Slashdot Mirror
Possible Evidence of Martian Bacteria
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."
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.
Owner of a Mensa membership card.
There's already lots of possible evindence, wake me up when there's hard evidence.
Ok, lets say we can determine that there were some bacteria on Mars. Aside from exclaiming, "hey that's cool" what would be the big deal? How would this be different from say, discovering bacteria in some otherwise uninhabited place on earth?
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?
It's like War of the Worlds in reverse, or something...
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.
...
...
...
...
...
...
"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"
Seems like their is a Major life on mars discovery every few months. Most of the time they are disproven within a couple of weeks. Take the wait and see approach and see if this "discovery" holds up to peer review.
Science press releases are usually half bs.. A good way to get research funding.
If the movies are correct, the martian bacteria will take over human subjects and create monsters out of them!
First, the martian origin of those SNC meteorites is not yet fully demonstrated. Yet, there are detritic layers on Mars that suggest there once were bodies of water. Provided the sulfide concentration was high enough, such bacteriae may have lived in those. If so, where would they have come from in the first place? Earth as a wild guess sounds likely, as many meteorites coming from our planet have spread in the solar system in those early ages. An isolated lifeform doesn't prove anything concening the martian origin of said lifeform.
Sprinkle some salt on your dinner and, no matter how careful you are, a little will always wound up on the table. -- JHVH, Day 7
"I have opinions of my own, strong opinions, but I don't always agree with them." -- George H. W. Bush
in pieces...
That movie rocked!
If you could be told what you can see or read, then it follows that you could be told what to say or think - BoC
"When you eliminate the impossible, whatever you have left, no matter how improbable, must be the truth." -- Sherlock Holmes ("The Beryl Coronet", Arthur Conan Doyle).
Dueling quotes on deductive reasoning at dawn! I shall see you on the morrow, sir!
-- Terry
The rock is from Mars. Atmosphere isotope ratios are unambiguous in such cases. Every planet has it's own "signature" that, with the right equipment, is possible to detect. This was demonstrated ages ago by Monica Grady and others in the UK.
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
How utterly boring. What happened to the 'superior intelligences' theory?
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
Blearf. Blearf, I say.
According to the press release, this rock is 4.5B years old. Since that is the approximate age of Mars itself, how could it possibly be life? Does this predate any signs of life found on earth so far?
If you just once bothered to read the damn study you just MIGHT have enough brain capasity to note that "compass theory" comes from a FACT that some of very-much-real-and-existing EARTH bacteria create same kind of "compass crystals".
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.
Don't all these repeated claims of life on Mars say more about us and our obsessions than they do about Mars itself?
Ceterum censeo subscriptionem esse delendam.
or there is some strange natural process
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).
Opinions on the Twiddler2 hand-held keyboard?
Well, we are not the only ones that use magnetic materials for compass. Birds do that, some others animals do that... they don't need to know that they use compass, or consciously do or build anything, it's just an instinct. Thus bacteria might do that as well, hard to think what they might need orientation ability for, but that doesn't mean it isn't possible.
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.
Why are they always looking for life on Mars? Quite simple. They're all self-centered chauvinists. Men are from Mars...
"Also, regarding life, it's unlikely that life would have evolved on any body that did not have liquid water."
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.
Yes, it could be, but that's politics for you. People don't matter because you can always make more. If you really want to make some sort of difference, find some sort of cause to get involved in in your locality. How can we expect the government to do anything if we ourselves refuse to? Governmental apathy stems from individual apathy.
I went to a talk some time ago, about 6 months after the "discovery of life in a martian rock" found in Antarctica. It was a half hour talk, at the AIAA confernce in Reno in mid-January 2000.
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.
Last night, a bright light came through my window and woke me up. I was levitated out into a strange craft, where spindly bipeds with almond-shaped eyes probed my body cavities. But get this: they were all sniffling and coughing!
Find free books.
In the press release 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 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" ...
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.
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, 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".
'extraordinary claims require extraordinary evidence' not carl.
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:
- Life here was created by random chemical/physical processes. Probability unknown.["Here" is this solar system, whether Mars or Earth]
- Life here is an extension of existing life in this galaxy. Probability unknown, but allows much longer time frame and once it happened once it can spread.
- Panspermia.
- Random cause: Bacteria or DNA from other solar systems seeded our biology.
- Directed cause: Life forms in other solar systems sent primitive life to other solar systems. Does not require intelligence, because a space-seeding plant is an increase in the probability of intersystem seeding.
- Gardening: Intelligent life seeded our solar system.
- Miracle: We just appeared here. Probability unknown. Several conflicting events recorded.
There are several possibilities for our own life forms. The possibilities of our origin give hints as to the chances of life existing elsewhere, but are not proof. We need more data.This data about life existing on Mars suggests several modifications in theory:
- Life was able to be created outside the conditions at Earth's orbit. If Mars was very different from old Earth when life formed on Mars, the probability of random life creation is increased due to a widening of the definition of a suitable environment.
- Life may have been created in two places within this single solar system. This suggests that the probability of random life creation is fairly large. It is possible that life is very unlikely and the coin just happened to land on edge twice here, but the suggestion is still toward a higher probability of life.
- If life was created on Mars and travelled to Earth, the probability of panspermia tends to be higher. Evidence of life which can survive space increases the probability that life can travel between solar systems (ignoring the possibility of close approaches by another solar system or rogue planets).
