According to all known mechanisms, the small, dead star – named RXJ0528+2838 – should not have such structure around it. This discovery, as enigmatic as it’s stunning, challenges our understanding of how dead stars interact with their surroundings.

Simone Scaringi, co-lead author of the new study, said:

We found something never seen before and, more importantly, entirely unexpected.

The researchers published their findings in the peer-reviewed journal Nature Astronomy on January 12, 2026.

Bow shock of a dead star

The star, RXJ0528+2838, is located 730 light-years away. And, like the sun and other stars, it rotates around our galaxy’s center. As it moves, it interacts with the gas that permeates the space between stars, creating a type of shock wave called a bow shock.

Noel Castro Segura, a collaborator in this study, described this as:

… a curved arc of material, similar to the wave that builds up in front of a ship.

Material outflowing from a central star usually creates these bow shocks. But in the case of RXJ0528+2838, none of the known mechanisms can fully explain the observations.

RXJ0528+2838 is a white dwarf – the left-over core of a dying low-mass star – and has a sun-like companion orbiting it. In such binary systems, the material from the companion star is transferred to the white dwarf, often forming a disk around it. While the disk fuels the dead star, some of the material also gets ejected into space, creating powerful outflows.

But RXJ0528+2838 shows no signs of a disk, making the origin of the outflow and resulting nebula around the star a mystery.

Scaringi said:

The surprise that a supposedly quiet, diskless system could drive such a spectacular nebula was one of those rare ‘wow’ moments.

Dead star discovery

The team first spotted a strange nebulosity around RXJ0528+2838 on images from the Isaac Newton Telescope in Spain. Noticing its unusual shape, they observed it in more detail with the MUSE instrument on ESO’s Very Large Telescope.

Krystian Ilkiewicz, study co-lead, said:

Observations with the ESO MUSE instrument allowed us to map the bow shock in detail and analyze its composition. This was crucial to confirm that the structure really originates from the binary system and not from an unrelated nebula or interstellar cloud.

An answer to the mystery?

The shape and size of the bow shock imply that the white dwarf has been expelling a powerful outflow for at least 1000 years. Scientists don’t know exactly how a dead star without a disk can power such a long-lasting outflow … but they do have a guess.

This white dwarf is known to host a strong magnetic field, which the MUSE data have confirmed. This field channels the material stolen from the companion star directly onto the white dwarf without forming a disk around it.

The results hint that the hidden energy source is this strong magnetic field. But this “mystery engine”, as Scaringi puts it, still needs to be investigated. The data show that the current magnetic field is only strong enough to power a bow shock lasting for a few hundred years. That means this only partly explains what the astronomers are seeing.

To better understand the nature of such diskless outflows, many more binary systems need to be studied. ESO’s upcoming Extremely Large Telescope (currently set to be operational in 2030) could be instrumental here, Scaringi foresees:

[It will help astronomers] to map more of these systems, as well as fainter ones and detect similar systems in detail, ultimately helping in understanding the mysterious energy source that remains unexplained.

Bottom line: Astronomers have spotted a beautiful shock wave around a dead star and can’t fully explain how it’s possible.

Source: A persistent bow shock in a diskless magnetized accreting white dwarf

Via ESO

Read more: Hungry white dwarf devours surprisingly icy Pluto-like world

The post Strange shock wave around dead star surprises astronomers first appeared on EarthSky.

from EarthSky https://ift.tt/dAjyFZx

Contemplate the apex of the sun in January

From the Northern Hemisphere, on January evenings, not long after sunset, you can stand facing northwest, and you might spot the bright star Vega. If your sky is dark, you might also see its constellation Lyra the Harp. In its journey around the galaxy, our sun moves toward bright Vega. The point toward which we move – or the apex of the sun – is called the “solar apex.”

EarthSky’s 2026 lunar calendar is available now. Get yours today! Makes a great gift.

Contemplate the apex of the sun in January

From Northern Hemisphere locations on January evenings, look northwest. You’ll see the bright star Vega in the constellation Lyra the Harp. Our star, the sun, and its planets are moving through space toward the general direction of Vega. Astronomers call the sun’s direction of motion through its Milky Way neighborhood by a great old name: the solar apex or, more romantically, the apex of the sun’s way.

