Earth rocks on Mars

[Leovinus]

Some meteorites have been found on Earth that have been analyzed and determined to have originated on Mars due to their composition. Presumeably, such rocks were blasted into space by some other impact on Mars.<br /><br />If it can work that way, then presumeably a similar impact on Earth could shoot debris out into space and eventually land on Mars. How would some future Martian geologist look at such a rock and know that it came from Earth? Is there anything on the current Mars rovers that could determine this if they got really, really, lucky and found an Earth rock? <div class="Discussion_UserSignature"> </div>

 

[Aetius]

I don't know if Spirit or Opportunity could check for it, but I would think that the minute quantities of gas trapped inside tiny rock crystals would carry the atmospheric signature of Earth. That is to say, Earth at the time the rocks were blasted into space. Our atmosphere probably had a slightly different composition when the K-T extinctor blasted some Earth rocks into interplanetary space [65 million years ago], for example.

 

[igorsboss]

<font color="yellow">The big problem with an asteroidal impact large enough to blow something off the surface of the earth and into space is that the material would be largely melted or vaporized first, by the intensity of the impact</font><br /><br />I'm sure this is true for the vast majority of the ejecta. I agree that an impact envornment is incredibly violent.<br /><br />Even so, I still wonder if there could be a ring of material, towards the outer edges of the crater, which would not suffer such intense forces, and yet still achieve escape velocity. Some of the debris might be tossed out as boulders or chunks.<br /><br />If so, then there may be crevices in that boulder in which organisms could survive the ejection process. For example, the inside of a geode might provide a survivable environment.<br /><br />I'm just not convinced that all the escape-velocity ejecta will be sterilized.

 

[igorsboss]

<font color="yellow">Accelerating a mass from rest at the earth's surface requires it to be moved well past escape velocity, due to air resistance, which the mass must first move thru to get into orbit.</font><br /><br />That's assuming the same old stable atmosphere we see today. However, such a large impact event would temporarily disrupt the atmosphere.<br /><br />The atmosphere could be ripped away locally by such a large event. My "little geode that could" might be moving along with this ejected atmosphere, then find the atmosphere dissapates around it as it encounters the vaccuum of space.<br /><br />I agree the odds are very slim. Most ejecta is incandescent, but not to the point of total, complete sterilization. Very little will survive, but I think a tiny fraction just might.<br /><br />Why do I care? Because this process would be a necessary step in a possible natural interplanetary spread of life. It is important to know whether or not this is truly impossible or not.

 

[yurkin]

I think the most difficult part would be clearing Earth’s gravity well. Earth has a much larger gravity well then Mars so much less ejected matter will reach deep space. This isn’t even taking into account the atmospheric effects.<br /><br />Going from Earth’s orbit to Mar’s orbit isn’t a whole lot harder then going the other way. It takes energy to cause a change in an objects orbit either way. If it didn’t then Mars would just role down the gradient towards

 

[rogers_buck]

I read an article, somewhere, in connection with the martian meteorite. The article was interesting because if featured the results of computer simultaions for material ejected from the three terrestrial planets and the time it would take for the material to reach another of the worlds. Material blasted from Venus would reach the earth orders of magnitude more slowly than material blasted from mars. The reason given, as I recall, was the gravitational attraction of the sun. It was a much slower journey uphill than downhill, so to speak. I don't recall where I read the article or how many years ago it was, or how to find it again... Sorry.<br /><br />There was an interesting thread about an SDC article on finding traces of ancient earth and other inner planets in moon dust. Just look back a few pages and your find it if you are interested.<br /><br />The thing to remember about impacts is that the resulting energy of the ejecta follows a gausian pattern. There is a non-zero probability that some stuff will have the energy needed to escape with trapped gasses intact.<br />

 

[vogon13]

Would it be safe to say the vast majority of earth sourced material around the solar system would have originated during the Odyseus event? <div class="Discussion_UserSignature"> <p><font color="#ff0000"><strong>TPTB went to Dallas and all I got was Plucked !!</strong></font></p><p><font color="#339966"><strong>So many people, so few recipes !!</strong></font></p><p><font color="#0000ff"><strong>Let's clean up this stinkhole !!</strong></font> </p> </div>

 

[najab]

><i>...then it will be vaporized because of the high speeds involved...</i><p>Not necessarily. Some metorites are <b>cold</b> when they are found right after they fall, in fact there was recently a case were a they found a chunk of ice that had fallen from space. Remember it's compressional heating, not frictional, so if the fall (or rise) is fast enough, only the outer layers of the body will heat up.</p>

