The answer right now is we don't know. The two possible answers would be either: 1) there was a supernatural creator who made life out of nothing. 2) life began by groups of chemical compounds grouping in such a way as to create more of the same, and beginning the reproduction cycle, eventually evolving into more complex forms. Even if life on earth was started from some ET experiment, or from deposits from some comet, life had to begin first somewhere. Number 2 can be experimentally attempted, number 1 can't. Until we demonstrate number 2 is possible, then we really can't say what's right.
For the theists: Another option is a combination of 1 and 2 - God influenced chemical reactions and so on to create life. See? Science and religion are not incompatible.
Probably, Steve, but we cannot say it as a likely fact until we either simulate the whole process in the lab and/or observe it happening elsewhere (hopefully one or the other happens soon). Finding life elsewhere that is a bit different might help give clues also as to how these events may happen. Unfortunately we can't say it definitely happened just as we can't say the Big Bang definitely happened or that the Moon definitely came from a collision. They're just our best theories so far to match the data we have...
I go with Steve on this one. We could go to Titan to find out. If there is prebiotic life there it is most likly like the stuff that was on earth 4 billion years ago. If life started before the solar system then we would find out by discovering life of very similar genetics on Mars and Europe
Almost there.... http://saturn.jpl.nasa.gov/index.cfm Between Mars, Europa, and Titan, I actually think Europa might have the most promise for finding something larger than cellular, and it most likely wouldn't have a shared origin with us, unlike Mars. If we find Mars rocks here, then there might have been a reverse contamination in the past. But Titan will be a good look into what Earth's past might have been like, prefrozen. Then again, we might truly be alone in this system...
I disagree I think life is very chemically common… Its intelligent sentient life that’s rare, heck most humans are not even that yet Please Register or Log in to view the hidden image!
I hope you're right, having abundant life in just this system, with the potential of it being everywhere, would change the egocentric attitude of humans... Please Register or Log in to view the hidden image! For a few weeks anyway... Please Register or Log in to view the hidden image!
Just a small not to say all the (complex dna ones) life-forms on the planet have right-handed DNA... There is no reason not to have a left-handed form. It would be a good test to see, if anything were found, whether it had the left handed version.
life? given the age of the universe, where ever life (carbon-based) CAN occur, it WILL occur. given that, don't expect life to be like earth's. it's likely that life will be carbon based, therefore protein based, but the information storage and replicating molecule will probably not be DNA.
Maybe not DNA, but DNA-like, serving the same purpose. A virus, even in its limitations, used DNA to pass its characteristics to the next generation. You're possibly right about life popping up wherever conditions are right, and that will strengthen if we find life elsewhere in this system. However, we can't say for sure until we find at least one more instance.
The fact that life arose on the planet quickly is a good indication . But of course it may be that... 1) it was due to `luck`. 2) it came from somewhere else (and had evolved over a long time) 3) Pre-life creates the right conditions (it`s self) to evolve into life...
Re: reply to Jaxom I realize that, my point was that even they as sub-life have to pass their information on via DNA, so a similar functioning structure must be created to do the same in other life. It may be very close to DNA, if the chemical nature dictates that only those types of forms work. It may be something extremely different. But the necessity of trait passage must be done by something. Otherwise there's no structure or order, and each reproduction would make something very different, if it could even occur at all without some instruction set. Evolution will form wings where flying is a good trait to have, fins where swimming is needed, legs to move on land. They won't look the same, but they serve the same function. Same with DNA and other cellular structures.
some viruses contain RNA instead of DNA RNA could have been the ancestral information storage device. RNAs can also act as enzymes similar to proteins.. some people say that clay might have contained the first structure, and therefore information?
