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Three studies map out the shores of ancient seas that scientists say once existed on Mars.
One study, appearing in Sunday's issue of Nature Geoscience, contends that a vast ocean probably covered a third of the Red Planet's surface 3.5 billion years ago. The University of Colorado's Gaetano Di Achille and Brian Hynek came to that conclusion after looking at 52 delta deposits and thousands of dry river valleys on the Martian surface.
Elevation readings from a variety of NASA probes as well as Europe's Mars Express orbiter were fed into a geographic information system, or GIS, for an analysis of the valley and delta patterns. What emerged was a map indicating that much of Mars' northern hemisphere was underwater early in the planet's history. The ancient sea would have contained about 30 million cubic miles (124 million cubic kilometers) of water. That's about a tenth of the total volume of Earth's oceans today, on a planet that's slightly more than half of Earth's size.
This study was funded by NASA's Mars Data Analysis Program.
Another research report, in the Journal of Geophysical Research-Planets, detected roughly 40,000 river valleys on Mars. That number is about four times as high as previously thought, said Hynek, who conducted this study with University of Colorado colleagues Michael Beach and Monica Hoke.
It would take a sustained level of precipitation to create so many valleys, Hynek said in a university news release. "This effectively puts a nail in the coffin regarding the presence of past rainfall on Mars," he said.
Some researchers have suggested that the water-carved features seen on Mars today were created by massive flash floods early in its history, while others say ancient Mars had a longer-lasting hydrologic cycle like Earth's, complete with rainfall, running rivers, seas and evaporation. Clearly the latter scenario is more favorable for the development of life. "If life ever arose on Mars, deltas may be the key to unlocking Mars' biological past," Hynek said.
Yet another survey, by a different group of researchers, came up with a similar map: This survey was based on an analysis of topographic and geological data from NASA's Mars Global Surveyor, Mars Odyssey and Viking orbiters, and concentrated on the lakes that appear to have existed in Mars' southern hemisphere. Leslie Bleamaster, a research scientist at the Arizona-based Planetary Science Institute, said the mapping project supports the idea that lakes once existed within the Hellas impact basin and elsewhere in the Martian south.
"This mapping makes geologic interpretations consistent with previous studies, and constrains the timing of these putative lakes to the early-middle Noachian period on Mars, between 4.5 and 3.5 billion years ago," he said in a news release.
USGS
A map of Mars' Hellas Planitia shows how river valleys and shorelines might have looked billions of years ago.
You can get a closer look at the map and an accompanying pamphlet on the U.S. Geological Survey's website. (USGS serves as a repository for geographical data about other worlds as well as our own.) The project was supported through NASA's Planetary Geology and Geophysics program.
So where did all the water go?
Because Mars is so much smaller than Earth, scientists suspect that its molten core cooled down relatively quickly, which caused the planet to lose its global magnetic field. Without a magnetosphere like Earth's, Mars was less able to fend off electrically charged particles from the solar wind. In time, those particles might have blasted away much of the Martian atmosphere, disrupting the hydrologic cycle.
An alternate explanation would be that Mars was less able to hang onto its atmosphere simply because of its weaker gravitational pull. In either case, the Martian atmosphere was reduced to a stripped-down layer of carbon dioxide. And without an airy blanket to keep it warm, the planet went into a deep freeze. Today, Martian H2O exists mostly as ice, at the poles or mixed in with the chilly soil. Some of the water appears to have reacted with minerals to form carbonate rocks, and scientists recently reported signs that water trickled out to the surface 1.25 million years ago.
Hynek said figuring out where all the water on Mars went is "one of the main questions we would like to answer." Future Mars missions could provide better answers to the question. The University of Colorado at Boulder happens to be managing one of those missions for NASA: the $485 million Mars Atmosphere and Volatile Evolution mission, or MAVEN, which is due for launch in 2013.
More about Mars:
- Special report: Return to the Red Planet
- Gallery: Greatest hits from Mars
- Water found (and lost) on Mars
- Mystery solved: Mars had large oceans
Join the Cosmic Log corps by signing up as my Facebook friend or hooking up on Twitter. And if you really want to be friendly, ask me about "The Case for Pluto."
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Now this is the sort of article that deserves focus!!....I once tried to project the mars dems from pigwad using the ersi viewer but I had trouble matching the spheroids since earth is almost twice as big as mars, The first projection I saw was in arc user (a magazine for ERSI users) and looked a little different, the oceans may have evolved over time so an accurate static view may be more time dependent but at least we have good that a vast ocean(s) really were there. The real importance IMHO is that now we know where the coastlines may very well have been, we can look for signs of oil, wait, strike that, I mean LIFE!!, It would seem to me that silver dollars are one of the best organisms for spreading life around the cosmos via asteriod stikes, BUT, it seems on earth that the coastlines are always brimming with life, the turbulance insures against stagnation and brings new materials to the boundry (that is a big inference to suggest tides on mars). Thanks alan, I hope more people post cause when there are two or more pages of posts I can see the rest of the article on the second page!!....is it my viewer or malhtm???
