Free Flow on Mars

Join Our Community of Science Lovers!


On supporting science journalism

If you're enjoying this article, consider supporting our award-winning journalism by subscribing. By purchasing a subscription you are helping to ensure the future of impactful stories about the discoveries and ideas shaping our world today.


Deposits formed in Martian gullies during the past seven years suggest that liquid water exists on Mars today. An image taken by the Mars Global Surveyor spacecraft in 2005 shows a downhill track on the wall of a crater that was not present in the previous image of the crater, taken less than four years earlier. In subsequent views of the deposit, the sun's light is coming in at different angles, but the light-colored material remains, suggesting it is not a trick of the light or the result of dry erosion. Similarly, images of another crater from February 2004 show the beginnings of a second deposit, which has grown in subsequent images, according to a report in the December 8 edition of Science. Finding additional examples might be tricky, given that NASA lost contact with the Mars Global Surveyor last November after nearly 10 years of operation.

It’s Time to Stand Up for Science

If you enjoyed this article, I’d like to ask for your support. Scientific American has served as an advocate for science and industry for 180 years, and right now may be the most critical moment in that two-century history.

I’ve been a Scientific American subscriber since I was 12 years old, and it helped shape the way I look at the world. SciAm always educates and delights me, and inspires a sense of awe for our vast, beautiful universe. I hope it does that for you, too.

If you subscribe to Scientific American, you help ensure that our coverage is centered on meaningful research and discovery; that we have the resources to report on the decisions that threaten labs across the U.S.; and that we support both budding and working scientists at a time when the value of science itself too often goes unrecognized.

In return, you get essential news, captivating podcasts, brilliant infographics, can't-miss newsletters, must-watch videos, challenging games, and the science world's best writing and reporting. You can even gift someone a subscription.

There has never been a more important time for us to stand up and show why science matters. I hope you’ll support us in that mission.

Thank you,

David M. Ewalt, Editor in Chief, Scientific American

Subscribe