Life Out There

Possible but unlikely to be similar to us (humans) due to variations caused by evolution over many millennia (although it depends on your definition of 'similar').

Like the evolution of language there are just to many variables that would result in major differences, even when starting with completely identical human test groups, worlds, conditions, etc.

No matter how optimistic you are I don't think someone like Luke Skywalker is living in a galaxy far away.

Hey, where did you get that notion from? And by the way, in case you've forgotten, Luke Skywalker's my son .

There is intelligent life in the universe. It has used this planet for its loony bin.

Not really. But your use of the word possible rather than likely does make a difference that improves the odds. However, you have framed the essential anthropic question in cosmology. Rather than me blather, here's an authoritative site.

Here's a very brief excerpt from http://www.anthropic-principle.com/primer.html

"Let's look at an example where an observation selection effect is involved: We find that intelligent life evolved on Earth. Naively, one might think that this piece of evidence suggests that life is likely to evolve on most Earth-like planets. But that would be to overlook an observation selection effect. For no matter how small the proportion of all Earth-like planets that evolve intelligent life, we will find ourselves on a planet that did (or we will trace our origin to a planet where intelligent life evolved, in case we are born in a space colony).

"Our data point—that intelligent life arose on our planet—is predicted equally well by the hypothesis that intelligent life is very improbable even on Earth-like planets as by the hypothesis that intelligent life is highly probable on Earth-like planets. This datum therefore does not distinguish between the two hypotheses, provided that on both hypotheses intelligent life would have evolved somewhere. (On the other hand, if the "intelligent-life-is-improbable" hypothesis asserted that intelligent life was so improbable that is was unlikely to have evolved anywhere in the whole cosmos, then the evidence that intelligent life evolved on Earth would count against it. For this hypothesis would not have predicted our observation. In fact, it would have predicted that there would have been no observations at all.)

In my mind, This boils down to a statistical sample size problem. Who makes grand inferences / refutes null hypothesis from a single sample?

milo

Eyes.

Weird things on earth have eyes.

Forget about everything else but eyes.

Depends, in my opinion (not exactly a wise learned one) yes its possible, but if you speak to some statisticians/biologists/astronomers etc. they will tell you its a wonder we are even here, some believe its merely a fluke that life beyond single cell organisms exists, and some say its less than 1 in 100 trillion that life exist on any planet (seems a hell of a small chance to me). Then theres the theologists which will more times than none tell you no way. I think there is somethign else though, not close to human, and probably not little green men with oval black eyes, but rather some exotic plant like creatures (one could only hope) or more likely new forms of bacteria.

Someone should ask the dolphins, if anybody would know they would........42

It is only reasonable to postulate that at some time or another a possibility exists for life on another planet. As to the form of that life, we have very little capacity to anticipate what we may be able to find. Try to imagine what it must have been like for the native people of the America's when the explorers from Europe arrived. At least the explorers looked a lot like the natives.

Now, imagine finding another earth like planet covered with great gigantic creatures (or dinosaurs). While that would count as "life" on another planet, I don't think that would be counted as intelligent. I'm not sure I would want to be the first human to initiate contact with a bunch of overgrown reptiles.

Humans have been occupants of this planet for a relatively short time. The dinosaurs ruled the earth for 165 million years and their impact on the environment is considered to be negligible. But my point is that if one discovers an earth like planet, there is no way to predict what condition it may be in.

Few people realize how special this little blue-green ball is with respect to other planets. For instance, a variation of our orbit (around our very own star) of 1% would make this planet uninhabitable. Without the tilt of the earth we would have no seasons. Instead there would be habitable zones and uninhabitable zones. Without a magnetic field, all life would be exposed to deadly radiation. Without the moon(s) there would be no tide and the oceans would be less productive. Also without the moon, the planet would be subject to every asteroid that got caught up in the gravitational field.

Imagine what life would be like if the rotation of the planet was very slow or very fast. What would it be like if the planet rotated in just 8 hours? What would it be like if the planet rotated only once in six months? What would life be like under different conditions? It may be more likely to find a planet where intelligent life had flourished and then been wiped out. Or it may be possible to find a planet where intelligent life is just beginning. So the point is that the variables are much greater than most people realize. Every day is a gift and so few of us appreciate it. A catastrophic event may occur at any time and we could do nothing about it. So enjoy life, because there are no guarantees anywhere!