How long is a day on Mars? Great question! There are two ways to determine the length of a day on any celestial body. The sidereal day and the solar day. A sidereal day on Mars is the length of time that it takes the planet to rotate once on its axis. A sidereal day on Mars lasts 24 hours 37 minutes and 22 seconds. The solar day is how long it takes the Sun to return to the meridian. This position changes slightly each day, but a solar day on Mars lasts 24 hours 39 minutes and 35 seconds.
There are many interesting facts about Mars beyond how long the day is. Here are a few of them that we hope will inspire you to research the planet further.
It snows on Mars. In 2008, NASA’s Phoenix Lander found water ice in the polar regions of the planet. This was an expected finding, but scientists were not prepared to observe snow falling from clouds. The snow combined soil chemistry experiments led scientists to believe that the landing site had a wetter and warmer climate in the last few million years. More extensive experiments will be preformed by the Mars Science Laboratory mission in 2011. The rover on that mission, Curiosity, will examine rocks and soil for geologic processes in hopes of learning more about the present and past habitability of the planet.
Many people have talked about the man in the moon, but Mars really does appear to have a face. Not a real one, but a visual mind trick called pareidolia makes a mesa in the Cydonia region on the Martian surface appear to be a face.
Mars can be dominated by dust storms from time to time. These storms have been known to grow to be thousands of kilometers across, occasionally encircling the entire planet and covering everything in a thick haze of dust. When these storms become that large, they prevent direct observation of the Martian surface. The global dust storms warm up its atmosphere. Sunlight warms up the dust particles in the air and can raise the surface temperature by dozens of degrees.
As you can tell from the facts in this article, Mars can be a harsh and volatile planet. Just knowing the answer to ”how long is a day on Mars?”, will only give you a small picture of what is happening on the Red Planet. Good luck finding out the rest of the story.
Want more information? Learn about living on Mars time. NASA has a great clock for calculating Mars time.
Finally, if you’d like to learn more about Mars in general, we have done several podcast episodes about the Red Planet at Astronomy Cast. Episode 52: Mars, and Episode 91: The Search for Water on Mars.