National Geographic News
Self-portrait of Nasa's Curiosity Rover on Mars.

NASA's Curiosity rover has delivered some cool findings from its trips across the red planet.

Photograph courtesy NASA/JPL-Caltech/MSSS

Marc Kaufman

for National Geographic

Published December 9, 2013

NASA's Curiosity rover, which has been on Mars for almost a year and a half now, just delivered its largest and most important downlink so far of findings, discoveries, and conclusions. (Also see video: "Mission to Mars.")

While the six papers released by the journal Science report on different aspects of Mars and do it from different scientific perspectives, together they present the beginnings of a new understanding of the red planet, especially in its early epochs, three to four billion years ago.

Early Mars, it has become increasingly apparent, was in many important ways similar to Earth. (See also "Did Life on Earth Come From Mars?")

"If you put together all that we're learning about Gale Crater and Mars, you really begin to chip away the rock and the sculpture inside emerges," said Pan Conrad, an astrobiologist with NASA's Goddard Space Flight Center and a co-author on several of the papers.

As described in the six Science papers, that hidden but slowly materializing landscape looks something like this:

1. Early Mars was habitable, perhaps for a long time.

After concluding that rivers and streams once flowed into Gale Crater, the Curiosity team has now reported that a lake existed there as well. That surface water, as well as groundwater that likely went down hundreds of meters, possessed all that was needed to support microbial life.

The period when Gale Crater was warmer, wetter, and habitable was broadly between 3.5 and 4 billion or more years ago. That period is when life on Earth is understood to have arisen.

Was Mars once home to primitive extraterrestrial life? Curiosity can't and won't make that determination, but its discoveries have made the possibility of Martian life significantly more plausible.

2. Water once flowed on many parts of Mars.

And that water was there at times and in forms that scientists didn't believe to be possible not long ago.

One of the major achievements of Curiosity so far has been to "ground-truth" observations made in recent years by the satellites orbiting the planet. Those instruments found strong hints that Mars had a watery past, and at Gale Crater they were found to be on target.

As a result, the mission has given greater credibility to the view that thousands of additional fossil formations of what appear to be ancient streams, channels, deltas, and lakes likely are just what they appeared to be.

3. "Follow the carbon" has been vindicated.

The search for Martian carbon-based organic compounds—one of the major goals of the Curiosity mission—has been and will continue to be complicated and trying.

While as many as six different organic compounds have been identified so far by the miniature chemistry lab called Sample Analysis at Mars (SAM), their origin remain unclear.

"There's no doubt that SAM has identified organics, but we can't say with confidence yet that they are Martian in origin," said Douglas Ming of NASA's Johnson Space Center, and author of one of the six Curiosity papers in Science.

There are at least two sources of the confounding results: The presence on Mars of a chlorine-based compound that, when heated in the SAM oven with any organic material, largely destroys the compounds. And the leak into the SAM ovens of an organic solvent brought to Mars as part of a wet chemistry experiment.

The search for Martian organics is nonetheless making progress. With each collection of Martian sand or rock, the number of organics found and their concentration has increased—suggesting that different samples of Martian material are leading to different results. If the organics were all contaminants from Earth, those concentrations would likely be more steady.

"SAM is probably the most complex and important instrument ever brought to another planet," Ming said. "Inevitably, it has taken time to figure out how best to work with it."

4. Mars gets pounded by radiation.

Galactic cosmic rays and solar eruptions bombard Mars, and their high-energy particles break the bonds that allow organisms to survive. The Radiation Assessment Detector on Curiosity has made the first measurements ever of radiation on the surface of Mars, and the results are sobering.

In another Science paper, RAD principal investigator Donald Hassler reports that the radiation would almost certainly be fatal within a few million years to any microbial life on the surface or less than several meters deep.

The RAD team used as their model the terrestrial bacteria Deinococcus radiodurans, which is capable of withstanding enormous doses of radiation, to make that assessment.

Notwithstanding the high levels of radiation, Hassler reported that life could theoretically still survive on Mars today under special circumstances. If a bacteria similar to D. radiodurans appeared when early Mars was wetter, warmer, and had a more protective atmosphere, he wrote, it could have survived over the epochs through long periods of dormancy.

5. Mars radiation also damages normal chemistry.

Many on the Curiosity team point to radiation damage of all carbon chemistry on Mars as a major reason why it has been so difficult to identify organics on the surface.

