Astronomy Essentials

Mars at its biggest and brightest tonight!


We have our best views of Mars only once every 2 years. And that time has come! Watch a replay of our livestream for more information about Mars.

  • Mars can appear bright or faint in our sky. 2024 was mostly a faint year, but Mars has been steadily brightening, and it’s very noticeable now, nearly as bright as the sky’s brightest star. The perfect time to observe Mars for this two-year period is here.
  • Mars grows brighter as Earth catches up with Mars, in our smaller, faster orbit around the sun. The opposition of Mars – when Earth will pass between it and the sun, bringing Mars closest and brightest – takes place tonight, January 15-16, 2025.
  • Watch for Mars! It’s up in the east by late evening, following blazing Jupiter across the sky.

The 2025 EarthSky lunar calendar is available now. Get yours today!

Mars in 2024 and 2025

Opposition for Mars last fell on December 7-8, 2022. That’s when our planet Earth last flew between Mars and the sun. Mars will reach opposition again at 3 UTC on January 16, 2025. Throughout November and December of last year, Mars was growing brighter. It’s now easy to spot late at night through dawn.
Mars was closest to Earth at 14 UTC on January 12, 2025. It was 5.3 light-minutes away at a distance of 0.642 astronomical units (59,703,891 miles or 96,084,099 kilometers).
How to see Mars in the sky: Mars is now about as bright as Sirius, the sky’s brightest star. On January 13, 2025, Mars appeared very close to the full Wolf Moon. In fact, some observers saw the moon pass in front of – or occult – Mars. See a photo gallery here.
Note: Mars reaches opposition about every 26 months, or about every two Earth years. Tonight, the night of January 15-16, it’s at opposition, the point at which Earth catches up with Mars as our planet races along our smaller, faster orbit around the sun.

Charts for Mars in January 2025

Chart showing the moon as an almost round disk. Two dots lie to its left, Castor and Pollux. A red dot, Mars, lies below the two dots, almost in a line with them.
On the evening of January 12, 2025, the bright waxing gibbous moon moved close to Mars and the twin stars of Gemini, Castor and Pollux. They rose around sunset and set around sunrise. Mars was closest to Earth on January 12. The red planet will be at opposition – when Earth flies between it and the sun – on January 15-16. Mars will be at its brightest for 2025 this month. Chart via EarthSky.
Chart showing a white disk as the full moon. It lies next to a red dot representing Mars and below the white dots of the stars Castor and Pollux.
The full Wolf Moon fell at 22:27 UTC (4:27 p.m. CST) on January 13, 2025, and was close to the red planet Mars. Observers in parts of North America, northwest Africa, Azores and Cape Verde Islands saw the moon occult – or pass in front of – Mars at 4 UTC on January 14 (10 p.m. CST on January 13). See a photo gallery of the occultation. Also nearby were Castor and Pollux, the twin stars of Gemini. The moon, Mars and twin stars were almost in a straight line and visible all night. Chart via EarthSky.
Chart showing a red dot for Mars moving to the upper right along a red line and past two white dots on the left for Castor and Pollux.
Mars is on display this month and closing in on the bright stars Castor and Pollux. The red planet will be visible all night this month. Mars was closest to Earth – about 5.3 light-minutes away – on January 12. Mars was near the full moon on January 13 and was occulted by the moon at 4 UTC on January 14. Then it’ll lie opposite the sun from Earth – or at opposition – on January 15-16. It’ll reach magnitude -1.4, matching that of Sirius, our brightest star. Mars is closest to Earth roughly every 2 years. So we won’t see Mars this bright again until 2027. Chart via EarthSky.

Sometimes, Mars is faint

Mars last reached opposition on December 8, 2022. It remained bright through early 2023, then started to rapidly fade through the end of the year. Mars reached superior conjunction – when it passed behind the sun as viewed from Earth – on November 18, 2023. It began 2024 as a faint object, far across the solar system from us. But now Mars looks big and bright again.

4 photos of Mars, ranging in size from full size, to about half size, to a tiny dot.
The geometry of Mars’ orbit is such that it spends much longer periods of time at large distances from the Earth than it does close to us, which provides added incentive to observe it in the weeks around opposition. When it passes opposition, every 2 years, Mars appears large and bright for only a few weeks. Here’s a comparison of the apparent size of Mars when seen at its closest opposition, around its opposition in 2025, and at its farthest opposition. Also shown is how Mars appears when it’s most distant from the Earth at solar conjunction. Image via Dominic Ford/ In-The-Sky.org. Used with permission.

Sometimes, Mars is bright

Mars’ dramatic swings in brightness (and its red color) are why the early stargazers named Mars for their god of war.

Sometimes the war god rests. And sometimes he grows fierce! These changes are part of the reason Mars is so fascinating to watch in the night sky.

Five images of Mars, full size, about 3/4 size, and half size or less, for succeeding dates.
When Mars passes opposition, every 2 years, it appears large and bright for only a few weeks. The panel above shows the change in Mars’ apparent size from November 20, 2024, to March 12, 2025. Mars will appear 14.6 arcseconds wide on January 15, 2025. Image via Dominic Ford/ In-The-Sky.org. Used with permission.
Diagram: 12 spheres representing Mars in 2024 showing its size changes month to month.
As Mars races towards its next opposition in January 2025, it grows in apparent size and increases in brightness. Chart via Guy Ottewell’s 2024 Astronomical Calendar. Used with permission.

Want to follow Mars? Bookmark EarthSky’s monthly night sky guide.

Mars isn’t very big

To understand why Mars varies so much in brightness in Earth’s sky, first realize that it isn’t a very big world. It’s only 4,219 miles (6,790 km) in diameter, making it only slightly more than half Earth’s size (7,922 miles or 12,750 km in diameter).