The solar apex isn’t exactly in Vega’s direction. It’s located in our sky in the direction of a constellation that’s harder to pick out … the constellation Hercules. This constellation is southwest of the star Vega and its constellation Lyra. It’s a location on the celestial sphere with these coordinates: 18h 28m 0s in right ascension, 30° N in declination.

How do we know our sun is moving in this direction? Astronomers find this point on our sky by measuring the motions of stars near the sun.

A star chart showing the location of the solar apex in the sky. It’s not far from Vega. Image via Stellarium. Used with permission.

Sun’s motion in its galactic neighborhood

Think back to when you last walked on a busy sidewalk. In general, most people are walking at a similar pace. At a distance, they look close together. But if you pick up your pace when walking toward them, people appear to be moving apart.

As the sun travels along its galactic sidewalk with neighboring stars, it moves slightly faster than the mean velocity of its neighbors. If you could fast-forward over several hundred thousand years, you’d notice the following: Nearby stars appear to move away from the solar apex. On the opposite side of the celestial sphere, called the antapex, you’d see the opposite: The distance between stars in the sky appears to get smaller.

You can see this effect in an animation from the European Space Agency, based on data from the Gaia space telescope. Scientists extrapolated the motion of 40,000 stars over 1.6 million years to see how they would appear to move in the sky. All these stars had known motions that Gaia measured and were within 326 light-years of the sun.

The trails show how far the stars move on the celestial sphere. It’s a pretty busy animation. But if you look closely, you’ll notice, towards the end, many (not all) stars on the upper left appear to be moving away from a central point: That’s the solar apex. And on the right, they appear to be getting closer to each other: That’s the antapex, which is opposite on the sky from the solar apex. You can read more about this video the ESA website.

Looking toward the solar apex

Vega is a bright star. So you can look for it and find it pretty easily. At this time of year from mid-northern latitudes, Vega appears over the northwestern horizon at dusk and early evening. It also appears low in the northeast sky in the predawn and dawn hours. To see a precise view – and time – for Vega from your location, try Stellarium Online.

So look for the star Vega and contemplate the fact that our sun and family of planets travel more or less toward it.

With its blue-white color, Vega also happens to be one of the loveliest stars you’ll ever see.

The blue-white star Vega is near the apex of the sun’s way, our sun’s direction of motion through space. Image via Fred Espenak at AstroPixels.com. Used with permission.

Sun’s motion in our galaxy

A friend from Australia wrote:

I seek to find out what speed our sun is traveling at and also how many years it takes to circumnavigate the galaxy.

Our sun takes a long time to circumnavigate the Milky Way, which is a collection of several hundred billion stars with an estimated diameter of about 100,000 light-years. There are various estimates for the speed the sun travels through the galaxy, but its speed is in the range of about 140 miles per second (225 km/sec).

Likewise, there are multiple estimates for the length of time it takes the sun to complete one circuit of the galaxy, but a typical estimate is about 230 million years.

That period of time – the length of the sun’s orbit around the Milky Way’s center – is sometimes called a cosmic year.

The solar antapex, opposite on the sky from the solar apex

The solar antapex is located opposite the solar apex on the celestial sphere, near the bright star Sirius. Therefore, our sun and planets travel more or less away from Sirius (that’s in the constellation Canis Major). Sirius is the sky’s brightest star. Not surprisingly, Vega and Sirius lie in opposite directions in Earth’s sky.

You can look for Sirius at this time of year, too. Remember, Vega resides almost exactly opposite Sirius. If you have an unobstructed horizon, this evening you might see Sirius low in the southeast as Vega sits low in the northwest.

At mid-northern latitudes, you’ll possibly see both stars around 7 to 8 p.m. local time (the time on your clock wherever you are) in early January. Sirius swings low in the southwest sky by around 3 to 4 a.m., at which time Vega reappears in the northeast sky (at mid-northern latitudes).

Use Orion’s Belt to find Sirius, the brightest star of the nighttime sky. From mid-latitudes in the Northern Hemisphere, you might see Sirius low in the southeast, as Vega sits low in the northwest.

Bottom line: Our sun – and solar system – are moving in space in the general direction of the solar apex, which is located near the star Vega.

The post Contemplate the apex of the sun in January first appeared on EarthSky.

from EarthSky https://ift.tt/YWPLZA3

From the Northern Hemisphere, on January evenings, not long after sunset, you can stand facing northwest, and you might spot the bright star Vega. If your sky is dark, you might also see its constellation Lyra the Harp. In its journey around the galaxy, our sun moves toward bright Vega. The point toward which we move – or the apex of the sun – is called the “solar apex.”