 

[earthseed]

Research by Jay Melosh and others shows that not all material ejected into space by a meteorite impact will be highly shocked. From this paper:<blockquote><em>Older work on the maximum velocities achieved by impact ejecta focused on the relationship between the pressure in the shock wave generated by the impact and the velocity of material just behind the shock. Measured directly in laboratory experiments, the shock pressure needed to accelerate material to planetary escape velocities--2.4 kilometers per second (about 5,000 miles per hour) for the Moon, and 5.0 kilometers per second (about 11,000 miles per hour) for Mars, implying pressures of 0.44 and 1.5 megabars (a megabar equals 1 million times Earth's atmospheric pressure at sea level) for lunar and martian basalts, respectively-would have been high enough to melt or even vaporize the ejected rock. Yet study of the lunar meteorites indicates that their ejection was accompanied by no more than about 0.2 megabar of shock, and the most highly shocked martian meteorites (which contain pockets of once-melted glass) still indicate only about 0.4 megabar.<br /><br />The problem with the pressure-velocity relationship is that it applies only to material completely engulfed by the shock wave. Very close to the target surface, however, the ambient pressure is zero. No matter how strong the impinging shock wave, the free surface can never be raised to a pressure higher than zero. This effectively shields surface rocks from strong compression. However, the pressure increases very rapidly with depth below the surface, which translates into a powerful acceleration that throws lightly shocked surface rocks our at speeds comparable to the original impactor's speed.<br /><br />...<br /><br />Impacts such as the one that created the 180-kilometer diameter (110-mile) Chicxulub crater in Yucatan 65 million years ago (and incidentally caused a profound extinction that wi</em></blockquote>

 

[toymaker]

The Moon has a small but insignificant atmosphere:<br />http://en.wikipedia.org/wiki/Moon#Atmosphere<br />"The Moon has a relatively insignificant and tenuous atmosphere. One source of this atmosphere is outgassing — the release of gases, for instance radon, which originate deep within the Moon's interior. Another important source of gases is the solar wind, which is briefly captured by the Moon's gravity."

 

[najab]

NO!! NOT AGAIN!!! <img src="/images/icons/shocked.gif" />

 

[toymaker]

"The lunar atmosphere is so utterly tenuous(less than 0.5 millibar compared to earth's 1000 mbars), that in cases of heating from mass being blasted off the surface by meteor and asteroid impacts, there will be no effective frictional heating, as compared to the heating from the substantial and highly significant terrestrial atmosphere. "<br />True true...but not vacuum <img src="/images/icons/smile.gif" /><br /><br />"As usual you miss the forest for the trees"<br />Nope.I'm just pointing out that a single tree isn't a desert <img src="/images/icons/smile.gif" />

 

[rogers_buck]

It just occured to me, there have been many earth rocks on mars. Just about every wake up call sent to a lander has been earth rock.

 

[najab]

><i>Nor does it mention tektites, which were all once molten, and strongly suggest a real, existing counter example of the article's claims.</i><p>I could be wrong, but I believe that <blockquote>"Of these fragments, a small fraction, perhaps 1 in 500, would have been so lightly shocked that internal temperatures remained below 100 degrees Celsius (212 degrees Fahrenheit)."</blockquote> implies that the other 499 would have been heated to <b>over</b> 100 degrees Celsius, which would include those that became tektites.</p>

 

[najab]

><i>That's pretty much a vacuum in the common sense of the term. Far more so than even in light bulbs on the earth.</i><p>I was going to let this go, but you had to bring up the lightbulb non-argument again. Once again, the pressure inside a lightbulb is only <b>very slightly</b> less than ambient, in fact when the bulb is lit there's actually <b>positive</b> pressure. The reason the filament doesn't oxidise instantly is because there's no oxygen in there (well, very little)!<p>><i>Frankly, you're not reading English, clearly, but what's new around here?</i><p>Yet another ad hominem.</p></p></p>

 

[toymaker]

"The vacuum of the moon is so nearly complete" <br />Nearly <img src="/images/icons/smile.gif" /><br />""Significantly, effectively, nearly total lack of atmosphere, utterly tenuous" <br /><br />Which of those qualifiers did you ignore? Surely not All of them? "<br />None.You did ignore "nearly" though <img src="/images/icons/smile.gif" />

 

[igorsboss]

Toy,<br />You're right. Absolutely right.<br /><br />By the way, when did you graduate from the Karl Rove Scientific Institute?

