Aliens by 2031!

Over at CNN there is a story that Russian astronomer Andrei Finkelstein says aliens are out there and he expects we'll encounter them within 20 years.

Well to say the least, that would be quite a story.

Folks I've been a SciFi fan since I was a kid, long enough to remember when the term "SciFi" was deemed somewhat offensive (we preferred "SF," pronounced "ess-eff,") and I hate to say this but I find this argument unconvincing. With the proviso that the journalist was, 1) almost certainly not terribly scientifically literate, and 2) whatever Finkelstein said was filtered through a translator who probably wasn't either.

There's a few problems with this story, which tends to happen when you have journalists with time on their hands writing sensationalist science stories. For one, the story doesn't define "encounter."

Does this mean detecting radio signals from deep space? Archeological evidence of past visits by extraterrestrials on earth, or more likely the moon? (More likely because artifacts left in the lunar environment would have a better chance of surviving for possibly millions of years.) Or does he expect a UFO to land in Red Square?

Quoting from the story, "The astronomer added that 10 percent of known planets circling suns in the galaxy resemble Earth, making life on such planets highly likely..."

Dig into that one and you'll find that "resemble Earth" means planets that resemble earth about as much as Venus does, with its poisonous atmosphere 100 times thicker than ours and surface temperatures hot enough to make molten lead run in rivers.

However the planets around other suns discovered so far are almost certainly a tiny fraction of those that exist, so there's hope.

Or maybe not. Scientists looking at Earth and its place in the solar system are coming to realize just how many conditions had to be just right for our life-friendly environment to exist and maintain stability long enough for, 1) large complex life forms to arise, 2) at least one species to evolve intelligence, 3) that intelligent species to create scientific/industrial civilization, and 4) that civilization to last long enough to invent space travel and/or radio transmission. There has to be a Jupiter-sized planet at just the right distance to sweep most of the dangerous meteors and asteroids out of nearby space. The Earth had to have a relatively huge moon to stabilize its orbital wobble so the climate remains relatively stable over time, etc.

After an initial period of optimism in the 20th century, a fair number of scientists began to suspect there may be a lot of bacteria out there, but maybe not many environments full of those large complex multi-celled organisms.

Back in the 1950s scientist Enrico Fermi, who led the project to create the first nuclear reactor, asked the question now known as the Fermi Paradox.

Fermi said, there are an estimated 200–400 billion stars in the Milky Way galaxy. Assume only a small fraction of them have planets, and intelligent life occurs on only a fraction of these planets, and technical civilization arises among only a fraction of these species. Even if that assumed fraction is as little as a tenth, or even a hundredth, the number of civilizations in the galaxy must still be enormous.

This led Fermi to ask, "So where are they?"

We've now been actively listening for radio signals from other civilizations for about 50 years, and heard nothing. Scientists call this The Great Silence, and it's beginning to worry some.

Science/SF writer Arthur C. Clarke put it, "Two possibilities exist: Either we are alone in the Universe or we are not. Both are equally terrifying."

One of the scary speculations has to do with what scientists involved in SETI (Search for Extraterrestrial Life) call "filters." This is the notion that at every step in the progress towards intelligent species with technic civilization, there are hazards along the way.

We've encountered some of the filters already. To our knowledge two intelligent species have arisen on Earth, our noble selves and Neanderthals. Only one of us made it so far, and we don't know what still lies ahead for us either. Maybe the first space-traveling civilization decided the galaxy was only big enough for themselves and made it their policy to nip any competition in the bud as soon as it came to their attention.

Or for a more benign possibility, maybe we are the first intelligent species advanced enough to begin the exploration of the universe. And why not? There had to be a first, how do we know it's not us?

We live in a fantastic time where we can actually ask such questions with at least the hope of getting answers within our own lifetime.

And as Clarke also said, "If we have learned one thing from the history of invention and discovery, it is that, in the long run - and often in the short one - the most daring prophecies seem laughably conservative."