Scientists Offer 'Overwhelming' Evidence Terran Life Began in Space 556
An anonymous reader writes "Using data from recent comet-probing space missions, British scientists are reporting today that the odds of life starting on Earth rather than inside a comet are one trillion trillion (10 to the power of 24) to one against. That is, we're not originally from around here. Radiation in comets could keep water in liquid form for millions of years, they say, which along with the clay and organic molecules found on-board would provide an ideal incubator. 'Professor Wickramasinghe said: "The findings of the comet missions, which surprised many, strengthen the argument for panspermia. We now have a mechanism for how it could have happened. All the necessary elements - clay, organic molecules and water - are there. The longer time scale and the greater mass of comets make it overwhelmingly more likely that life began in space than on earth."'" jamie points out that the author of this paper has many 'fringe' theories. Your mileage may vary.
Others? (Score:3, Interesting)
Extrapolation of probability using two variables?? (Score:5, Interesting)
Re:Others? (Score:3, Interesting)
For stuff outside of our own solar system, I think right now we're only just beginning to learn how to detect planets smaller than Jupiter, so finding an object smaller than a planet that far out is probably beyond our capabilities at the moment.
Even so, if you're looking for really complex life (such as intelligent life), you'd be better served to find planets that comets crashed into rather than the comets themselves.
We're not alone (Score:4, Interesting)
It's probably also worth pointing out that this result has probably increased the chance of life existing elsewhere in the universe by a similar amount. There are far more commets than planet and they are a truly huge number of stars.
Moreover, it is more plausible that a comet could fertilize many star systems if it was knocked out of the orbit of various stars in its life-time. While this sort of event is in itself unlikely it is orders of magnitude more likely than life being liberated from a planet from a violent impact. The life would have to survive the fiery, high G, exit from whatever atmosphere there was surrounding the planet and would still have to have sufficient momentum to escape the star. These properties taken together pretty much eliminate any chance of that happening.
Compare this to the following comet hypothesis. Life gets started on a comet with a highly elliptical orbit billions of years ago. How this happens is open question but for the moment assume it does. As the star uses up its fuel it loses mass and the orbit slowly stretches. Eventually, the comet is able to free itself from the gravity of the parent star. Hundred of millions of years later, the star goes supernova. The blast wave from the supernova gently accelerates the comet into a planetary nebular. It just happens to be the one that our Earth was forged in. As the nebular condenses the life that started inside the comet transfers itself to the billions of water droplets and mineral material. You can guess what happens next.
I've always suspected we are not alone. It's just whether we're all too far away from each other for the knowledge to make any difference.
Simon
But.. (Score:1, Interesting)
Re:Huh? (Score:1, Interesting)
And what are the odds of those concentrations being high enough to keep things warm and toasty without being high enough to fry the potentially developing life?
Old News (Score:1, Interesting)
Re:Extrapolation of probability using two variable (Score:5, Interesting)
We know that life was here between 3.5 and 3.9 billion years ago, with some iffy evidence suggesting it was even older. That gives us a net time advantage for any given comet of no more than about 500 million years. That sounds like a lot, but in reality it really isn't that big a span. Beyond that, considering that our knowledge of cometary history is still rather sketchy, and that our sample size is exceedingly small, this is nothing more than a pretty substantial "what-if", itself based upon one particular abiogenesis theory, which has been somewhat supplanted in recent years.
If we're going to start talking about interstellar comets, to add more time to the equation, someone is going to have to a) provide evidence of such bodies and b) provide evidence that radioactive decay is going to produce heat long enough for liquid water within the body to act as an incubator for the VERRRY long stretches of time that some organisms or proto-organisms are going to survive.
Now, weight all of this against the fact that the early Earth had all the ingredients for life to develop; *plentiful* amounts of liquid water and lots and lots of energy (in the forms of solar radiation, atmospheric conditions like lightning and geothermal energy from oceanic vents and vulcanism). Can someone kindly explain to me how a comet, even with clays or clay-like crystaline minerals and some sort of low-level radioactive decay (it has to be pretty low-level too, because anything too energetic or in too high a quantity is more likely going to be delerious than helpful) is going to provide this more wonderful environment.
