Is Mars home to the solar system's largest single impact scar?

3488 · Jun 25, 2008

Studies by Mars Reconaissance Orbiter & Mars Odyssey suggests that much of the northern hemisphere of Mars is one giant impact basin, dwarfing the Caloris Basin on Mercury & the Valhalla Basin on the Jupiter moon Callisto.The impactor may had been larger than Pluto or Eris. Article here. Edited. Just received the below from JPL on this very subject.MEDIA RELATIONS OFFICE JET PROPULSION LABORATORY CALIFORNIA INSTITUTE OF TECHNOLOGY NATIONAL AERONAUTICS AND SPACE ADMINISTRATION PASADENA, CALIF. 91109 TELEPHONE 818-354-5011 http://www.jpl.nasa.gov Guy Webster  818-354-6278 Jet Propulsion Laboratory, Pasadena, Calif. guy.webster@jpl.nasa.gov Steve Cole  202-358-0918 Headquarters, Washington                         stephen.e.cole@nasa.gov David Chandler  617-253-2704 Massachusetts Institute of Technology, Cambridge dlc1@mit.edu NEWS RELEASE: 2008-119 June 25, 2008 NASA Spacecraft Reveal Largest Crater in Solar System PASADENA, Calif. -- New analysis of Mars' terrain using NASA spacecraft observations reveals what appears to be by far the largest impact crater ever found in the solar system. NASA's Mars Reconnaissance Orbiter and Mars Global Surveyor have provided detailed information about the elevations and gravity of the Red Planet's northern and southern hemispheres. A new study using this information may solve one of the biggest remaining mysteries in the solar system: Why does Mars have two strikingly different kinds of terrain in its northern and southern hemispheres? The huge crater is creating intense scientific interest. The mystery of the two-faced nature of Mars has perplexed scientists since the first comprehensive images of the surface were beamed home by NASA spacecraft in the 1970s. The main hypotheses have been an ancient impact or some internal process related to the planet's molten subsurface layers. The impact idea, proposed in 1984, fell into disfavor because the basin's shape didn't seem to fit the expected round shape for a crater. The newer data is convincing some experts who doubted the impact scenario. "We haven't proved the giant-impact hypothesis, but I think we've shifted the tide," said Jeffrey Andrews-Hanna, a postdoctoral researcher at the Massachusetts Institute of Technology in Cambridge. Andrews-Hanna and co-authors Maria Zuber of the Massachusetts Institute of Technology, and Bruce Banerdt of NASA's Jet Propulsion Laboratory in Pasadena, Calif., report the new findings in the journal Nature this week.  A giant northern basin that covers about 40 percent of Mars' surface, sometimes called the Borealis basin, is the remains of a colossal impact early in the solar system's formation, the new analysis suggests. At 8,500 kilometers (5,300 miles) across, it is about four times wider than the next-biggest impact basin known, the Hellas basin on southern Mars. An accompanying report calculates that the impacting object that produced the Borealis basin must have been about 2,000 kiolometers (1,200 miles) across. That's larger than Pluto. "This is an impressive result that has implications not only for the evolution of early Mars, but also for early Earth's formation," said Michael Meyer, the Mars chief scientist at NASA Headquarters in Washington. This northern-hemisphere basin on Mars is one of the smoothest surfaces found in the solar system. The southern hemisphere is high, rough, heavily cratered terrain, which ranges from 4 to 8 kilometers (2.5 to 5 miles) higher in elevation than the basin floor. Other giant impact basins have been discovered that are elliptical rather than circular. But it took a complex analysis of the Martian surface from NASA's two Mars orbiters to reveal the clear elliptical shape of Borealis basin, which is consistent with being an impact crater. One complicating factor in revealing the elliptical shape of the basin was that after the time of the impact, which must have been at least 3.9 billion years ago, giant volcanoes formed along one part of the basin rim and created a huge region of high, rough terrain that obscures the basin's outlines. It took a combination of gravity data, which tend to reveal underlying structure, with data on current surface elevations to reconstruct a map of Mars elevations as they existed before the volcanoes erupted. "In addition to the elliptical boundary of the basin, there are signs of a possible second, outer ring -- a typical characteristic of large impact basins," Banerdt said. JPL manages the Mars Reconnaissance Orbiter for NASA's Science Mission Directorate, Washington.  For more information about the mission, visit: http://www.nasa.gov/mro . - end -Andrew Brown.  <div class="Discussion_UserSignature"> "I suddenly noticed an anomaly to the left of Io, just off the rim of that world. It was extremely large with respect to the overall size of Io and crescent shaped. It seemed unbelievable that something that big had not been visible before". Linda Morabito on discovering that the Jupiter moon Io was volcanically active. Friday 9th March 1979.http://www.launchphotography.com/ http://anthmartian.googlepages.com/thisislandearthhttp://web.me.com/meridianijournal </div>

