"...a universe that produces sophonts as casually as it produces snowflakes."
-Poul Anderson, "Outpost of Empire" IN Anderson, Captain Flandry: Defender of the Terran Empire (Riverdale, NY, 2010), pp. 1-72 AT p. 7.
"...a universe where life of any kind was so rare as to seem well-nigh a miracle."
-Poul Anderson, Genesis (New York, 2001), PART ONE, VII, p. 85.
Which kind of universe do we inhabit? I have heard it argued that the universe must be full of civilizations simply because of its size but that does not follow. The universe is expanding so its size is a function of its age but it had to reach a certain age and size before it could produce any life so we might be the first.
But, even if there are other civilizations, how frequent are they? One in every six galaxies in the entire history of those galaxies' existences? In other words, so few that they will never contact each other?
Barrow and Tipler argue that the Weak Anthropic Principle should have shown that the steady state universe was very improbable but I do not understand their argument.
Apparently, three-dimensional mathematical physics has properties necessary for intelligent information-gathering and consciousness so maybe we inhabit a three-dimensional cross-section of a multi-dimensional universe?
9 comments:
The problem is that until very recently we couldn't observe extrasolar planets, and until -very- recently we couldn't detect Earth-type ones at all.
So we're proceeding from a very small sample.
Look at the way the theories of solar system formation had to be junked when we -did- begin
Fairly soon we'll be able to analyze extra-solar planets' atmospheres. Since free oxygen is a pretty certain indicator of life, that will solve some questions.
We already know that -planets- are common as dirt, even around stars we thought couldn't have them.
But we have to refine our observations before we know if life is common or rare, and if rare how rare.
And of course until very, very recently -we- would have been invisible to observers.
Kaor, Paul!
I agree with Stirling's comments. I will only add that it seems so WASTEFUL to think ours is the only planet in the galaxy--never mind the universe!--with intelligent life.
A good Catholic treatment of this question is Brother Guy Consolmagno's booklet INTELLIGENT LIFE IN THE UNIVERSE? (Catholic Truth Society, 2005).
Ad astra! Sean
One should also keep in mind the sheer -scale- of the universe.
There are about 100 -billion- stars in the Milky Way.
That means that even if life is very rare per star, there should be a fair number of life-bearing planets.
And of course our galaxy is only one among, according to the latest estimate, two -trillion- galaxies in the universe.
That cuts the odds further, though that's academic given the distances involved.
Sean,
But remember the argument that the universe had to be at least ten billion years old and ten billion light-years across before there could be any life in it so we could be the first.
Paul.
Kaor, Mr. Stirling and Paul!
Mr. Stirling: And our galaxy could be even bigger! If we can trust Wikipedia, the Milky Way has from 100 to 400 billion stars--and at least that many planets.
And I certainly hope evidence is soon found of other planets with free oxygen atmospheres. I also believe we should not think life can exist ONLY on terrestroid planets with liquid water and oxy/nitrogen atmospheres. SF writers like Hal Clement and Poul Anderson have speculated about very different forms of life arising on non-terrestroid planets.
Paul: Where did you find that argument? In Anderson's IS THERE LIFE OTHER WORLDS? or in other works? It doesn't really seem to be something Anderson would say. I think he was much more cautious in the above mentioned book.
Ad astra! Sean
Sean,
In the Anthropic Principle book and elsewhere. Heavy elements had to be synthesized in a first generation of stars so that life would be possible on planets of second generation stars.That takes a lot of time.
Paul.
Kaor, Paul!
I think I kind of realized that after I posted my comment at "11 June at 05:48" comment.
I also recalled Anderson speculating in his book that on Earth mankind might have been one of the earlier intelligent races in the Milky Way galaxy to achieve a high tech civilization. That could explain why we have not seen (yet) any hard evidence of non-human high tech civilization--because they had not yet gotten that far.
Ad astra! Sean
Another reason that has been given for thinking humanity might be among the first intelligent species is gamma ray bursts. One of those can severely damage a planetary ecosystem. They appear to be more common in the early universe, so earth might be one of the earliest planets to have enough time between GRBs hitting it for a technological species to arise.
Kaor, Jim!
A good if scary point! I have read of how destructive gamma ray bursts could be.
Ad astra! Sean
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