Possible Evidence of Martian Bacteria 190
half-seas-over writes "NASA issued a very interesting press release today. It highlights a recent study that compared tiny magnetite crystals in the Allan Hill meteorite to similar magnetite crystals that are created here on Earth by bacteria (who use the magnetite as a compass). The study (abstract available here (PDF) from this site) uses fairly strict criteria to determine that 25% of the magnetite content of the meteorite was created by ancient (>3.9Gyr ago) martian bacteria... either that or there is some strange natural process that makes very pure, isolated magnetite crystals that we haven't imagined or seen on Earth which is present on Mars. We'll have to wait and see what happens next, 'extraordinary claims require extraordinary evidence' -Carl Sagan."
Translation in normal human language: (Score:1, Troll)
An important tool is to create intresting but ominous scientific claims which a only be verified by going to Mars.
There is still to problem with the "robots only" league, but I expect further onimous arguments in this direction.
But on the other hand, what's useful for science can't be wrong, right ? At least it's not such a brainless waste of money like the dotcom hype.
Re:Translation in normal human language: (Score:1)
There's also this thing about people wanting to believe that there's life on mars so they'll probably go even though they figure out how the magnetite got formed.
btw, anyone have any luck with the link to the press release on ftp? It seems to be asking for id/auth once in a while.
Re:Translation as brainfull and overfitted (Score:1)
Re:Translation in normal human language: (Score:1)
Re:Translation in normal human language: (Score:2)
Re:Translation in normal human language: (Score:2, Offtopic)
So obviously we have the means *right now* to end all hunger on the planet. We simply don't care (because most of the people who are starving are black and in countries with no political importance), can't (because those countries are openly hostile to us and either won't accept our help or steal what help we do send), or won't (does anyone know the last time we sent aid to Cuba? I know Castro offered to provide medical care to the people of Appalachia, which has some of the poorest people in the country.).
Remember when the Russia sub sank? We offered to help and they wouldn't take it because of pride. A similar situation occured a few years before that where we needed help but we wouldn't take the Russians up on their offer because, well, duh, they're the Ruskies.
That having been said, I don't think a human mission to mars is the way to go. I've always been in favor of colonizing permanent space stations, then the moon, then from there to Mars.
Better to send a robotic mission to Mars when searching for life, to eliminate any chance of possible contamination, no matter how small that chance is.
our humanitarian outlook (offtopic) (Score:1)
Re:Translation in normal human language: (Score:2)
What about the gobs of useless money we spend on our oversized military? What about how we pay farmers to not farm their crops?
If we were only concerned about immediate serious problems, we would not have: Communications sattlites, AMERICA (hey, Columbus's voyage was gratuitus), computers, etc, etc, etc.
If all we are concerned about is education and the starving children of Namibia, we will go nowhere. Humanity will stagnate.
zZzZz (Score:1, Insightful)
Re:zZzZz (Score:3, Interesting)
They've found a crystal with no known pathway for its creation apart from a directed one.
The three conclusion options are
1) On earth it's directed by microbes, on mars it's directed by God.
2) On earth it's only directed by microbes, on mars the laws of physics permit it to happen without direction
3) On earth it's directed by microbes, on mars it's directed by microbes.
Get out your Ockham's razer - which of the two are you more inclined to pare away?
YAWIAR.
Re:zZzZz (Score:1)
The experiments that prove the existance of other subatomic particles are simply looking at the fingerprints left on the earthly matter after interactions.
And how did we prove the existence of the standard nuclear model of the atom in the first place - we (well, Rutherford) looked at the fingerprint caused by particle scattering.
YAWIAR.
Re:zZzZz (Score:1)
Let's try a simple example:
Scenario 1) You come home from the pub and you see a man taking letting the air out of your tyres
Scenario 2) You come home from the pub and you see that your tyres are flat.
Scenario 1 is _hard evidence_ that there's someone who's letting down tyres in the neighbourhood, scenario 2 is _not_. Are you really sure your 20 year old Lada doesn't have fucked valves?
Sheesh, don't they teach ACs to think any more?
YAWIAR.
Re:zZzZz (Score:2)
BTW,
Scenario 1 is _hard evidence_ that there's someone who's letting down tyres in the neighbourhood, scenario 2 is _not_. Are you really sure your 20 year old Lada doesn't have fucked valves?
