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Topic:
Extraterrestrials: real, or a hoax? v.2
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Jabbadabbado
Title: Senate Floor Moderator
Registered:
Mar '99
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Date Posted:
1/12/07 2:33pm
Subject:
RE: Extraterrestrials: real, or a hoax? v.2
- Date Edited:
1/12/07 2:37pm (1 edits total)
Edited By:
Jabbadabbado
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This is all pretty exciting stuff I think. Sort of summing up the academic approach to the problem:
Copernican principle: (mediocrity principle): earth-like planets are a common phenomenon
Drake Equation: estimate for the number of advanced civilizations in the Milky Way, starting from the number of stars in the galaxy, then looking at number of sun-like stars, with earth-like planets, and so on. Mostly a bunch of wild guesses, concluding that there are "plenty" of intelligent species in our galaxy.
Fermi's Paradox: "if they're out there, why haven't we seen any evidence of their existence?"
Occam's Razor: "the reason we haven't seen any evidence is because they aren't out there."
SETI: a scientifically credible attempt to answer Fermi's paradox. So far, still no signs of life out there.
UFO sightings: nonscientific evidence of extraterrestrial life on the level of credibility with Loch Ness Monster sightings.
Rare Earth hypothesis: a critical refinement/refutation of the Drake Equation, suggesting that there may be no more than one race of intelligent beings per galaxy, if that.
Problem of scale/distance: Even if there are 100,000 technologically advanced intelligent species in the galaxy, they are likely to be so widely dispersed that interspecies communication may be effectively impossible, let alone space tourism.
Almost all rigorous thinking about the problem of ET life has been built around the idea that intelligent life only develops on earth-like planets in a somewhat earth life-like manner. If you throw out that assumption, you have almost no basis whasoever for making any kind of conjecture about the odds of intelligent life elsewhere. Absent that moment of contact, it remains a black hole of total ignorance, other than these facts: the universe is full of stars and has been around for a long time, and intelligent life has arisen at least once.
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VadersLaMent
Registered:
Apr '02
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Date Posted:
1/12/07 2:45pm
Subject:
RE: Extraterrestrials: real, or a hoax? v.2
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The only parameter for "Earth-like" is a world where liquid water is present. You can get more Earth-like: an Earth-sized world, an Earth-sized world around a yellow sun, and Earth-sized world around a yellow sun with oxygen etc. But the term "Earth-like" is just a very general term for a water where water is present.
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Jabbadabbado
Title: Senate Floor Moderator
Registered:
Mar '99
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Date Posted:
1/12/07 3:21pm
Subject:
RE: Extraterrestrials: real, or a hoax? v.2
- Date Edited:
1/12/07 3:22pm (1 edits total)
Edited By:
Jabbadabbado
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I don't want to quibble about semantics. Peter Ward's book sets just those kind of limits for a planet that can develop and sustain life. Each galaxy has a narrow "habitable zone" band. Each star has its own narrow "habitable zone." And G type stars are relatively uncommon. Using those kinds of assumptions about where life can form, the odds of intelligent life elsewhere in our galaxy are perhaps not great.
As I said, it depends on the assumptions made about how life can form.
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VadersLaMent
Registered:
Apr '02
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Date Posted:
1/12/07 4:09pm
Subject:
RE: Extraterrestrials: real, or a hoax? v.2
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There are approx 10 billion stars like ours in the Milky Way. Sometimes our Sun is called typical which is false since they only make up 10% of the stellar population in our galaxy, but 10% when dealing with numbers like these is still enormous.
I wasn't trying to get into a semantic quibble, just making a clarification.
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farraday
Registered:
Jan '00
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Date Posted:
1/12/07 9:26pm
Subject:
RE: Extraterrestrials: real, or a hoax? v.2
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Also we have absolutely no data on the odds of a life bearing planet developing intelligent life since of course we have no clue there.
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Darth Mischievous
Registered:
Oct '99
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Date Posted:
1/12/07 10:19pm
Subject:
RE: Extraterrestrials: real, or a hoax? v.2
- Date Edited:
1/12/07 10:23pm (2 edits total)
Edited By:
Darth Mischievous
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Another problem is that such a planet with life must rotate on its axis in a similar fashion to our own planet; otherwise land life similar to our own would be extremely difficult, if not impossible. Our planet would 'wobble' on its axis far too greatly to support land life were the moon to vanish.
The stabilizing influence of our rather large moon to our planet (i.e., moon to planet ratio) is probably not something that is common in the galaxy.
If there are habitable worlds in a 'green zone', it would be even more miniscule a number that would have such a set up... a midsize rocky planet with abundant water and differential elements coupled with a large moon to stabilize planetary rotation.
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DorkmanScott
Title: Manager Emeritus
Registered:
Mar '01
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Date Posted:
1/12/07 11:09pm
Subject:
RE: Extraterrestrials: real, or a hoax? v.2
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Jabbadabbado posted:
So, if you propose an extraterrestrial race advanced enough to scout out our solar system in vehicles capable of interstellar travel, dip into the atmosphere and abduct a few people/farm animals, you're indeed proposing a species so much more advanced than us, with access to an almost infinitely more powerful energy source, that the earth probably wouldn't interest them much per se, unless they have a policy of destroying any intelligent species they encounter.
And if it's a species that far advanced, we probably wouldn't count as one anyway.
