Life on Mars? Why Not? 267
Guillaume Filion writes "IEEE spectrum has an interesting article about a new probe sent to Mars searching for life: 'Recent missions to Mars have focused on the search for water, past or present, as a surrogate for life itself. But now a British-led team is working to renew the search for life directly, fueled by doubts about the equipment that prompted NASA to declare Mars a dead world some 26 years ago.'"
fueled by doubts... (Score:3, Interesting)
Re:fueled by doubts... (Score:4, Funny)
Re:fueled by doubts... (Score:4, Funny)
Re:fueled by doubts... (Score:5, Funny)
Re:fueled by doubts... (Score:2, Funny)
Re:fueled by doubts... (Score:5, Funny)
The organisation has a history of almost-but-not-quite developing revolutionary new fuel sources, last year NASA stopped developing their faster-than-light 'bad news' powered rockets as they were unwelcome everywhere they went.
Re:fueled by doubts... (Score:2)
Oh Boy! (Score:4, Funny)
Just think of all the death it could bring!
Go now! Make SARS look weak!
Re:Oh Boy! (Score:4, Funny)
Evidence of Life on Mars.... (Score:2, Funny)
Re:Evidence of Life on Mars.... (Score:2)
Mars:Dead or Alive? (Score:3, Informative)
A miniaturized marvel of engineering aspires to rewrite the textbooks about life on the Red Planet
By Barry E. DiGregorio
Recent missions to Mars have focused on the search for water, past or present, as a surrogate for life itself. But now a British-led team is working to renew the search for life directly, fueled by doubts about the equipment that prompted NASA to declare Mars a dead world some 26 years ago.
If all goes according to plan, a Soyuz-Fregat booster rocket will lift off from Baikonur cosmodrome next month carrying an extremely compact and sophisticated life detection probe that might finally settle one of the most intriguing questions in science: did Mars once harbor microbial life-and is it still there?
The probe is hitching a ride on the European Space Agency's (ESA's) Mars Express orbiter as part of the agency's first home- grown mission to the Red Planet. Named Beagle 2[see photos], in honor of the HMS Beagle in which Charles Darwin made the historic voyage of discovery that led him to the theory of evolution, it was designed by scientists from Britain's University of Leicester and Open University in collaboration with Martin-Baker Aircraft and Matra Marconi Space Systems. Once the orbiter reaches Mars, Beagle 2 will be sent down to dig around on the planet's surface.
But even after it has dropped off its passenger, the Mars Express orbiter will not be idle. It will use a sounding radar called Marsis to search below the surface for water. It will have an ultraviolet and infrared spectrometer called Spicam to study the atmosphere over the course of a Martian year. And it will relay data transmitted from the lander back to Earth.
Did Viking get it wrong?
The first spacecraft with dedicated equipment to look for life on Mars were NASA's twin Viking landers, which touched down on the surface in 1976. Why send another now?
On board both Viking landers were miniature life detection laboratories, and some of the data they returned could indeed be interpreted as evidence for life on Mars. Yet the majority of the project's scientists became convinced that inorganic oxidants in the soil were responsible for the ambiguous data. The next year, NASA publicly announced its conclusion: that Viking had found no life.
Was the U.S. agency jumping to conclusions? In recent years, questions have been raised about the effectiveness of a key instrument-a combined gas chromatograph and mass spectrometer (GCMS)-that swayed most of the Viking scientists into the no-life camp. The GCMS failed to detect any organic molecules on the Martian surface at all, which posed something of a puzzle, as even the barren surface of the moon is host to some organic molecules. To explain the anomaly, scientists postulated a harsh chemical environment that supposedly made the planet self-sterilizing by actively destroying organic matter [see "Why NASA Said No to Life on Mars"].
To find out if this picture is correct, Beagle 2 is designed to search for organic material below, as well as on, the surface of Mars. In addition, it will study the inorganic chemistry and mineralogy of the landing site, says Mark Sims, the Beagle 2 mission manager who is based at Leicester University.
