"Why we haven't met any aliens" by Geoffrey Miller

[oabmarcus]

Are you aware of the special theory of relativity?

yes, supposedly there these wormholes that provides a "shortcut" between 2 pts.  I haven't seen one though, so it's also just theoretical

[MN Dave]

I have met the aliens and they are disguised as groundhogs for reasons only their alien minds can understand.

[karlhenning]

I have met the aliens and they are disguised as groundhogs for reasons only their alien minds can understand.

I knew you would not disappoint, MN Ralph!

[MN Dave]

I knew you would not disappoint, MN Ralph!

Oh, do watch that!

[oabmarcus]

Oh, do watch that!

they voted Republican?

[Opus106]

yes, supposedly there these wormholes that provides a "shortcut" between 2 pts.  I haven't seen one though, so it's also just theoretical

It's General Relativity which dug out the wormholes.

[Scarpia]

It's General Relativity which dug out the wormholes.

And as far as I know, the farthest anyone has ever gotten is to convince themselves that it they can't prove wormholes don't exist.

The ramifications of special relativity are:

1)  You can't go faster than the speed of light, with is actually rather slow, compared with cosmological distances and times.

2)  It takes an infinite amount of energy to reach the speed of light, which means you have to be content to move at a small fraction of the speed of light. 

3)  Even if a wormhole existed it would only allow you to take a shortcut to another specific location, which is no more likely to contain life than any other, nearby or distant part of the universe. 

4)  Anything you see in the universe (except out immediate vicinity), doesn't exist anymore, because it took so long for light to reach you. 

5)  Even if you could make a wormhole (which would probably require manipulating masses comparable to the mass of the galaxy), the thing you made it to reach wouldn't exist anymore by the time you got there (see 2 above). 

So the possibility of aliens visiting earth seems remote.

[Elgarian]

4)  Anything you see in the universe (except out immediate vicinity), doesn't exist anymore, because it took so long for light to reach you. 

I think what Scarpia means to say is that our information is always out of date, and the further away the object is, the more out of date our information is. So if we're looking at an object 10 million light years away, we're seeing it as it was 10 million years ago, not as it is now. I don't think he meant to say that it doesn't exist - I think he meant to say that it no longer exists in the state in which we see it (which in the case of an alien civilisation, may include the fact that it no longer exists at all).

[drogulus]

And as far as I know, the farthest anyone has ever gotten is to convince themselves that it they can't prove wormholes don't exist.

The ramifications of special relativity are:

1)  You can't go faster than the speed of light, with is actually rather slow, compared with cosmological distances and times.

2)  It takes an infinite amount of energy to reach the speed of light, which means you have to be content to move at a small fraction of the speed of light. 

3)  Even if a wormhole existed it would only allow you to take a shortcut to another specific location, which is no more likely to contain life than any other, nearby or distant part of the universe. 

4)  Anything you see in the universe (except out immediate vicinity), doesn't exist anymore, because it took so long for light to reach you. 

5)  Even if you could make a wormhole (which would probably require manipulating masses comparable to the mass of the galaxy), the thing you made it to reach wouldn't exist anymore by the time you got there (see 2 above). 

So the possibility of aliens visiting earth seems remote.

    That's an excellent point about extreme time and distance. That's why I focused on the relatively near systems. Even one of our nearest galactic neighbors, the Andromeda Galaxy, is over 2 million light years away. If they sent us a message today we'd get it in 2.3 million years, and if we replied immediately they'd get that message in another 2.3 million years.

[Cato]

The recently discovered (late 1990's) unknown right now in "Big Physics" is the acceleration of the expansion of the Universe, possibly connected to Dark Matter and Dark Energy.  The expansion was a shock and counter-intuitive: entropy would seem to slow the expansion down, but something has been adding energy to cause the acceleration.

What does it mean?  One melancholy scenario has the expansion ripping apart everything, even atoms!  Some claim that inter-stellar travel or at least inter-galactic travel will be impossible, i.e. no aliens can visit us and vice-versa, unless they are fairly close by.

On the other hand there may be properties of Dark Matter/Dark Energy which will allow warps or other as yet unimagined things to overcome the expansion: that assumes of course that intelligence will reach a point where it can harness the stuff, and that assumes that it exists to begin with (still highly debatable, but the odds are looking better for its reality).

[drogulus]

      One consequence of the expansion is that in the far future there will be fewer visible stars. Of course there won't be anyone here to see this since our system will be dead by then.

      The last new stars that form will come to maturity in what appears to be a total void beyond the local group. A civilization that develops on a planet there will have to discover that there once was a visible Universe rather than a vast emptiness. So we're lucky.

[Scarpia]

The real issue is whether it will be possible to relocate life on Earth to another planet before the sun dies.  I'm not up on this sort of thing, but I think the sun has probably run about half its useful lifetime (before its output changes enough to make earth uninhabitable).  Can life survive that theshold?  (Well, can intelligent life even maintain itself another thousand years, given the rate at which humans are consuming resources?)

[oabmarcus]

The real issue is whether it will be possible to relocate life on Earth to another planet before the sun dies.  I'm not up on this sort of thing, but I think the sun has probably run about half its useful lifetime (before its output changes enough to make earth uninhabitable).  Can life survive that theshold?  (Well, can intelligent life even maintain itself another thousand years, given the rate at which humans are consuming resources?)

you really think we can last that long?