As with every generation of panspermia advocates, the underlying argument is essentially "We don't think there was enough time for life to develop on the early earth, so we've got to find a way to add more time." Even if we give them this part of the argument (and I frankly think even that is FAR too generous), they still have to explain how conditions elsewhere (comets, other planets orbiting other stars) are somehow more environmentally-friendly to abiogenesis than Earth was.
This is not to slight the largely unrelated idea that comets could have been the source of organic molecules that could have been some sort of organic "seeds" for early self-replicators to develop and to use as raw materials and energy.
Re:Extrapolation of probability using two variable (Score:3, Interesting)
Re:Of course it started in space (Score:4, Interesting)
Department name is somewhat appropriate... (Score:5, Interesting)
As to the relative plausibility of comet-seeded or locally-formed progenitors to life, given that reactions propagate, commonly leading to repeating and self-feeding cycles of reactions, the only argument for extra-solar is the added timescale and potential additional area for productive area for pre-life to evolve in.
Given that the universe is 13.7 billion years old, and the earth is 4.5 billion years old, and life on the earth is nearly that old, and that the universe has only been cool enough to support planets or life for much of that time, I don't believe panspermia buys us that many more orders of magnitude of time to work with.
So, it doesn't buy us time, how about area? Again, I can only guess using very rough psuedo-numbers here, but the matter we could get from previously existing worlds or small super-fertile comets has to come from somewhere previous. Given the expanding nature of the universe, we're generally only going to be getting a pie-slice of potential sources for any life-by-projectile, and each of these sources has to have been fed by enough nuclear sources to make the building blocks of simple pre-life. I can imagine a multiplication of potential sources this way, and even though it would only take one source to seed the whole set... just imagining the mass that actually makes it into out solar system, and then actually hits our earth... that likelihood doesn't seem much stronger than the numbers we think of with abiogenesis via selective pressures here on earth.
Ryan Fenton
Re:Extrapolation of probability using two variable (Score:5, Interesting)
My flatmate, who was a paleobotany postgrad at the time, had some very disparaging things to say about him. He had co-authored a few papers claiming the Archaeopteryx was a hoax, based on his poor understanding of the subject matter.
http://en.wikipedia.org/wiki/Archaeopteryx#Authen
Re:Yeah right (Score:1, Interesting)
(likelihood of life starting on a comet) / (likelihood of life starting on Earth) = (amount of comet) / (amount of earth)
for an extremely simplistic view.
Re:Others? (Score:3, Interesting)
Organic compounds are everywhere at the Solar System. It is so easy to detect them at dust released by commets or at surfaces that it doesn't make even news anymore.
Re:Curious but probably wrong (Score:3, Interesting)
I do recognize that the total mass of comets is larger than the terresterial planets. However, I dispute that the usable volume is as high as the authors might want to claim. Much of the cometary volume is too cold, with short-lived radioisotopes for heating (particularly 26Al). Terresterial planets get consideral benefit from gravitational heating and convection to create long-lived zones with stable temperatures and limited ionizing radiation.
I think we can safely say that the odds of multicelled life developing on comets are very low. Conversely, some biologically relevant molecules do form in comets. The question is how far toward life comets can take you. Skepticism is warrented for any 'origin of life' paper. Multiple by ten for any paper that claims to present a decisive argument (as this one does).
Real life? (Score:1, Interesting)
http://www.nytimes.com/2007/08/14/science/14tier.
The argument, in a nut shell, is as follows: Dr. Bostrom assumes that technological advances could produce a computer with more processing power than all the brains in the world, and that advanced humans, or "posthumans," could run "ancestor simulations" of their evolutionary history by creating virtual worlds inhabited by virtual people with fully developed virtual nervous systems.
