Thursday, March 3, 2016

Early Origination of Life – Organic Oceans – Part 5

This blog is about finding aliens, or, barring that, finding out why they are hidden and not showing up, in particular here on Earth, which we all know is a very nice place to hang out. One of the essential requirements for having aliens showing up to hang out with us is aliens. There has to be some.

The hypothesis this subset of posts has been discussing relates to the origination of aliens, or more specifically, the origination of life which, under the right conditions, might evolve into aliens. You have to have life before anything else can happen. The peculiar hypothesis is that life does not spring into being on Earth as we know it. Specifically, it says that it springs into being only during a very early era on Earth, even before there was fossilization or almost any records, and then, once it did, it evolved in such a way that it could stick around for billions of years until it produced the ultimate in living organisms, human beings. Maybe not the ultimate. But us, anyway.

Furthermore, it says that this is the way to produce life anywhere and that life doesn't originate any other way, or at least it could say that. Maybe there is another way, but we haven't even found one way yet so the chances of there being two are fairly remote. To spell it out more explicitly, the organic oceans hypothesis says that life only originates in the very early formation stage of a planet's history, when condensing gases were making up the planet and they included lots of organic compounds, including those which were immiscible with water. After some time, chemistry eliminates such compounds, and the chances for life originating go to zero.

If we see a planet, and can get a rough concept of its age, probably by dating the star it revolves around, we know how long life has been around there, assuming it originated. If we are looking at a planet which is Earth-like, and we assume that the same length of time for life to evolve from some chemicals on a meniscus to cities of ten million inhabitants holds for that planet, we know what stage they are in. If this is a star which formed after ours, there may be life, but it might still be in the alien dinosaur stage, rather than the aliens we talk to stage. If this is a star which formed considerably before ours, we can figure the alien civilization there ran through its resources and is all burned out by now. Nothing there, probably, but some hunters living on the bounty of the planet, meaning its renewable resources.

Of course there is a variation in the speed at which various critical steps of evolution would take place. When we understand a little more about evolution, we can figure out if the rate is governed by the rate of mutation or by something else. Is there a 1% variation or a 5% or a 10%? For the interim, we might assume 10% is a reasonable band, so that if a star is less than 90% of the age of the sun, life is still big lizards or whatever their equivalent is, and if it is more than 110% of the age of the sun, the alien civilization there is past its golden age, past its silver age, past its copper age, and has retrogressed back to its wooden age.

There are a lot of stars out there in the galaxy, and so if we are going to point listening devices at them, or do some detailed study of their atmospheres, or some other wonderful obserational technique that hasn't been invented yet, we might want to not waste our time with the <90% ones or the >110% ones, at least for starters. This might reduce our effort by something of the order of 10.

There are other implications as well. It is physically possible to build radio dishes so one planet in one solar system can communicate, albeit with long delays, with another planet in a different solar system, if they are not too far apart. In some posts here, we noted that it would be ever so nice if we happened to be close to the beam path between two planets that were communicating. Then we could at least detect the signals, even though we couldn't understand them. Now, by using the organic oceans hypothesis, this reduces the number of planets that could mount this technology, to those which possess the correct approximate age. There is no point in trying to totally eliminate those planets which do not meet this criteria, but for the first few we look at, we might as well pick the best bets.

Here's another implication. If we took the organic ocean hypothesis as something like a working hypothesis, it might be useful to try and figure out how long such an ocean might live on a newborn planet. What triggers the formation, besides the right temperature of the cooling planet, and what triggers the disappearance of it? Is the period of existence suprisingly short? Does the liquid ocean, with all its dissolved salts and what-not, eat away at it so it lasts only ten million years? That means that the origination phenomena happen relatively quickly, in a geological timescale. It also raises the concern that other planets may have had a shorter period, and therefore didn't make it to the stage of life which could transfer location to the water ocean. Perhaps the evolution of a G6 star is different than that of a G2 or a G8 or anything else, and this affects the duration of the unique conditions that might originate life.

Wouldn't it be the most interesting thing if some brilliant astrophysicists or exo-geologists found out that G2 stars like our sun have the longest time for such an ocean to exist? Different factors play a role, and it just so happens that G2's are at the maximum. The implications of this are obvious. Only a G2 has an organic ocean around for long enough to evolve life. There aren't aliens anywhere else.

Clearly such a surprise would only be possible after a lot of theorizing and computing and general thinking about the formation of planets from dust disks around stars, and how fast they condense, and what factor impacts play, and how does the geology settle out. Does the core form after ten million years or a hundred? How about the crust? What controls the temperature profile with time? Such interesting questions may lead us to a very deep understanding of our place in the universe.

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