New evidence of oceans on Mars!

By Phil Plait | November 17, 2008 1:30 pm

Update: if you like this story, please Digg it!

Does this map show an ancient ocean floor on Mars?

A map of Mars showing the location of possible ancient ocean. Credit: U. Arizona

New evidence says "maybe". But it’s a pretty good maybe!

It’s been argued for years that Mars may have once had oceans of water, billions of years ago. Some catastrophe dried them up, making the evidence for them difficult to detect. Topographic (relief) maps look like there may have been two oceans in one spot, for example, separated by some time. There appear to be two separate shorelines, with one smaller, later ocean existing where there once had been a much larger ocean.

But that’s circumstantial. More direct evidence is needed.

So some scientists speculated a bit. Rocks containing elements like potassium, thorium and iron would get made in the highlands (near volcanoes), then get transported down into the lowlands. If there were an ocean there, those elements would get leeched out of the rocks by the water. Then, when the water evaporated, those elements would be deposited in a thin layer on the surface.

On board the orbiting probe Mars Odyssey is the Mars Gamma-Ray Spectrometer, a device which can measure the abundance of elements on the Martian surface. When it was trained on the lowlands of Mars, it found evidence to support the existence of those oceans! The elements in question were most abundant below the shorelines, as expected, when compared to regions outside (above) the shorelines. The regions with higher concentrations of potassium are marked in red and yellow in the map above, right where the lowlands are.

While this doesn’t prove an ocean as big as the United States once occupied a large chunk of Martian real estate, it’s further evidence of it. Scientists are still arguing over whether Mars had long-lasting, ponded water, or if it was released in short, transient events, only to evaporate quickly away. But either way, we’re not arguing over whether Mars had water, just how long it lasted.

Either way, Mars is an incredible planet. It may have once been much more Earth-like, but then something went wrong. Maybe it was the formation of the giant volcanoes (indicated by the red arrows in the above image), or the loss of its magnetic field that exposed its atmosphere to erosion by the solar wind. As we study Mars more, we get closer to figuring this out. And make no mistake: knowing where Mars went wrong gives us great insight into our own planet. If you think we’re wasting money on researching Mars, then I suggest you take a cold, hard look at that cold, hard planet, then look out your window at our own home world.

There but for the grace of science may go us.


Comments (57)

  1. We never waste our money when we explore and attempt to understand something that could have a lesson for how our own planet may operate.
    Money well spent is how I term it. I remember the walk on the moon and I remember all the scientific advances that occurred because of that spur to the imagination of mankind. This teaches us in a different but no less moving way.

    Bravo for oceans on Mars and the scientists who had the imagination to look in this way.
    Here’s to the Mar’s teams and all their hard work and all their exciting discoveries!

    Thank you, BadAstronomer for your insight and fine articles. It’s much appreciated.

  2. This is yet another reason I love science!!!

  3. Of COURSE Mars had oceans. They were a thriving planet until that mess with the magnetic field threw them into chaos. Fortunately, they thought ahead and seeded that nice blue planet this side of Venus. The Martians are gone but we’re here thanks to their generosity and foresight. It was nice of them to hurl a big rock at our planet to get rid of those nasty dinosaurs, too. Now if some other civilization would do something about the Republicans down here… But I digest.

  4. redx

    I’m dumb. How would a planet go about loosing it’s magnetic field?

  5. Ryan Turner

    @redx: If it cools to the point that its core stops spinning, no more dynamo, no more generation of magnetic field. Mars is much smaller than the Earth, therefore has a much greater surface to volume ratio, therefore would cool more quickly.

  6. I still cannot fathom the narrow minded view that anything like planetary exploration (or nearly any legitimate field of science) could be construed to be a waste of money. What sort of wonderless world do these people live in?

