For example, if the universe outside of our solar system appeared to be very different, on average, to conditions here, then that might present a barrier. Though that wouldn’t rule out abiogenesis either. Until a demonstrable process, or suite of processes can be shown not to require large amounts of time there is no reason – other than faith – to assume the reverse.My view is that we shall likely (80% probability) eventually demonstrate such a suite of processes. Maybe the next generation of supercomputers might allow for complex enough simulations for us to find out. That is why I said it does not affect abiogenesis research really, because we simply don’t know enough for it to affect the research. You claimed the exact opposite, that no practical barriers can be thought of…which is rubbish. Originally Posted by TheBiologista we do know that abiogenesis worked at least once somewhere, if not here. but it does add a major extra step to a process that hasn’t yet been shown to require that step.

In an eternal universe panspermia must occur sometimes, so abiogenesis is unnecessary. Then there is the problem of how it got on its little vessel to begin with. I did not say that it is for lack of understanding of biochemistry. But by observation is seems it does not differ, in fact the universe appears rather homogeneous. Who knows, maybe many different forms of proto life arose (well, I think probably) and then a complex mix of symbioses ensured that it stuck.IMHO But we haven’t really spotted them in our observations.

The conditions found on an asteroid, comet, whatever, are simply not suitable for the preservation of life…to allow life to traverse from where it originated to Earth. Originally Posted by Pong Not for certain. In an eternal universe panspermia must occur sometimes, so abiogenesis is unnecessary. There might even be more than one way for it to develop which allows for both a fast and a slow way. There remains a significant probability that we shall not be able to do so, because that is not how life originates. i.e., while life may be inevitable and commonplace it does not necessarily arise swiftly.

Where ever life began it would have had to been on a planet with conditions similar to Earth. In fact we currently take precautions to prevent our panspermia within this solar system and beyond. This depends of course under what conditions life arose. Far more likely that life simply arose on the planet(s) that you find it on and not some other source. How did Laika the dog get into space? It was quite a challenge, yes.Now we have to be a lot more careful, because we’re landing probes on comets and soon, moons composed of liquid water.

For starters I didn’t state that we cannot imagine barriers to life emerging elsewhere, of course we can. If you are open minded you may see how much religion hinges on this, and how difficult an eternal universe must be for most folks to accept. Seriously. My assertion is that overall there are no barriers to the emergence of life “elsewhere”, based upon what we do know. I think his point is, and I agree with him, is that the process has not yet been shown to not require too much time either. That is why I said it does not affect abiogenesis research really, because we simply don’t know enough for it to affect the research. Originally Posted by chadn737 But the universe is not eternal…a finite amount of time and a finite amount of matter and space. Enough said.

Not for certain. So it is not the case that panspermia had to have happened.On the contrary, I consider it rather ridiculous. Originally Posted by Ophiolite Originally Posted by spuriousmonkey Except that there is no reason to assume that the origin of life needed vast expansions of time.

However, we do know that abiogenesis worked at least once somewhere, if not here. Maybe the next generation of supercomputers might allow for complex enough simulations for us to find out. So even if we were somehow to find out that that is how life came to be on earth, it would still not negate abiogenesis research. I don’t have any numbers for the energy required to to keep liquid water inside a comet (against radiative loss) and that’s my fault. And even if https://student.unsw.edu.au/ you assume some of the Big Bang models that avoid an absolute beginning, then there is still a finite amount of time since the periods of the universe where the conditions for life are simply impossible.

Even with our limited technology, we’ve already identified over 300 extrasolar planets and the overall trend (taking into account observational bias and our limitations) indicates that our solar system is not unusual by any of the measures we can currently assess.So, yes we can imagine barriers to the emergence of life elsewhere, but I am contending that we have not observed them. But it must be less than accomplished by our little guys that live in icebergs, since conduction isn’t happening, and sublimation isn’t either (see Saturn’s icy rings, non-sublimating). Hi , I’m no scientist or expert in such matters but why do you discount the possibility of extremeophiles travelling to earth on/inside meteorites ? Is it a theory or are there bacteria known to man that can withstand such conditions as inside a meteorite ? Wasn’t the earth itself a hunk of inhospitable chemicals in the beginning with extreme temperatures ?BARCUD Despite the popularity of ideas like the RNA world, we know pretty much jack. One reason is that it happened so many billions of years ago, but the other is that there are a vast number of practical barriers based on the biochemistry.Since we understand the biochemistry fairly well, we can think of practical barriers to the processes that we know had to occur in order for life to form. But that is largely an opinion. The conditions are totally suitable.