Without question, the Beagle 2 lander manifests an enormous leap of scientific engineering. It costs only US $40 million versus Viking's $1 billion, and weighs in at a mere 60 kg at launch, as opposed to 661 kg for each fully fueled Viking lander. In its set of scientific instruments are the first ever optical microscope to fly to Mars, as well as a gas analysis package (GAP) that will directly challenge or confirm the results of Viking's gas chromatograph-mass spectrometer (GCMS).
Beagle 2's destination on Mars is a region known as Isidis Planitia [see map]. This relatively flat basin may have been formed by sedimentary deposits and was chosen not just for the chances of finding life there but with a view to the safety of the lander as well.
It's life, Jim, but not as we know it... (Score:5, Interesting)
Hint: Chances are, no matter what we do, we're never gonna see a green spectral line or test for clorophyll.
Instead, we need to examine soil for the most basic types of life we know of... creatures or cells similar to viruses, bacteria, and amoeba.
Re:It's life, Jim, but not as we know it... (Score:5, Informative)
On the other hand, your nomenclature is a bit confused.
Viruses are neither cells nor creatures. Furthermore, although they are not complex, they require fairly complex hosts in order to thrive. Martian cellular life might have useless or parasitic DNA, but I rate it unlikely that this DNA kills the hosts (which must be rare,) or packages itself into particles in order to spread. In any case, the viruses would have to be more difficult to detect than their hosts.
Amoeba are not simple, either. They are single celled, but they can sense and react to their environment in amazingly complex ways - early life almost certainly could not. They are, in fact, among the most complicated single-celled lifeforms on this planet.
Modern bacteria are turning out to have complex features, such as the ability to communicate with one another, which we had not suspected.
Nevertheless, ancient bacteria, or proto-bacteria, very ancient life on earth; things similar to that might be found on Mars.
Depending on how old you think such life or proto-life is (estimates vary from 2.5 to 5 billion years) it is conceivable that some sort of nasty event could have deposited some on another planet or vice versa - but I think this is highly unlikely, to say the least.
So, what should we be looking for? Nucleic acids, particularly RNA.
This is based on the RNA-world hypothesis. Basically, it says that before modern life evolved, which is characterised by the fundamental theorem of molecular biology:
DNA makes RNA makes Protein
There was life that used only RNA. In this life, or proto-life, RNA served as both the store of genetic information (we use DNA for this) and as the catalytic workhorse of life (we use Protein for this). RNA has unique chemistry which may make it the only chemical, in the universe, capable of originating life - RNA can catalyze it's own synthesis, so it can reproduce all by itself.
So, this Martian life is probably descendended from RNA molecules, like we are, and probably still contains RNA, just like we do.
On the other hand, this argument is premised on the concept that any life we find must have a chemical origin similar to our own. Unfortunately, I think this is probably the case (so no aliens made of Quartz, sorry,) but maybe not. If it ISN'T the case, we have NO IDEA what to look for, so back to square one.
If RNA is the sole origin of life, then, basically, you need water to have life (RNA only has these desirable properties when dissolved in water.) This leads us back to the rather pedestrian xenobiology of trying to find evidence of liquid water in Mars' past.
On a final note, I think Io is probably a better bet to find extra-terran life. There is definitely liquid water, and it is rich in complex organic molecules (including RNA, I believe) it has a temperature comparable to that of the early earth, and it has rich sources of the sulfur and nitrogen compounds that early life probably used as food.
This raises a significant risk, however. There are living organisms on earth that could probably survive being transplanted to Io (the same is not true, by the way, of Mars.) So, we'd have to be extremely careful not to contaminate the place.
Re:It's life, Jim, but not as we know it... (Score:2, Interesting)
This is just plain hooey. The only way life could evolve would be once it achieved nearly perfect self repr
Amazing find... (Score:4, Funny)
Oh, what's that? The probe sanitizer was on leave before packaging and launch? Ah, well, maybe it'll grow up to be like it's parents...
why water? (Score:5, Interesting)
We were either created for this world or evolved into what we are by it. Doesn't it make sense that life on other worlds would be fit for theirs in the same way?
Why is water so damn important? Couldn't life be based upon a different liquid than water? A different solid than carbon?
Re:why water? (Score:5, Insightful)
What you said is ENTIRELY true. We have no clue as to how other types of life can be formed. However, we DO know that water CAN cause life (worked for us, right?), so that's the 'first step' to finding life. Find stuff that formed like we did. Once we rule that out, we go into the void known as theoretical life, and try to piece something together.
