I’m so far behind with this blog I may never get caught up! Time flies when you’re having fun. And, when you’re writing. I’ve been working on a short essay, hoping to get it into shape to submit to the CBC contest, since they’ll take online entries. That’s used up my writing focus for the past several days.
But I don’t want to let the blog dribble into nothing. So I’ll just plunge in and write about last Saturday’s open night at the Canopis Observatory here in Hobart. It was a Galileo night. This year marks the 400th anniversary of Galileo’s discoveries, and I suppose almost the beginnings of astronomy as we know it. Certainly what he say when he held that telescope to his eye completely altered the European understanding if the Earth and its relationship to the rest of the heavens.
Galileo’s text was called Sidereus Nuncius or Starry Messenger—a lovely title for a deep change in perception and understanding.
The Observatory is small, and its own telescopes are not the kind you can look through to see the stars. They operate digitally, collecting data and feeding it back to computers I think. The larger one was shown to us, its mirrors and the track that light takes through them pointed out. Outside the observatory buildings several amateur astronomers and sky-watchers had set up their own telescopes and were offering views of the moon (somewhat less than half-full) and of Jupiter. To see the moon’s surface clearly the scope was aimed at what the man called the terminator—that’s the line where the bright side meets the dark. The surface looked a pale grey and was as pock-marked as you’d expect. Why am I always so startled and thrilled when things turn out to look like their photographs? Jupiter was a little blurry—I found myself wondering if that was because of the speed at which it turns, but more likely it was distance and/or slight cloud. It was indeed striped with colours, a couple of dark bands interspersed with pale yellows, sandstone-like. There were four moons visible, three in a line to the right of the planet, and one to the left. Apparently Jupiter has over 50 moons, though some of them are only the size of small rocks.
The Observatory is involved in interesting and important international research projects. We heard a presentation on it, principally on the search for new planets or exo-planets. (I meant to look that term up, but haven’t.) Three methods of discovering planets exist: the Doppler Wobble (best name!), transit, and microlensing. The last, microlensing, is the method of the Canopus project. It involves, if I understood correctly, the recording and measuring of light emitted by a star from directly behind another star. The position is important because the light bends around either side of the front star, an d creates a curve. If there’s a spike in the curve the light has been interrupted and a planet is the interruption.
Apparently this method is the one most likely to yield planets or systems of planets that are most like our own Solar System. It reveals planets that are 1-10 times the mass of Earth and a half to three times our Sun-Earth distance from their own star/sun. Quite a few planets have been found that fit within these numbers, though the research is relatively new.
The event was a slightly dizzying combination of facts and numbers and diagrams which provided interesting if sometimes hard to follow information, and the astonishing experience of staring at the grey surface of the moon and the round colours of Jupiter trailing its moons as tiny dots of light.
No comments:
Post a Comment