  7. JoeSmithCA


    There is something that just seems wrong in calling Mr. Plait a Bad Astronomer :)

    You could also hyperlink in a Google english to spanish conversion of Phil’s blog on your site. :)

  8. Brian

    En el anterior mapa topográfico de Marte se indica la posible localización de un antiguo océano. Algo más de información aqui
    In the previous topographic map of Mars the possible localization of an ancient ocean is indicated. Some more information here.

  9. justcorbly

    Oceans, smoceans. I want evidence of a damn boat!

    Preferably something that looks good on a canal.

  10. Chris P

    Umm – maybe he’s a bad astronomer because his own department has shown pictures of there currently being water on Mars.

    IOW – Mars HAS water

    Chris P

  11. Tom

    I think it is a global imperative to settle Mars. The self sufficiency that a settlement on mars would require would also bring together global self sufficiency in food, water, air, energy, in resources and a whole host of technologies needed in a world that has reached global resource constraints.

    The global age consumerism is now over.
    The global age of population growth is now critical and must be ended.

    The demand for our global society is less people, more self sustainable lives & societies. Mars can teach us that…and so can the moon.

  12. Ad Hominid

    Mark, La Flame Magnet:

    “Now if some other civilization would do something about the Republicans down here… But I digest.”

    You probably mean “digress” unless of course you are a cannibal as well as a proponent of mass murder. How interesting that you assume, even in jest, that mass-murderers would be on your side. Perhaps at some level you sense the truth of history. I remember the joy in liberal anti-war circles when Pol Pot completed his “liberation” of Cambodia in 1975, only to see this sucked down the memory hole by a thirty year campaign of revisionism and denial that the activist media pioneer Joseph Goebbels would envy.

    Wanting the other side killed, even as a joke, is not part of a genuine democratic process or civilized discourse, leftist pretensions of intellectual superiority notwithstanding.
    It does, however, reflect the totalitarian hypocrisy of the current media culture, but I digress.

    If I said something similar about Democrats or Greens or Muslims, there would be demands from the usual proponents of free speech (for themselves that is) that I be prosecuted and sent away for reprogramming by community activists.

    Are jokes about mass murder really suitable for a family website? I guess they are if they come from the right (that is, left) side of the aisle. A couple of years ago, I got death threats, real ones, from good pop-culture conformists for simply daring to say in public that people do in fact have the right to criticize entertainment celebrities and other leftist authorities.

    It isn’t a bit funny, though I have to admit to cracking a smile when the perp was hauled off to jail.

  13. Mark Roberts

    @ Tom: no, we won’t be learning those lessons by colonizing other planets. It’s much easier to create solutions for Earth, on Earth. But it’s an interesting idea nonetheless!

  14. IVAN3MAN

    Dr. Phil Plait: “Update: if you like this story, please Digg it!”

    Phil, because you were a good sport to let me post images/videos on your blog, I registered today with Digg especially in order to do as you requested; it’s the least that I can do to show my appreciation.

  15. Chip

    @Ad Hominid Says:
    “… I remember the joy in liberal anti-war circles when Pol Pot completed his “liberation” of Cambodia in 1975, only to see this sucked down the memory hole by a thirty year campaign of revisionism and denial that the activist media pioneer Joseph Goebbels would envy.”

    I’m a Liberal of that era and I don’t remember anything of the kind. Liberals, Conservatives and all other civilized people, (back in the days when they argued but all basically accepted each other,) were equally appalled at the barbarous atrocities of Pol Pot. I lost a cousin there. The only revisionist lies are those you’ve just made up or perhaps got from the shock-jock windbag Rush Limbaugh. There’s a blunt, open-minded, horrific and basically Liberal book (and movie) titled “The Killing Fields” that tells just one story of what happened in Cambodia. Right wingers like Rush and Goebbels would not have allowed that film to be shown. They’d prefer to assign blame for Pol Pot on the very people Pol Pot destroyed. So – Enough! Correct a bad joke if you must but avoid adding someone else’s rightwing propaganda all over again.