Its easier to prove something exists when you have a good understanding of it before looking at something that could be 'anything'.
SETI? (Score:2)
Granted there's more logic in expecting other life to evolve from water as we did, than other species using the same radio freq we do.
Re:why water? (Score:5, Funny)
beer
A different solid than carbon?
pizza
Re:why water? (Score:4, Funny)
Scientists discover new life form
Based on a previously-unknown element, tentatively termed pizzate, the only other substance the collegen studentious needs to survive is based on a fermented grain.
The collegen studentious primarily lives in small square rooms, but very ocasionally can be found in large rooms when chalkboards are present. Mostly nocturnal, at night they usually spend their time trying to breed, gathering socially with others wherever their fermented nourishment is dispensed.
Re:why water? (Score:2)
Re:why water? (Score:5, Insightful)
Definately a good point. Too often, scientists are so intent on studying planets like the earth, and ignore other possibilities. Not to say they are ignorant in doing so: if there is life on our planet, why not narrow down the search to planets like the earth, i.e. similar amount of water, carbon based life, similar atmosphere, similar pressure, etc.
Also, it is possible for life to take different forms based on the environment. Here on earth, water is a liquid, neutral, and readily found. If a planet has a different amount of gravity and pressure, other substances may be found in liquid form, and could harbor life. And Carbon doesn't have to be the building blocks of life forms, it just so happens it has good properties for such on earth. Elsewhere in the universe, Carbon may not be as easily found in solid form...
So... there are infinate possibilities to be honest. But there may be a greater chance to find life similar to what we find on earth if we search first through the earth-like planets.
Re:why water? (Score:3, Insightful)
For example, oxygen combines with a large number of elements to oxidize them (at a wide range of pressures and temperatures).
When you have oxygen coming out of something when the chemistry says it should be going in, that is a hint of life. This could apply to a wide range of reversals of expected chemical react
Re:why water? (Score:2)
Re:why water? (Score:2)
Care to propose another one? Life doesn't care whether or not carbon, phosphorus, nickel, or molybdenum is liquid, solid, or encased in a purple gel. It'll -make- it liquid, it just needs to have it, and of all of the elements on the periodic table, carbon is unique. You think it's a coincidence that life
Why water is nifty (Score:5, Informative)
- Water is highly polar, and therefore has the ability to dissolve ions. Without ions, complex chemistry could not take place.
- Water is liquid at a "reasonable" temperature, meaning water in liquid form is not hot enough to destroy most complex molecules.
- The density of ice is slightly less than that of water, so ice floats on top of water. This is vital, because it allows bodies of water to form a frozen cover which protects against further freezing. This is not common among substances.
- Water blocks ultraviolet light, which would otherwise destroy fragile molecules and organisms.
- Water has a very high specific heat, making it ideal for carrying out chemical reactions -- exothermic reactions can dump their heat into the water, and endothermic reactions can draw their heat from the water. This allows energetic reactions to occur without raising the temperature too high.
Basically, water is a very unusual substance with many favorable properties, and it's likely that life will take advantage of water, if it is present.That's not to say that life cannot exist without water, but it certainly makes life much more plausible.
As for non-carbon-based lifeforms, people have been pondering that for decades. Carbon is interesting because it can bond with itself pretty much ad infinitum, forming complicated structures. It also combines readily with oxygen, nitrogen, hydrogen, sulfur, the halogens, and a host of other elements. Complex life based on some non-carbon element would have to have the ability to form long chains of atoms, branching structures, and structured which curl up into specific shapes (i.e. proteins and enzymes). A carbon-silicon combo might work.
Re:Why water is nifty (Score:5, Interesting)
You're not giving water enough credit. Basically, the important thing is to qualify what is life: life is the creation of complex systems that can adapt and increase in complexity over time. That's a decent definition of life - it excludes fire, for one, which is always a difficult one. In order to satisfy that definition, you need a framework which allows you tons of complexity, which is what water gives you. Gotta love water.