qso1 · Jun 26, 2008

Might even be a factor in why Mars did not develop or retain any potential life that we know of. <div class="Discussion_UserSignature"> My borrowed quote for the time being:There are three kinds of people in life. Those who make it happen, those who watch it happen...and those who do not know what happened. </div>

Smersh · Jun 26, 2008

You beat me to it Andrew! I was just going to start a thread about this myself. This is quite an amazing discovery imo.The diameter of the crater, at 5300 miles / 8500 kilometers, is more than the diameter of Mars itself [4200 miles / 6800 kilometers.]  Is it possible, I wonder, if it could have been caused by an impact with another planet, early in the Solar System's history? Earth perhaps? Maybe even causing the Moon to be formed, after a large lump was ejected away from one of the planets? <div class="Discussion_UserSignature"> <h1 style="margin:0pt;font-size:12px">----------------------------------------------------- </h1>Lady Nancy Astor: "Winston, if you were my husband, I'd poison your tea." Churchill: "Nancy, if you were my wife, I'd drink it."Website / forums </div>

Smersh · Jun 26, 2008

Just thought of something else. A collision with another body, that caused the Asteroid Belt to be formed? <div class="Discussion_UserSignature"> <h1 style="margin:0pt;font-size:12px">----------------------------------------------------- </h1>Lady Nancy Astor: "Winston, if you were my husband, I'd poison your tea." Churchill: "Nancy, if you were my wife, I'd drink it."Website / forums </div>

derekmcd · Jun 26, 2008

Replying to: <DIV CLASS='Discussion_PostQuote'>Just thought of something else. A collision with another body, that caused the Asteroid Belt to be formed? Posted by Smersh</DIV>Certainly lends credence to why we find Mars rocks here on Earth.  <div class="Discussion_UserSignature"> <div> </div> <div>"If something's hard to do, then it's not worth doing." - Homer Simpson</div> </div>

DrRocket · Jun 26, 2008

Replying to: <DIV CLASS='Discussion_PostQuote'>You beat me to it Andrew! I was just going to start a thread about this myself. This is quite an amazing discovery imo.The diameter of the crater, at 5300 miles / 8500 kilometers, is more than the diameter of Mars itself [4200 miles / 6800 kilometers.]  Is it possible, I wonder, if it could have been caused by an impact with another planet, early in the Solar System's history? Earth perhaps? Maybe even causing the Moon to be formed, after a large lump was ejected away from one of the planets? Posted by Smersh</DIV>If this thing was 200 km in diameter and Mars is 6800 km in diameter, then assuming equal densities, the impacting body would be 8.65% of the mass of Mars.  Shouldn't there be significant evidence of that body somewhere ?A mission like Phoenis, to land at  the impact point, might be interesting.  <div class="Discussion_UserSignature"> </div>

DrRocket · Jun 26, 2008

Replying to: <DIV CLASS='Discussion_PostQuote'>Certainly lends credence to why we find Mars rocks here on Earth.  Posted by derekmcd</DIV>I have heard such assertions before, but have not been able to confirm.  Do you have evidence supporting the existence of rock on Earth with a Martian origin ? <div class="Discussion_UserSignature"> </div>

derekmcd · Jun 26, 2008

Replying to: <DIV CLASS='Discussion_PostQuote'>I have heard such assertions before, but have not been able to confirm.  Do you have evidence supporting the existence of rock on Earth with a Martian origin ? Posted by DrRocket</DIV>I'm not sure how you would go about showing 100% comfirmation... maybe MW would know.  I would imagine how they go about the chemical analysis can tell a lot about a rock.  It's one of those deals where I just take their word for it.  Here's a list of 'known' mars meteorites:http://www2.jpl.nasa.gov/snc/ <div class="Discussion_UserSignature"> <div> </div> <div>"If something's hard to do, then it's not worth doing." - Homer Simpson</div> </div>