That effort, however, may have gotten a significant boost from one of the most unexpected developments to come out of the mission so far―a method to date how long surfaces have been exposed to the sky on Mars.

Using measurements of radioactive decay also employed on Earth, Kenneth Farley of the California Institute of Technology reports that the surface of Yellowknife Bay has been exposed for some 80 million years.

The discovery points to a method for finding places for the rover to drill where there has been less chemistry-damaging radiation exposure.

Essentially, Farley said, the team has to look for cliffs or overhangs being undercut by the surface wind―as happened in Yellowknife Bay―and where radiation would be blocked by the rocks above. "If we find that kind of formation," he said, "drill there."

6. Detours sometimes turn out to be interesting.

The Curiosity rover was scheduled to head for the scientifically alluring Mount Sharp in the center of Gale Crater soon after landing. More than 480 days into the mission, the rover is still months away from its prime destination.

The detour to Yellowknife Bay is the main reason why, and it has turned out to be a gold mine of data. But now the rover is on what is called the "rapid transit route" to three-mile-high Mount Sharp, driving most of the time and passing many potentially interesting sites.

Having already found and analyzed the first potentially habitable environment ever discovered on Mars, the Curiosity team will be looking for more. And with their increased knowledge about which potential drill sites are likely to have been protected from radiation, the search for Martian organics will go into high gear as the rover approaches the target-rich Mount Sharp.

31 comments
vinthai M.
vinthai M.

Great. it is a great achievement of the human mind....imagine a machine responding to controls from earth...research, science in search of knowledge must go on. not Mars alone but many more planets and systems need to be explored... knowledge has no stopping... Great job NASA and the science guys there and elsewhere. only our brain and will will take us forward- nothings else.  

Robert Bowen
Robert Bowen

If a landlord rents you his house, and you mess it up, you are in breach of contract and he will evict you as sure as nuts.   This magnificent Earth, is out home.   We have positively ruined from end to end.   Do you really believe we will not be evicted?

Robert Bowen
Robert Bowen

Norma C: Do you regard man;s efforts to end the scourge of cancer, among every other endeavor "successful"? 

Robert Bowen
Robert Bowen

The way man has ruined our beautiful earth, he has no right on any other planet.   Isn't it enough that the earth is now poisoned to death, so what's with wanting to relocate to another and ruin it too?   Man has proved himself unfit as a planet's caretaker.. 

Giancarlo Testi
Giancarlo Testi

Dante's Ulysses wrote " we were not born to live as beasts, but to search for virtue and knowledge". The Martian probes are a sound way to show our willingness to continue our mission!

Ray Cobb
Ray Cobb

While I'm strongly in favor of more exploration (it's a human instinct), I'm not so sure that finding fossils on Mars will be conclusive proof that that life originated on Mars. The meteorite that wiped out the dinosaurs on Earth was just one of many that hurled countless tons of rocks, fossils, and living microbes off our planet. Some of them doubtless landed on Mars. Will we ever know for sure that the fossils we find are actually Martian in origin?

Laurence Smith
Laurence Smith

I don't know too much about fossils and their longevity, but I wonder if looking for fossil remains might be a goal as a part of future rovers' excursions? I would think that there should be the capability of looking for fossils that are the size of microbes and on up to larger sizes. I don't think fossils would be affected by radiation. Just a thought; I am totally transfixed by the Curiosity Rover's findings and capabilities. And another wild thought: it would be tremendous if Curisoity found some kind of fossils with its cameras.

In any case, there is somethinig 'in me' that feels there might be an awesome discovery on the mesas, slopes, striated rock, and probable rocky overhangs as they near Mount Sharp.

Norma Cunningham
Norma Cunningham

I don't doubt that sometime in the future mankind may have to re-locate to another planet in our solar system - maybe it will not be Mars. However I am sure that we will eventually succeed in our search for a second Earth! Whatever humans decide to try somehow seems to eventually be successful - quite a mystery to me! Never stop trying!

Mukhtar Kiyani
Mukhtar Kiyani

wow.is it that we on earth are not the first ones,to live on planet earth.That many more civilizations have lived and may be still be living on many,many other planets?

Garrick Meadows
Garrick Meadows

Brilliant stuff, not covered by the sensationalist scandal-fixated press!

