New discoveries are making scientists change some old ideas: They now suspect that Mars may be more like Earth than they thought. Most interestingly, Mars seems to have small bits of water spread around its surface.

The new information was uncovered by a car-sized robot named Curiosity. This robot, or rover, was launched by NASA from Earth in 2011. It is equipped with very advanced scientific instruments. In 2012 it landed in Gale Crater on the Martian surface.

One thing is making scientists especially excited: Curiosity has spotted tiny traces of water. The water was found in fine dust. And what's more, the dust seems to cover the whole planet. This may explain mysterious water signals picked up by satellites orbiting Mars.

The newly found water was spotted by one of Curiosity's fancy gadgets: the laser-shooting Chemistry and Camera instrument. It's nicknamed ChemCam.

Coarse Soil, And Very Fine Dust

Curiosity's ChemCam was first used to study Martian soil. It found that there are two major types: One is coarse, and probably came from surrounding rocks. The other is very fine.

The fine-grained soil doesn't really match the rocks around it. But it does match soil found where other rovers have landed. That means it's probably spread over much or all of the planet. Most likely it is spread by the fierce dust storms that give Mars its nickname, the Red Planet.

But one thing in particular was surprising about this fine soil: It turned out to have hydrogen in it. Water, of course, is two parts hydrogen and one part oxygen.

"It's actually kind of exciting," said geologist John Grotzinger. The job of geologists like Grotzinger is to study rocks.

A Fascinating Rock Called Jake M

Curiosity used another of its tools to cook up a tiny bit of soil: It turned out that roughly 1.5 to 3 percent was made of water. Scientists think this water came from the atmosphere. In other words, it was pulled out of Mars' thin air.

Another study looked at the rock known as Jake M. This was named in memory of NASA engineer Jake Matijevic. Jake M is unlike any rock seen on Mars: It's rich in something called alkaline magma. This told scientists that it was created under high pressure. And also perhaps in water.

In fact, it looks something like a type of rock on Earth called mugearite. This is found on ocean islands and near underwater volcanos.

Grotzinger finds all this very interesting. Perhaps, he said, Mars was once more like Earth than scientists ever believed.]]>