Intelegent life in the Universe, how common is it?

[reds4ever]

Originally posted by Dauphin


Drake's equation is not a disprovable equation. Its a probablity statement.

Put garbage in you get garbage out.

Im not getting into a semantics debate, its a load of cr@p spouted when SETI needs funding.

Like I said as soon as your first variable is 'number of stars in the galaxy' your onto a winner.

[Dauphin]

It is an issue of distance

You just shifted a goal post. You say "if they sent a probe that passed our sun to find a life-bearing planet" and then say "then the likelihood for them to have sent a bunch of probes our way... is remote".

As I have said before its not how long the probes have to travel. The probes would have had time to get here. The problem is that there are a lot of planets to inspect, that the chance of us knowing/detecting when a probe comes is remote, and the chance of a probe arriving here at the same time as we pop into a galactically aware world is small.

[Boris Godunov]

Distance is STILL an issue, because at greater and greater distances, the usefulness of them knowing about us is diminished. If they're 10,000 ly away, then it would take 100,000 years, at the LEAST, to get a probe here, and then how many more years for it to get back to them, and then how many more years for them to do something about it? Add up all those years and you get a huge time span for them to get info about just one system 10,000 ly away. But if they were 4 ly away, then those problems would be much less. We would, probably, have meaningful contact with them by now (assuming they were very advanced). So distance is indeed a factor, because the further away you are, the feasability of meaningful contact diminishes.

Timing and detection on our part are big problems, too, yes. I've been saying that. But you can't just dismiss vast interstellar distances as having no consequence to contact.

[reds4ever]

Theres no way we'd spot a probe if something the size of Sedna has taken us this long.

[Dauphin]

Originally posted by Boris Godunov


Distance is STILL an issue, because at greater and greater distances, the usefulness of them knowing about us is diminished. If they're 10,000 ly away, then it would take 100,000 years, at the LEAST, to get a probe here, and then how many more years for it to get back to them, and then how many more years for them to do something about it? Add up all those years and you get a huge time span for them to get info about just one system 10,000 ly away. But if they were 4 ly away, then those problems would be much less. We would, probably, have meaningful contact with them by now (assuming they were very advanced). So distance is indeed a factor, because the further away you are, the feasability of meaningful contact diminishes.

Timing and detection on our part are big problems, too, yes. I've been saying that. But you can't just dismiss vast interstellar distances as having no consequence to contact.

We are not discussing meaningful contact, we are discussing detection.


Edit - I'm not dismissing the vast distances as being important for any meaningful contact. Put it this way. Assume that every star was only a years travel distance from any other. That change would in only a minor way effect the probability that we would have detected a probe coming from another star. This is because the number of potential stars that probes could have been sent to is so large that we may not have been sent one, even if we were sent one it could have been at any time in history, and even it occured in the last 100 years it would still be highly unlikely that we would have been able to see it.

[Atahualpa]

At first I thought this is a Europe Bashing Thread (Europa is german word for Europe)

[Last Conformist]

Originally posted by reds4ever


Like I said as soon as your first variable is 'number of stars in the galaxy' your onto a winner.

I, based on my encyclopaedic knowledge of just about anything, guestimate the chance of intelligent life to rise on an earth-like planet to be zero. Remind me, what is then the expected number of technological civilizations in the galaxy at any one point in time?

[Last Conformist]

@Boris Gudonov: If the alien race was actively searching for other intelligences, they would presumably leave a probe in each system potentially capable of supporting life permanently.

[:) Smiley]

What's with the idea that it'd stop with a probe? If aliens behave in the ways we know intelligent life (namely us) do, following the probe will be subdivisions, Hard Rock Cafes, bad movies, and other hard-to-miss things.

[Last Conformist]

They might be figuring that the market is not yet mature for their products.

[reds4ever]

Originally posted by Last Conformist

I, based on my encyclopaedic knowledge of just about anything, guestimate the chance of intelligent life to rise on an earth-like planet to be zero. Remind me, what is then the expected number of technological civilizations in the galaxy at any one point in time?

Now thats just being lazy LC, check my original post I stipulated >1

EDIT: To save you wearing yourself out!

Quote: When your first variable is such a large number (ie stars in the galaxy), all the other numbers can be pretty much anything you like (>1) and you'll get an answer that tells you the gaxaxy is teeming with life!

[Last Conformist]

Exactly what formulation of Drake's are you using? In the one I'm familiar with, only the first and last factors can be >1.

(Actually, the version I'm familiar with doesn't feature the total number of stars in the galaxy at all, but could easily be modified to do so.)

[DanS]

Please note that I'm not ruling out the possibility that human beings are the diaspora (probes) and that we're looking at the best evidence of sentience in other solar systems when we look in the mirror.

It would seem to take an alien species that has a unique sense of humor to send us out as probes, but I'm not ruling out the possibiity.

What's with the idea that it'd stop with a probe? If aliens behave in the ways we know intelligent life (namely us) do, following the probe will be subdivisions, Hard Rock Cafes, bad movies, and other hard-to-miss things.

Heaven help them (and us), if true.

[reds4ever]

It's either % of the total number of stars in the galaxy that are capable etc..... or you can just cut to the chase and say number of stars in galaxy capable of etc....., either way it's the same, I suppose the second way cuts out a 'calculation'.

My point remains the same though the initial figure is so high that it's hard to get a result that says we're the only life in the galaxy and small differences in the values of the other guesses skew the end result wildly

[Last Conformist]

Originally posted by reds4ever
It's either % of the total number of stars in the galaxy that are capable etc..... or you can just cut to the chase and say number of stars in galaxy capable of etc....., either way it's the same, I suppose the second way cuts out a 'calculation'.

My point remains the same though the initial figure is so high that it's hard to get a result that says we're the only life in the galaxy.

In the version I familiar with, the first number is the number of Sun-like stars (F, G and K main sequence dwarfs, I guess) born in the galaxy per year. This is ten or so.