The Planet Mars, Earth's Neighbor

Could We Live on Mars?

Ever since astronomers in the 1800s noticed markings on Mars that looked like canals, people have imagined that there could be life on the planet (Martians!).

• Of all the planets, Mars’ climate is most like Earth’s.  Our other neighbor, Venus, is hotter than humans could ever endure.
• Still, Mars is not exactly like Earth. The air on Mars is as thin as the atmosphere 55,000 feet above Earth, and it’s almost entirely carbon dioxide. (That’s what we exhale. We inhale oxygen.)
• Mars has seasons like Earth. However, the average temperature on Mars is about -80°F (-62°C). Humans will have to build and live in climate-controlled, synthetic bubbles if they are going to survive on Mars!

Mars Geography

Scientists know a lot about Mars, thanks to two rovers, Spirit and Opportunity, that landed on the planet in 2004 and sent back photographs. (Spirit is now a stationary research platform after getting stuck in a Martian sandtrap.)

• Mars has polar ice caps, like those in the Arctic regions on Earth.
• It has deserts similar to Death Valley.
• Mars has craters that were once volcanoes like the ones in Hawaii. One of the most amazing land features on Mars is Olympus Mons, a 15-mile-high volcano.
• Another impressive feature on Mars is Valles Marineris, a huge canyon that is as wide as the continental United States!

How Far Away is Mars?

Mars is about half the size of Earth, so it’s not easy to see. Although the two planets are closest together every 26 months or so, the distance between them at this time can vary, and Mars can be hard to view even then.

• On average, Mars is about 45 million miles from Earth.
• Every 15 years or so, it comes as close as 38 million miles.
• In August 2003, Earth and Mars were closer than they have been in 60,000 years—close enough to get people thinking about visiting our reddish relative.

The best time to see Mars is in the late summer. Look low in the sky during August and September for the yellow-orange ball. It will be the brightest thing you see.

Martian Facts

• Tuesday (Mardi, in French) was named for Mars. So was March.
• More than half the space probes to Mars have blown up or disappeared.
• A Martian year is 687 Earth days.
• A meteorite from Mars was found in Antarctica.
• The names of Mars’ two moons, Phobos and Deimos, come from the Greek words for fear and panic.
• Although Mars is smaller than Earth, both have the same land mass because so much of Earth is covered by water.