    Mars – with ancient oceans: That’s what this is about and I wonder if the question of how those bodies of water existed, transient or long standing, will be answered with either more sophisticated robotic experiments or human beings camped there on-site, or both.

  16. Nigel Depledge

    Ad hominid said:

    A couple of years ago, I got death threats, real ones, from good pop-culture conformists for simply daring to say in public that people do in fact have the right to criticize entertainment celebrities and other leftist authorities.

    Since when did entertainment celebs count as leftist authorities?

  17. Nigel Depledge

    Mark Roberts said:

    It’s much easier to create solutions for Earth, on Earth.

    Yeah, assuming we can overcome the problems created by human nature…

  18. Nigel Depledge

    Anyhoo, back on-topic…

    Phil, thanks for another excellent essay bringing planetary science to a wider audience. I love it when your enthusiasm overflows out of the computer screen.

  19. “Since when did entertainment celebs count as leftist authorities?”
    Since when you expect from political trolls any coherence?

  20. Torbjörn Larsson, OM

    How would a planet go about loosing it’s magnetic field?

    That turns out to be an interesting question – google it, and you see proposals anywhere from Mars field being drained away by coupling to retrograde asteroids to core cooling. But apparently Mars is more interesting than that – the south half of Mars has the bipolar field (see the last figure in the ubiquitous Emily Lakdawalla’s post:

    More recently, a suite of papers published in Nature gave credence to the idea that the crustal dichotomy formed as a result of a truly gigantic, oblique impact that blasted away a massive chunk of the crust of the northern hemisphere, and that this happened very early in Mars’ history (I’ve written about this before). Furthermore, the papers showed that because the impact struck Mars a glancing blow, it would not have delivered enough heat to the planet to melt its whole crust. So the impact could reasonably leave Mars with a thin northern hemisphere crust and a thick southern hemisphere crust. But that still leaves geophysicists with the problem of explaining how the north didn’t become magnetized, despite the fact that the dynamo was operating well after this putative giant impact.

    Enter Sabine Stanley and her coauthors with their neat idea. In their Science paper, they show (using a numerical model, that is, a computer simulation) that it’s possible to have a dynamo operating inside Mars that only produces a dynamo in a single hemisphere. The way they made this happen is by “impos[ing] a degree-1 variable heat flux pattern at the core-mantle boundary in a dynamo simulation.” To translate: instead of assuming a spherically symmetrical Mars, they made the northern hemisphere core-mantle boundary hotter than the southern hemisphere core-mantle boundary, a reasonable initial condition to impose if you very suddenly remove a huge amount of crust atop that part of the planet with a giant impact.

    Then they ran their simulation. And here’s what they found. The top map shows a magnetic field simulated for a planet with no temperature difference at its core-mantle boundary; the bottom map shows their simulated Mars. Guess what? There’s a strong magnetic field only in the southern hemisphere.
    [Links removed. So is a very suitable joke about spherical cows, that Phil loves to retell. :-)]

    So it is possible that the same late impactor that seems to have decided Mars final topography also set up a temperature asymmetry across Mars core-mantle boundary that resulted in an early skewed field, and an early loss of atmosphere despite still having an appreciable magnetic field:

    And here’s another neat trick of Stanley’s model: if ancient Mars had a magnetic field only in the southern hemisphere, then there would be no protective field to prevent the solar wind from stripping away the atmosphere from the northern hemisphere. But the atmosphere flows where it will, regardless of magnetic field lines; so atmosphere would flow from south to north, and continually be lost from the north. So you could still have Mars losing its atmosphere early in its history, even while it had an active dynamo.

    It’s all theoretical and really a very simple model, but it explains so many mysteries about Mars, that it’s a very attractive idea.

  21. Torbjörn Larsson, OM

    Btw, if an impactor is responsible for Mars early atmosphere loss as recounted in my previous comment, it is IMHO a fair degree of irony in this.