3488 · Jun 26, 2008

Replying to: <DIV CLASS='Discussion_PostQuote'>If this thing was 200 km in diameter and Mars is 6800 km in diameter, then assuming equal densities, the impacting body would be 8.65% of the mass of Mars.  Shouldn't there be significant evidence of that body somewhere ?A mission like Phoenis, to land at  the impact point, might be interesting.  Posted by DrRocket</DIV>Thank you DrRocket,That would be some impactor. I like the idea of the Phoenix type mission to the suspected ground zero. I hope that further observations will reveal where the centre is & yes I agree totally, send a Phoenix type lander there. Wonder if the Ground Zero is near the martian North Pole? I really need to take some time & study the MGS MOLA maps as well. They will show the shape quite well.The dichotomy is pretty well aligned with much of the equator & Phoenix has certainly landed within the 'impact basin', but another similar craft sent to the actual Ground Zero, would be an amazing mission. I will send your suggestion, credited to you (it's your idea not mine) to TPTB. Lets see what they say. IMO it's a must. Replying to: <DIV CLASS='Discussion_PostQuote'>I'm not sure how you would go about showing 100% comfirmation... maybe MW would know.  I would imagine how they go about the chemical analysis can tell a lot about a rock.  It's one of those deals where I just take their word for it.  Here's a list of 'known' mars meteorites:http://www2.jpl.nasa.gov/snc/ Posted by derekmcd</DIV>Thank you Derek.I think the initial 'clincher' were trapped gas bubbles, that matched precisely the martian atmosphere as measured by the Viking Landers & chemical composition of the actual meteorites themselves closely matching much of what was analysed by Mars Pathfinder & the MERs. Of course, it is not 100% proof, but is certainly 99.9% with perhaps a 0.1 % uncertainty. We will really only know with 100% certainty when we get samples back ourselves & then compare, with rocks we know for sure are from Mars. I think myself the SNC meteorites are of Martian origin, but we cannot say for 100%sure that they are, but they are an astonishingly close match to rocks studied in situ on Mars.Andrew Brown.  <div class="Discussion_UserSignature"> "I suddenly noticed an anomaly to the left of Io, just off the rim of that world. It was extremely large with respect to the overall size of Io and crescent shaped. It seemed unbelievable that something that big had not been visible before". Linda Morabito on discovering that the Jupiter moon Io was volcanically active. Friday 9th March 1979.http://www.launchphotography.com/ http://anthmartian.googlepages.com/thisislandearthhttp://web.me.com/meridianijournal </div>

Smersh · Jun 27, 2008

Replying to: <DIV CLASS='Discussion_PostQuote'>Thank you DrRocket,That would be some impactor. I like the idea of the Phoenix type mission to the suspected ground zero. I hope that further observations will reveal where the centre is & yes I agree totally, send a Phoenix type lander there. Wonder if the Ground Zero is near the martian North Pole? I really need to take some time & study the MGS MOLA maps as well. They will show the shape quite well.The dichotomy is pretty well aligned with much of the equator & Phoenix has certainly landed within the 'impact basin', but another similar craft sent to the actual Ground Zero, would be an amazing mission. I will send your suggestion, credited to you (it's your idea not mine) to TPTB. Lets see what they say. IMO it's a must ... Posted by 3488</DIV>I think that's a good idea, but if nobody is certain exactly where the ground zero is, wouldn't such a potential mission, if carried out too soon, be quite possibly a waste of money? Surely further investigation / observation needs to be carried out first, to determine the exact impact point? <div class="Discussion_UserSignature"> <h1 style="margin:0pt;font-size:12px">----------------------------------------------------- </h1>Lady Nancy Astor: "Winston, if you were my husband, I'd poison your tea." Churchill: "Nancy, if you were my wife, I'd drink it."Website / forums </div>

nimbus · Jun 27, 2008

Would this impact have played any part in Mars' large inclination in the past?  I can't find the estimated time of that past tilt, and only an estimate of 4.4BY ago for this impact. <div class="Discussion_UserSignature"> </div>

