Life Could Have Evolved 15 Million Years After the Big Bang, Says Cosmologist 312
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."
This is frightening (Score:5, Interesting)
This is pretty scary. One of the major unsolved problems right now is the Fermi problem- 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 or the like. Whatever is blocking this is the so-called Great Filter https://en.wikipedia.org/wiki/Great_Filter [wikipedia.org]. Now, some of the Filter could be in our past. It may be tough for life to arise or for multicellular life to arise, etc. However, the more disturbing possibility is that it exists in our future: maybe civilizations before they can spread out manage to wipe themselves out with their technologies, such as through nuclear war, bad nanotech, engineered bioweapons, resource depletion, environmental damage, or something we haven't even thought about before.
Over the last few years, more and more evidence has suggested that a lot of the obvious filtration events in the past aren't serious filters. For example, we've found that planets are common. This is not only an example of more such evidence, but it suggests that if life got started it would have had billions years more to evolve, meaning that evolutionarily based filters will be substantially less effective. Worse, it undermines one of the easier ways to try and get around a filter, to suggest that the conditions for complex life didn't arise until recently. There are serious problems with that idea already (especially the fact that life on Earth spent hundreds of millions of years in near stasis), and this makes those problems even more severe. If this checks out, it will be strong evidence that a substantial portion of the filter is in the future. If so, it is likely that the Filter is something that is going to happen to us within the next few hundred years, since it gets harder to wipe out a civilization once they spread beyond their initial planet, and most obvious things that would do so are also more noticeable.
Re:Problem (Score:4, Interesting)
That would be true regardless of whether there was life on other planets or not. No matter how closely those planets resembled Earth, they're not Earth, and while they *might* provide us with every vitamin and protein we need it does seem somewhat unlikely...
Re:This is frightening (Score:3, Interesting)
We can't see extra-solar civilizations because our technology sucks. We don't even know whats on the bottom of our own oceans and you're thinking Aliens that are probably millions of years more advanced that us at the very least would still use Radio waves and think of a Dyson Sphere as anything more than obserd joke? Do you think that we'll still be emitting radio waves in even 500 years time? How about 1000?
Warm and dark (Score:5, Interesting)
That period in the history of our universe may have been warm, but I imagine that, at the time, the average hospitable planetary surface would have been pretty dark. After all, if the Goldilocks zone is what you get without having a nearby star at all, then having a star nearby would make things too hot. So, any planetary surface suitable for life to evolve on would have been a necessarily dark place.
An unfortunate consequence of this warm universe is that it will have taken longer for planetary bodies to cool down after their formation. The question is, would even a Mars-sized body have have enough time to form and cool down so that standing water could have existed on its surface during this Goldilocks era? Somehow, I doubt it.
As the background temperature cooled to below the freezing point of water, the habitable volume of the universe suddenly became restricted to the areas around stars. These early stellar Goldilocks zones will initially have been huge, but would soon become much smaller. And as they became smaller, they also became more brightly lit.
Well known filter is currently active (Score:5, Interesting)
The following is nothing new, but few people want to face up to what it really means for us. The 6th Mass Extinction [wikipedia.org] is well under way, and it has nothing to do with cuddly pandas and (less cuddly) tigers and rhinos disappearing. It's the microscopic life such as oceanic biota, nearly all of it unseen by most people, that's disappearing at a devastating pace like nothing that's ever happened before on this planet.
We can live without the top-end mammals that make the extinction news on the TV. We can't live without the microbiota. We are not independent of them, they keep the biosphere running and our crops producing, and without the biosphere we are no more.
The collapse of biodiversity is, on geological scales, vertically downwards, and at some point it simply hits the zero axis. It could happen even more suddenly if a tipping point is reached, because species are inter-dependent. The current decline is not the normal sort of gradually falling curve as seen in the past 5 extinctions. On the biodiversity graph, this event is an abrupt termination of all life. You can't argue with the biodiversity curve.
We don't really need more Great Filter theories. This one is not a theory, it's measured, and it's quite enough all by itself.