EarthSky’s 2026 lunar calendar is available now. Get yours today! Makes a great gift.

Contemplate the apex of the sun in January

From Northern Hemisphere locations on January evenings, look northwest. You’ll see the bright star Vega in the constellation Lyra the Harp. Our star, the sun, and its planets are moving through space toward the general direction of Vega. Astronomers call the sun’s direction of motion through its Milky Way neighborhood by a great old name: the solar apex or, more romantically, the apex of the sun’s way.

The solar apex isn’t exactly in Vega’s direction. It’s located in our sky in the direction of a constellation that’s harder to pick out … the constellation Hercules. This constellation is southwest of the star Vega and its constellation Lyra. It’s a location on the celestial sphere with these coordinates: 18h 28m 0s in right ascension, 30° N in declination.

How do we know our sun is moving in this direction? Astronomers find this point on our sky by measuring the motions of stars near the sun.

A star chart showing the location of the solar apex in the sky. It’s not far from Vega. Image via Stellarium. Used with permission.

Sun’s motion in its galactic neighborhood

Think back to when you last walked on a busy sidewalk. In general, most people are walking at a similar pace. At a distance, they look close together. But if you pick up your pace when walking toward them, people appear to be moving apart.

As the sun travels along its galactic sidewalk with neighboring stars, it moves slightly faster than the mean velocity of its neighbors. If you could fast-forward over several hundred thousand years, you’d notice the following: Nearby stars appear to move away from the solar apex. On the opposite side of the celestial sphere, called the antapex, you’d see the opposite: The distance between stars in the sky appears to get smaller.

You can see this effect in an animation from the European Space Agency, based on data from the Gaia space telescope. Scientists extrapolated the motion of 40,000 stars over 1.6 million years to see how they would appear to move in the sky. All these stars had known motions that Gaia measured and were within 326 light-years of the sun.

The trails show how far the stars move on the celestial sphere. It’s a pretty busy animation. But if you look closely, you’ll notice, towards the end, many (not all) stars on the upper left appear to be moving away from a central point: That’s the solar apex. And on the right, they appear to be getting closer to each other: That’s the antapex, which is opposite on the sky from the solar apex. You can read more about this video the ESA website.

Looking toward the solar apex

Vega is a bright star. So you can look for it and find it pretty easily. At this time of year from mid-northern latitudes, Vega appears over the northwestern horizon at dusk and early evening. It also appears low in the northeast sky in the predawn and dawn hours. To see a precise view – and time – for Vega from your location, try Stellarium Online.

So look for the star Vega and contemplate the fact that our sun and family of planets travel more or less toward it.

With its blue-white color, Vega also happens to be one of the loveliest stars you’ll ever see.

The blue-white star Vega is near the apex of the sun’s way, our sun’s direction of motion through space. Image via Fred Espenak at AstroPixels.com. Used with permission.

Sun’s motion in our galaxy

A friend from Australia wrote:

I seek to find out what speed our sun is traveling at and also how many years it takes to circumnavigate the galaxy.

Our sun takes a long time to circumnavigate the Milky Way, which is a collection of several hundred billion stars with an estimated diameter of about 100,000 light-years. There are various estimates for the speed the sun travels through the galaxy, but its speed is in the range of about 140 miles per second (225 km/sec).

Likewise, there are multiple estimates for the length of time it takes the sun to complete one circuit of the galaxy, but a typical estimate is about 230 million years.

That period of time – the length of the sun’s orbit around the Milky Way’s center – is sometimes called a cosmic year.

The solar antapex, opposite on the sky from the solar apex

The solar antapex is located opposite the solar apex on the celestial sphere, near the bright star Sirius. Therefore, our sun and planets travel more or less away from Sirius (that’s in the constellation Canis Major). Sirius is the sky’s brightest star. Not surprisingly, Vega and Sirius lie in opposite directions in Earth’s sky.

You can look for Sirius at this time of year, too. Remember, Vega resides almost exactly opposite Sirius. If you have an unobstructed horizon, this evening you might see Sirius low in the southeast as Vega sits low in the northwest.

