While I Have Your Attention: Sighting aliens sits in the same bracket as seeing real Santa
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Bless them! Tomorrow night they’ll be writing their Santa notes and leaving out their reindeer food with great hopes that the elves haven’t been on strike along with the rest, so they’ll get a visit.
A young child’s unerring belief in Santa Claus includes the acceptance of improbabilities inconceivable to an adult. The sheer early lack of critical thinking lends credibility to the notion of some hoary old codger in a sleigh with reindeer visiting hundreds of millions of homes across the Earth’s 80 million square miles and delivering exactly the right present to each one.
And that’s before considering more philosophical questions like what do non-Christian households do? How does Santa manage in premises without chimneys? And don’t all these snacks make the reindeer terribly fat?
But we still give the electoral vote to kids who have spent more than half their lives believing all this.
Santa’s fictional ultra-rapid travel always reminds me of two very real questions. Do aliens exist? (Very probably). And have they visited here? (Almost certainly not).
On the first, the universe contains an estimated million billion billion stars – that’s one with 24 zeros after it – many with several planets. Now, the vast majority of these planets would not meet the very specific criteria for life to exist, but that still leaves a huge number where it might, so to me it’s all but inevitable that, somewhere, it must do.
It’s also probable that many planets have life forms more advanced than our own and hence technology that allows them to leave their immediate host enviroment. In other words they, like us, are capable of space travel. However, I think that them reaching us is as unlikely as us reaching them due to two limiting factors – the vastness of the universe and the speed of light.
Einstein showed that it’s not possible to travel faster than the speed of light,186,000 miles per second. However for practical reasons ranging from the acceleration survivable by a living body to the fuel required to drive such a space craft, reaching even an appreciable fraction of that speed would be unlikely. Then Einstein poses another problem because as any body approaches the speed of light, its mass approaches infinity, making it very difficult to accelerate any further.
Despite light taking just over a second to travel here from the moon, this is a mere snail’s pace compared with the vastness of the universe. It would take 100,000 years simply for light to travel across our own galaxy, the Milky Way, and the universe has an estimated 125 billion galaxies.
There’s one other star as close to us as 4.25 light years, so even travelling at the speed of light, it would take over four years to get there and the chance of a star that close having one of Star Trek’s “Class M planets” is very low indeed. Limited by the speed of light, and even with brand new dilithium crystals, Captain, I see no practical way of covering such huge distances within any meaningful timescale.
And aliens shouldn’t try to “phone home”. It could take millennia for the signal to get there.
Sighting aliens must therefore sit in the same bracket as Santa, the reindeer and the elves. Merry Christmas.