[Scarpia]

you really think we can last that long?

No, I don't. 

[oabmarcus]

Actually, we could surivive that long, or maybe even longer. Baring a major catastrophe (whatever that killed the dinos), i think technological progress will be fast enough that "saves" our planet from running out of natural resources. It's a bit of economics really, when resources are more scarce, people tend to look for alternatives. E.g. there must have been a time where  primitive people found swimming from one island to the other were too costly and dangerous. So they invented boats. I think we have plenty of options for a fading sun. We could harness wind power or even make an artificial sun using nuclear energy or something.

[Scarpia]

Actually, we could surivive that long, or maybe even longer. Baring a major catastrophe (whatever that killed the dinos), i think technological progress will be fast enough that "saves" our planet from running out of natural resources. It's a bit of economics really, when resources are more scarce, people tend to look for alternatives. E.g. there must have been a time where  primitive people found swimming from one island to the other were too costly and dangerous. So they invented boats. I think we have plenty of options for a fading sun. We could harness wind power or even make an artificial sun using nuclear energy or something.

The earth hasn't always been like it is now.  The climate has been dramatically different.  If a perturbation makes the earth climate dramatically unstable it could become uninhabitable for life.  (I'm not talking next year, or next century, but a million years from now.)  If the earth turns into another Venus, no amount of technology will save us.  What if the oceans boil?  Then what will be left on earth?  No people, just thermophilic bacteria.

[oabmarcus]

The earth hasn't always been like it is now.  The climate has been dramatically different.  If a perturbation makes the earth climate dramatically unstable it could become uninhabitable for life.  (I'm not talking next year, or next century, but a million years from now.)  If the earth turns into another Venus, no amount of technology will save us.  What if the oceans boil?  Then what will be left on earth?  No people, just thermophilic bacteria.

yeah, but see, the scenario you just described happens gradually. As long as it happens slowly, future humans will pick up the cues, and figure out clever ways to get around the problem.

and even if, the doomsday comes, so what? we had a good run, didn't we? plenty of history, accomplishment, everything comes at an end.

[drogulus]

yeah, but see, the scenario you just described happens gradually. As long as it happens slowly, future humans will pick up the cues, and figure out clever ways to get around the problem.

      A Dyson Shell or some other megastruture seems more likely than extinction.

      The question of whether life has meaning if it comes to an end doesn't really disturb me. As individuals it comes to an end for everyone. Meaning is a product of our kind of life, and if there is no such life there is no question to ponder. I do wonder what it would be like for the last generation of intelligent beings looking at imminent extinction. They may have a very different understanding of time than we have, though. Even for us there is something a little odd about putting the emphasis on the future alone, as though that was the sole measure.

      Maybe it doesn't make any more sense to see the "end of time" as an actual boundary between existence and....what?.....as it is to see a physical boundary between the Universe and.....see, it doesn't really work there, either. You can't have a fence between existence and nonexistence with a Keep Out sign. At least I don't see how. That's why I've been interested in that pre-Socratic dude who said there's no such thing as nothing. And from the standpoint of physics an absolute vacuum doesn't look like anything real. The concept seems to negate itself.

[Cato]

      A Dyson Shell or some other megastruture seems more likely than extinction.

      The question of whether life has meaning if it comes to an end doesn't really disturb me. As individuals it comes to an end for everyone. Meaning is a product of our kind of life, and if there is no such life there is no question to ponder. I do wonder what it would be like for the last generation of intelligent beings looking at imminent extinction. They may have a very different understanding of time than we have, though. Even for us there is something a little odd about putting the emphasis on the future alone, as though that was the sole measure.

      Maybe it doesn't make any more sense to see the "end of time" as an actual boundary between existence and....what?.....as it is to see a physical boundary between the Universe and.....see, it doesn't really work there, either. You can't have a fence between existence and nonexistence with a Keep Out sign. At least I don't see how. That's why I've been interested in that pre-Socratic dude who said there's no such thing as nothing. And from the standpoint of physics an absolute vacuum doesn't look like anything real. The concept seems to negate itself.

An interesting - some would say "crackpot" - hypothesis comes from Tulane professor of Physics Frank Tipler in his The Physics of Immortality, wherein he is confident that life will be able to transfer itself as a technological emulation and seize control of the forces of the Universe, thereby allowing a re-animation of all life and a re-creation of the Universe's history.

In essence, it is animism, where God is inside a Humpty-Dumpty Universe attempting to unify itself throughout Time.

Tipler melds the theology of Teilhard de Chardin with modern cosmology and quantum mechanics: the scientific community in general does not accept his claims.

[drogulus]

Tipler melds the theology of Teilhard de Chardin with modern cosmology and quantum mechanics: the scientific community in general does not accept his claims.

     I thought it sounded familiar, like the Omega point where everything finally becomes God after keeping us all in suspense.....for all it's crackpottery I always liked one thing about the Teilhardian thesis, that it actually observed the basic evolutionary principle that meaning, purpose and intelligence is a product rather than the cause of a Universal evolutionary process. Otherwise it's Looney Toones, I guess.