How are we going to talk to the neighbours?

Non-geeks will not likely enjoy this entry; you should skip to the previous one and take the quiz. Maybe I’ve been particularly bored but I’ve been thinking about life on other planets again. It seems to me a mathematical impossibility that there isn’t other life in the Universe.

The International Astronomical Union estimates there to be 70 sextillion stars in the known Universe, minimum.

Cosmologists now say planetary formation is common, most stars seem to have planets, but even imagining there is only 1 planet per million stars, and that only 1 out of every million planets is capable of supporting life that leaves 70 billion planets capable of supporting life.

Even if only 1 out of every million planets capable of supporting life happens to develop complex life, that still leaves, by the most conservative estimate possible, 70,000 planets with complex life forms in the known Universe.

Some respected estimates, such as that of Frank Drake (of the famous Drake Equation), even put the potential number of “communicating civilisations” (ie. intelligent) in our Galaxy alone at 10,000, which would mean there were trillions in the known Universe!

If the development of life on Earth was basically an accident and there are 70 billion planets with similar conditions, how is it possible that ours is the only place it happened? And if it happened one single other time wouldn’t that prove it’s not a once in a Universe anomaly? If it’s happened more than once it likely happened many times.

So it seems almost certain there is (or was) other life out there, and probably many occurrences, the only question then is the whether it’s life that we’d recognise and whether we could ever communicate with it.

For this the same basic math estimations work in reverse. Even if there are billions of intelligent civilisations out there the odds that we’d ever communicate with them starts to look small. SETI (Search for Extra Terrestrial Intelligence) searches for radio signals and while that is the most logical form of contact, what are the odds that a civilisation would be using the same technology at the same time—the history of human high-tech being the tinniest blip of a micro-second on the scale of cosmic history.

Human’s have only been using radio signals for 100+ years and may very well move onto something better and different within 100 years. Earth is estimated to be about 5 billion years old, the Universe anywhere from 12 to 20 billion years old. Two hundred years is not a long time on that kind of scale (comic understatement). That doesn’t even take into account the complicating factor that it takes light 50,000 years to cross half our own little Galaxy, therefore the window of opportunity for civilisations to communicate seems small.

Also, the nearest Galaxy is 2 million light years away, meaning if we got a signal from a roughly technologically equivalent civilisation, they would be 2 million years more advanced when we recieved it—or long gone of course. Considering all of human history is only about 100,000 years what would a civilisation 2 million years more advanced look like? Let alone a billion years more advanced. I don’t know what any of this means, just some thoughts, just having fun blathering. I’ll stop.