Atmospheres

Wanderer · #1 February 20th, 2003, 02:24 AM

Quote:

Originally posted by capnq:

quote:
You are not going to go to another galaxy and find that suddenly the laws of physics stop applying or get changed

There are a number of science fiction stories where this assumption turns out to be false.

I think it's more than an assumption - although we might not have travelled to other parts of the universe, we have observed them with all manner of telescopes and not noticed any glaring differences.

For example the WMAP probe (whose first results were published Last week) read temperatures differing by just millionths of a degree in the cosmic background radiation from different directions. Were the rules of physics different in different regions of the universe we'd expect to see a lot more variety.

Of course, science fiction gives you the liberty to create your own rules, thank goodness.

A side note concerning the atmosphere: oxygen is actually toxic for humans above a certain partial pressure. The figure US Navy divers came up with was 1.6 bar. That is, if you breathed in pure oxygen at more than 1.6 times atmospheric pressure (or normal air at more than 8 times atmospheric pressure) you'd experience dizziness, vomiting, black-outs and, eventually, death. This is why divers don't usually carry 100% O2 in their tanks as it limits them to staying within 6m of the surface... one man's meat is another man's poison.

Fyron · #2 February 20th, 2003, 02:36 AM

Quote:

Originally posted by capnq:

quote:
You are not going to go to another galaxy and find that suddenly the laws of physics stop applying or get changed

There are a number of science fiction stories where this assumption turns out to be false.

Yes, and those are science fiction. I was not talking about fiction, where pretty much anything can be made up at random.

couslee · #3 February 20th, 2003, 03:20 AM

All this has been fun to read. But I guess what I was meaning, in another term, is who is to say how evolution will take place on those planets that have other atmospheres. No one can say for certain that life can not exist on those planets, anymore than someone can say we know all there is to know about all elements and that the human table of elements is complete. How does one know how any given element reacts under the all vast atmospheres. Or how time impacts things as well. If you look at a piece of coal, how could you "logicaly" conclude that over time and under extreem pressure it would become a diamond? To borrow a line from JP, life has a funny habit of "finding a way".

[ February 20, 2003, 01:22: Message edited by: couslee ]

Slick · #4 February 20th, 2003, 03:39 AM

Here are some neat things:

There is a theory that even protons are unstable and will decay over time. The postulated half-life is on the order of the age of the universe. There have been experiments to look for a decaying proton, but none have been observed. Would be interesting if true. And would play a part in the ultimate fate of the universe.

If another galaxy were made entirely of anti-matter, we would not be able to tell. Light given off from stars burning anti-Hydrogen and anti-Helium would give the same spectra. Most all of chemistry and physics would work in a similar manner (there would be some minor differences). If there were sentient life there, they would think that the entire universe was made of antimatter for the same reasons. There is a small minority of astrophysicists that are trying to prove this one way or another. The reason that it is even postulated in the first place is that equal amounts of matter and anti-matter should have been produced in the big bang, but as far as we can tell, everything that we can see is matter. Where did all the anti-matter go? If there were a slight imbalance of matter over anti-matter and the rest anihilated, the mass/energy state of the observable universe doesn't add up. Certainly an interesting question.

For SE4 purposes an antimatter race could be made. An antimatter race would have trouble colonizing a planet made of matter, though.

Slick. (casual reader of astronomy stuff)

Cheeze · #5 February 20th, 2003, 03:40 AM

Hey, do you know what element a P&N atmosphere is primarily composed?

AAAAAAAAAAAAARRRRRRRRRGON!!!!!!!!!

HA HA HA HEE HEE HEE HO HO HO!!!

[ February 20, 2003, 01:42: Message edited by: Cheeze ]

Slick · #6 February 20th, 2003, 03:47 AM

Quote:

Originally posted by Cheeze:
Hey, do you know what element a P&N atmosphere is primarily composed?

AAAAAAAAAAAAARRRRRRRRRGON!!!!!!!!!

HA HA HA HEE HEE HEE HO HO HO!!!

Hey Cheeze, why are Pirates so cool?

Because they just AAAAAAAAAAAAAAAAARRRRRRRRR.

Slick.

Ragnarok · #7 February 20th, 2003, 03:52 AM

Quote:

Originally posted by Slick:

quote:
Originally posted by Cheeze:
Hey, do you know what element a P&N atmosphere is primarily composed?

AAAAAAAAAAAAARRRRRRRRRGON!!!!!!!!!

HA HA HA HEE HEE HEE HO HO HO!!!

Hey Cheeze, why are Pirates so cool?

Because they just AAAAAAAAAAAAAAAAARRRRRRRRR.

Slick.

Did you see the previews to the movie about the Pirates?

It's rated AAARRR.