 

[chew_on_this]

Good article on survivability of extremeophiles about 2/3 of the way down. Pretty much refutes just about every position ol' steverino blathers on against.<br /><br />http://www.sciencedaily.com/releases/1998/09/980902055654.htm

 

[igorsboss]

Some of the best survivors are spores from spore-forming bacteria. As I understand it, in very dry conditions, these bacteria dry out, forming a spore which can resurect itself when liquid water becomes available again. While in a spore state, these bacteria can withstand space travel for a very very long time. (I think it remains vulnerable to UV radiation, however.)<br /><br />Now, suppose a chemotrophic bacteria forms a spore inside a dry geode, and that geode is ejected into space by an impact, then lands on a wet planet. The geode cracks open, and one tiny bacteria seeds a whole planet.<br /><br />A lot of things have to go just right for such a scenario to play out. Such a theory is very hard to prove one way or another. The odds are incredibly small, for sure. That one bacteria has to get incredibly lucky.<br /><br />Steve makes a completely valid point that most rocks will be vaporized in an impact. My point is that some rocks just might survive ejection. Not many, but a few.<br /><br />So, are we just cosmic weeds?<br /><br />Since the question is a matter of history, probability calcuations are insufficient, because probability only concerns potential (future) events. The event may have happened even if the calculated probability is zero.<br /><br />The strongest evidence to the affirmative is the fact that Earth was alive almost as soon as it formed. Since we don't know how life arose from non-life, we are forced to consider the possibility that life may have arrived here from elsewhere.<br /><br />Arrived How? I find it facinating that a possible all-natural answer exists, which does not depend on the intervention of alien races or supernatural powers.

 

[najab]

><i>Extremophiles have never been shown to be able to survive on Mars.</i><p>Has anybody actually done this study? Where are the verifiable, quantifiable, scientific results? Until you post them, I cannot accept your statement as anything but wild, baseless speculation. <img src="/images/icons/tongue.gif" /><p>><i>As has been stated before, even extremophiles have highly fastidious requirements for living. Very few of which are found, for a fact, on Mars.</i><p>But, this means that some are, in fact, found on Mars. So your contention that extremophiles cannot live on Mars is nothing but yet another example of how you presuppose such things before they are known to be the case.<p>><i>It is upon YOU to show clear, solid, living cells outside the earth. That you have not done (nor anyone else so far in history)...</i><p>Two words: Surveyor 3.</p></p></p></p></p>

 

[najab]

><i>Until it can be shown that Extremophiles can live, grow and metabolize on Mars independently of lab conditions, then it's an hypothesis which is not substantiated.</i><p>The (somewhat subtle) counterpoint which you appear to have missed is that until it is shown that they <b>cannot</b> survive on Mars, both points have equal weight. The only possible, correct answer to the question "Can life exist on Mars?" is "We don't know."</p>

 

[najab]

><i>And Surveyor 3 did NOT produce clear, unequivocal evidence for life on mars. What was found was not consistent with biological result & further is unknown, unlike your contentious commetn indicated.</i><p>That would have been a very unlikely result, considering that Surveyor 3 was a <b>LUNAR</b> mission!!! Read up on it, and then we'll discuss some more.<p>><i>Even Sagan denied it was clear evidence for life on Mars, as have most scientists who looked at the evidence...</i><p>I always knew that Sagan chap was a bright spark. <img src="/images/icons/wink.gif" /><p>><i>Your message is full of mistakes and misinterpretations.</i><p>P K B.</p></p></p></p></p>

 

[Leovinus]

Wasn't Surveyor 3 the one where Apollo 12 brought back parts? They might have studied those parts to see if any Earth microbes survived those years in the harsh lunar environment and then used those results to try to extrapolate information about survival on Mars. <div class="Discussion_UserSignature"> </div>

 

[najab]

Yes, that's the mission. But the importance of Surveyor 3 is that they <b>did</b> find living bacteria in and on the TV camera. I don't think anyone ever tried to extrapolate those results to Mars though, as Steve and others are so fond of reminding us, Mars is <b>very</b> different to the Moon.<p>The reason I brought up the Surveyor was in response to Steve's assertion that Earth life had never been shown to have survived on another planetary body.</p>

 

[Leovinus]

I would think that the Moon would be a much harsher environment than Mars and that if microbes can survive on the Moon then they should be able to survive on Mars. <div class="Discussion_UserSignature"> </div>