Mars Close to Earth | Universe Today

Written by Fraser Cain

Earth is the 3rd planet from the Sun, and Mars is the 4th planet. There are times when they're on opposite sides of the Sun, and other times when they're on the same side of the Sun; this is called opposition, when Mars is closest to Earth. So, when is Mars close to Earth?

Earth takes 365 days to orbit the Sun, and Mars takes a total of 687 days to complete one revolution. That means that Mars takes 1.88 times longer to go around the Sun than Earth. It turns out that Earth and Mars are close to one another every 26 months.

When Mars is close to Earth, it's only 55.7 million km from Earth. That's when Mars is in opposition. And then when Earth and Mars are on opposite sides of the Sun, Mars is 401.3 million km from Earth.

Here is a list of Mars opposition dates, when Mars will be closest to Earth:
January 29, 2010
March 3, 2012
April 8, 2014
May 22, 2016
July 27, 2018
October 13, 2020

You might have heard a rumor that Mars will look incredibly large when it's closest to Earth, but that's actually a myth. Even at its closest point, Mars never looks any bigger than a bright star.

We've written many articles about Mars for Universe Today. Here's an article about how Mars can't look as big as the Moon in the sky, and here's an article about the closest planet to Mars.

You can learn more about the Mars close to Earth hoax from Snopes.com.

We've recorded several episodes of Astronomy Cast about Mars. Listen here, Episode 52: Mars.

Filed under: Astronomy