M. Scott
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VadersLaMent
Registered:
Apr '02
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Date Posted:
1/13/07 5:13am
Subject:
RE: Extraterrestrials: real, or a hoax? v.2
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I see alot of Rare Earth tidbits being thrown about. Though the book has merits it is really not much more than a description of how life arose here on Earth that tries to tell the reader how life must arise here and elsewhere.
It reminds me of an article this past year that flat out stated that we will find evidence for intlligent life elsewhere within 20 years because of how advanced our computer technology will be to analyze all the data, and if we don't it means we are alone.
Well that's just stupid. If another civilization is 1,000 lightyears away and went so far as to directly send us a message in the last 100 years we won't recieve that message for another 900 years no matter how complex our computers and assuming no faster than light communications or travel.
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Any sufficiently advanced extraterrestrial intelligence is indistinguishable from God--Michael Shermer
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Jabbadabbado
Title: Senate Floor Moderator
Registered:
Mar '99
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Date Posted:
1/13/07 6:06am
Subject:
RE: Extraterrestrials: real, or a hoax? v.2
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That's a fair critique of Ward's book I think. I also agree with your comment about the limits of SETI. If, for example, we have to wait for an alien species to pick up evidence of our civilization then beam a signal for us, we could be waiting for a long time. News of our existence travels at the speed of light, and it may not be very convincing news in any case.
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VadersLaMent
Registered:
Apr '02
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Date Posted:
1/13/07 6:33am
Subject:
RE: Extraterrestrials: real, or a hoax? v.2
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Not only that, but it is my understanding that if an extrasolar civilization had a radio telescope the size of Arcebo(sp) they could not even detect us from the nearest solar system, or at least the signal would be so weak it would be overidden by other noise.
It will probably be use of an optical telescope that we will detect an Earth sized world, then a better one that may take a direct picture and check for indications of possible life. There is also a possibility of using an optical telescope to image artifical structures of large scale...say, Moon sized...which would obviously mean things with smarts on another planet.
Arcbo is of course not the limit for radio telescopes, and larger arrays are in the works, so it is still not impossible for radio to be the tool for such a discovery. We just need far bigger arrays. If we could pepper an area(On the Earth or Moon or in space) with numerous small radio dishes and cover a diameter 100 times that of Arcebo then we can extend the radio detection range out to 50 lightyears or so, 1,000 X gives us 500 lightyears, and so on. Those are approximations, I could be off a bit.
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Any sufficiently advanced technology is indistinguishable from magic--Arthur C. Clarke
Any sufficiently advanced extraterrestrial intelligence is indistinguishable from God--Michael Shermer
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Darth_wanderguard
Registered:
Apr '05
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Date Posted:
1/17/07 8:46pm
Subject:
RE: Extraterrestrials: real, or a hoax? v.2
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DarthBoba posted:
Beowulf posted:
Actually, the universe that we can see is expanding. It has been proven by astronomical observations. But we don't know exactly how big the universe is, mostly cause we can only see so far.
which means that there may be civilizations beyond our capacity to detect, for all you doubters out there. 
I like this thread; it's something that's wholly intangible, ie, no one side is right or wrong. It's less of a debate and more of an open forum for concepts & ideas.
That's why I posted it This type of thread usually makes for much more civilized discussion.
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DarthBoba
Registered:
Jun '00
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Date Posted:
1/18/07 3:59pm
Subject:
RE: Extraterrestrials: real, or a hoax? v.2
- Date Edited:
1/18/07 4:38pm (1 edits total)
Edited By:
DarthBoba
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Darth_wanderguard posted:
DarthBoba posted:
Beowulf posted:
Actually, the universe that we can see is expanding. It has been proven by astronomical observations. But we don't know exactly how big the universe is, mostly cause we can only see so far.
which means that there may be civilizations beyond our capacity to detect, for all you doubters out there.
I like this thread; it's something that's wholly intangible, ie, no one side is right or wrong. It's less of a debate and more of an open forum for concepts & ideas.
That's why I posted it This type of thread usually makes for much more civilized discussion.
Well, good job. I know my posts haven't done much more than state the obvious (:p) but that's what you get for leaving the lofty Senate open to people with GEDs.
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Beowulf
Registered:
May '99
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Date Posted:
1/18/07 9:40pm
Subject:
RE: Extraterrestrials: real, or a hoax? v.2
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I find it amusing to discuss the existence of NTIs, because it is 100% speculation and imagination. The sheer number of encounters with similarl descriptions of events should point to one of two "basic" theories:
1) There is a true unconscious connection between all humans that traces back into the stretches of genetic code that make little sense even with our current knowledge of the human genome.
2) There are extraterrestrials visiting our planet on a regular basis.
If we follow Occam's Razor, which one is the simplest?
As much as I would like to believe that we are the only "advanced" creatures in this vast universe, it just isn't realistic.
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BAR_BAR_DRINKS
Registered:
Apr '03
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Date Posted:
1/18/07 11:05pm
Subject:
RE: Extraterrestrials: real, or a hoax? v.2
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IF contact is ever made (or already has=conspiracy  ), what then?
would they bring us their god?
would they give us gift blankets?
enslave us?
hinder or help?
teach?
bring peace?
ask us to join the United Life on Other Planets Across the Universe?
.....i dunno....
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Eleventh_Guard
Registered:
Dec '05
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Date Posted:
1/19/07 7:49am
Subject:
RE: Extraterrestrials: real, or a hoax? v.2
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I would think that such an advanced culture that could contact us would be interested in us, as a curiosity if nothing else; however, if they're that advanced, we might not be that interesting after all.
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