3488 · Jun 27, 2008

Replying to: <DIV CLASS='Discussion_PostQuote'>I think that's a good idea, but if nobody is certain exactly where the ground zero is, wouldn't such a potential mission, if carried out too soon, be quite possibly a waste of money? Surely further investigation / observation needs to be carried out first, to determine the exact impact point?Posted by Smersh</DIV>Hi Smersh,Good point, I am sure that NASA, ESA, JAXA, etc are looking at all data now gathered to determine the Ground Zero. I see what you mean about the lander issue. IMO, no lander to Mars is a waste of money, no matter where the landing site is. Yes it would be daft, if a lander was sent to what was thought to be Ground Zero & it turned out that Ground Zero lets say was 500 KM to the south, but that lander would still carry out a very interesting & important scientific mission, furthering our knowledge of Mars from another site on the surface & to me, my opinion & I'm sure that I'm not alone on this, would not be a waste of money.But yes, lets find the Ground Zero, then put a proposal in for a lander / rover to that point. DrRocket certainly has a great idea there, one that is definately worth pursuing.Replying to: <DIV CLASS='Discussion_PostQuote'>Would this impact have played any part in Mars' large inclination in the past?  I can't find the estimated time of that past tilt, and only an estimate of 4.4BY ago for this impact. Posted by nimbus</DIV>Cheers nimbus. I too cannot seem to find anything else. I think that this finding is so new, much background info has not yet been compiled.Andrew Brown. <div class="Discussion_UserSignature"> "I suddenly noticed an anomaly to the left of Io, just off the rim of that world. It was extremely large with respect to the overall size of Io and crescent shaped. It seemed unbelievable that something that big had not been visible before". Linda Morabito on discovering that the Jupiter moon Io was volcanically active. Friday 9th March 1979.http://www.launchphotography.com/ http://anthmartian.googlepages.com/thisislandearthhttp://web.me.com/meridianijournal </div>

JonClarke · Jun 27, 2008

The Mars meteroites (the SNC family) wre launched from Mars much more recently than this giant event.  They are also all made of much younger rocks.Jon <div class="Discussion_UserSignature"> Whether we become a multi-planet species with unlimited horizons, or are forever confined to Earth will be decided in the twenty-first century amid the vast plains, rugged canyons and lofty mountains of Mars Arthur Clarke </div>

bearack · Jun 27, 2008

Andrew, wouldn't that be hard to determine considering we are unable to understand impacts on the large gas giants? <div class="Discussion_UserSignature"> <img id="06322a8d-f18d-4ab1-8ea7-150275a4cb53" src="http://sitelife.space.com/ver1.0/Content/images/store/6/14/06322a8d-f18d-4ab1-8ea7-150275a4cb53.Large.jpg" alt="blog post photo" /> </div>

