Monday, 4 November 2013
The Gosh Wow Factor
Anyone who knows me, Noble Reader, will tell you that I am a man of serial enthusiasms. I develop a spike of interest in something which peaks and dies away with a period of perhaps two years: cactuses, steam engines, spiral staircases, &c., all have come and gone. But the one life-long interest that has stayed with me is astronomy.
When I was 13 years-old I used to go along to Rossall College, a minor public school in the north west of England, where a venerable, and to me, gigantic, telescope had been made available through the kindness of one of the house masters. I would bicycle three miles to the said institution and collect the keys and a box of eyepieces and make use of this neglected observatory which housed a big, brass refractor made by Thomas Cooke and Sons of York.
Picture, if you will, the biblical Saul on his way to Damascus, and the moment when the scales fell from his eyes. Well, I had my own equivalent epiphany of sorts, and it happened in Rossall College observatory.
What happened was this. One particularly crisp, clear night I spent an hour in candlelight (there was no mains electricity) lining the telescope up and setting the clock drive so that it would remain pointed at a particular point in the sky. What I wanted to see was located in the constellation of Andromeda, which was just rising to its highest point. It was the famous M31, a neighbouring galaxy, the only one easily visible to the naked eye, and an object pretty similar to the galaxy we live in, which we call the Milky Way. When I say "neighbouring", I should add that M31 is a couple of million light years away, which means that it's so far from us that light takes a couple of million years to get to us. Considering that light always travels at 186,000 miles per second, that's really quite a long way. Actually, when it coms to galaxies, M31 is pretty well our closest, the furthest that we've measured being more than thirteen billion light-years away.
Anyhow, there was I, all set up with that big six-inch refractor pointing at M31. I positioned myself at the gently moving eyepiece and shut my eyes. The idea was to get "dark adaption." If you shut your eyes, they get used to the darkness, so that when you open them again very faint objects appear momentarily much brighter. I thought I'd give myself twenty minutes. Then I looked.
A faint patch of haze with a slightly brighter centre. Big deal. But to me it was a very big deal. While I had had my eyes closed I had been reflecting on what was actually about to happen. The particles of light -- photons -- that were coming down that telescope and would soon be hitting the retina of my right eye had come from more than a hundred million different stars. Those photons had travelled across 2 million light years of empty space and would find their final destiny interacting with the light-sensitive chemicals in the retina of my eye. Amazing enough in itself, but the more I thought about it, the more amazing it became: that photon journey had begun two million years ago -- before my own species had even evolved.
That's quite a thought, and on the whole, I'd say it rates both a gosh and a wow.
These are pictures of Rossall College!