Well, you are only seeing the effects of Scenario 1 also. Light interacting with the person and your car gets focused strikes your eye in a way to form an image of someone fucking with your car. How do you know it isn't just a big phased array optic screen right there put up by aliens for some reason?
My point is that those paths can only be subatomic particles. Do you have a different theory?
Re:zZzZz (Score:1)
Double barrelled - all ten toes removed.
Well done.
YAWIAR.
Re:zZzZz (Score:1)
This one is more probable because you are more likley to discover a new law of physics than you are to discover life on another planet. Just because you theorise in the possibility of life on another planet, doesn't make the possibility any more probable than it was before people made theories about it.
In the past 100 years how many times have people discovered new physics laws vs discovered life on other planets?
Head Tail Tail Head HTTTTHTHHTHT Edge (Score:5, Insightful)
In the past 100 years how many times have people built houses vs built computers? Obviously there are no computers because so many houses have been built. Slashdot vanishes in a cloud of irrelevant improbabilities...
The probability of an event happening does not affect whether the event actually happens.
For that matter, we are here. The obvious choices for the existence of life here are:
This data about life existing on Mars suggests several modifications in theory:
A non-Mars item affecting life probabilities: Recent evidence suggests that life existed on Earth only a short time after Earth cooled. Although the probability of life being randomly created on Earth is unknown, a shorter time of appearance is a hint at a larger probability. Only a hint, as with a single event it is possible that a nearly impossible event just randomly happened here. The same situation is present if life appeared on Mars shortly after it cooled. If life appeared independently in both places shortly after it cooled, that is two hints at a larger probability.
Re:Head Tail Tail Head HTTTTHTHHTHT Edge (Score:1)
He asked for the occams razor answer. I gave it to him. If you apply occams razor to this situation then you will dismiss the theory about it being formed by martian life.
the real odds (Score:1)
However we do know enough to make some interesting calculations. For example, all proteins in all living things known today are made up exclusively of 19 chiral and one non-chiral amino acid. On average, roughly 8% of bacterial protein amino acids are glycine (the non-chiral one). So in a smallish protein of only 450 amino acids, there are (0.92)*(450) or 414 chiral amino acids.
There is no natural process outside living cells that generates amino acids of one chirality; everything generates nicely racemic (equally L and R) mixtures.
It is fairly simple to calculate just how likely it would be to get just one protein to form randomly (proteins form sequentially, and since they need more than one copy of each amino acid, this must be done by the probstat model of "with replacement") from an unlimited supply of amino acids. To make the case easy, and to heavily tilt the odds towards the formation of proteins, let's ignore the energy gradient in aqueous solutions (which tends towards dissociation of proteins, not their assembly). So to calculate the odds of getting all 414 amino acids that are chiral to all be the correct chirality is one in 2^414 (or one in over 10^124).
To give some concept of that number, consider the assumptions made by fans of the Drake equation [activemind.com] for example, and be generous. They estimate 200 billion (2*10^11) stars in our galaxy, and 20% of those having planets, with 3 to 5 possibly life-bearing bodies per star that has planets. Let's just say 10^12 possible planets, an order of magnitude higher than the upper limit of those Drake numbers. Also consider that the universe at 20 billion years is less than 10^18 seconds old. Let's say the earth has 10^50 atoms in it (slightly higher than estimates [prodigy.net]). So if you have one protein formed per each atom on every habitable planet in the galaxy (10^50*10^12 == 10^62) every millisecond since the big bang (10^18*10^3 = 10^21) you'd have 10^83 proteins formed. So the odds of getting one properly chiral protein by having 1000 formed per second per atom on all habitable planets and moons in our galaxy since the big bang would be 124-83 = one in 10^41. The universe is 10^28 inches across...
Now consider the odds of getting just one protein to have a particular sequence, which is immensely harder than the above which just focussed on getting the chirality alone correct. Plain fact is, random chance alone just will never be anywhere near adequate to explain the origin of life.
Re:the real odds (Score:2)
calcuations:
1. That life on Earth started out using its
current molecular basis of amino acids.
2. That life on Earth started out using the
full complement of 19 amino acids
3. That life on Earth has not evolved from a
much simpler molecular basis.
4. That the terran molecular basis for life is
is only possible form.