    AFAIU Earth (as well as Mercury and other rocky bodies) also got hit by a late great impactor that left a remaining impression (well, in a way), but here it was beneficial. The impactor was Mars sized, and netted a Moon sized mass of material in orbit, consisting mainly of crust, while leaving heavier core material but also lighter gases and liquids from the impactor. Thus easing Earth plate tectonics by contributing to a thin crust and plenty of lubricating/rock transforming water.

    While Mars may have got hit by a Moon (?) sized impactor, which perhaps blew away some material (“Mini-Moon” sized ? ;-), but not enough (no plate tectonics so no atmosphere stabilizing geodynamics, as in the carbon cycle) or too much (skewed magnetic field so loss of atmosphere), depending on your preferred disaster.

  22. SF Reader

    Is there any reason to think that the bombardment of ice that gave the Earth its oceans didn’t hit Mars as well to make its oceans? After that, the local conditions interfered and it all went away…


  23. Cheyenne

    So if Mars had liquid water, it probably had an atmosphere that was more like Earth’s in the past. Life anybody? I really want to know if she had some.

    I so wish we could increase the number and quality of the probes we send there. As we get better at building these I’m sure we could build some that could find life. That would be epic, epic, epic to find life somewhere else.

    If only there was something that we could cut from NASA’s budget to free up some funding for true science and exploration of that planet (and others). Ideally it would be something that is just shy of totally worthless, costs an enormous sum of money, is just a public works project to keep scientists employed, and something that we won’t even have our own access to in the near future without sticking our proverbial thumbs out. Is there anything like that?

  24. Jason Heldenbrand

    Phil. An interesting question I would have, being a total science novice that maybe you might answer in an upcoming article or redirect me to a decent source… what would be required for terraforming Mars? Such as making it habital for human life without the need for more than the cold weather gear?

    Is it even possible with modern/not-so-science-fiction-future equipment?

  25. Will. M

    A useful discussion for this blog could be the possible terraforming of Mars: how to do it, how far away would it be technologically, and how to get water in useable amounts back on the planet. I’d find it fascinating, anyway.
    Will. M

  26. MarkH

    NASA’s $17.6 billion dollars is miniscule compaired to say the:
    $644 billion – Social Security or
    $408 billion – Medicare or
    $224 billion – Medicaid or
    $360 billion – Unemployment/Welfare/Other mandatory spending or even
    $260 billion – Interest on National Debt

    The above is Fed. “MANDATORY” spending. I’m not saying appropriate funds from these programs but how about finding additional fund from some of these other Depts.

    $515.4 billion – United States Department of Defense or
    $145.2 billion(2008*) – Global War on Terror or
    $70.4 billion – United States Department of Health and Human Services or
    $59.2 billion – United States Department of Education or
    $44.8 billion – United States Department of Veterans Affairs or
    $38.5 billion – United States Department of Housing and Urban Development or
    $38.3 billion – State and Other International Programs or
    $37.6 billion – United States Department of Homeland Security or
    $25.0 billion – United States Department of Energy or
    $20.8 billion – United States Department of Agriculture or
    $20.3 billion – United States Department of Justice or

    $1 billion from each of these would nearly double the NASA budget…..
    I’m just sayin’

  27. Frank Palazzolo

    Knowing this, doesn’t it seem like we should send probes to that little reddish area in the picture? Intuitively, it seems that if there is evidence of aquatic life on Mars, it would have all concentrated down into the smallish patch of remaining area, while water was still available.

  28. Daffy

    Ad Hominen,

    Stop getting your “facts” from Rush Limbaugh. The man is a shameless liar and you only make yourself look foolish by believing him.

    The conservative viewpoint is a valid one (even if I personally disagree with it most of the time), but Rush Limbaugh is just dishonest to his very bones.

  29. Cheyenne

    Mark – I’m well aware of what the various gov’t agencies spend, and there is a lot of waste, I would like to see it cut, and I would definitely like to see NASA’s budget expanded (big time I might add- provided it’s spent well).

