We have our best views of Mars only once every two years. And that time is approaching! Watch a replay of our livestream for more information about Mars.
Mars can appear bright or faint in our sky. 2024 has been mostly a faint year, but Mars has been steadily brightening. It’s beginning to get bright! The time to start observing Mars for this two-year period is here.
Mars is growing brighter as Earth catches up with Mars, in our smaller, faster orbit around the sun. The next opposition of Mars – when Earth will pass between it and the sun, bringing Mars closest and brightest – will come on January 15-16, 2025.
By the end of 2024, Mars will shine brightly at -1.2 magnitude. That’s brighter than most stars! Start watching it now.
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 2024, Mars has been growing brighter. It’s now easy to spot late at night or in the morning before dawn. How to see Mars in the sky: Mars will be shining at magnitude -0.3 by the end of November. It’ll also be rising several hours after sunset by month’s end. Note: Mars reaches opposition about every 26 months, or about every two Earth years. So Mars alternates between appearing bright and faint in our sky. It was bright in late 2022 and early 2023. But by September 2023, Mars faded dramatically in brightness and disappeared in the sunset glare in October 2023. It last passed behind the sun on November 18, 2023. It’s now racing toward its January 15-16, 2025, opposition.
Mars chart for December
Mars will lie in front of the constellation of Cancer the Crab and not far from the twin stars of Gemini: Castor and Pollux. And it’ll make a beeline toward the Beehive star cluster. It’ll rise in the late evening and will be obvious in the sky before dawn. Mars brightens to magnitude -1.0 this month and will be at its closest to Earth in January 2025. The moon will occult – or pass in front of – Mars at 9 UTC on December 18, visible from parts of Canada, Greenland, eastern Russia and Alaska and other locations. Chart via EarthSky.The waning gibbous moon will lie close to the red planet Mars on the evening of December 17, 2024. At 9 UTC on the morning of December 18, 2024, the moon will occult – or pass in front of – Mars, visible from parts of Canada, Greenland, eastern Russia and Alaska and other locations. Also nearby will be the twin stars of Gemini: Castor and Pollux. They’ll rise several hours after sunset and be visible through dawn. 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 is getting bright again.
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.
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.As Mars races towards its next opposition in January 2025, it’ll grow in apparent size and increase in brightness. Chart via Guy Ottewell’s 2024 Astronomical Calendar. Used with permission.
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.
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.
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
View at EarthSky Community Photos. | Paolo Bardelli of Italy made this composite image and said: “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 del Toro (Taurus). By coincidence, in February 2023 the path of comet C/2022 E3 (ZTF) crossed the noose.” Thank you, Paolo!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 of Taurus with the planet Mars between these 2 … below near the horizon the imposing constellation of 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 its 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?
Bottom line: Mars is getting bright! And it has shifted into the evening sky. By the end of 2024, it’ll become much more noticeable. Its opposition, when it’ll be brightest for this two-year period, will fall in January 2025.
Our Editor-in-Chief Deborah Byrd works to keep all the astronomy balls in the air between EarthSky's website, YouTube page and social media platforms. She's the primary editor of our popular daily newsletter and a frequent host of EarthSky livestreams. Deborah created the EarthSky radio series in 1991 and founded EarthSky.org in 1994. Prior to that, she had worked for the University of Texas McDonald Observatory since 1976, and created and produced their Star Date radio series. She has won a galaxy of awards from the broadcasting and science communities, including having an asteroid named 3505 Byrd in her honor. In 2020, she won the Education Prize from the American Astronomical Society, the largest organization of professional astronomers in North America. A science communicator and educator since 1976, Byrd believes in science as a force for good in the world and a vital tool for the 21st century. "Being an EarthSky editor is like hosting a big global party for cool nature-lovers," she says.
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