Re:the real odds (Score:1)
And I said 19 chiral and one non-chiral, that's a total of 20 amino acids. If some form of life existed (Terran or otherwise) with a different basis, where's the evidence? If you believe in it without evidence, you're in a purely faith-based paradigm, not a scientific one. I for one am comfortable with that if you're willing to agree it's faith based not fact based.
Re:the real odds (Score:1)
There are several possible natural processes. [vuletic.com]
Proteins did not have to be created for life to appear, and proteins could then have been assembled by primitive life. [vuletic.com]
Irrelevant. [vuletic.com] The assembly didn't have to be random, and many enzymes can have the same effect. Even with random chance, an existing sequence might just have been the first to happen of many possible solutions -- or maybe a different sequence was used in the first life and was later replaced by the one used now.
An ignorant question... (Score:1, Interesting)
Perhaps this might somehow affect our understanding of life on earth or our origins or something... but like, how?
I'm not dissing the pursuit of knowledge for knowledge's sake, but I guess I'm asking this ignorant question-- are we expecting the discovery of bacterial life on mars to have any repercussions aside from the "hey cool" factor and maybe religious fundimentalists having to rework parts of the bible to jam martian bacteria into Genesis? Are there outstanding scientific theories or questions that this discovery might help answer? How might our world change if this ancient bacteria were confirmed to be really martian?
Re:An ignorant question... (Score:2)
The effect on understanding life on earth and origins etc depends a lot on your worldview. For people like me, no effect at all. Others might have to totally rethink their views.
In summary, there's no repercussions whether we do or don't find life on Mars. And as one of those "religious fundamendalists" (read Bible believing Christian in my case), there's absolutely no need at all to rewrite Genesis, whatever happens.
Re:An ignorant question... (Score:2)
Other than that, science/technology/etc is all just "hey, that's cool", until a use is found for it.
a grrl & her server [danamania.com]
Re: (Score:2, Interesting)
Re:An ignorant question... (Score:2)
-
Re: (Score:1)
Re:An ignorant question... (Score:1)
Either way its fascinating. Evolutionary Biology has essentially ignored the possability that there may be interplanetary contributions to the process. Changes the game entirely. Alternatively if we discover that life did evolve independently on Mars, thats huge. Remeber we bascially have an N of 1 in studying evolution.
Seems to me this may be the biggest "hey that's cool" discovery in our lifetimes.
Re:An ignorant question... (Score:2)
Evolutionary Biology has essentially ignored the possability that there may be interplanetary contributions
Well, speaking as an evolutionary biologist I don't think that's entirely fair.
Lots of people in the evolution community have an interest in astronomy and are no strangers to Hoyle's Panspermia notion, the idea of a primary seeding of Earthly life from Martian life, and associated concepts.
What has been missing, obviously, is any kind of evidence to suggest that there is an interplanetary contribution to Earthly evolution (sans pretty clearly established ones like impact effects). If anyone can provide solid evidence of such a link then evolutionary scientists would be all over it like a dirty shirt, believe you me. :) Any paper solidly demonstrating such a thing would be an instant Nature or Science publication.
Re:An ignorant question... (Score:2)
I think that's a perfectly fair question - you really didn't need to post it as AC :)
The question (and the possible answer) are fundamental, vis, is life on Earth a great cosmic coincidence, or is it something which can happen anywhere in the universe given the right starting conditions?
Right now we don't know the answer - volumes of speculation exist to say both "yes" and "no", but in the end we do not know the answer. If we find indisputable evidence that life has evolved elsewhere, this is a big answer - the know that the universe may actually be bursting with life-filled planets (esp. since we'd have two such planets in one solar system, barring the primary transfer hypothesis of course). This isn't somebody's obscure interest in the origins of some spectral line in the atmosphere of a single star somewhere, this is a deeply fundamental question about the universe.
Re:An ignorant question... (Score:2)
Would Martian bacteria be dangerous to terrestrial systems? What about carrying earth bacteria in the other direction? Will we breaking the Galactic Federation's laws regarding the transfer of biologically active material? Will Florida, Texas, California and other entities establish agricultural inspection stations at NASA launch and reception facilities? It can be a VERY big deal.
Re:An ignorant question... (Score:2)
Have no concerns about that. The Catholic Church is an old and adaptable organization that has long since taken steps to avoid the extremes of fundamentalists. My point is that the religious fundamentalist mentality - which is not limited to Christianity - will tend to have problems with any discovery that appears to move humanity and the earth even farther from the centrality and uniqueness they hold to be our real place in the universe.
