There is plenty of life on this planet, yet we are still alone, in that we can't have any meaningful communication with a single other species.

What is it going to feel like when we find little cockroaches on Mars, or fish in the oceans of Europa? It's going to be profound in that we're not the only place where life has developed. It will be scientifically interesting because we will want to know how life developed differently, is there an alternative to DNA, for example. Is it non-water based, non carbon-based?

But many many people are going to have a 'meh' reaction. We have plenty of life surrounding us that we can't talk to. What's the big deal.

What if life developed on the remote planet that is 99% as sophisticated as us, like chimps for examples, but didn't make the final step to civilization because they didn't have opposable thumbs or something. They won't be able to comprehend us, or what we are.

There's a recent Onion article covering this topic:

"Nation Demands NASA Stop Holding Press Conferences Until They Discover Some Little Alien Guys"

http://www.theonion.com/article/nation-demands-nasa-stop-hol...

> in that we can't have any meaningful communication with a single other species.

I don't think so. I think anyone with a pet would disagree. There is more to meaning than abstract concepts. There is more to communication than mutually understood symbols.

Then again there's more to "meaningful communication" than a dog who adores its owner...

Let me guess: You've never had a dog.

We had 3 dogs growing up as a kid (2 spaniel brittons and a german shephard).

Myself, I have 2 cats (persian + siamese).

But it's not the kind of meaningful communication the parent refers to, obviously.

Starting with the postulate that nature abhors a vacuum of any kind, I think it wouldn't be too far-fetched to posit that higher orders of life can exist across computer systems, their mandibles invisible tendrils interconnecting billions of organic beings interfaced via an optical-aural-touch I/O system. Its metabolism at the low-level a complex reciprocal action composed of dopamine response from its base food-source transmogrified into encoded information via physical input excreted from the cerebrum of a human.

Dang, I just fed the beast.

It's also important to think about the implications of articles such as "What's 96 Percent of the Universe Made Of? Astronomers Don't Know"

http://www.space.com/11642-dark-matter-dark-energy-4-percent...

If 96% of the universe consists of dark matter, we should start with the assumption that 96% of life is built of dark matter. Disproving that becomes the work of exploration, but that is the obvious default starting assumption.

Dark matter is estimated at 23% of the universe, not 96%. The other 73% is dark energy.

And I'd argue that it's reasonable to presume that life would be "normal" matter, simply because life requires structure, which requires both attractive and repulsive forces over nontrivial distances. Dark matter, by definition, does not interact electromagnetically; the strong and weak nuclear forces are too short-range to give rise to meaningful structures; and gravity provides only attractive force, not repulsive force.

More generally, a certain amount of humility and skepticism about these issues is good, but I have almost a pet peeve sort of relationship with people who think we must profess total ignorance. We really don't. If they live in this universe, they play by the same rules we do, and that will shape them every bit as much as it does them. While I have no reason to believe that in the style of pulp sci-fi we will stroll out into the universe to find a universe of interbreedable humanoids, there's really no reason to believe that we will understand nothing about the aliens.

In fact it's sort of a violation of the general Copernican principle... we are not so special that we will be uniquely unable to understand anybody else. We are, probably, fairly normal.

I had this stray thought the other day, that dark matter is really the rest of civilizations shielding and hiding themselves from us and other unevolved civilizations. That's why we cant find life in the galaxy, and once its unblocked we will see all of the 1000s of civilizations that exist.

It is possible that dark matter interacts with forces that we have not discovered.

We have been able to make some inferences about the structure of dark matter, but I believe our methods are not precise enough to detect small features.

If we had no prior knowledge, then that would be a safe assumption. However, we have the prior knowledge that we exist as life of normal matter, which biases the probabilities to normal matter being more supportive of life.

How do we know 'life' can't evolve in some other way? I find it interesting how scientists are always looking for 'earth' like planets... then again it is a good place to start.