At mid-northern latitudes, you’ll possibly see both stars around 7 to 8 p.m. local time (the time on your clock wherever you are) in early January. Sirius swings low in the southwest sky by around 3 to 4 a.m., at which time Vega reappears in the northeast sky (at mid-northern latitudes).

Use Orion’s Belt to find Sirius, the brightest star of the nighttime sky. From mid-latitudes in the Northern Hemisphere, you might see Sirius low in the southeast, as Vega sits low in the northwest.

Bottom line: Our sun – and solar system – are moving in space in the general direction of the solar apex, which is located near the star Vega.

The post Contemplate the apex of the sun in January first appeared on EarthSky.

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Foxes know the secret to surviving in nearly any habitat

Masters of adaptation and lightning-fast hunters, with a laugh you won’t forget! Foxes are full of surprises. Image via Jeremy Hynes/ Unsplash.

Foxes can be found in ecosystems all around the world. You can find different species of fox in dense forests, grasslands, arid deserts and even the icy Arctic. So what is the secret to their success? Foxes are intelligent animals that can adapt their behavior to fit with their environment. They have highly developed senses and impressive hunting skills, and they’re not afraid to eat whatever is available. In areas populated by humans, they can alter their schedules and change their diets. Plus, evolution has given them remarkable adaptations that allow them to thrive even in harsh environments.

Surprising facts about foxes’ amazing skills

Foxes can adjust their activity patterns according to food availability or the presence of other predators. And their tails are extraordinary tools. They provide stability while running, enable communication through subtle movements and act as an insulating layer that regulates temperature in both cold and warm climates.

Some of their most remarkable behaviors include:

Leaps of up to 7 feet (2 meters): In snowy areas, some foxes use a technique called pouncing. They spring into a rapid, precise arc to land on the snow and catch hidden rodents. Before leaping, they tilt their heads to listen to movements beneath the surface and calculate distance with astonishing accuracy.

Watch this red fox pouncing headfirst into snow. Video via Smithsonian Channel.

Strategic food hiding: When they acquire more food than they can eat, foxes bury it in small caches scattered throughout their territory. Their spatial memory allows them to remember dozens of these hiding spots for weeks.

Precise territorial marking: Foxes use scent glands, urine and visual signals to define hunting, travel and resting areas.

Over 40 different vocalizations: Foxes use screams, short barks, growls and even high-pitched “laughter” to communicate alarms, social contact, play or warnings.

Tickles! Video via Saveafox.

Notable speed and agility: Foxes can reach up to 31 miles per hour (50 kph) and react swiftly to obstacles or prey.

Chameleon-like fur in some species: The Arctic fox, for example, changes its coat color with the seasons as camouflage.

Extraordinary adaptation: Their varied diet and flexible behaviors allow foxes to thrive in vastly different environments.

The habitats and food sources of foxes in the wild

Foxes can live in temperate forests, grasslands, mountains, tundras, rocky areas and even deserts. Their omnivorous diet includes small mammals, birds, reptiles, insects, fruits, seeds and carrion, allowing them to exploit nearly any available resource.

Their underground dens are essential for their well-being, providing shelter from predators, a safe place to raise young and crucial thermal protection in extreme climates.

Foxes are highly adaptable survivors, combining intelligence, agility and keen senses to thrive in diverse and often harsh environments. Image via Birger Strahl/ Unsplash.

The origin of foxes

Foxes belong to the subfamily Vulpinae, within the family Canidae, which also includes wolves, coyotes and domestic dogs. The genus Vulpes contains the “true foxes,” which belong to a single evolutionary group.

Other genera — such as Urocyon, Lycalopex and Otocyon — are commonly called foxes because they share the typical fox-like traits, such as slender snouts, bushy tails and erect ears. Plus they have similar behaviors. However, despite these similarities, the non-Vulpes foxes are not considered true foxes, as their ancestry and genetic lineage are distinct from Vulpes. In total, there are approximately 37 species of foxes, including both true foxes and these other fox-like canids.

Each genus of foxes — Vulpes, Urocyon, Lycalopex, Otocyon and others — has developed unique adaptations to survive in its environment. While all share characteristic fox-like traits and behaviors, each genus exhibits particular skills suited to its habitat. This diversity shows how foxes can look and act similarly, yet each faces its own challenges in the wild.

Fox species and their traits and adaptations

Here are facts about some of the most peculiar species of foxes.