Smersh · Jun 27, 2008

Replying to: <DIV CLASS='Discussion_PostQuote'>Hi Smersh,Good point, I am sure that NASA, ESA, JAXA, etc are looking at all data now gathered to determine the Ground Zero. I see what you mean about the lander issue. IMO, no lander to Mars is a waste of money, no matter where the landing site is. Yes it would be daft, if a lander was sent to what was thought to be Ground Zero & it turned out that Ground Zero lets say was 500 KM to the south, but that lander would still carry out a very interesting & important scientific mission, furthering our knowledge of Mars from another site on the surface & to me, my opinion & I'm sure that I'm not alone on this, would not be a waste of money.But yes, lets find the Ground Zero, then put a proposal in for a lander / rover to that point. DrRocket certainly has a great idea there, one that is definately worth pursuing ... Posted by 3488</DIV>Hi Andrew, yes I see your point. Of course, any lander that succesfully lands anywhere on Mars, would not be a "waste of money" as I described it, because of the huge scientific benefits that would follow. Maybe I should have said "comparative waste of money." What I'm trying to say is that NASA has a budget to keep to, because if funds were unlimited, we'd have landers all over the Martian surface by now. I'm just making the point that a mission that's specifically designed to find out the cause of this crater should have accurate information about where to land first, otherwise the budget may not be sufficient to send another mission afterwards, to the correct location, if the wrong place is chosen.  But yes, I'm sure the various space agencies will  now be working hard to determine where that location is.  <div class="Discussion_UserSignature"> <h1 style="margin:0pt;font-size:12px">----------------------------------------------------- </h1>Lady Nancy Astor: "Winston, if you were my husband, I'd poison your tea." Churchill: "Nancy, if you were my wife, I'd drink it."Website / forums </div>

3488 · Jun 27, 2008

Replying to: <DIV CLASS='Discussion_PostQuote'>Andrew, wouldn't that be hard to determine considering we are unable to understand impacts on the large gas giants? Posted by bearack</DIV>Hi Tim,It will be difficult, but Mars is as you know not a gas giant. When Comet Shoemaker Levy 9's 21 fragments slammed into Jupiter's atmosphere in July 1994,  the resulting scars, though persisted for an unexpectedly long time, where still erased by Jupiter's winds. The same will be true for comet impacts into the atmospheres of Saturn, Uranus & Neptune. With Mars, as DrRocket correctly surmised, that such an impactor is likely to leave a remnant of itself, possibly as a mascon (mass concentration). We already have a high resolution altitude global map of Mars, courtesy of the MOLA on board the now inactive MGS orbiter, MRO, Odyssey & Mars Express, between them have other instruments that can remote sense the surface or even ping raday to subsurface levels, not to mention, all three have very effective imaging devices as well as all three can be tracked, thus revealing a possible 'hard spot' or even a 'soft spot' in the martian crust where the impactor slammed into Mars.IMO, its difficult, but not impossible. Replying to: <DIV CLASS='Discussion_PostQuote'>Hi Andrew, yes I see your point. Of course, any lander that succesfully lands anywhere on Mars, would not be a "waste of money" as I described it, because of the huge scientific benefits that would follow. Maybe I should have said "comparative waste of money." What I'm trying to say is that NASA has a budget to keep to, because if funds were unlimited, we'd have landers all over the Martian surface by now. I'm just making the point that a mission that's specifically designed to find out the cause of this crater should have accurate information about where to land first, otherwise the budget may not be sufficient to send another mission afterwards, to the correct location, if the wrong place is chosen.  But yes, I'm sure the various space agencies will  now be working hard to determine where that location is.  Posted by Smersh</DIV>That's very true Smersh. Sorry I may have misunderstood.Andrew Brown.  <div class="Discussion_UserSignature"> "I suddenly noticed an anomaly to the left of Io, just off the rim of that world. It was extremely large with respect to the overall size of Io and crescent shaped. It seemed unbelievable that something that big had not been visible before". Linda Morabito on discovering that the Jupiter moon Io was volcanically active. Friday 9th March 1979.http://www.launchphotography.com/ http://anthmartian.googlepages.com/thisislandearthhttp://web.me.com/meridianijournal </div>

neuvik · Jun 27, 2008

Would a core sample of the martian terrain be able to find evidence or do we actually need rovers for it?The Discovery Channel often shows programs featuring the impact that killed off the dinosaurs, and in it they usualy have a geologist point out the layer of dust it spread around the globe.    So would a drilling lander be able to prove without a doubt the reality of this massive impact or are there too many impacts that may distrupt the readings?   I'd think something that big would leave a very large deposit of vaporized rock.  Edit:  I forgot they found that impact site in the Yucatan was found with gravametric scanning.   So maybe a rover is needed. <div class="Discussion_UserSignature"> I don't think I'm alone when I say, "I hope more planets fall under the ruthless domination of Earth!"SDC Boards: Power by PLuck - Ph**king Luck </div>

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