Water is the simplest dipole that can form. You can't make a dipole out of HX, and if you want H2X, water's the easiest choice. Is it really any amazing wonder that nature, needing a dipole (which allows for complex arrangements), chose the simplest one? Hmm. Bout as surprising that the elements used in life happen to be the most common in the universe (barring helium).
-Maybe- ammonia. Maybe.
Life -needs- a dipole. Life also needs a 'backbone' - a framework. Carbon's your only choice for that.
A carbon-silicon combo might work.
Why in the world would life EVER use silicon, when carbon is so much more abundant than it, and will be no matter where you go in the universe, and carbon doesn't need silicon? All it does is weaken the structure.
Carbon's a given - it's the only one that'd work.
Re:Why water is nifty (Score:3, Interesting)
Eh? You're giving water too much credit, now. The stuff on which all our beloved complex molecules depend is carbon--water is just a useful solvent. In and of itself, wate
Re:Why water is nifty (Score:2)
The parent post is very thorough, and very good guide to why we think water is important. A note regarding silicon compounds--molecules that contain silicon atoms in long chains (as carbon does in almost any biomolecule you could think of) can exist, and can be synthesized quite readily in the lab. Unfortunately, these long silicon chains tend to be very sensitive to water. They decompose--sometimes violently--when exposed to liquid water or its vapour. Even the trac
Frank Herbert (Score:2)
On the other hand, the sandworms were the source of spice, a substance that had pharmacol
Re:Frank Herbert (Score:2)
Re:why water? (Score:5, Interesting)
Of all the hundreds of elements that exist in the universe, only the Carbon atom is capable of connecting to (up to four) other Carbon atoms and thus creating arbitraily large molecules. For example, a strand of DNA is single Carbon based molecule about 2 meters long. I like to think of Carbon molecules as the Lego of the universe. It's why the profession of chemistry has been divided into organic (the study of Carbon based molecules) and non-organic (the study of molecules containing every other element but no Carbon). For the record, the organic chemists have many, many times more molecules to play with than all of the molecules non-organic chemists have to play with.
Re:why water? (Score:2)
Close to true...but not absolutely. In principle, it is possible to construct analogues of most organic compounds using a silicon backbone, rather than carbon. Silicon atoms also can form four covalent bonds to adjacent atoms. I've already noted in another post that they would perform poorly in most environments, howeve
Re:why water? (Score:2)
Re:why water? (Score:2)
What would you look for? How would you recognize it when you saw it?
We have a good understanding of life that is based on water and carbon, and we have no idea what life without water and organic carbon would be like.
There are thousands (hundreds of thousands?) of different chemical compounds on Mars, and you can't look at them all, so you look for the things you are most familiar wit
Re:why water? (Score:2)
We might not 'know' that water+carbon is the only way to go, but being 'pretty incredibly damned sure' is good enough, sometimes.
Life. Probably not (Score:2, Interesting)
OTOH, personally I believe that life was created on earth and not elsewhere, but I believe that it is our responsibi
Re:Life. Probably not (Score:3, Insightful)
What would lead you to that belief? All life needs to exist is the right materials, many of them quite plentiful in the universe; the right conditions, which Mars might not have had, but which many other places in the universe probably did; and enough time to get things done, again, Mars might not have provided.
As it is we have only looked at nine planets out of the possible trillions in the universe. How can we say that life has only
Airborne (Score:5, Interesting)
NASA's tests... (Score:5, Informative)
Testing the Face (Score:2, Funny)
reminds me of an old letter... (Score:3, Informative)
But I remember a letter sent my some professional gadfly comic...I want to say Joe Bob Briggs but I don't think that's it...who wrote to NASA saying something along the lines of "So you burnt up this soil sample to check for signs of life on Mars? That could only prove that there WAS life on Mars...you just killed it!"
(Sorry for the lack of references, the book I got that from is at home)
Re:reminds me of an old letter... (Score:2)
The results were considered anomolies resulting from chemical reactions within the clay, as best as I recall. (If someone has that issue to hand, please follow-up with the actual info)
IMHO, I'm more than a little concerned that, when they found data that did not agree with the "no life" hypothesis, it got classed as an anomoly. Unless there was considerably more data,
In a fascinating new development... (Score:5, Funny)
Do we always have to scream "FIRST!"? (Score:5, Insightful)
But I must object to the following:
Clearly, if the British lander does find life on Mars, a scientific symposium will have to be convened to sort out who may have discovered it first: NASA or ESA.