Red fox (Vulpes vulpes)

The red fox is the most widely distributed fox species in the world, found in Europe, Asia, North America and northern Africa. Its key strength is its exceptional behavioral flexibility. It quickly adapts to new climates, food sources and even urban environments, adjusting its habits to avoid danger and seize opportunities. This ability to learn and adapt has allowed the red fox to thrive on nearly every continent and in landscapes heavily altered by humans.

A red fox. Image via Cody Boileau/ Unsplash.

Gray fox (Urocyon cinereoargenteus)

Native to the Americas, the gray fox is one of the few canids capable of climbing trees. Its strong, curved claws, combined with excellent coordination, allow it to ascend sloped trunks and rest on elevated branches. This behavior gives it a unique advantage: it can avoid terrestrial predators and access fruits or nests in heights unreachable to other foxes.

A gray fox lying on a tree branch. Image via Mitchell Hamilton/ Unsplash.

Culpeo (Lycalopex culpaeus)

Native to the Andes and nearby regions of South America, the culpeo is the largest South American fox. It is highly social, hunting in small groups, which allows it to tackle relatively large prey like birds and rabbits. Working together gives it a survival edge across the varied landscapes it inhabits, from rugged mountains to dry shrublands.

A culpeo. Image via Juan Marcos Alvarez/ Pexels.

Bat-eared fox (Otocyon megalotis)

Native to Africa, the bat-eared fox is primarily insectivorous, feeding mostly on termites and other insects, which makes it unusual among foxes. It also displays a high level of social behavior, often foraging in pairs or small family groups.

A bat-eared fox. Image via Derek Keats/ Pexels.

Extreme cases: Foxes in ice and sand

Arctic fox (Vulpes lagopus), master of extreme cold

Perfectly adapted to temperatures that can drop below –58°F (–50°C), the Arctic fox has fur that changes with the seasons. It’s white in winter to blend with the snow and brown or gray in summer to match the tundra. Interestingly, some Arctic foxes carry a rare genetic variation known as the “blue morph.” These foxes remain dark all year, providing a striking exception to their seasonal camouflage.

An Arctic fox. Image via Jonatan Pie/ Unsplash.

The Arctic fox has paws fully covered in fur, which prevents heat loss and enables it to walk on snow, ice or sharp rocks. Its metabolism is so efficient that it can minimize energy expenditure during periods of scarcity.

Arctic foxes change color with the seasons, except the rare blue morph, which stays dark year-round. Image via Jonatan Pie/ Unsplash.

Desert fox (Vulpes zerda) or fennec, survivor of sand and heat

The desert fox is small, light and extraordinarily adapted to the desert. Its light-colored fur reflects some solar radiation, and its enormous ears — up to 6 inches (15 cm) — act as a natural cooling system.

The desert fox’s ears contain a dense network of blood vessels just under the skin. When the fox needs to cool down, blood flow to the ears increases. The blood cools as it passes through the thin, exposed surface and returns to the body at a lower temperature, reducing internal heat.

Its tail, moderately bushy compared to other foxes, helps protect against both daytime heat and nighttime cold. It also provides balance on sand and can be wrapped around the body, including the nose, while sleeping to conserve warmth. This combination of adaptations makes the desert fox one of the most specialized foxes on the planet.

A desert fox. Image via Darrenquigley32/ Pixabay.

Birth, growth and learning in fox cubs

Fox cubs, also called kits or pups, are born after about eight weeks of gestation in protected dens. At birth, they are completely dependent: blind, deaf and covered with soft, dark fur.

During their first weeks, they stay inside the den, where the mother feeds and protects them. As they grow, they begin to explore cautiously. In many species, both parents help raise the young: the male provides food while the female cares for the cubs.

Learning is crucial. Young foxes play games that simulate hunting, chasing and defensive techniques. By six to seven months of age, they already have the skills needed to become independent and establish their own territory.

Fox cubs have darker fur. Image via Rottonara/ Pixabay.

Conservation status of the fox

Many fox species maintain stable populations, like the red fox, but others are threatened by habitat loss, territorial fragmentation and climate change. Conserving ecosystems is key to their long-term survival.

With their soft steps and lively gaze, foxes traverse the world like little living enigmas, reminding us that even the most discreet animals have astonishing stories to tell.