On the other hand, consider Mars in contrast to Jupiter, the biggest planet in our solar system. Jupiter is 86,881 miles (140,000 km) in diameter. As an illustration, more than 20 planets the size of Mars could be lined up side by side in front of Jupiter. Basically, Jupiter always looks bright, because it’s so big.

Not so for little Mars, however. Rather, its extremes in brightness have to do with its nearness (or lack of nearness) to Earth.

Space photos of Earth and Mars side by side, on black background, with Earth much bigger.
Mars isn’t very big, so its brightness – when it is bright – isn’t due to its bigness, as is true of Jupiter. Mars’ brightness, or lack of brightness, is all about how close we are to the red planet. It’s all about where Earth and Mars are, relative to each other, in their respective orbits around the sun. Image via NASA.

Future Martian oppositions

As mentioned above, the next opposition of Mars – when will appear at its brightest in Earth’s sky for that two-year period – will be January 2025. Check out the chart at C. Seligman’s Mars oppositions page that lists all oppositions of Mars from 1995 to 2037.

Earth and Mars orbits with Mars in different sizes at different points around its orbit.
There’s a 15-year cycle of Mars, whereby the red planet is brighter and fainter at opposition. In July 2018, we were at the peak of the 2-year cycle – and the peak of the 15-year cycle – and Mars was very, very bright! In 2020, we were also at the peak of the 2-year cycle; however, Earth and Mars were farther apart at Mars’ opposition than they were in 2018. Still, 2020’s opposition of Mars was excellent. And, in December 2022, Mars had a good opposition but appeared smaller and dimmer than in 2020, since we were farther away from it. And the January 2025 opposition will find Mars smaller and dimmer than Mars was in 2022. Diagram by Roy L. Bishop. Copyright Royal Astronomical Society of Canada. Used with permission. Visit the RASC eStore to purchase the Observer’s Handbook, a necessary tool for all skywatchers.

EarthSky Community Photos

Composite of Mars path across the sky, a chain of red dots making a large loop against a starry background.
View at EarthSky Community Photos. | Paolo Bardelli of Italy made this composite image and wrote: “On January 16, 2025, Mars will be in opposition, the previous one occurred on December 8, 2022, when it became the brightest object in the night sky. During these periods, tracing the apparent motion of the red planet from evening to evening is very interesting, as a real ‘noose’ is created, with a double reversal of its movement. This put ancient sky observers in crisis at the time when the geocentric theory was dominant. Putting things in their place, it turned out to be a simple perspective effect, due to the mutual motion of Earth and Mars. This image is the sum of a sequence taken every useful evening, clouds permitting, from August 12, 2022, to March 22, 2023. The background is the sum of 22 shots of the area of the sky where Mars was located, the rich star field of the constellation Taurus. By coincidence, in February 2023 the path of comet C/2022 E3 (ZTF) crossed the noose.” Thank you, Paolo!
Starry sky with red Mars and Orion, Taurus, and the Pleiades over a rocky horizon.
View at EarthSky Community Photos. | Miguel Ventura in Fafe, Portugal, captured this image on August 28, 2022, and wrote: “Every now and then and in addition to its natural beauty, the night sky and the whims of the universe offer us moments like this. With some planning and luck in the mix (truce from the clouds) I was able to photograph this magnificent alignment. We can see the Pleiades and the constellation Taurus with the planet Mars between these 2 … below near the horizon the imposing constellation Orion appears, announcing the autumn sky.” Thank you, Miguel!

Seeing red

Mars appears as a reddish light in the sky and, therefore, is often called the red planet. Other obvious red dots in the sky are reddish-orange Aldebaran and the famous red supergiant Betelgeuse. So, it is fun to contrast Mars’ color and intensity of red with that of Aldebaran or Betelgeuse.

And then there is red Antares. Antares is Greek for rival of Ares (Ares being the Greek name for Mars). Antares is sometimes said to be the anti-Mars due to its competing red color. For a few months every couple of years Mars is much brighter than Antares. Also, every couple of years Mars passes near Antares, as if taunting the star. Mars moves rapidly through the heavens and Antares is fixed to the starry firmament.

What makes them red?

Surface temperature is what determines the colors of the stars. The hottest stars are blue and the coolest stars are red. In fact, from hottest to coolest, the colors of stars range from blue, white, yellow, orange and red. And while the colors of stars might be hard to detect, some stars – like Aldebaran, Antares and Betelgeuse – are noticeably colorful.

On the other hand, Mars appears red for a different reason. It’s red because of iron oxide in the dust that covers this desert world. Iron oxide gives rust and blood their red color. Rovers on Mars sampled the Martian dust and determined it contains three colors: reds, browns and oranges. So those three colors are what you may see when you gaze upon Mars.

Do you see red when you look at Mars, Aldebaran, Antares and Betelgeuse? Are they the same color? Do you see any other colors of stars?

Orange ball with well-defined dark marks and white spot at the north pole.
View at EarthSky Community Photos. | Nancy Ricigliano captured Mars from Long Island, New York, on October 6, 2020, when it was closest to Earth. Thank you, Nancy. See more photos of Mars at its closest in 2020.

Bottom line: Earth has been racing up behind Mars in orbit, bringing Mars to opposition tonight. That means Mars will look big and bright tonight. It will be nearly as bright as the brightest star in our sky!

Moon and Mars! Fav photos of December 7 occultation

Photos of bright Mars in 2018, from the EarthSky community

Photos of bright Mars in 2020, from the EarthSky community

Posted 
January 15, 2025
 in 
Astronomy Essentials

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