Holy S***! (Score:1)
Not again. (Score:2, Insightful)
This is juts a rehash of that nonsense about them claiming to have found "tiny fossilised bacteria" which also turned out to be dust, non-living, never living.
Re:Not again. (Score:3, Interesting)
I know the press release is very definite that the crystals were produced by bacteria, but I think they're being just a tad overconfident at this stage.
Re:Not again. (Score:2, Informative)
Re:Not again. (Score:2)
And so on (Score:4, Funny)
"Martian bacteria leaks out of NASA lab"
"Mutated animals sighted near NASA lab"
"Strange disease spreads through continent"
"President Bush announces state of emergency"
"President Bush renounces state of emergency"
"USA replaces national anthem with strange beeps and Coca-Cola switches water to sulphure dioxode in its drinks"
Re:And so on (Score:1)
Re:And so on (Score:1)
Compass? (Score:1)
Re:Compass? (Score:1)
Re:Compass? (Score:1)
The only time it helps to know which way to go is when you also know that it is the "right direction".So how do they know to head West for food? Got a map too?... or a waggle dance like bees?
A much more plausable explanation is that a 1 April message got stuck in someone's outbox for 4 months.
Easy tiger... (Score:5, Insightful)
Science press releases are usually half bs.. A good way to get research funding.
Re:Easy tiger... (Score:5, Informative)
How all this is portrayed in the media is often misleading and, yes, that is sometimes the fault of the scientists as much as the science journalists. The truth is that the media tends to dumb down science for the general public in the belief that real science is too boring for them. Whether this is justified or not is a matter of opinion.
Scientific press releases can be a good way to get research funding. It is also a very dangerous game to play, as scientists are often misquoted to their expense.
-Karl
Dr Karl Mitchell
Planetary Science Research Group
Environmental Science Dept.
Lancaster University
UK
Re:Easy tiger... (Score:2)
Well, maybe if the general public keeps eating these Mars stories up, they will demand greater funding for NASA and more Mars missions.
Re:Easy tiger... (Score:1)
-k
Re:Easy tiger... (Score:2)
Re:Easy tiger... (Score:1)
Re:Easy tiger... (Score:3, Funny)
1996: Maybe
1997: Not
1998: Maybe
1999: Not
2000: Maybe
2001: Not
2002: Maybe
Grown men fighting over tiny bug poop.
Re:Easy tiger... (Score:2)
Earlier, a number of other scientists observed chemical and visible (through an electron microscope) formations indicitive of biology. NASA astrobiologist Dr. Richard Hoover explains in an interview from December '96 [spie.org]:
Furthermore, on the skepticism, Dr. Hoover points out:
See my other comment on this story [slashdot.org] with links to pictures and more supporting background information.
Only one of five lines of reasoning (Score:2)
The following excerpt is from Gibson, E.K. Jr., McKay, D.S., et al. Life on Mars: evaluation of the evidence within Martian meteorites ALH84001, Nakhla, and Shergotty [nasa.gov]", Precambrian Research 106:15-34.
See also NASA's astrobiology news page [nasa.gov] and my earlier comment [slashdot.org].
Watch out! (Score:1)
Only adds to the confusion... (Score:1)
Re:Only adds to the confusion... (Score:1)
Also, Earth has a much larger gravitational pull (and hence escape velocity) than Mars, and is closer to the sun. Therefore transport from Mars to Earth is much more likely than Earth to Mars. It is far from satisfactorily demonstrated that meteorites could be transported from Earth to Mars, though I have to say that it seems probably, in small numbers. It has also not been demonstrated that life could withstand the energy of impact and re-entry.
-Karl
Dr Karl Mitchell
Planetary Science Research Group
Environmental Science Dept
Lancaster University
UK
Re:Only adds to the confusion... (Score:1)
Re:Only adds to the confusion... (Score:1)
-k
Re:Only adds to the confusion... (Score:1)
Besides, if it were so, it proves theories of panspermia, and several billion years is more than enough time for those bacteria to drift to nearby planets and moons (Titan, Europa?) and even into dozens of nearest solar systems and who knows what kind of lifeforms may have evolved from those same ancestors in different places at same time.
Crystals (Score:4, Funny)
"extraordinary claims..." (Score:4, Funny)
Dueling quotes on deductive reasoning at dawn! I shall see you on the morrow, sir!