A quiet gaze that holds the wisdom of the wild. Image via Greg Johnson/ Unsplash.

Bottom line: From Arctic snow to desert sands, foxes survive in the wild with cunning, agility and impressive adaptability.

Read more:

How the lynx beat extinction: Lifeform of the week

The yak is an imposing giant of the high mountains

Kangaroo rats are desert dwellers: Lifeform of the week

The post Foxes know the secret to surviving in nearly any habitat first appeared on EarthSky.

from EarthSky https://ift.tt/dbYA0xh

Masters of adaptation and lightning-fast hunters, with a laugh you won’t forget! Foxes are full of surprises. Image via Jeremy Hynes/ Unsplash.

Foxes can be found in ecosystems all around the world. You can find different species of fox in dense forests, grasslands, arid deserts and even the icy Arctic. So what is the secret to their success? Foxes are intelligent animals that can adapt their behavior to fit with their environment. They have highly developed senses and impressive hunting skills, and they’re not afraid to eat whatever is available. In areas populated by humans, they can alter their schedules and change their diets. Plus, evolution has given them remarkable adaptations that allow them to thrive even in harsh environments.

Surprising facts about foxes’ amazing skills

Foxes can adjust their activity patterns according to food availability or the presence of other predators. And their tails are extraordinary tools. They provide stability while running, enable communication through subtle movements and act as an insulating layer that regulates temperature in both cold and warm climates.

Some of their most remarkable behaviors include:

Leaps of up to 7 feet (2 meters): In snowy areas, some foxes use a technique called pouncing. They spring into a rapid, precise arc to land on the snow and catch hidden rodents. Before leaping, they tilt their heads to listen to movements beneath the surface and calculate distance with astonishing accuracy.

Watch this red fox pouncing headfirst into snow. Video via Smithsonian Channel.

Strategic food hiding: When they acquire more food than they can eat, foxes bury it in small caches scattered throughout their territory. Their spatial memory allows them to remember dozens of these hiding spots for weeks.

Precise territorial marking: Foxes use scent glands, urine and visual signals to define hunting, travel and resting areas.

Over 40 different vocalizations: Foxes use screams, short barks, growls and even high-pitched “laughter” to communicate alarms, social contact, play or warnings.

Tickles! Video via Saveafox.

Notable speed and agility: Foxes can reach up to 31 miles per hour (50 kph) and react swiftly to obstacles or prey.

Chameleon-like fur in some species: The Arctic fox, for example, changes its coat color with the seasons as camouflage.

Extraordinary adaptation: Their varied diet and flexible behaviors allow foxes to thrive in vastly different environments.

The habitats and food sources of foxes in the wild

Foxes can live in temperate forests, grasslands, mountains, tundras, rocky areas and even deserts. Their omnivorous diet includes small mammals, birds, reptiles, insects, fruits, seeds and carrion, allowing them to exploit nearly any available resource.

Their underground dens are essential for their well-being, providing shelter from predators, a safe place to raise young and crucial thermal protection in extreme climates.

Foxes are highly adaptable survivors, combining intelligence, agility and keen senses to thrive in diverse and often harsh environments. Image via Birger Strahl/ Unsplash.

The origin of foxes

Foxes belong to the subfamily Vulpinae, within the family Canidae, which also includes wolves, coyotes and domestic dogs. The genus Vulpes contains the “true foxes,” which belong to a single evolutionary group.

Other genera — such as Urocyon, Lycalopex and Otocyon — are commonly called foxes because they share the typical fox-like traits, such as slender snouts, bushy tails and erect ears. Plus they have similar behaviors. However, despite these similarities, the non-Vulpes foxes are not considered true foxes, as their ancestry and genetic lineage are distinct from Vulpes. In total, there are approximately 37 species of foxes, including both true foxes and these other fox-like canids.

Each genus of foxes — Vulpes, Urocyon, Lycalopex, Otocyon and others — has developed unique adaptations to survive in its environment. While all share characteristic fox-like traits and behaviors, each genus exhibits particular skills suited to its habitat. This diversity shows how foxes can look and act similarly, yet each faces its own challenges in the wild.

Fox species and their traits and adaptations

Here are facts about some of the most peculiar species of foxes.