    But all dumb spending should be cut- whether it’s for failed crop subsidies, a war in Iraq, or, quite honestly, a space station whose merits for existence are just, well, not really justifiable. The fact is NASA has to live within a budget that Congress creates. They should make the smartest choices possible. Spitzer, Chandra, Mars Rovers, Cassini, etc. – these all have provided massive science returns. ISS? Yeah, not so much. Fascinating toilets though.

    What do they do up there in the space station anyway? Where are the scientific results? We know they won’t use the station as a way point to Mars or the Moon. And the station isn’t “exploration” to boldly go somewhere. It’s low Earth orbit (yeah I know, “halfway to anywhere” when you get there- but they won’t use it that way!).

    I’m not knocking NASA. I think NASA rocks. I want them to go find life on other planets (imagine being the agency that does that! As I said, EPIC) and make other kinds of great discoveries of our Universe. And I think they will be much more equipped to do that when they make the very, very difficult decision of admitting that the ISS is mostly a public works project of dubious scientific value. And then redirect funds (as best they can) to more worthwhile projects.

  30. Cheyenne

    I hope I’m not hijacking the thread too much. Sorry, bit off topic from the really exciting Mars news (finding more evidence of water there is very cool).

    I really was wondering what science they do up there so I went to NASA’s official page on it.

    It’s so bad that I’m not even going to make fun of it. It’s so bad that even NASA knows it’s bad (and so fills it with repeated entries about “journals” and amateur radio and, and- we’re now sending MORE people up there to do absolutely nothing worthwhile?!).

    Oh, and Russia is going to be the sole gatekeeper to it for 5 plus years. Completely in control of access to it. They will have exclusive access to the “Sleep-Wake Actigraphy and Light Exposure during Spaceflight-Long” experiment! Those are journal entries of how good a night’s sleep somebody had! Priceless.

  31. Random Person

    @ Mark LaFlamme:

    Digest and Digress are not the same.

  32. Water can’t just disappear… it can change state from gas to liquid to solid, and it is doubtful that all the oceans of water just leaked into space leaving nothing, so there has to be firm evidence somewhere. It’s not like a puddle that dried up (vapor in the atmosphere) or that a lake was drained somewhere else, if there was a great deal of water there once, it is still on the planet somewhere. In ice in the poles? Locked up in rocks? Maybe. The point is, just like how water molecules don’t snuff out of existence on the Earth, they wouldn’t there either. If it is so difficult to confirm, it just might be likely that it wasn’t there in the first place.

  33. Loaf Of Bread

    One day, we will be asking a much more important question. Did the Martians have swimming pools? :)

    Great article, Phil, and one well worth spending part of a lunch hour reading.

  34. JoePublic

    Of course other plants are earthlike… even having life, perhaps even sapient life. It’s the moronic xtians who are the naysayers, and all due to their heinous egomanical racketeering ponzi scam. They are criminals against nature and obstructors of all knowledge. Please help end their fascist tyranny by boycotting religion. Vote with your money: don’t give to religious charities.

  35. dkary

    I hate to “rain” on the Mars Ocean parade, but over the last few years I’ve seen at least as many findings that were considered equally strong evidence wasn’t an ocean after all.
    For example, part of the original argument for an ocean was that there were features along the edges that looked like shore erosion. On closer examination, they turned out to be just wrinkle ridges in old lava flows: no sign of shoreline.

    Also, I’d be a little surprised to find that there could be such so much water around on the surface that it gives an ocean in the north without producing so much erosion that it completely erases more of those heavily cratered highlands in the south. A body of water that big should be able to produce a global-scale hydrological cycle, but in the south there is very little sign of that happening.

    So while a Mars ocean would be a cool thing, I’m afraid I’m going to remain skeptical on this one. Certainly there was water flowing on Mars at various times in the planet’s history, but the evidence for an ocean needs to get a lot more compelling yet (such as maybe finding those shorelines after all).