Tatyana Gasanova
Tatyana Gasanova

Все созвучно моим мыслям, догадкам прошлого и, конечно, научной фантастике. Она всегда немножечко впереди науки (Рей Бредбери for example)

Alfredo Soto
Alfredo Soto

This is a great. Mars should be our next mission. We should go there and explore this planet to help us set a foot print of ourselves in the universe.

john mcleay
john mcleay

I love science and will enjoy my new membership.

Harry Ashton
Harry Ashton

A great free standing pic of the Rover, but who took the picture???

Huang Yu
Huang Yu

Hope the Earth won't be another Mars

Andi Plantenberg
Andi Plantenberg

Thanks you for the summary. The initial articles on NASA yesterday really buried the headline, so to speak.

Debra Shein
Debra Shein

Thought you'd be interested in this, Dray!

David Alan McPartland
David Alan McPartland

In the vast expanse of the world we call Mars, we have only literally scratched the surface. Given time, who knows what intersting finds they will find under rocks and in caves. Life almost always find a way.

Miguel Rodriguez
Miguel Rodriguez

This is one of the reasons why science is so amazing and passionate: you always has to be open to new ideas, theories and facts. For all scientist involved in this Mars mission has to be a dream come true and a nightmare at the same time. They have the oportunity to achieve the key step in scientific method: experimentation. But despite their Curiosity, there are always the sensation of "I wish to be there". Congratulations to all of them.

Kristianna Thomas
Kristianna Thomas

It is beyond a shadow of a doubt that many ideas that we formulated in the early days are proving to be totally wrong.  Curiosity has a small lab and can't do the complex research that is needed , we need to send people and larger research facilities to Mars.  Mankind needs to spread its wings to the other planets and to expand the sum of its parts.  We want to send explorers to other planets via Orion, but we need to develop ships that are much larger than an Apollo era capsule.  We need to start thinking Star Trek Enterprise size and not the Minnow. 

Kevin Ye
Kevin Ye

hope there are more findings come to surface.

Leo Kretzner
Leo Kretzner

It's great to have this information nicely summarized - thanks!

King Booth
King Booth

@Robert Bowen Sir- I can easily identify with your sentiment's on Man's inability to be responsible, with pretty much anything.  I believe God exists, and because of that, It breaks my heart as well that we (human race) continue to devour one another, and mis-manage this majestic earth.   Our God given "dominion" of this planet inherently comes with a sense of duty to preserve this planet.  I used to shoot people when I was In the army, because that was my job to do so, but  I can't do that anymore.  Maybe you find that funny, maybe not.  Either way, thanks for your comments Sir

Laurence Smith
Laurence Smith

A good point, and one I didn't even think of, Ray. I don't know if the science exists, or will ever exist, that tells us whether a fossil would be extra-planetary or actually formed on Mars, even if fossils would be found. I can only say it would be interesting as heck, of course. I'm just speculating and dreaming of possibilities. So anyway, good thinking again Ray.

William Phillips
William Phillips

@Tatyana Gasanova  ... Не всегда впереди. Транспорт материи которая телевидение изображает в "Star Trek" должны были бы большая часть энергии всего космоса. Мы не увидим его в ближайшее время. Но в целом то, что вы говорите, правда. (Извиняюсь за плохой грамматики от Google...)

Wichie R
Wichie R

@Harry Ashton  The Mars Rover took the picture! NASA designed the Rover to do that...! duh!

Ray Cobb
Ray Cobb

@Kristianna ThomasI agree with you, but I'm afraid we'd have to get every nation on Earth to contribute to it. The cost of the Apollo program was $24 billion, not counting the technology that led to it. The cost of an "Enterprise" would probably exceed our current national debt. But we can hope!

Share

Feed the World

  • How to Feed Our Growing Planet

    How to Feed Our Growing Planet

    National Geographic explores how we can feed the growing population without overwhelming the planet in our food series.

See blogs, stories, photos, and news »

Latest Photo Galleries

See more photos »

Shop Our Space Collection

  • Be the First to Own <i>Cosmos: A Spacetime Odyssey</i>

    Be the First to Own Cosmos: A Spacetime Odyssey

    The updated companion book to Carl Sagan's Cosmos, featuring a new forward by Neil deGrasse Tyson is now available. Proceeds support our mission programs, which protect species, habitats, and cultures.

Shop Now »