Saturday, April 01, 2006

Tilt

I hear that it is Spring in Hong Kong just as it is Spring here.
Something puzzles me about seasons.
They are as I understand caused by the tilt of the earth towards the sun.
If it is the turn of the northern half of the globe to tilt towards the sun its summer in the north and winter at the bottom. As the earth goes round the sun in an ellipse the tilt relatively changes so that the bottom bit gets it’s turn in the sun and the top half takes its turn with the snow etc.
There is a big difference between winter and summer temperatures at least at our latitudes.
Life survives within a very narrow temperature range.
The Earth is 93 million miles from the sun.
It seems tremendously fortunate that we should be at just the right distance from the sun to evolve and it is the seasons that seem to underline that point to me. 93 million miles from the source and yet a ‘tilt’ on the axis of the Earth which accounts for big temperature ranges so far as life is concerned only brings the Summer Pole of the Earth closer to the sun by 3000 miles or so.
But then there is something called the anthropic principle which rather screws up this feeling of being specially selected.
I think this says that the only reason that there is this extraordinary set of circumstances is that there is somebody here to observe them. There might be a billion other ‘suitable’ planets where no observers have evolved.
Hold on though doesn’t that make life here even more improbable?
I am off to www.anthropic-principle.com see if I can make some sense of it all.

"I had that Bertram Russell in the back of my cab one day and I said 'Lord Russell, you're a philosopher. What's it all about then Guv?' - and do you know, he couldn't tell me"
from Sir Isaiah Berlin Memorial lecture

8 comments:

island said...

But then there is something called the anthropic principle which rather screws up this feeling of being specially selected.
I think this says that the only reason that there is this extraordinary set of circumstances is that there is somebody here to observe them. There might be a billion other ‘suitable’ planets where no observers have evolved.


If there is one finite unvierse, then we are "specially selected".

If there are an infinite number of universes, or one infinite universe with an infinite number of conditions, then we are "eventually inevitable", or whatever.

Try www.anthropic-principle.ORG instead.

MacDuff said...

Thanks
I think I see what you are saying. In an infinite universe given sufficent time all possible things will occur including life and presumably including Island writing your comment, again and again.
I dont see how in a finite one we are 'specially selected' though although I would like this to be the case. Ill definitely go and have a look at both websites properly but as I very rarely do what I say I am going to do when I say I am going to do it then it might take a couple of weeks.

island said...

I dont see how in a finite one we are 'specially selected' though although I would like this to be the case...

There are implications for specialness that are inherent to the "anthropic coincidences" if you don't have an infinite number of possibilities to lose this evidence in.

I think that the fact that specialness is implied in the observed universe scenario says a lot about the lameness of the rest of them. You don't look for an infinite number of smoking guns to prove that it wasn't a killers fault that he murdered somebody, since it had to happen in some universe. How lame is that?

Science took a hard left at infinity and uncertainty, and it never looked back to Einstein's reality. He never bought into that whole infinite universe crap either, but he had a theory whose most natural extension gave him good reason for his belief. He held onto that until the day that he died, in spite of the rest of them.

I think that says a lot too, but most scientists are unfazed by this sort of reasoning.

I'm the author of AP.ORG, so you're in lazy-luck... ;)

MacDuff said...

There are implications for specialness that are inherent to the "anthropic coincidences" if you don't have an infinite number of possibilities to lose this evidence in.
Yes I see what you say -that the probability of specialness in a finite universe is much higher because in a sense it is a real number you put on the probability wereas in an infinite universe of infinite age its a certainty at some time or place.
I never thought of that.

island said...

Yes, I should have said that you don't have an infinite number of possibilities to lose the *significance* of the evidence in, if there is only one, finite universe. Leonard Susskind said the same thing in his interview with Amanda Geftler for the "New Scientist" magazine interview, except that he WRONLGY stated that IDists would have a case for intelligent design if the "landcape" of universes does not exist.

You gave an example of one of the multitude of anthropic coincidences in your original posting, and the significance of this "goldilocks" scenario is that ALL of the anthropic coincidences are similarly *ecobalanced* between diametrically opposing runaway tendencies, which has a huge impact on the structure and life feasibility of the universe.

Now, the real question is where you go from here with this information.

Do you act like a real scientist and look for a good physical reason why humans might be specially required by the thermodynamic process of the universe... ?

... or do you act like a religious fanatic.. ?

... or do you act like an "antifanatic" and deny the significance even exists?

This kind of preconceived prejudice is what your up against... and more... when you start studying the anthropic principle.

Humour and last laugh said...

cognito ergo sum... or something like that.

Bill Cooper said...

I am with the antifanatics and cannot see that there is any significance in it. It happened because it could. We must therefore live in/on the best of all possible worlds.

island said...

Meaning what, bill, that you believe in infinity, for which a logical proof has never been given?...

What religion is that, anyway?