i know weve found bacteria and multicellular organisms in extreme conditions, which raises the possibility of life elsewhere. but is abiogenesis, life coming from non-life, hard to happen in space?
Member
i know weve found bacteria and multicellular organisms in extreme conditions, which raises the possibility of life elsewhere. but is abiogenesis, life coming from non-life, hard to happen in space?
Established Member
Do you mean in "empty" space?
Order of Kilopi
As likely to happen on an earthlike planet as it did on earth.
The previous sentence isn't very helpful when you think about it.
Member
i mean how hard or easy is it for abiogenesis to happen randomly on a planet. i heard that some scientists say that the chances of it occuring are so small
Established Member
Knowing the answer to that would require checking out a bunch of similar planets to find whether it happened there or not. We haven't done that study yet, and unless something like Star Trek's "warp drive" ever becomes possible, we probably never will.
Order of Kilopi
If we find life or the remains of life in our own solar system that didn't come from earth, then life would presumably be very common in the universe.
My own guess is that life isn't too unlikely to come about when you have liquid water a decent mix of chemicals and a large amount of time for things to happen in. However, that's only a guess.
Member
we still havent created any life. does it mean that life cant arise easy elsewhere
Order of Kilopi
i dont think that anybody really knows yet makaya.
Member
ur right. im getting very stressed out about this subject, and i fear if no other life is out there
Order of Kilopi
Depends on how you define life. Replicating molecules have been made in labs and they have even spontaneously generated under the right conditions. Most people don't consider these replicators to be life as the replicators are even simpler than viruses which often aren't considered alive and they only appear under special conditions and these conditions may never have existed on earth. However the fact that we can get replicators to form in a day in a beaker with the right substances in it, suggests that somewhere on a planet over millions of years conditions could develop that allow self-replicating molecules to form.we still havent created any life. does it mean that life cant arise easy elsewhere
Order of Kilopi
other solar systems
Originally Posted by Delvo
Delvo. Not true. The Enzmann starship, invented at MIT in the late 60's, early 70's, was a feasible technology for a round trip to Alpha Centauri in ~ 12 years, using off the shelf technology from then. The problem was, and is still....money. It would've taken the gross national product of all the world for a year to put one in orbit. It will happen, a lot sooner than you think with emerging hardware. pete
Established Member
Just because no researcher has done it does not mean it is impossible. All it means is that no-one could get the funding.
As I understand it, there was a proposal about 5 or so years ago to assemble a load of components into bacteria in a test tube. The components one might require (amino acids, ATP, a complete genome, DNA replication enzymes, DNA transcription enzymes, ribosomes, tRNAs, ribonucleotides [for mRNA], phospholipids, various cofactors and salts and so on) are fairly well understood. The tricky bit is persuading a funding body that the attempt is worthwhile.
This, however, is not very applicable to abiogenesis in an Earth-like environment. For a start, the first life on Earth probably bears no resemblance to any of its living descendents. Second, it had plenty of time and a whole world in which to experiment. Finally, it had no competition, so it didn't need to be very efficient.
Member
so do you think that we need more time to create life? ive heard life appeared 800 million years into earths history. that could mean prokaryotic life forms may be common elsewhere. but more complex organisms, like planets and animals, probably will occur less frequently. see im in the rare earth camp, but i still have belief complex life might exist on a couple planets
Established Member
Well life happened here - so why should it not happen on any other planet with similar conditions to our own and given enough time.
You seem to have got involved in several threads on this and similar subjects. Each time you seem to suggest that somehow life is very improbable. I still do not understand how you come to that conclusion.
I believe the density of life in our galaxy will be largely determined by how frequently star systems develop which have rocky planets with a reasonably dense atmosphere and large quantities of water in liquid form.
If such planets develop in only one in every ten thousand star systems then life is going to be rather spread out. If they develop in one in every hundred star systems then life in likely to be fairly common. However intelligent life is a very different issue. Evolutionary processes here on earth had no built in predispostion to produce a technological life form. If something had snuffed out our direct ape-like ancestors around 6 million years ago then there is nothing to suggest that some other species would have been launching satellites by now. Instead life would have gone on evolving and adapting to changing environments just like it has always done. There is no golden rule that says evolution should produce an intelligent tool using creature after 600 million years 800 million or 3 billion. I expect that largely similar rules are likely to govern how life develops on other planets.
Therefore if one in every 100 star systems produces habitable planets then there are probably a lot of very diverse ecosystems out there to be discovered. On the other hand very few of them may actually have produced a city dwelling, metal smelting, engine building species.
As I said in another thread in this section. The fact that we have carried out maybe a hundred or so experiments, with a few litres of chemicals, over perhaps a 30 year period, in our attempts to investigate how life got started hardly compares with the time and resources this planet had to experiment with soon after its formation. Therefore to say that just because we have failed in just 30 years of experiments is a very weak argument to suggest that it is difficult for life to get going on a planet like ours.
If you want to get a handle on how common life is in the galaxy then the start point is finding other worlds with similar conditions to our own. Once we are able to obtain data that will allow us to determine how common or rare our planet is then we will be in a good postion to estimate how common life is.
If you want a number to start with - then my guess is probably one star system in 500 produces at least one planet like ours - Mind you that is just a guess I have no data to back that up. If that is the case then life of some sort has probably evolved on almost every one of those planets. However it may well be the case that our planet was the only one which happened to throw up a species which had the right combination, processing power, memory, manipulatory appendages and which lived on land thus was able to exploit combustion as a means to further its technology and dominance. Which in turn enabled it to break away from the traditional rules of natural selection and move instead towards a mechanism of competitive culture.
Last edited by 3rdvogon; 2006-Nov-20 at 11:54 AM.
Member
thanks for ur input
Order of Kilopi
3rdVogon said it all really, I expect that in the medium term we will discover a large(ish) number of observable rocky planets. I also suspect that within around 100 years we will have in place an array telescope in orbit that may eve allow a crude visual of an extrasolar rocky planet. By then I'm sure we will also be able to detect life by-products elsewhere.
In terms of creating life... yup, I think you just need a lot of time... al lot of time. Luckily the universe has quite a bit of that.
Member
so should we expect it to arise in space more likely than in a lab.?
Order of Kilopi
Those scientists are talking out of their hat, Makaya. There is no way of knowing how likely something is based on only one example, particularly when the only evidence available is billions of years old. The only thing you can say accurately is that it's possible based on the evidence that life exists, so at some point, that life must have started existing. To say how likely or unlikely it is is pure guesswork, nothing more.
Last edited by Noclevername; 2007-May-10 at 12:31 AM. Reason: .
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