Re:Extrapolation of probability using two variable (Score:2, Interesting)
Re:Even if it is true, we cant explain the origin (Score:3, Interesting)
That makes a big difference, though. It's a question of probability. If life cannot spread through space, then it must have begun here of its own accord, and so we're looking for a theory that allows good odds that life will start on any planet chemically and environmentally favourable for it to do so. If life, once started somewhere in the Universe, can spread through space by natural means (i.e. without first needing to evolve intelligence and build starships), then we're allowed much longer odds, because of the far wider range of space and time. If you have a million worlds all rolling the dice on abiogenesis, you have far better chances than with only one.
Re:No kidding (Score:4, Interesting)
I'd post spoilers, but I'm lazy. 8^P Suffice it to say that all the main characters survive and it is implied that they live happily ever after - except Marvin who can't help it.
worms survived the Columbia crash (Score:4, Interesting)
http://science.slashdot.org/science/06/01/04/0334
http://news.com.com/8301-10784_3-6016657-7.html [com.com]
They got it wrong i explain here (Score:2, Interesting)
For panspermia to work and to seed a galaxy much more then a milion years are required.
And more radiation will aply in space destroying complex moleculair life bounds.
If you would say but the comet could include the right kind of clay.
Well we allready had lots of it here
So its more likely its te opposite chance
How much did it cost who sponsored them and what was their budget idea... tahts the main question.
Re:two things (Score:2, Interesting)
If you think that your own innate sense of decency is superior guide to goodness than what can be achieved by humility before God, and instruction from Him, you might want to reflect on the fact that you have sectioned off vast parts of humanity as deserving to be mocked, apparently without any objections from your lofty sense of decency. If you are looking for the source of evil in this world, I suggest that it is precisely this lust for a sense of superiority over our fellow man, and the actions that proceed from it. Though this lust can infect the religious as well as the non-religious, humility before God leads also to humility before one's fellow man, and wisdom from God commands love of one's fellow man. Your stated positions imply that your innate decency has somehow failed to bestow these lessons upon you.
Re:Extrapolation of probability using two variable (Score:3, Interesting)
ID is yesterday's news. The latest scam is Teach the Controversy.
Re:Others? (Score:5, Interesting)
Space is very big, and planets are very small. Given enough time (billions of years), any rogue comet may eventually be influenced by a planet's gravity. But that doesn't mean it will hit it. Gravity doesn't work like a frog catching a fly; chances are the gravitational influence will merely change its course. And chances are that influence will be small, unless it passes close to a large planet. The comet would have to be heading pretty much straight at a planet in order to hit it. Even if it were to skim the outer atmosphere, it's unlikely that it would enter a terminal orbit.
Consider this: The Earth is 8000 miles in diameter. The distance from the Earth to the moon is 239,000 miles. The distance to the Sun is 93,000,000 miles. To put this into perspective, imagine a walnut on your desk. That's the Earth. The Moon is a blueberry on the other side of your desk. The Sun is a car three blocks away. Jupiter is a pumpkin a mile from the Sun Car. Mix in the other planets at their proportional distances, and you still have a lot of space in which a comet (anything from a grain of sand to a pea at this scale) can miss everything as it passes through the solar system.
The only object that will definitely have a strong influence is the Sun, and even it may or may not pull the comet into orbit.
Re:Extrapolation of probability using two variable (Score:4, Interesting)
Except that it doesn't really. If the timeframe Earth has been around is 1/1000th of the average time you'd expect the abiogenetic process to yeild life on average, well that's ok. There are likely to be 1000s of Earth-like planets in the galaxy. All those stochastic molecular events are not only taking place on the surface of primative earth, but every other primative earthlike planet in the universe. It only has to happen once for us to be here and puzzle at how rare we are. I mean, the chances of winning the lottery are extremely low, but someone usually wins.
Given the choice between lots of time-consuming chemistry reasearch and a hypothesis which is impossible to falsify or really even research but allows a lot of poetic pseudo-philosophical nonsense in the vein of "we are children of the stars", "cosmic bortherhood", and "the thrut is out there", which do you think people will choose ?
You are right there. No doubt about it.
Comment removed (Score:3, Interesting)