-- Terry
Re:"extraordinary claims..." (Score:3, Insightful)
This works fine if you never make mistakes, you can be sure you've really examined every possibility, and you always wind up with exactly one remaining explanation. However, the only place that ever occurs is in fiction.
In reality, there's always a strong chance that you've failed to consider some possibilities, or you've declared impossible something that actually is possible, or that after eliminating the impossible you're left with either zero or multiple possibilities.
Re:"extraordinary claims..." (Score:1)
Re:"extraordinary claims..." (Score:1)
If all I had one bare-recognizable fossilized skeleton and made the conclusion that some long extinct species of sloth only had 3 toes, would you question my research so closely?
Alein Bacteria? (Score:5, Funny)
NASA, we demand smart aliens, with tentacles and bug eyes and all. Don't you scientists read comic books?
You're not doing your job. Bacteria? If these are the only aliens you can come up with then LOOK HARDER.
Harumph.
mutter mutter misappropriated tax dollars mutter
Re:Alein Bacteria? (Score:1)
Re:Alein Bacteria? (Score:2)
Well, some of this is a matter of perspective. If you (or viewer) were *tiny* enough, then these giant iron-farting wormy blobs would seem pretty ugly and menacing.
Re:Alein Bacteria? (Score:2)
Clearly you don't understand the true ramifications of this work. If there are alien bacteria, then not only is there intelligent life, but we also know that they're germy, and they sneeze all over the place. These are truly historic findings.
4.5 Billion Years old (Score:3, Interesting)
Re:4.5 Billion Years old (Score:1)
Re:4.5 Billion Years old (Score:2)
Earth's surface was probably destroyed one or more times after its formation, so it is also quite plausible that the oldest life on Mars is older than anything we find on earth.
Obsession (Score:1)
Mere pedeantry, perhaps: (Score:2)
It's merely a pedantic quibble, but life is a
strange natural process.
Unless, of course, you're a creationist (or, same thing, a proponent of "Intelligent Design" theories).
I can see where all this leads... (Score:2, Funny)
Argument for life (Score:2)
To summarise his arguments: They found some interesting crystals in a rock. They'd never seen anything like it. They looked for other places these crystals occurred. They looked and looked (He was quite adamant on this point), and couldn't find them anywhere except in some bacteria. Therefore these crystals can only be made by bacteria. Therefore these crystals are evidence of life.
You'll have to excuse my scepticism that this in any way constitutes proof. I'm quite willing to believe that there is bacteria on mars, just not that this is proof of it.
Re:Argument for life (Score:1)
Re:Argument for life (Score:2)
But that's kind of the point, really, isn't it. If it was a common natural phenomenon we would've found it long ago. Maybe it's not natural here on earth, at this current temperature and pressure, under this magnetic field, this UV concentration. There are plenty of natural phenomena which don't appear on earth, but do appear in other places. Try Mazers for one.
There can be a lot of other indications of life. Try microfossils like stromatolites, interesting chemicals, wear patterns, oxidation, and a lot of others. I think that drawing the assumption of life from these crystals, is like drawing the assumption of civilisation from an axehead, which is to say, that they may be right, but the evidence is a bit sparse.
more evidence (Score:1)
(press release) = (science * 100) (Score:4, Informative)
In the press release [nasa.gov] we read " new evidence confirming that 25 percent of the magnetic material in the meteorite was produced by ancient bacteria on Mars. ... This means that
one-quarter of the magnetite
crystals ... in Martian meteorite
ALH84001 require the intervention of biology to explain their
presence.
"
The words "confirm" and "require" are very strong, indeed.
However, in the abstract of the scientific report [nasa.gov] we read something quite different: " On Earth such ...
magnetites are known to
be produced by magnetotactic bacteria. We suggest that the observation ...
are [sic] both
consistent with, and in the absence of terrestrial inorganic analogs,
likely formed by biogenic processes."
So, the scientists suggest that something is consistent with a proposition, and the press-releasers convert that into confirmation of the proposition.
Sure, scientists' language often needs to be modified for public consumption, but here we have a case of changing the entire thrust of the story.
This sort of mistake would be unacceptable from a high-school science student, and that makes me wonder whether this exaggerating rewriting might have been deliberate. I remember a story of crying "wolf" ...
