How Mars Turned Red: Surprising New Theory

Mars was not always red, according to a new theory for how the planet took on its characteristic ruddy hue.

Until recently, Mars' color

"That was a surprise to everybody," said Jonathan

Now new research has found a possible mechanism to explain

In the lab

To test the idea, Merrison and colleagues sealed samples of

The scientists then added powdered magnetite, an iron oxide

As the researchers continued to tumble the samples, they

"We think we have a process that explains how the dust

As the sand grains turned over in the flasks and hit each

Hematite is an iron oxide that is deep red in color. It only

"When we finished we could see red stuff on the side of

Same on Mars?

Though they can't yet prove that this is what happened on

In fact, since the process can occur relatively quickly, it

"I think it means that Mars wasn't always red,"

Merrison presented the results last week at the European

Clara Moskowitz is a science and space writer who joined the Space.com team in 2008 and served as Assistant Managing Editor from 2011 to 2013. Clara has a bachelor's degree in astronomy and physics from Wesleyan University, and a graduate certificate in science writing from the University of California, Santa Cruz. She covers everything from astronomy to human spaceflight and once aced a NASTAR suborbital spaceflight training program for space missions. Clara is currently Associate Editor of Scientific American. To see her latest project is, follow Clara on Twitter.