Weird! Ray, if you're having problems I'd love it if you could write a message to the address listed in the header above (if you can see the header above) and I'll pass that along to the technical folks. They thought they fixed the problem last week, but from what you're saying I assume that you're still having problems. Thanks for the uplifting message on Mars!
Ray - I have had some page formatting problems recently with Firefox (probably need to update) but IE shows this page fine. Just a hunch. Thanks for the post.
I think, that what really happened to mars, is that it was originally the northern hemisphere that actually had all the land. Poles switched. I bet mars used to be earthlike in temperature... and that ultimately, when the poles switched the planet basically screwed itself over. possibly even flinging some of its water into space?
Why not, John? This stuff totally blows away all my mom's Ray Bradbury books. Now if only the Star Wars movies didn't take themselves so seriously.
I lack the scientific background to make truly intelligent comments on the science or the various theories but I would say this article certainly packs the "WOW" factor. I find all the speculation about Mars water and what may have happened to it just fascinating. I also wonder what implications, if any, it has for Earth's future. Has anybody checked to see if BP was doing any drilling on Mars 3.5 billion years ago?
MY NEW THEORY is an earlier BP drilling accident is what really killed the dinosaurs. Hey, that would explain the la brea tar pits, right?
The archives listed conjoint w this article are really great and a valuable record of what, in my opinion, is the most spectacular exploration effort in all of scientific history. To see the "shores of Mars", see the tire tread trail of the rovers, see the dusty plains and rubble fields is more than just amazing. Now that the Obama era NASA team has decided on a "lunar bypass" in favor of an attempt to land a manned exploration expedition to Mars, our red neighbor comes more and more into focus. On Earth, water = life. So the big question going back to Schiaparelli and Lowell may get an answer in this century. BUT...is a manned effort truly necessary at this time? Is a "lunar bypass" really the right way to go? I don't make any of these decisions. A launch to Mars at this time, in my opinion, is only an engineering stunt, very costly, proving only what we already know. It can be done. Is NASA working from fear and worry that Hindus or Chinamen might be first on Mars? Is being there first really scientifically important? Mars, at this time is very very far away and bypassing The Moon for a shot at Mars will be very costly and may not be all that necessary. Robotic exploration to date has been exceptionally productive and successful.
Skip, funny you should bring up implications for our own world's future! Since they have been keeping records our planet's magnetic field appears to be diminishing. And as of late its apparent degradation has accelerated. Is this a long term fluctuation or as some suspect a decline that is exponentiation in nature. Has the self sustaining nature of our molten core now been tipped towards irreversible cooling and ultimately the death of our magnetic field.
Whoa Tank, that's exactly what I was afraid someone would share. I've long held the personal belief that we should regard Mars as an example of what could happen to the Earth at some point and those long-range thinkers with the scientific knowledge might want to burn a few brain cells on possible solutions or at the very least a delaying strategy.
Sadly, that would probably involve the loss of many of the luxuries we take for granted like the proliferation of paved roads and personal transporation. It would also mean the death of the big cities and a return to more small rural communities. It would also probably mean the halt to our current attempt to deforest the planet.
I wonder if the Martians scratched their heads in wonder at the mysterious disappearance of honey bees and other species and then went right on cutting down trees, polluting their water and covering their planet with asphalt and concrete with the assumption they had a god-given right to do so?
NOT THAT I WANT TO INTRODUCE RELIGION INTO THIS DISCUSSSION. No offense to any Christians reading this blog. Please, don't anybody go off on a tangent on this. I'm just trying to say, maybe, just maybe we should start to take global warming and the destruction of the planet's resources a little more seriously or else some day, a few billion years from now some insect on Venus will look at Earth and wonder if it ever had liquid water and could have supported life.
Alan, if you or any of your readers are interested in joining our LinkedIn Group called Terraforming Research Network, please be my guest. You need to be a member of linkedin.com to join (basic membership is free).
I don't think true christians worry about anything except the inability to be able to witness or being accused of offending someone. We are happy Jesus is given glory and credits for the wonderful universe he created.
Skip,
Why did you use the word religion in your comment? What does it have to do with oceans on Mars? Now you got Lenorse going. Wait for the avalanche of hallelujias and genuflecting.
Interesting comments from Ray and Tank. Magnetic field degradation is definitely one area that needs to be further researched. Could be the true demise of Earth, not the Sun expiring. Glad it is in the distant (human time) future.
Sorry guys, I love this blog and read it almost every day. But I hate it when it degenerates into discussions about religion or politics. I was just trying to head that off and instead I turned the conversation in exactly the direction I wanted to avoid. And of course that unintentional redirection has caused everyone to miss the point.
We don't need fossil fuels for transportation or many of the products now containing petroleum products. We have alternatives and I think we should begin developing those alternatives before we end up like the late great planet Mars.
Ok, I'm done. Thanks for reading my comments and responding and Alan, thanks for the very informative blog.
Skip,
Maybe we "headed it off at the pass". No worries.
Are we looking for canals? Weird that there was all that time that we thought there were canals like there really was water.
Oh well, this should drive the desire to get more telemetry on the Martian ground. It appears that there could have been life. It is imperative that humanity get the information.