Suggest is State (Score:2)
Problem is, you've been diluted by too much modern media where they state with '100% certainty' and when wrong say simply 'oops'.
Re:(press release) = (science * 100) (Score:2)
Require is strong, yes, but perhaps you should consult the definition of confirm [dictionary.com]. It is an acceptable word to use, since it can also mean the same as to reinforce or support, which is basically what evidence does. Because of confirm's other meanings however, a word such as reinforce or support may have been clearer to those who don't understand how evidence works, and thus wouldn't think to use the other meaning of confirm.
it was hume who said (Score:2, Informative)
Re:it was hume who said (Score:2)
Do you have any extraordinary evidence of that?
8-) 8-) 8-) 8-)
There is a perfectly natural answer (Score:3, Informative)
Just out of curiosity ... (Score:1)
Re:Just out of curiosity ... (Score:1)
The planetary scientists develop these models based on emmitted gases etc (a bit more PhD-ish than just saying "Red rocks come from Mars").
Having made the model, we go out and find a rock on earth that, according to our model, belongs on Mars. WTF? We have two options: (a)Recall all our research papers and say our model is broken -or- (b) Say awmigosh a Martian Rock. Fund me!
Carl Sagen.. (Score:2)
On another note there has been a discussion on space.com about life on other planets and the scientists think that we are likely to find bacterial life on mars or on one of Jupiters moons. So this is just the theory that life in some form may exist on another planet.
The real question is not if life exists, but has life evolved elsewhere?
Re:Carl Sagen.. (Score:2)
Yes, but fortunately he was able to speak while alive and left us with some insightful quotes.
The one quoted in this Slashdot article, unfortunately, is often only half quoted. The full version is:
"I believe that the extraordinary should be pursued, but extraordinary claims require extraordinary evidence."
-- Carl Sagan
Rather than a criticism of scientists who make extraordinary claims, this sounds to me more like a call to action to seek out the extraordinary evidence required for us to know the truth.
Kick us when we are down (Score:2)
Richard Hoover, Astrobiologist, said so for years. (Score:2)
SPIE-The International Society for Optical Engineering [spie.org] captured the bulk of Dr. Hoover's presentation in an interview published in their December '96 magazine [spie.org]. This September 1998 article [panspermia.org] offers pictures of the fossils found, as does a July 1997 article [panspermia.org]. Another story announces a fossil find in another meteorite [cosmiverse.com] that fell on Murchison, Victoria, Australia.
Many people question the science, but it would seem people should question the scientific community which has held its hands over its eyes when faced with the prospect of life on other planets. The community is just now peeking between its fingers and beginning to accept that there might be life elsewhere. In the presentation I attended, Dr. Hoover noted that NASA set up rules in advance of the Viking missions - that any one of the several (4?) tests coming back positive would be indicative of life on the red planet, but once some of the tests came back positive, they decided that all of the tests had to be positive to confirm the existence of life on Mars. Such has been the distinctly non-scientific approach of the community when confronted with the distinct possibility of life on other planets.
More links:
Then You Go (Score:1)
That movie [imdb.com] rocked!
Re:Mars rock (Score:5, Interesting)
You're correct that it's easier to get a meteorite from a smaller body, and we do get loads of them (positively identified Martian meteorites number in the dozens rather than the thousans). However, Mars is massive and has had many massive impacts. The amount of material ejected from it's surface means that it would be amazing if none had reached the Earth.
Also, regarding life, it's unlikely that life would have evolved on any body that did not have liquid water. Liquid water has always been unstable on asteroids, whereas there have significant periods of Martian history (likely when the impact occurred) where liquid water was thought to be stable, possibly over hundreds of millions of years. In fact, there are even points on present day Mars where, for a limited period during the year, water can be stable on the surface. Of course, if you believe Fred Hoyle, life could be everywhere, but, based on an Earth model, life seems far more likely to have evolved on Earth and/or Mars.
The evidence for this being a result of biological activity is still highly ambiguous however, which is why we need to get samples back from Mars.
-Karl
Dr Karl Mitchell
Planetary Science Research Group
Environmental Science Department
Lancaster University
UK
Re:Mars rock (Score:1)
Okay, I'm *not* a planetary science type or a molecular biologist type(being a lit grad student), but haven't they been discovering bacterial life in some really weird places on Earth? Places with both extremely cold and extremely hot temperatures? So it is possible that some bacterial life might survive in those frozen seas that have been discovered on Mars. I do agree with you, though; no point in speculating too wildly until we have samples to study.