Um, a random thought (Score:2, Interesting)
Subjectively that second would have been like billions of years to them. And could they have left traces, like manipulating the fabric of space to encourage life to form in atomic matter? Like the universe for them would have been the size of a watermelon and they'd have had energy at scales to make quasars look like a cheap eBay LED flashlight?
Re:This is frightening (Score:4, Interesting)
We don't have a complete theory of abiogenesis, true. But we don't need it to see that our plausible hypotheses don't make life arising to be that unlikely. And we have empirical evidence as well: we have traces of life that date back to very soon after Earth became hospitable. The Late Heavy Bombardment http://en.wikipedia.org/wiki/Late_Heavy_Bombardment [wikipedia.org] ended some 3.8 billion years ago. The oldest fossils date to around 3.5 billion years ago. See http://www.paleosoc.org/Oldest_Fossil.pdf [paleosoc.org] This suggests that life can arise in under 300 million years. It is possible of course that life arose during the LHB, and we cannot rule out panspermia. But together with the fact that many of the basic chemicals (e.g. many amino acid) used in life are not much more complicated than those that occur through non-living processes, we shouldn't at all expect there to be some magic time period it takes before life can form.
As to your statement that "primordial soup experiment was bullshit"- I presume you are taking about the Miller-Urey experiments http://en.wikipedia.org/wiki/Miller-Urey_experiment [wikipedia.org]. Why don't I just quote from the introduction of that Wikipedia article.
After Miller's death in 2007, scientists examining sealed vials preserved from the original experiments were able to show that there were actually well over 20 different amino acids produced in Miller's original experiments. That is considerably more than what Miller originally reported, and more than the 20 that naturally occur in life.[7] Moreover, some evidence suggests that Earth's original atmosphere might have had a different composition from the gas used in the Miller–Urey experiment. There is abundant evidence of major volcanic eruptions 4 billion years ago, which would have released carbon dioxide (CO2), nitrogen (N2), hydrogen sulfide (H2S), and sulfur dioxide (SO2) into the atmosphere. Experiments using these gases in addition to the ones in the original Miller–Urey experiment have produced more diverse molecules.[8]
You may want to look at the section "Other experiments http://en.wikipedia.org/wiki/Miller-Urey_experiment#Other_experiments [wikipedia.org]. So, yes by all means, please point me and others where to go to read up on how Milley's work was "bullshit" since I don't see it in any of the obvious places.
universe as incubator, temporary nursery (Score:3, Interesting)
Re:Anthropic Principle (Score:4, Interesting)
Re:This is frightening (Score:5, Interesting)
We can probably ignore the sun's background radiation: if an alien civilisation is advanced enough to see our planet next to the sun in visible light (reflection from the sun's rays) they can probably focus enough to pick up our radio signals (the sun's radio frequency waves will not be deflected by the Earth much if at all). The fact that there are radio signals coming from our planet should be the giveaway. No other planet in our solar system is producing such signals. And that's of course assuming this alien entity is using radio waves themselves for communication, and as such thinks it's a good idea to look for radio waves as a sign of the presence of intelligent life.
Same for this SETI, I don't think we'll ever be able to understand alien signals beyond the mere fact that they are out there.
Re:Anthropic Principle (Score:5, Interesting)
Yes. There would have been a lot more stars blowing up right in your vicinity, but more importantly, the newly-formed heavy elements would have been naturally accompanied by their usual radioactive isotopes, but why bother a physicist with the laws of biology, eh? :)
It is commonly thought that life evolved when it did because it's the time it took for radioactive elements to decay.
Of course, ratios of radioactive to stable isotopes vary from place to place, depending on which star blew up to create them and how old it was. But you can't really say the whole universe was a goldilocks zone. It would have taken a special place with more than just water - and the oldest galaxy we know of is 380 million years old. And let's not forget that 15 million old Earth was just a giant ball of magma... constantly being hit by giant asteroids. The Hadean period (Hades = the ancient greek version of Hell) is thought to have lasted about 600 million years.
I doubt a 15 million year old universe would have been little more than atomic soup. Water may have existed, but not as we know it. It takes more than 15 million years for a star to form and blow up, where would you have gotten enough heavy elements for a planet to arise? :)
The first stars are thought to have formed 100 million years after the Big Bang, not 15. Dude's on crack.