Must we? Could we for once view science as the continuous stretch of micro-advances that it really is? Whether it's flight, or the TV, or beer the credit for doing it "first" seems to overwelm the real credit that I will lavish on the Brits at the end of the mission, and that is: the credit for doing it well.
Re:Do we always have to scream "FIRST!"? (Score:2, Interesting)
ooops.... (Score:2)
Asked and Answered (Score:3, Funny)
Only if it's followed by "POST!"
Re:Do we always have to scream "FIRST!"? (Score:2)
Its all about money.
Re:Do we always have to scream "FIRST!"? (Score:3, Informative)
I thought Kuhn put that silly idea to rest awhile ago?
Re:Do we always have to scream "FIRST!"? (Score:3, Informative)
Re:Do we always have to scream "FIRST!"? (Score:2)
If some "space agency" invents a StarTrek like transporter and beams a chunk of Mars back to Earth, they can have the "First" title. But all the early space "Firsts" were a matter of strapping humans to the tips of bigger and badder rockets. I hate to simplify like that since a great deal of that silly increment
Mars and life. (Score:5, Funny)
Don't let the government lie to you any longer. Mars is teeming with life. There has been a conspiracy of silence since the 70s to keep this news under wraps. The major concerns of the US government has been how life on another planet will impact belief systems on Earth. Once people lose their faith in religion, faith in government is not far behind.
I have hundreds of pages of "photostat'd" (that was the term back then) documents to back this up but fear for my life. I'm thinking of putting them out on Freenet.
Fact: There is life on Mars.
Re:Mars and life. (Score:3, Funny)
Re: (Score:2)
Re:Mars and life. (Score:5, Funny)
Funny? I didn't intend for this to be funny. It's the hard, cold serious truth.
Don't take it personally. (Score:2, Funny)
It's just that there's no moderation setting for "+1, Loony".
Re:Don't take it personally. (Score:3, Insightful)
Oh, but there absolutely should be, don't you think?
Mars = Disaster (Score:2, Funny)
I've seen movies that show us the downfalls of this. Introducing a foreign entity to our enviorment is a prelude to a disaster. Think about it, who knows what that will mutate to once it interacts with our atmosphere? People will begin dying of some *mystery* virus that our ecosystem cannot handle.
Re:Mars = Disaster (Score:2, Insightful)
If there was life in our solar system, then there could possibly be new and crazy microbes on any one of the thousands of meteors that hits us daily.
There could be life in the little chunks of mars that have landed on earth.
It's a good thing that watching a bunch of scary sci-fi movies doesnt make for real science!
Fueled by doubts? Not quite... (Score:5, Interesting)
You make it sounds as if NASA has already made up their mind. Even the NASA scientists in charge of the Viking science experiments have doubt about their past data and equipment: Every good scientist questions their own research.
NASA has a pretty active Astrobiology [nasa.gov] department, which spends alot of resources looking for life and favorable environments [nasa.gov] on Mars.
Tenacity (Score:2)
Thank god they're doubting. There is every reason to re-examine things that were already examined years ago, regardless of how complacent we've become of our facts. Centuries ago, the most modern equipment missed several bodies in our solar system. Aren't you glad we rechecked?
HOWTO test for life on other planets (Score:5, Funny)
Send a manned mission. If they find nothing, the planet can be considered dead. If they find something, it obviously isn't. And if the team doesn't return, the natives are probably intelligent.
Re:HOWTO test for life on other planets (Score:2)
Or just big and hungery.
Beagle2 (Score:3, Funny)
We found life on Mars, but the beagle ate it.
Strange comparison (Score:2, Interesting)
What's odd about the Moon having organic material and Mars not? Isn't the theory that the moon was made from a collison [nasw.org] with the Earth? Wouldn't that be one explaination for the organic material?
Why not? (Score:5, Funny)
Because it would shake our religious and moral philosphies to their very core! Because, everything we believe in would be proven wrong!! What's wrong with you? Lord, man, I'm shaking just thinking about it.
