Stephen Hawkings & AliensFollow

LONDON - British physicist Stephen Hawking says aliens are out there, but it could be too dangerous for humans to interact with extraterrestrial life.

Hawking claims in a new documentary titled "Into the Universe With Stephen Hawking" that intelligent alien life forms almost certainly exist — but warns that communicating with them could be "too risky."

"We only have to look at ourselves to see how intelligent life might develop into something we wouldn’t want to meet," Hawking said. "I imagine they might exist in massive ships ... having used up all the resources from their home planet. Such advanced aliens would perhaps become nomads, looking to conquer and colonize whatever planets they can reach."

The 68-year-old scientist said a visit by extraterrestrials to Earth might well be like Christopher Columbus arriving in the Americas, "which didn't turn out very well for the Native Americans."

He speculated that most extraterrestrial life would be similar to microbes, or small animals. Microbial life might exist far beneath the Martian surface, where liquid water is thought to trickle through the rock. Marine creatures might also conceivably live in huge oceans of water beneath a miles-thick layer of ice on Europa, a moon of Jupiter.

But if a scientific census could be extended beyond our solar system to the rest of the Milky Way and beyond, the odds in favor of life's existence rise dramatically, Hawking said.

"To my mathematical brain, the numbers alone make thinking about aliens perfectly rational," he said. “The real challenge is to work out what aliens might actually be like."

"If the same holds for intelligent aliens, then they might not last long," he said. "Perhaps they all blow themselves up soon after they discover that E=mc2. If civilizations take billions of years to evolve, only to vanish virtually overnight, then sadly we've next to no chance of hearing from them."

While that may be true, that's only the planets that originated life "by accident". We all ready know of organisms that can survive in space, so they could have spread via comet or meteor from pretty much anywhere. This would also, presumably, speed up evolution. AS Hawkings says, even with astronomical odds, someone always ends up hitting the lottery. And there are billions of galaxys, with billions of stars with planets "hitting the lottery" in order to get life as we know it.

And there very well could be life that could exist "not as we know it" (Carbon Based, Energy/food/water fueled), Hawkings hypothesizes the possibility of silicone based & even weirder (stuff that could live in star, which is kind of poetic given Carl Sagan's thoughts on stardust)organisms.

There is a formula that hypothetically calculates the probability of life evolving in any given galaxy, but I can't find or remember it. I originally saw it while delving into Wikipedia articles of very large numbers.

I am not smart enough to play in Hawking's sand box. That being said, I'm not sure the math works out for me.

If you use very conservative number to come up with 1*10^22 stars in the universe (the number is likely closer to 5*10^22) and take a simple average of the most liberal of estimates on the likelihood of random sequencing of amino acids to create life (1:1*10^20) you get some long odds. Factor in 13 billion or so years to slam those complex organic molecules together (assuming the same billion years it is estimate to have taken on Earth for the first pre-cells to come together) and you have the potential for maybe a couple thousand rocks in the universe to have simple organisms on them. I don't doubt that there's life out there, but I am less than enthusiastic about the odds of ever worrying about getting intergalactic syphilis from Antaran Nomads.

Our sun is just under 5 billion years old. Earth is about 4.6 billion years old. Fossilized microbes have been found in rocks up to 3.5 billion years old. Therefore, life took about 1 billion years to come into existence on this planet, a far cry from "13 billion or so years to slam those complex organic molecules together".

There are a lot of numbers out there, and nobody knows the exact truth, but it's easily observable that people with a greater faith generally choose numbers on the most conservative end of the spectrum (those that are least likely to allow for extraterrestrial life), while people with a lesser faith generally go with more liberal numbers (and a higher chance of extraterrestrial life). Nobody on this forum (including me) is qualified to make a valid claim either way, so I'll just roll with the numbers given to me by some of the world's top astrophysicists and astrobiologists, which are generally more liberal than yours.

I'm curious about naysayers of possible extraterrestrial life in general though. IF life is discovered, say, under Mars' surface or Europa's potential underground oceans, how does that affect your perception of the numbers? Wouldn't that be the equivalent of neighbors winning powerball at the same time? Probability is still just probability, but wouldn't that seem suspect to the general expectations of chance?

but if you have been given better numbers by preeminent astrophysicists and astrobiologists, by all means let's see them.

Either you're not reading or your not addressing me, because I clearly stated I don't doubt that there's life out there.

There is probably intelligent life out there, we will probably never encounter it, ever.

Somebody just discovered the movie "Independence Day".

If that was actually a problem for you, perhaps you should limit your movie-going experiences to documentaries.