Some of these possibilities are mutually exclusive. If life on Earth was seeded by Mars then although the possibility of Panspermia is increased, an increase in the possibility of random life is then not suggested. We then still have only one example of the creation of life in this solar system, it merely happened on Mars instead of the previously assumed location of Earth.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.
Well yes ... NASA is a brainfull waste of money on overfitted data, but Nick Hoffman said that 30 years ago. Beats building pyramids or digging trenches .... doesn't it ?
Got Wisdom?
How is it determined that one of these rocks is from Mars and not from somewhere else? If it is from Mars, how did it get here? It would seem to me that hard evidence of this would be required BEFORE coming to any conclusions as to whether this proves that there is life on mars or not.
-- Jim
In Scientist-speak, the word 'suggest' is synonymous with "is" or "state". But you don't publish like that. Publishing is done so that you do not appear 'too wrong' in the future.... go back and read some journal articles from the 50s :) Very important but very lax in thrust.
Problem is, you've been diluted by too much modern media where they state with '100% certainty' and when wrong say simply 'oops'.
Yes, they are discovering bacterial and other forms of life (extremophiles) in weird places on the Earth. For example, algae living within rocks in sub-zero temperatures in the Antarctic, that can reside in a frozen state for years, even centuries, until freak warm/wet spells allow it to breed. There are even microorganisms that flourish within nuclear reactors. So yes, I (and most scientists I know) see no reason not to think that life couldn't have survived on Mars. In fact, most of the biologists that I know think that if life ever did exist on Mars, then it would have undoubtedly adapted to survive almost anything that nature could throw at it, and therefore that if there was life, there still is.
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
These bacteria are often referred to as being 'magnetotactic', although not all precipitate magnetite - I've seen one piece of research in which greigite (Fe3S4) and iron pyrite (FeS2) were precipitated instead.
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.
It has been a long time since I read this, however, bacteria in aqueous environments need to orient to sources of food, energy, and other needs. I believe that the hypothesis was tested and verified to the researchers' satisfaction by manipulating the magnetic environment around experimental laboratory populations of bacteria.
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.
------ The only greater hazard to your liberty than n politicians is n+1 politicians.
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?
Only 'flamers' flame!
Yet another Goddammed source of H1B's discovered.
Table-ized A.I.
What nonsense, really. Why would a bacteria care about magnetic North? Do they have little maps or something? We could make a fortune selling them nanotechology GPS receivers. Unless they use their little compasses to find magnetic South, which something we as humans rarely hear about. A blatant case of boreacentrism.
Bacteria really aren't affected by gravity. So some use magnetism for orientation. Maybe you should read the article.
If you don't understand any of my sayings, come to me in private and I shall take you in my German mouth.
SPIE-The International Society for Optical Engineering captured the bulk of Dr. Hoover's presentation in an interview published in their December '96 magazine. This September 1998 article offers pictures of the fossils found, as does a July 1997 article. Another story announces a fossil find in another meteorite 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:
I hate call waitin`~+~~~
NO CARRIER
You asserted that the probability of life randomly arising somewhere in the universe is unknown. That's certainly true for our current scientific state, since we can't yet claim to know all the intimate details of every single function of cellular life.
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 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). 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.
Got Wisdom?
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", Precambrian Research 106:15-34.
See also NASA's astrobiology news page and my earlier comment.
I hate call waitin`~+~~~
NO CARRIER
Agreed Mars does not have a significant magnetic field. However, there is some evidence that it has had a magnetic field in the past (remnant magnetism). Mars has also been extremely volcanically active throughout most of it's history (until at least 1 billion years ago, possibly even in the last few tens of millions of years), which implies that there was at least a partially molten core for much of this time. In addition, mantle convection models predict that each major volcanic centre on Mars would only be active for about 1 million years out of 100, and seeing as there are somewhat less than 100 volcanic centres, it seems unlikely that, even if Mars was active, it would be active at any one time (i.e. present). A molten core is not essential for volcanism, even when the heat source is nuclear decay (as we suspect for Mars). It seems unlikely that a planet could remain active for long (over billions of years timescale) without a magnetic field, but the possibility that Mars could be active at some time over the next few million years has not been ruled out by planetary scientists.
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
Sorry. I didn't see this e-mail first. Your reply was very clear.
There have been a lot of questions about how we know that SNC (or Martian) meteorites come from Mars. This used to be a bit of a "hot topic" in planetary science, but over the last few years an international consensus has arisen supporting the hypothesis that these meteorites come from Mars.
The clearest explanation I can find for this can be found at http://www.nhm.ac.uk/mineralogy/grady/mars.htm- the author, Monica Grady, is one fo the world's leading authorities in this field.
In short, the ratios of the three stable isotopes of oxygen (16, 17 and 18) are characteristic for any given planet. The SNC meteorites contain small quantities of atmospheric gases within isolated pockets. Since the oxygen isotopic composition of these gases have been shown to be different from that of the Earth, they cannot have come from here, leaving Mars as the a viable proposition for the meteorites' origin. This is supported by measurements of the isotopic composition of Mars' atmosphere by the viking landers.
I hope that answers some of your questions.
Regards,
-Karl
Dr Karl Mitchell
Planetary Science Research Group
Environmental Science Dept.
Lancaster University
UK
Get real - how is a bacterium going to use this info?
Engineering is the art of compromise.