  36. Fen

    Heh – these damn scientists are so wet behind the ears when they come up with this tripe –
    “Well there is water but maybe not – well there is this and there is that ”

    Its quite simple – Stop trying to hide the fact – there was water there – probably still is.
    I guess its this horrid idea that close minded bible bashing / muslim extremists just can’t handle the fact that God and Allah didn’t make planet earth the chosen planet for us (Humans) in this massive universe and leave every other planet dead and at a temp of 2000 degrees.

    Next thing they will come up with is – “Well it appears there may have been life here too!?”


    Well I think a medal is in order smarty pants.

  37. Feldwebel Wolfenstool

    I wonder what the local Mullah thinks about all this?

  38. @Ad Hominid – I know he said digest, but who said anything about eating people?
    Maybe he ate an apple?

  39. IVAN3MAN

    Fen: Heh – these damn scientists are so wet behind the ears when they come up with this tripe –
    “Well there is water but maybe not – well there is this and there is that”

    I think that those “damn scientists”, as you refer to them, are just sticking to the principle of E-Prime; e.g., avoiding the use of the verbs: be, is, am, are, was, were, been, being, and also their contractions.

    The rationale behind the use of E-Prime suggests that it leads to a less dogmatic style of language that reduces the possibility for misunderstanding and for conflict.

  40. I was going to digg this page, then saw the annoying begging at the top and decided not to. Just a data point.

  41. This is yet another reason I love science!!!

  42. Dunc

    what would be required for terraforming Mars?

    Depends on what you mean by terraforming, exactly… Without a viable magnetic field or active plate tectonics, you can’t really terraform it.

    What you definitely would need is a very long time. It took about a billion years to terraform Earth.

  43. I never really thought about how Mars could be an example of what would happen to our planet. It really makes you think about how what we are doing to our planet will effect us in the future. I know that theres all this talk about global warming, but I don’t think that anyone actually ever realizes what could happen to us. The world in what we live in could completely change for the worse, but we can do something to change that. So I hope there is more research done on Mars, they say that the best way to learn is to find out more about ourselves first.

  44. Big deal, where are the martians?

  45. Torbjörn Larsson, OM

    To add to the irony of the possibility of a Mars impactor resulting in an early loss of atmosphere despite retaining a substantial magnetic field, I see that it is possible the skewed magnetic field itself helps the atmospheric loss:

    What happened next is not 100% certain, but Global Surveyor’s readings are consistent with the following scenario: “The joined fields wrapped themselves around a packet of gas at the top of the Martian atmosphere, forming a magnetic capsule a thousand kilometers wide with ionized air trapped inside,” says Brain. “Solar wind pressure caused the capsule to ‘pinch off’ and it blew away, taking its cargo of air with it.” Brain has since found a dozen more examples. The magnetic capsules or “plasmoids” tend to blow over the south pole of Mars, mainly because most of the umbrellas are located in Mars’ southern hemisphere.

    Instead of protecting poor Mars from solar wind it is possible it join forces to strip the atmosphere.

  46. The following website contains an analysis of purported shorelines on mars:

    The results indicate that the purported shorelines delineate two “containers” that could hold large amounts of water.

  47. We have the technology to for a maned craft, lets just do it and get some real answers instead of educated guesses and theories. Let us see Mars poles are made of methane,,,,,,,,, Mars had water at one time and still does?Lets go find out !!!!! NOW…..

  48. Brett

    Impactor aside, small size probably killed Mars. It probably never held an atmosphere as thick as Earth’s for a long period, had a core that cooled and hardened, and lost internal heat that would have generated steady vulcanism and outgassing to replenish the lost atmosphere.

    A pity it couldn’t have switched places with Venus early in solar system history.

  49. AndresMinas

    @ 34Random Person – Mark LaFlamme must have meant, “being too brief or doing a shortcut” for his choice of the word “digest” instead of the word “digress”.


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