Oh, I thought you said wifes in bars.
never mind
Re:Why not? (Score:2)
Christian beliefs indicate that the Jesus in the Bible had to be a human sacrifice to atone for the wrongdoings of mankind. For this whole atonement thing to work, it was important that this act be performed not just by god, but by some sort of "merger" between god and man. Therefore, it was paramount that this Jesus would actually be born as a human, live as a human, and die as one. By this philosophy, the same Jesus could not have died for the sins of other, alien spieces that may exist.
Re:Why not? (Score:2)
I don't know about that. I'm a Christian, and it isn't shaking me to the core. I'm just not uptight about shit like that. Of course, most Christians are uptight and would scold me for my use of the word shit, so perhaps I'm not representative. But I'd like to think that the church would shrug and continue onward.
(In fact, there is some precedent
Re:Why not? (Score:2)
I said "churches", not "christians". People are individuals, churches are collectives. Not everyone in a church may agree on every point, but there does tend to be a consensus about what is accepted and what is not, regardless of what one particular individual within the church may feel.
I don't care what they find... (Score:2)
Solar winds... (Score:2, Funny)
Highly Unlikely (Score:5, Informative)
All life takes in energy and matter from the environment, extracts energy, and produces waste. This process causes chemical imbalences in the atmosphere. Therefore to test for the presence of life, you only need to determine whether the atmosphere is in chemical equilibrium. Mars' atmosphere is, and has been for many millions of years.
Apparently this line of reasoning upset NASA, because they wanted to go to Mars, so they made their probes without his help, and when they arrived on Mars, found no traces of current life.
If they send more probes, they could very well find evidence of past life, but there is nothing going on there at the moment.
However I remember reading a story a while ago on Slashdot about how the atmosphere of Venus is operating far from chemical equilibrium, and that there may be some primitive life in the 400 degree acid in the atmosphere. Maybe someone should pay more attention to Venus...
Re:Highly Unlikely ...and Highly Loopy, Too (Score:2)
What the hell does that mean?
Chemists, meteorologists, and others who actually know what they're talking about are invited to comment.
I Am Not A Chemist...thank God.
Re:Highly Unlikely ...and Highly Loopy, Too (Score:2)
For example, if you have some acid and mix it with a metal, you get a reaction. That mix you have is not in equilibrium at the start. But after it reacts for a while, it will use up all it's potential energy, and stop reacting. It's then in chemical equilibrium.
Re:Highly Unlikely (Score:2)
Re:Highly Unlikely (Score:2)
Unfortunately I lent the book in question (Stuart Kauffman's) to a friend so I can't verify if it was him or not, but yeah I'm pretty sure.
Gaea Hypothesis (Score:3, Interesting)
A couple things against Lovelock's ideas. Didn't the Earth have a reducing atmosphe
Re:Highly Unlikely (Score:2)
And don't forget that you need to worry about the cold/heat cycles as you're traveling. And temperature cycling is a great way to make cracks... and cracks form a very nice place for corrosion t
Re:Highly Unlikely (Score:2)
See also John Lovelock; he was an atmospheric chemist who may have been the original proponent of the atmospheric disequilibrium test for life.
Although it's a good test, and I think it's an excellent one to use when we search for life on extrasolar worlds, it falls down in at least a few cases I can think of off the top of my head.
First, if there isn't very much life on Mars. It's dying out, or it only ever existed in small niches, etc. You won't be dumping enough
Re:Highly Unlikely I hope not. (Score:2, Interesting)
Terra Forming is Star Drek sci-fi. Obviously there will be no rapidly evolving "life" as we understand it on the present Mars.
If there are single celled organisms or even clustering goo, it will prove to be of little scientific interest. Even the genetics of these oganisms will be useless: UNLESS we find that these organisms contain code that closely resembles similar organisms on Earth!
Then the implications are that just m
Re:Highly Unlikely (Score:2)
Interesting line of reasoning. I hadn't heard of it before. However, I have my own reason not to put any hope in the search for extraterrestrial life, namely, there is no known mechanism by which life can naturally form without the involvement of other life. IOW, not only has no one ever seen abiogenesis work, no one even has a workab
"Mars:" A Ridiculous Liberal Myth (Score:2, Funny)
I am an astronomer myself, and I can tell you from personal experience that there are lots
Life Found on Mars!!! (Score:2, Funny)
All three apparently retreated off to the ice caps to hibernate after being bitterly disappointed at what they found on Mars; Welles didn't find anything to drink, Lewis didn't find God, and Bradbury was devastated over the lack of people with shiny coins for eyes.