Red fox (Vulpes vulpes)

The red fox is the most widely distributed fox species in the world, found in Europe, Asia, North America and northern Africa. Its key strength is its exceptional behavioral flexibility. It quickly adapts to new climates, food sources and even urban environments, adjusting its habits to avoid danger and seize opportunities. This ability to learn and adapt has allowed the red fox to thrive on nearly every continent and in landscapes heavily altered by humans.

A red fox. Image via Cody Boileau/ Unsplash.

Gray fox (Urocyon cinereoargenteus)

Native to the Americas, the gray fox is one of the few canids capable of climbing trees. Its strong, curved claws, combined with excellent coordination, allow it to ascend sloped trunks and rest on elevated branches. This behavior gives it a unique advantage: it can avoid terrestrial predators and access fruits or nests in heights unreachable to other foxes.

A gray fox lying on a tree branch. Image via Mitchell Hamilton/ Unsplash.

Culpeo (Lycalopex culpaeus)

Native to the Andes and nearby regions of South America, the culpeo is the largest South American fox. It is highly social, hunting in small groups, which allows it to tackle relatively large prey like birds and rabbits. Working together gives it a survival edge across the varied landscapes it inhabits, from rugged mountains to dry shrublands.

A culpeo. Image via Juan Marcos Alvarez/ Pexels.

Bat-eared fox (Otocyon megalotis)

Native to Africa, the bat-eared fox is primarily insectivorous, feeding mostly on termites and other insects, which makes it unusual among foxes. It also displays a high level of social behavior, often foraging in pairs or small family groups.

A bat-eared fox. Image via Derek Keats/ Pexels.

Extreme cases: Foxes in ice and sand

Arctic fox (Vulpes lagopus), master of extreme cold

Perfectly adapted to temperatures that can drop below –58°F (–50°C), the Arctic fox has fur that changes with the seasons. It’s white in winter to blend with the snow and brown or gray in summer to match the tundra. Interestingly, some Arctic foxes carry a rare genetic variation known as the “blue morph.” These foxes remain dark all year, providing a striking exception to their seasonal camouflage.

An Arctic fox. Image via Jonatan Pie/ Unsplash.

The Arctic fox has paws fully covered in fur, which prevents heat loss and enables it to walk on snow, ice or sharp rocks. Its metabolism is so efficient that it can minimize energy expenditure during periods of scarcity.

Arctic foxes change color with the seasons, except the rare blue morph, which stays dark year-round. Image via Jonatan Pie/ Unsplash.

Desert fox (Vulpes zerda) or fennec, survivor of sand and heat

The desert fox is small, light and extraordinarily adapted to the desert. Its light-colored fur reflects some solar radiation, and its enormous ears — up to 6 inches (15 cm) — act as a natural cooling system.

The desert fox’s ears contain a dense network of blood vessels just under the skin. When the fox needs to cool down, blood flow to the ears increases. The blood cools as it passes through the thin, exposed surface and returns to the body at a lower temperature, reducing internal heat.

Its tail, moderately bushy compared to other foxes, helps protect against both daytime heat and nighttime cold. It also provides balance on sand and can be wrapped around the body, including the nose, while sleeping to conserve warmth. This combination of adaptations makes the desert fox one of the most specialized foxes on the planet.

A desert fox. Image via Darrenquigley32/ Pixabay.

Birth, growth and learning in fox cubs

Fox cubs, also called kits or pups, are born after about eight weeks of gestation in protected dens. At birth, they are completely dependent: blind, deaf and covered with soft, dark fur.

During their first weeks, they stay inside the den, where the mother feeds and protects them. As they grow, they begin to explore cautiously. In many species, both parents help raise the young: the male provides food while the female cares for the cubs.

Learning is crucial. Young foxes play games that simulate hunting, chasing and defensive techniques. By six to seven months of age, they already have the skills needed to become independent and establish their own territory.

Fox cubs have darker fur. Image via Rottonara/ Pixabay.

Conservation status of the fox

Many fox species maintain stable populations, like the red fox, but others are threatened by habitat loss, territorial fragmentation and climate change. Conserving ecosystems is key to their long-term survival.

With their soft steps and lively gaze, foxes traverse the world like little living enigmas, reminding us that even the most discreet animals have astonishing stories to tell.

A quiet gaze that holds the wisdom of the wild. Image via Greg Johnson/ Unsplash.

Bottom line: From Arctic snow to desert sands, foxes survive in the wild with cunning, agility and impressive adaptability.

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