Re:Mars rock (Score:2)
However, nearly everyone I know working in this field seems to think that some sort of fluid, preferably water, would be necessary.
One thing that the new discoveries (suboceanics life, microorganisms in frozen climates, etc.) have demonstrated, however, is that sunlight is less directly important than previously though, which is good news for those hoping to find life on Mars.
Of course, this doesn't eliminate the possibility that life might evolve completely unlike that on Earth. However, the only tested models for life are those on Earth, and I'm not a biochemist (just a physicist who studies volcanoes and water on Mars) so I can't really say much about alternative models without being extremely speculative. Just from a structural point of view however, I expect that some sort of fluid is necessary, just so a lifeform can have moving parts (and movement is involved in cell splitting), and I don't think there is any evidence for materials in a fluid state on asteroids (unlike Mars - loads of ice and loads of fluvial features). They may be able to transport life in cryostasis, but I doubt that life could flourish or even be sustained for long in an active state without fluids.
All the best,
-Karl
Re:Mars rock (Score:1)
Please take a few minutes staring at the Moon and reconsider. The many huge craters on it hint at the number of impacts which hit planets...and remember the lava-covered flat 'marias' used to have visible craters too. Also consider the Moon itself as evidence of the power of impacts. The Moon was blasted loose from the Earth by an impact. [psi.edu]
You're probably underestimating the number of collisions, the violence of the collisions, and the effect of the low Mars gravity. Also, any rocks leaving Mars would be in an orbit similar to Mars -- near the ecliptic (the plane of all the planets). Rocks with a velocity slower than Mars (whether due to the impact or repeated close encounters with Mars) would head toward the Sun, crossing Earth's orbit. Space is very empty, but having the objects in similar planes and orbits greatly increases the chances of encounter.
There also are indications here on Earth of energetic impacts. If you look at the meteorite impact site maps [usgs.gov], you'll see there have been many dozen of these impacts (most of Earth has not been mapped for impacts). These are impacts which were so violent that they changed the magnetic pattern in rocks "at some depth".
Re:Crazy causality. (Score:1, Informative)
AND that those created by bacteria are notably DIFFERENT from those that result from chemical reactions in non-living things. AND that the one in Martian rock resemble those created by Earth-bacteria, and not those randomly formed ones.
Re:Crazy causality. (Score:1)
BTW, Little cars that burn methane wouldn't produce methane (because it was burned!) but CO2... which bacteria also produce. One could argue that bacteria don't HAVE little cars, but that they ARE little cars. Or maybe aircrafts or boats. Nano"technology" Von Neumann Machines... nature beats us in everything.
But in "life in mars?" -debate it doesn't really matter whether they use it for compass or is it just a byproduct of something other they do with ferrites. The important point is that for one reason or another, bacteria DO produce magnetite, and that their magnetite is distinguishable from inorganic magnetite crystals.
Re:Crazy causality. (Score:1)
A good place to start is a paper by Frankel, Blakemore and Wolfe in Science 203, pages 1355-1356, 1979.
There's nothing really that odd about this type of thing if you think about it. Most organisms which are capable of movement also require some point of reference against which they can determine their own motion. Such references can include chemical concentration gradients, the sun, or images of surroundings. Bacteria don't have eyes, and so this last option is not available to them.
Re:Crazy causality. (Score:2)
Evolutionarily, the two ready means for living systems to map their environment are radiation sources such as light and heat, and magnetism. If bacteria simply relied on chance to locate such sources of necessary materials, they may be at a competitive disadvantage to bacteria who are able to "map" sources of necessities. The strange part of the idea is not the tiny, bacterial compasses; it's the idea that bacteria can store information at some level. It raises some very interesting questions about memory.
Re:Crazy causality. (Score:2)
Bacteria really aren't affected by gravity. So some use magnetism for orientation. Maybe you should read the article.
Re:Magnetic orientation? (Score:1)
Whether Mars remains volcanically active or not, it certainly was 3.9 billion years ago, and the concensus seems to be that Mars did have a strong magnetic field then. Given the evidence of water-carved channels on the surface and volcanism dating from this time, it is likely that the atmosphere was thicker, and that water was stable on the surface for long periods of time. As such, this would have been a very suitable environment for the evolution of life, as we understand the process.
-Karl