How Far is Mars? | Universe Today

Written by Fraser Cain

How far is Mars from Earth? The minimum distance from Earth to Mars is 55.7 million km, or 34.6 million miles.

This number is a minimum, though. Keep in mind that Earth and Mars are both orbiting around the Sun. They're at their closest when they're lined up Sun – Earth – Mars. At this closest point, the two planets are only 55.7 million km apart. But they're at their most distant point when they're aligned Earth – Sun – Mars. Then they're 401.3 million km apart.

With such a big variation in distance, Mars can be dim or bright in the sky depending on how far it is. And this closest point is achieved every 26 months or so, which astronomers call opposition. Just before a Mars opposition is the best time to launch spacecraft to make the long journey to Mars. It allows them to use the least amount of fuel, reaching the Red Planet in just a few months.

We have written many articles about Mars for Universe Today. Here's an article about a strange rock found on Mars. And here's an article about how spacecraft might be able to make the trip to Mars in only 39 days in the future.

If you'd like more info on Mars, check out NASA's Mars Exploration page. You can get more info from NASA's World Book on Mars.

We have also recorded an entire episode of Astronomy Cast all about Mars. Listen here, Episode 52: Mars.

Filed under: Astronomy