How Big is Mars? | Universe Today

Written by John Carl Villanueva

Planet Mars' Olympus Mons holds the record for the tallest known peak in the entire Solar System. Having a height three times taller than Mount Everest's and a base wide enough to prevent an observer at the base from seeing the top, you would have expected Mars to be on a relatively big planet. But did you know that Mars is much smaller than Earth? So how big is Mars?

The radius of Mars is only about half that of the Earth's radius; roughly 3,396 km at the equator and 3,376 km at the poles. For comparison, the earth's equatorial radius is 6,378 km, while its polar radius is 6,357 km.

These radii give Mars a surface area roughly only 28.4% of Earth's or 144,798,500 km². The Pacific Ocean is even larger, with an area of roughly 169,200,000 km².

The dimensions of Mars also gives it a volume approximately equal to 1.6318×10¹¹ km² and a mass approximately equal to 6.4185×10²³ kg. That's only about 15.1% and 10.7% that of the Earth's, respectively.

Despite its noticeably smaller size than the Earth, Mars has more majestic geographical features.

For instance, there's Valles Marineris, a 4,000 km-long and 7 km-deep canyon that spans about one-fifth of the entire planet's circumference. It is so long that it's even longer than the length of Europe. If you compare the Grand Canyon to it, Colorado's pride and joy won't look so grand anymore.

Want to know how long the Grand Canyon is? 446 km. That's very long, yes. But that's only a little over 10% the length of Valles Marineris.

That's not the only large geographical feature on Mars. Ma'adim Vallis, is another canyon on Mars that's larger then the Grand Canyon, with a length of 700 km. Then there's an impact crater that's been found to be larger than the combined surface area of the continents of Asia, Europe, and Australia.

Now that you know about these extremely majestic geographical features on Mars, the next time someone asks you, "How big is Mars?" you can tell them how it is much smaller than the Earth … but you can also add the salient features that make the Red Planet much more interesting when it comes to a discussion on sizes.

We've got more articles about the Planet Mars here on Universe Today. Click on that link or read about interesting facts about the Planet Mars.

There's more from NASA: "Unmasking the Face on Mars" and "Mars Shoreline Tests: Massifs in the Cydonia Region"

Here are two episodes at Astronomy Cast that you might want to check out as well:
Stellar Roche Limits, Seeing Black Holes, and Water on Mars
The Search for Extraterrestrial Intelligence

Filed under: Astronomy

Tags: how big is mars, Mars, olympus mons, pacific ocean