发布时间： 2017年01月03日
For centuries, humans have wondered whetherthere is life on Mars.
Scientists have asked why Mars is losing itsatmosphere. Last week, the question was answeredwith a song.
“The answer, is blowing in the wind,” said MichaelMeyer, taking a line from a Bob Dylan song. Meyer is the lead scientist for NASA’s Mars ExplorationProgram.
It turns out solar winds from the sun are slowly stripping away Mars’ atmosphere. That is whatNASA scientists explained at a press conference Thursday.
Bruce Jakosky is principal investigator on the MAVEN team. MAVEN stands for Mars Atmosphereand 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 saysit used to be much different.
“When we look at ancient Mars, we see a different type of surface. One that had valleys that lookedlike they were carved by water, lakes that were standing for a long periods of time. We see anenvironment 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 thisimportant? 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 findliquid water? Meyer explains:
“It means that we have a resource. And when we’re looking at sending humans to Mars, water isone of the key things that we need to have. Not only for the astronauts to drink, but also to makeoxygen, to make fuel, and so having a ready resource there on the planet make a big difference interms 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 spaceagency has even started a recruiting campaign to hire new astronauts. Those chosen might fly anynumber of space vehicles still in development.
Both U.S. government and private industries are developing rockets and spacecraft to get people toMars.
Many questions need to be answered: How do you protect humans from radiation in space? How doyou 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 MikhailKornienko, are spending a year on the International Space Station circling the Earth. Scientistswant 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 mightbe 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 theretoday, if it ever got started there in the first place. Finding life, however small, on another planet inour 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 thatwould 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 wholeuniverse.
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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