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Life Could Have Evolved 15 Million Years After the Big Bang, Says Cosmologist
KentuckyFC writes "Goldilocks zones are regions around stars that are 'just right' for liquid water and for the chemistry of life as we know it. Now one cosmologist points out that the universe must have been through a Goldilocks epoch, a period in which warm, watery conditions could have existed on almost any planet in the entire cosmos. The key phenomenon here is the cosmic background radiation, the afterglow of the Big Bang which was blazing hot when it first formed. But as the universe expanded, the wavelength of this radiation increased, lowering its energy. Today, it is an icy 3 Kelvin. But somewhere along the way, it must have been between 273 and 300 Kelvin, just right to keep water in liquid form. According to the new calculations, this Goldilocks epoch would have occurred when the universe was about 15 million years old and would have lasted for several million years. And since the first stars had a lifespan of only 3 million years or so, that allows plenty of time for the heavy elements to have formed which are necessary for planet formation and the chemistry of life. Indeed, if live did evolve a this time, it would have predated life on Earth by about 10 billion years."
I always wondered what the point was with considering panspermia. If life could have appeared anywhere in order to make it to Earth, it could have just as easily originated on Earth to begin with. There's nothing miraculous about Earth, but there is nothing sub-standard about it either.
It would be interesting to know if terrestrial life started elsewhere, but what problems does that hypothesis solve? The only one I can think of is why all almost all Star Trek aliens look like humans with different foreheads.
At cosmological time scales that's a blip. Our radio waves will most likely never be heard again just like we'll never hear theirs.
For the record I think that there is life everywhere in the universe because the laws of physics will be the same.
But let me guess, you believe the aliens use magical particles like tachyons and gravitons to communicate and we're just too stupid to figure it out but when we do we'll be invited to the galactic fraternity, right?
mod up.
From the GP, "why we don't see any signs of civilizations other than our own, not just no radio transmissions but no Dyson spheres (and yes, we've looked http://home.fnal.gov/~carrigan/infrared_astronomy/Fermilab_search.htm [fnal.gov], stellar uplifting, ringworlds"
What would you expect to see? Realistically? We've been listening for about 50 years (less, on a semi-professional basis). That's fifty years. Civilsation on Earth has been going about 5000 or so (very roughly, I'm not in the mood for pointless arguments about what constitutes "civilisation" when we compare Neolithic with Mesolithic, thanks). Mankind has been around for very roughly 100,000. 100,000 years is *nothing*, and yet for almost all of that time we've been totally invisible. It's only in the last 100 years that we've been blasting radio waves out to the cosmos. For the last decade or so, much of that has been encrypted and therefore looks like noise. It may not look like *random* noise, but it looks like noise. How do you expect an alien race, less than ten light years away, to possibly decrypt communications sent in a language they don't speak, through a character set they don't use, through mappings that make no sense to their computers, passed through encryption they don't have a handle on? They can't, it's a foolish belief. Even without encryption, modern digital transmission is refined enough that it's unlikely an alien race would be able to rapidly decode our transmissions, if at all.
So if you accept this line of argument, we've basically transmitted approximately a century's worth of information out to the heavens, in a very thin shell of expanding radiation. That radiation grows horrifically weak very quickly and would be hard to pick up over the Sun's background noise. What we're expecting, if an alien race is to even know of our existence, is that they are at the exact point in their development that they can somehow pick out our unencrypted transmissions above the Sun's natural noise, and then somehow decode those transmissions and make sense of them. Most of those transmissions are crappy 1970s sitcoms, or endless radio adverts. Fortunately no-one will know this, because it relies on there being a civilisation extraordinarily local to us, at exactly the same level of development as us, and actually listening to the outside world. Those chances are excruciatingly poor.
That goes the other way round.
For the rest, Dyson spheres? A myth. Freeman Dyson is close to a legend, but Dyson spheres are not a realitic proposition - not for us, and not for anyone.
Ringworlds? Lol.
I don't even know what is meant by "Stellar uplifting". If it involves doing anything to do with manipulating the Sun... yeah, you go ahead, I'll do something less likely to kill me.
The problem that panspermia theories are supposed to "solve" is the ease or difficulty of "bootstrapping" life --- how likely is it to get self-replicating, self-organizing complex systems out of simpler chemical precursors. In the case that this is "really really unlikely," then panspermia allows the earliest forms of life to occur only in a few rare cases, but then spread to populate more of the universe. On the other hand, this is unnecessary if the initial chances of life formation are reasonable (given a few billion years and a planet-sized cauldron of random chemical soup). So far, scientists in the lab have been able to generate a lot of life precursors (amino acids, etc.) under "early Earth" conditions, but not demonstrate the "leap" to self-replicating systems; however, this may not prove too much, since scientists haven't had a billion years and a planet-sized petri dish array to try everything out.
Earth is pretty new as these things go. An 8 billion year head start is an awful lot.
Help stamp out iliturcy.
I personally see the whole panspermia with regards to the origin of life concept as not significantly different from the notion of intelligent design with respect to how we came to be.... they both just push the actual problem they claimt to solve back one level and do not actually offer any additional predictive power that genuinely scientific theories enjoy.
File under 'M' for 'Manic ranting'
If there is an important distinction, it's that panspermia pushes the problem back one level to "known science" --- it provides an "amplification" mechanism for rare events in plain old organic chemistry, based on ordinary physics principles; while "intelligent design" introduces a whole new layer of metaphysical complication entirely outside of scientific knowledge.
I'm not personally a proponent of panspermia theories, based on the "space is frickin' big" principle. Interplanetary transfer within the solar system is one thing --- we know chunks of rock can travel between planets (and, ultimately, this can be tested: if we don't find clear evidence for Earthlike life at some earlier stage in Mars' development, then interplanetary panspermia isn't happening much). Interstellar panspermia is correspondingly far, far less likely. Given that we have all the "raw ingredients" available here, it seems that requiring panspermia to fill in the gap between "pools of organic sludge brewing for a billion years" and "life happens" is premature.
Amen! I'm a Christian and ardent "evolutionist" and I have to put up with listening to ID all the time. It is never presented as a complete scientific framework, rather I'll be discussing some biological feature and the word "design" will pop up in the conversation, getting louder and more frequent until I give in. At that point, I explain that what we call "science" is more properly called "natural science" and seeks to provide natural explanations for our observations. ID is a supernatural explanation so it falls outside the realm of natural science. It's also intellectually lazy; anything that they can't comprehend is simply explained away with hands thrown in the air and "well, God did it". Thank God actual scientists actually seek out the truth, as we would still be living in the stone age with their level of thought.
Do you have ESP?