But are you not also making an unfounded assumption? That abiogenesis required too much time, despite a dearth of information supporting that? I wouldn’t rule out panspermia, but it does add a major extra step to a process that hasn’t yet been shown to require that step. Though that wouldn’t rule out abiogenesis either.Anyway it’s just a matter of time before we ourselves actualize panspermia.

Despite the popularity of ideas like the RNA world, we know pretty much jack. Theres a reason origin of life research is still pretty much inconclusive. Originally Posted by chadn737 Then there is the problem of how it got on its little vessel to begin with. There might even be more than one way for it to develop which allows for both a fast and a slow way. Originally Posted by BARCUD Hi , I’m no scientist or expert in such matters but why do you discount the possibility of extremeophiles travelling to earth on/inside meteorites ? Is it a theory or are there bacteria known to man that can withstand such conditions as inside a meteorite ? Wasn’t the earth itself a hunk of inhospitable chemicals in the beginning with extreme temperatures ?BARCUD Yeah sure, that is the panspermia debate. I see your point now, sorry. I think you’ve also misunderstood me. Ever heard of vacuum packaging? Freeze drying?

Besides that, space is not a very hostile environment. The earth is thought to be about 4.5 billion years old and as far as I know, the earliest signs of life are found in 3.5 to 4 BY old rock. That leaves 500 million to a billion years for it to have emerged. So we are not dealing with an infinite amount of time here, but a finite amount of time and a finite amount of matter and space.

Also, once the first self sustained proto life emerged it would be without rival and could conceivably initially have hugely proliferated before competition for resources had to start and evolution to become needed. Are there possible barriers to specific abiogenesis hypotheses? Sure, I wouldn’t dispute that for a moment.

Anybody please correct me if I’m wrong – I thought our finds of early life are even pushing geology back, so the proto-Earth could not have remained hostile so long as we’d imagined. I think his point is, and I agree with him, is that the process has not yet been shown to not require too much time either. How did that life form suddenly find itself on some comet or asteroid? How did that organism find itself on a rock that somehow managed to escape the gravitational pull of its home planet and solar system on a trajectory for Earth? When you think about panspermia to any great extent….its really not that viable. But the universe is not eternal. If we keep finding life existed sooner than we’d thought possible, not much later than the first solid rock, then apparently life appeared “right away”.I’m open to informed correction. We’ll probably see some very exciting developments in that regard in the next decade or two.

I mean where once we reckoned a smoldering hell we have cells embedded in rock. You claimed the exact opposite, that no practical barriers can be thought of…which is rubbish. Cold is not a big problem, and a little cold is probably good.Radiation’s not an issue when you’re buried under meters of snow, water being an excellent radiation shield.

We simply do not have enough understanding or even basic data to decide one way or the other at present. Originally Posted by KALSTER but it does add a major extra step to a process that hasn’t yet been shown to require that step. I’d imagine there’s all manner of genuine possible routes through abiogenesis. Originally Posted by chadn737 You misunderstand. The thing is that those extremophiles also had to originate somewhere, if indeed that is how life came to earth. I have to concede those are scientific truths, not religious beliefs. One reason is that it happened so many billions of years ago, but the other is that there are a vast number of practical barriers based on the biochemistry.Since we understand the biochemistry fairly well, we can think of practical barriers to the processes that we know had to occur in order for life to form. Alright, let’s see how our sample of 1 (Earth) can and inevitably will make it happen, in this finite universe, just for fun… Originally Posted by chadn737 The conditions found on an asteroid, comet, whatever, are simply not suitable for the preservation of life.

Certainly, simulation will help us figure out the starting conditions and chose the likeliest option. On the contrary, I said the exact opposite:We understand enough about the basic properties of amino acids, DNA, RNA, fatty acids, carbohydrates, etc to to make all sorts of inferences about the formation of various polymers, enzymatic activity, structures, etc. Originally Posted by chadn737 So it is not the case that panspermia had to have happened.On the contrary, I consider it rather ridiculous. In fact, I am pretty sure that more than one mechanism exist whereby life can arise, so research could eventually shine some light on a few of those.

It’s a fantastic insulator, so yes technically what little how to write an economics essay a level
matter the vacuum contains is “cold” but that “cold” does not have much effect on, say, some organisms slowly gnawing at the core of a big snowball.