28 Nov 11
Originally posted by RBHILLWe haven't even ruled out life on the various planets and moons in our own solar system. As for planets and moons around other stars, we have not yet imaged a single one clearly enough to even rule out a thriving civilization.
80% of the Universe has been looked at so far, so chances are the other 20% has no life.
29 Nov 11
2 edits
Originally posted by joe shmoWhy do you think fear is involved? Are you afraid of being alone in the universe?
What are you afraid of?
Granted, the O.P.'s question is phrased in an awkward manner. Perhaps he's trying to pose Fermi's paradox.
I must say, it does seem a little odd to me that if intelligent alien life exists, we haven't detected it yet. I think it's important that people keep in mind that the theory that intelligent life exists is only a theory -- and one without a shred of evidence.
Nothing wrong with a little healthy skepticism, is there?
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29 Nov 11
2 edits
Originally posted by WoodPushThere is an important distinction to be drawn between life in the universe, and in our galaxy.
Why do you think fear is involved? Are you afraid of being alone in the universe?
Granted, the O.P.'s question is phrased in an awkward manner. Perhaps he's trying to pose Fermi's paradox.
I must say, it does seem a little odd to me that if intelligent alien life exists, we haven't detected it yet.
I think it's important that people keep in mind t ...[text shortened]... thout a shred of evidence.
Nothing wrong with a little healthy skepticism, is there?
The chances of us being the only intelligent life in the universe are effectively zero.
The universe is just so vast, and the number of possible places for life to form and evolve so
huge, that its effectively certain that alien life exists elsewhere.
However our galaxy, while still vast, is immensely smaller than the universe as a whole and while
still unlikely, it's conceivable we are the only currently present intelligent life in the galaxy.
However we haven't searched 80% of our galaxy (or our own solar system even), let alone the
universe.
If the OP wants to discuss Fermi's paradox, or if you or anyone else does, then say so.
I for one would be more than happy to discuss it.
There is no need to post a cryptic, half formed, controversial statement to start an interesting debate.
EDIT: Also some might be taking the OP's known opinions and theology into account when responding.
30 Nov 11
Originally posted by WoodPushGiven the vast distances, the limit of light speed and the length of time it takes for intelligent life to develop I would think it VERY ODD if intelligent alien life were detected!
Why do you think fear is involved? Are you afraid of being alone in the universe?
Granted, the O.P.'s question is phrased in an awkward manner. Perhaps he's trying to pose Fermi's paradox.
I must say, it does seem a little odd to me that if intelligent alien life exists, we haven't detected it yet. I think it's important that people keep in mind tha ...[text shortened]... thout a shred of evidence.
Nothing wrong with a little healthy skepticism, is there?
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30 Nov 11
Originally posted by wolfgang59Hmmm, less relevant perhaps than the length of time for intelligent life to develop is how long it lasts.
Given the vast distances, the limit of light speed and the length of time it takes for intelligent life to develop I would think it VERY ODD if intelligent alien life were detected!
Solar systems like ours are thought to have formed billions of years before ours and so if they took a
similar length of time to develop intelligent life (and it's entirely possible that it could take less time,
we have no reference as to how long we took vs the average) then that life could potentially have
had billions of years to colonise the galaxy, which is plenty to colonise the entire thing even with sub
light speed travel times.
Given that aliens don't appear to be here it's probably safe to assume that intelligent life has a lifespan
of detectability. The question is how long that lifespan is.
30 Nov 11
Originally posted by WoodPushI assume, you mean intelligent alien life that has got to the technological stage of transmitting radio waves? Remember that man has been as intelligent as he is now for about 50,000 years, and only in the last 200 years or so has he been transmitting anything that would be detectable.
I must say, it does seem a little odd to me that if intelligent alien life exists, we haven't detected it yet.
But even our civilizations current transmissions are not that easy to detect.
Can anyone here give an estimate of what percentage of our galaxy we have searched for basic terrestrial radio signals?
My first guess would be that we haven't yet ruled out the nearest star.
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30 Nov 11
Originally posted by twhiteheadWell the place to go to find that out would be SETI.
I assume, you mean intelligent alien life that has got to the technological stage of transmitting radio waves?
Remember that man has been as intelligent as he is now for about 50,000 years, and only in the last 200 years
or so has he been transmitting anything that would be detectable.
But even our civilizations current transmissions are not that eas ...[text shortened]... trial radio
signals?
My first guess would be that we haven't yet ruled out the nearest star.
I don't know over what kind of range they could detect the alien equivalent of tv signals,
but I am pretty sure they have ruled out our nearest neighbours.
However they are mainly looking for signals actually intended to be detected by us, and
for most of their history they have been technologically limited to searching a narrow frequency
band and thus have had to guess what frequency the aliens would pick to broadcast on
and hope.
Now they are gaining the ability to scan more frequencies and can broaden their search,
but even if aliens were broadcasting to the galaxy in an attempt to make contact it's not certain
that they would do it via radio waves.
If it is possible to transmit (or travel) information at FTL speeds then they would almost certainly
be using that. Even if that's not possible, they may prefer the higher data rates of different frequencies.
And it's entirely possible that they don't broadcast the the galaxy at all for fear of relativity bombs.
Assuming the OP wasn't completely pulling figures out of his posterior, it's possible that 80% of the sky
has been searched for signals, but only with limited sensitivity, on a limited frequency range, and thus
far from conclusive.
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01 Dec 11
Originally posted by googlefudgeI would dispute this. Exactly because the universe is so vast, and we've seen so little of it, and only a single planet up close - and that planet seems to be exceptional - that the chance of us being alone in the universe are neither zero, nor one, nor anything in between, but completely unknowable.
The chances of us being the only intelligent life in the universe are effectively zero.
The universe is just so vast, and the number of possible places for life to form and evolve so huge, that its effectively certain that alien life exists elsewhere.
We have no serious way of estimating the odds of life existing elsewhere in the universe. No experiment we have done on Earth has a real meaning for the rest of the universe, if only because Earth is unique in one fundamental way: we already know it has life on it. No formula we can devise has any meaning until we go out there and gather some real data.
All we've done to date is have a peek at some tiny portion of close-by stars through squinted eyes. The results are highly interesting, but as far as a prediction worth printing is concerned, they're like saying all oceans are always near freezing after dipping your toes in off Newfoundland.
The Drake "equation" is particularly ridiculous. It purports - if not originally, then certainly as it is currently used by "cosmobiologists", the most laughable and Readers Digest-like of cryptobiologists - to give a scientific estimate of the number of civilisations out there, but only at the first two factors can we currently have reasonable guesses - and those are constantly changing as science progresses! The rest of the factors, well, they range from nothing better than semi-scientific speculation to complete wild-arsed thumb-in-wind work.
We might as well say that the chances of intelligent life outside Earth are zero - we have never seen any other civilisation except for ourselves - as one - we have only ever seen one planet up close, and that is teeming with the buggers. But if we don't want to prove that there is preciously little intelligence on Earth as well, what we ought to say is that, frankly, we haven't the foggiest.
Richard