For centuries, humans have wondered whether there is life on Mars.

Scientists have asked why Mars is losing its atmosphere. Last week, the question was answered with a song.

"The answer, is blowing in the wind," said Michael Meyer, taking a line from a Bob Dylan song. Meyer is the lead scientist for NASA's Mars Exploration Program.

It turns out solar winds from the sun are slowly stripping away Mars' atmosphere. That is what NASA scientists explained at a press conference Thursday.

Bruce Jakosky is principal investigator on the MAVEN team. MAVEN stands for Mars Atmosphere and Volatile Evolution. It is a spacecraft that collects information from Mars as it circles the planet.

Today, Mars has a thin atmosphere. It is cold and dry, with a desert-like environment. Jakosky says it used to be much different.

"When we look at ancient Mars, we see a different type of surface. One that had valleys that looked like they were carved by water, lakes that were standing for a long periods of time. We see an environment that was much more able to support liquid water."

NASA scientists have used the phrase "follow the water" in their work to understand Mars.

Recently they found a kind of liquid water that flows with salt down a mountain area of the planet. But, it is not always there.

Scientist Michael Meyer describes what they found:

"We're seeing water, with the salt that's able to flow down the sides of the cliff. Why is this important? That means there is water on Mars, on the surface of Mars today."

Scientists already knew that ice exists at the polar caps of Mars. So why is it important to find liquid water? Meyer explains:

"It means that we have a resource. And when we're looking at sending humans to Mars, water is one of the key things that we need to have. Not only for the astronauts to drink, but also to make oxygen, to make fuel, and so having a ready resource there on the planet make a big difference in terms of how much stuff you have to bring with you."

Sending humans to Mars is still in the distant future. NASA is aiming for the 2030s. The space agency has even started a recruiting campaign to hire new astronauts. Those chosen might fly any number of space vehicles still in development.

Both U.S. government and private industries are developing rockets and spacecraft to get people to Mars.

Many questions need to be answered: How do you protect humans from radiation in space? How do you grow food in space ships on the way to Mars? How do they grow food once they arrive on Mars? Having access to water on the planet will be critical to that effort.

Meanwhile, American astronaut Scott Kelly just passed a halfway mark. Kelly, and Russian Mikhail Kornienko, are spending a year on the International Space Station circling the Earth. Scientists want to know how the human body reacts to being in space for long periods of time.

Whether there is life on Mars remains unanswered. But some scientists say they think there might be some kind of microbial life on the planet.

Michael Meyer is more cautious, saying it has yet to be proven. He says there could be life there today, if it ever got started there in the first place. Finding life, however small, on another planet in our solar system would be so exciting:

"Whether or not there's life on Mars doesn't matter, whether or not I think so, or don't think so. I'm a scientist, I want to go and find out. The real point is we don't know, but it's a good question. It's a reasonable question. It's something we should be pursuing. ‘Cause imagine how exciting that would be to find evidence of life somewhere else, not on our planet."

And that, finding life on another planet, would certainly change the way we view the whole universe.

Anne Ball reported this story. Kathleen Struck was the editor.

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Words in This Story

strip (ping) - v. to remove matter from something

distant - adj. far away

microbial - adj. extremely small living thing

cautious - adj. careful

solar system - n. our sun and the planets that move around it

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