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"There are as many living worlds as there are grains of sand on a beach."
-can't remember where i heard that
 
Once you've comprehended the images from the Hubble Deep Field and Ultra Deep Field projects you won't think for a minute there's nothing out there.

An estimated 10,000 galaxies in a part of the sky that appeared totally dark.


No. Us humans must co-exist in this universe with scientologists.

I lol'd.
 
My guess is that we're not alone, but I don't consider the statistical argument to be a proof, just a good argument in favor of the prospect.

When a so-called proof begins like this:
Suppose one out a million planets like ours has life, and one out a million solar systems with a sun like ours has a planet like ours, and one out a million stars is like our sun...​
not only does it pick unsubstantiated percentages but it assumes that each of these conditions is uniform throughout the universe and uncorrelated with the other conditions. Maybe the rules are different in other galaxies. We don't really know.

Well, more correctly, you don't really know. I've been to other galaxies to check them out, but I'm not allowed to talk about it.
 
. . . it assumes that each of these conditions is uniform throughout the universe and uncorrelated with the other conditions. Maybe the rules are different in other galaxies. We don't really know.
Perhaps, although in science one must not assume there is anything special about our current position in the universe. In other words, there's no reason to believe the universe isn't distributed in a uniform manner. Also, it's my understanding that this has been confirmed through observation (namely data collected by Hubble, Chandra, and Spitzer space telescopes).
 
Okay, given that our Solar System is quite young. And that it only takes a few millions years for intelligent life forms to evolve. We have trillions^2 of stars out there, some with planets, some of those with planets that could harbour life. Life on any of those planets could have started billions of years before us.

So where are they? Maybe they all suffered from the same problems we face, they over populated, ran out of food, and didn't get enough time to colonise other planets.

With our current technology, we can send someone into space with about $100 million per person. It costs about $1million per kilogram of cargo (made that one up). So how are we expected to put up enough resources to make...say Mars, livable?

Sorry about the tangent.

Why don't we wait for them to answer that for us? Higher beings 'discover' those below them. Like humans discovering new species of animal. Tech-superior aliens will 'discover' us in due time.

In the words of Kent Brockman: "And I, for one, welcome our new insect overlords" :D
 
it only takes a few millions years for intelligent life forms to evolve.

That's not true. It took 2 or 3 billion years to get from the origins of life as we best understand it - to the first multi-cellular organism.

In the approx 4.6 Gyear history of life on earth - 'animals' have been around for the last 600 million years.
 
At least 10 intelligent civilisations have existed at sometime elsewhere in the universe.
Watch Carl Sagan explain Drakes Equation here (from TV show 'Cosmos')


"There are as many living worlds as there are grains of sand on a beach."
-can't remember where i heard that

Sounds like a variation on something William Blake wrote that Jacob Bronowski used as an intro/outro for his TV series 'The Ascent of Man'.

But it could be from 'Days Of Our Lives':D
 
Drakes Equation

Unfortunately ( and I'm very fond of Carl's stuff ) - we're not even confident on the orders of magnitude for many of the Drakes Equation valuables. Indeed - some of them are guesses to SEVERAL orders of magnitude.

Putting a value on 1/2 for life occuring on a habitable planet is a complete guess. It could be 1/100,000,000 - 1/2 is almost certainly an upper limit, not a likely value ) .

Almost all the extra-solar planetary systems we have found are not going to have earth like planets. Rapidly orbiting super-jupiters and Earth like orbits are mutually exclusive. Now, this is almost certainly a symptom of how easy the super-jupiters are to find, and how hard it would be to find an extra-solar Earth ( COROT and Kepler will hopefully tackle this one )

You can put entirely plausable values into Drakes equation and get an answer that's just a tiny tiny fraction of 1, or more than a million.

As I said earlier - currently - we just don't know.

You can guess with the tool at the bottom of this page - http://www.activemind.com/Mysterious/Topics/SETI/drake_equation.html

But like Carl - you'll just be guessing.
 
Carl is guessing, 1/2 is very optimistic.
I like his enthusiam.

It's happened once (us), so that's telling me it could happen twice.
I'm optimistic too:D
 
I honestly think it's quite likely there is life very close to us, let alone out in the far reaches of the universe. The right elements are all here in our part of the galaxy, and we already know there are quite a large number of planetary systems within a 100 light year radius of Sol.

As for there being intelligent life, well that's another thing entirely, but until planet Earth produces some we're not really in a position to judge are we.
 
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