No, in all likelyhood, it would never get the chance to arise again to a level where competition is a meaningful word to use. The thing is that the building blocks of life are also generally food for life. Thus, once life exists, the environment in which life could spontaeneously arise is destroyed, never to return.

Cars are always good for a few analogies. Imagine a mechanic, trying to build a car from scratch out of spare parts lying around. But he's surrounded by mechanics working on whole cars, and they also want the parts. In order to hold on to a part, it has to be fitted into a complete car. So he can never finish the car, because any part he finds will be snatched up by someone else before his car is complete. And he'll never actually get to race any of the others.
Skepticism is always reasonable, but are you familiar with the Miller-Urey experiment?

Heard of it, know enough about the field to claim to be familiar? No.

That link does have information about the experiment I'd not heard before. I vaguely recall hearing that it might have been contaminated, but that doesn't explain the chirality.

It's not clear to me how they can tell whether the planet is tidally locked if they can only detect it based on its gravitational interactions... any ideas?

Perhaps not so much of a trick as living under one ton per centimeter of pressure, in temperatures exceeding 200 degrees Fahrenheit! Such as the case with Pyrococcus CH1

Yep. The gravitational drag from any nearby planets is sufficient to cause the sun to "wobble" in it's orbit. The magnitude of this wobble is proportional to the gravitational force exerted upon the sun by the planet, from which the mass of the planet can be obtained.

Because the sun itself is so bright, our telescopes cannot actually see the planets at that range. But we can tell they're there, and approximately where they are by looking at the movement of the sun.

Look at tidal forces over the cause of the sun's orbit I guess. If the exact same effects reappear in the exact same locations, then the source of those effects has to be "in synch" with the orbit of the sun, pointing towards a tidally locked planet.

Or you might look at force / mass / time / distance relationships. For near-sun objects, the gravitational pull from the sun produces a massive tidal force which elongates the whole planet along the axis of force exertion. This in turn produces a torque on the near-sun side which basically acts to "synchronize" rotation and orbital period because the total angular momentum of the sun-planet system is always conserved.

Or the sun itself may show signs of being in a tidal lock with another object; this however would normally require a fairly large planet.

It's extremely hard to determine though - we used to think Mercury was tidally locked with the sun until we got continuous readings from radar observations.

But how do you keep an atmosphere on only half a planet?

Actually, that's not a problem at all. We know what is required for life (as we know it) to form: carbon, hydrogen, oxygen and nitrogen, plus a medium that will allow those elements to combine (water) and a spark of energy to initiate the reaction. This has already been replicated in the laboratory and proven to the point where we know if those conditions exist, life forming molecules are inevitable. That doesn't necessarily mean life itself will form, but the conditions and components necessary for life will. The current thinking is that the conditions that exist around those volcanic fumaroles on the ocean's floor are not only exactly like what started life here on Earth, but also that the life found there is actually the most primitive and basic life form still found on Earth. If we look for conditions similar to that on other planets, the odds of finding life, even if it is just simple microbial life, are very good.
It's not a fallacy, it's simply pragmatic. Sure, we have theories and ideas on how life could form in other ways, such as silicon instead of carbon based life, or the ammonia you mention, but we have no real examples of life like that. Why bother looking for the theoretical when we know that the conditions here on Earth have already produced life based on facts, not theories?

This isn't the first time we've confirmed one only to find out later it wasn't after all. Give them a year, if they still think it's habitable by then, it probably will be.

Also: http://xkcd.com/893/ read the alt text.

We won't reach a population limit in terms of resources in a very, very, very, very long time. What we will run out of, what we've been short on since the beginning of time, is economy; and therefore spending a shit ton of what economy there is on playing around in space with little to show for it (because unless we manage to make ourselves a small, lightweight sun, it's always only going to be a little to show for it), offworld colonization is an extremely poor solution.

But it makes for awesome science fiction, and I wouldn't change that for anything.

We spend more money yearly blowing shit up that we already built than we do on space by orders of magnitude. There could be a ton to show for getting into space, but we'll never know, because it's more profitable to blow stuff up that we already built.

Problem is except for putting satilletes in orbit for communications, there is really not much profit to be made in space so far, and the costs of exploration are huge. It has to be done on a non profit basis. I agree NASA should be more efficent, but I an not sure that running everything for profit is a guaranetee of efficency.

I hate to say this, but on the whole I agree with nondeplumage. Space exploration is not very feasable right now or in the near future ie: for as long as we live to care. In time mankind may come up with technology that helps us travel to planets with ease, until then, I think we will continue to come up with other more 'down to earth' technology. We will find a way to grow crops in such amounts that population, no matter how high will not lead to starvation for most. I recall reading an article in Popular Science, I don't remember the whole thing, but, the gist of it was being able to have farms in high rise buildings, that are solar powered, and reuse most everything put into them, and thats with technology that we have now or will soon.

I think I'm like most of us, when I play a space game, man I wish I was out there for real, because it is awesome, to explore, to wonder, to dream (and of course to fire laser beams!). However, much to my sadness, there are just so many problems in the world now that need help fixing, that space exploration and expansion, are not even close to the top of any governments list of to do's. The only thing that may spur a government into doing anything (and I doubt that it would), is the threat of a planet killer astroid coming to wipe us out, or some other planet wide catasrophe, man-made or not. Really though, until the major problems of earth are fixed (big Until I know), I really think going to other planets will only be for those of us who play video games.

Like what? Satellites and Teflon?

It would be far off if our governments would actually use the stupidly spent money (such as the budget for space exploration :>) to fight poverty around the globe. Because as we all know, the wealthier a population is the less offspring they tend to produce. But even now the most recent predictions say that in a few centuries the human population will stagnate and stay on an equal level.

didnt know anything about this planet..thanks for the info :D very interesting stuff!