Of course there is life on Mars (Score:2, Interesting)
I hope not (Score:2, Interesting)
It certainly woulnd't the end of the Gaia Hypothesis-it might be that loss of atmosphere on a low G world is one of the few things life can't prevent-but it would certainly be a point against it.
With a bit of punctuation change (Score:2)
Life on Mars, why not.
Only now the question is complicated (Score:2)
There are so many buggers here on earth, do we know for sure that our missions were clean?
Life on Mars? Why Not? (Score:2, Interesting)
Well what if there is life on Mars from Earth? Lets suppose the probes sent to Mars had living cells on them when leaving this planet. They would almost have to had contained living cells since Earth is full of tiny single cell organisms; some of which do not use oxygen. Would it be possible for us to have caused contamination of Mars and there actually be living cells on Mars from ~30 years ago?
"Dead world"? (Score:2, Informative)
Lovelock's Hypothesis (Score:3, Interesting)
Lovelock, a atmospheric chemist and inventor who made his fortune on the ion-capture gas chromatography detector, is the author of the so-called Gaia [asu.edu] Hypothesis. [auz.com] Romantic name aside, it's the idea that the presence of life alters a planet's environment to be more favorable to life. (The idea and name have been appropriated by eco-mystics who take it to mean that there actually is some sort of earth deity, but that's emphatically not what Lovelock is saying.)
On our planet, many atmospheric gases are grossly out of equilibrium. For instance, although the atmosphere is about one-fifth oxygen, there are detectable traces of methane, mostly from termites and "the farts of ruminants". If life were not continually renewing the methane, it would combine with the oxygen, and disappear in a few hours.
Of course, the presence of oxygen itself is an anomaly. It is so reactive that if it were not renewed by photosynthesis, it would bind with the copious free carbon lying about.
Lovelock gives many other examples in his excellent book, Gaia, A New Look at Life on Earth. [barnesandnoble.com] (He also mentions that the presence of fluorocarbons, like Freon, in the atmosphere is a clear sign, not just of life, but of intelligent life. Since you can determine atmospheric composition by spectrometry through a telescope, this gives a way to detect civilization if only you can image a planet hosting it.)
There's a clue in the simple appearance of the planets from space: compare the complex and constantly-changing appearance of the Earth's patchy clouds, liquid-water ocean, and of course its wildly varying landmasses (including snowcaps, yellow deserts, chlorphyll-green jungles, and seasonal temperate forests and grasslands), with the dead, relatively static appearance of any other planet in the system. Our nervous systems have life-detection circuits built in; honestly now, do you see any when you look at Mars?
The key is that Earth is alone in all the solar system in having a disequilibrium chemistry. This doesn't mean that there wasn't life elsewhere at one time; it may not even mean that there aren't small, isolated outposts that support some life, but not enough to control the entire planet. Certainly, life on Earth had to start that way.
Nevertheless, although there may indeed have been a time, early in its history, when life florished on Mars, it seems dead now.
Sweet nostalgia (Score:2)
Ingenous rationality from the nation that pioneered using pencils in space. (think about that statement a little more closely before you hit me with a salvo of
Re:Oh Brother (Score:4, Insightful)
On that same token, it's impossible for NASA to 'learn' that there is no life outside of Earth until it has visited all of the other planets throughout the Universe.
So, no, NASA will never learn that there is no life outside our planet - but in their quest, they will probably learn many other things (perhaps even useful ones).
Re:Oh Brother (Score:5, Interesting)
Re:Oh Brother (Score:5, Informative)
How about a BBC article [bbc.co.uk]
The fungi that did the damage, Novikova said, included members of the genera Aspergillus, Penicillium, and Cladesporium - all very common on Earth. [rense.com]
Davak
Re:This is good and all, but (Score:2)
Re:This is good and all, but (Score:2)
Re:Who knows.... (Score:4, Informative)
Re:Hollywood (Score:2)