Date: January 3, 2011
Title: Looking Up
Podcaster: Andy Briggs
Organization: Science File
Description: Reflections on a night under the stars.
Bio: Andy Briggs is an amateur astronomer living in Spain. He has been observing the heavens for more than 40 years. He is the publisher of sciencefile.org (http://www.sciencefile.org), a website for anybody with any interest in science.
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Podcast for 365 Days of Astronomy, Jan 3rd 2011
Abstract: Reflections on a night under the stars
By Andy Briggs, Science File
The astronomer sets his telescope up well before night falls. He needs to align its spotter scope: one of those really fiddly ones with three screws to adjust, and the astronomer knows from experience that it could take some time. Wrestling with the screws, after much frustration he finally manages to centre a distant TV aerial perfectly in the middle of the field of view at three different magnifications.
It’s looking like a beautiful night. Already the sun has set and the sky is passing through darkening azure shades. There’s a little cloud laying across the eastern horizon, but nothing that seriously threatens to spoil the night’s viewing. The astronomer goes inside the house to take a telephone call, and when he returns the summer sky is suddenly dusted with stars.
Time to align the telescope. The astronomer selects two guide stars from the hand-held computer’s database and centres each in turn in the eyepiece. Deneb and Arcturus are his guide stars of choice, because they are bright, easy to find and emerge early out of the dusk. Once aligned, the telescope bleeps softly to itself, and tracks almost imperceptibly across the darkening sky, countering the rotation of the Earth. The astronomer remembers the days when none of this automation was possible, and finding an object in the night sky meant patiently hopping from one star to another until you found it. Patience is a pre-requisite for any astronomer; it’s something which one can acquire through experience though, because if you’re not prepared to wait you will never see anything. In the days before computerised, go-to telescopes, the astronomer had stood many times in the freezing night air, trying to show friends or relatives the glories of the night sky, and had kept them waiting in the cold, stamping their feet in an effort to stay warm, while he tried to find galaxies or nebulae. For them, it had probably not been a good first experience of astronomy.
But nowadays, the telescope’s computer would suggest a tour of interesting objects in the night sky, based on what was currently visible, and would guide the telescope to each object in turn. It was nothing short of an astronomical and technological revolution, because in one night you could show dozens of objects to your friends or relatives in a very short time, with no hanging around in the cold needed. The astronomer was struck by the thought that, paradoxically, the main beneficiaries of the revolution were not the astronomers themselves but those who were not astronomers.
The sky is dark now, as dark as it is going to get at this time of year, and it is time to select some targets. Many are old friends: M27, the Dumb-Bell nebula; the double-cluster in Perseus; M13, the fantastic globular cluster in Hercules. And like old friends, the astronomer never tires of seeing them again. Then it is on to M31, the Andromeda galaxy, once visible to the naked eye from towns and cities but now lost forever in sodium’s orange glow. The astronomer selects it from the computer’s database and waits while the telescope moves slowly towards it, bleeping and whirring in an indecipherable conversation between the telescope’s computer and its motors. And there it is in the eyepiece – the bright central core of M31, the nearest spiral galaxy to our own. The rest of the galaxy is too faint to see with the eye: only a long photographic exposure will bring out the glory of its spiral arms and dust lanes. The astronomer knows that if it were possible to see the entire galaxy with the naked eye, it would be as wide as the full moon in the sky. And one day, billions of years hence, M31 will loom huge in the sky as it approaches the Milky Way towards the inevitable collision and the merging of the two into a giant elliptical galaxy. What a sight that will be in the night sky….yet the eyes which gaze up at it will not be human eyes, but whatever humans have become in three or four billion years – if indeed the Earth is still habitable.
Suddenly a meteor lances through Cygnus: probably an early Perseid – the peak is still a couple of weeks off. As the astronomer looks up, he sees a satellite rising into the northern sky – travelling north-south, it is probably Russian. The astronomer knows that during his night under the stars he may well see a dozen or more satellites. It was surprising how many people didn’t know that you can see satellites with your own eyes; the astronomer had met many people who flatly refused to believe it, even when he was able to tell them exactly what satellite they were looking at. For that matter, most people didn’t even seem to know that planets are visible to the naked eye!
Time passes. Constellations wheel; the Earth turns. The Milky Way is clear tonight, like a white cloud arcing across the heavens. No matter how many times he looked at it, the astronomer never ceased to be filled with a sense of enormity as he visualised exactly what it was: the spiral arm of our own Milky Way galaxy, comprising untold millions and millions of stars. It made the astronomer feel very, very tiny in the scheme of things: some people found this sense of microscopic existence too frightening to even contemplate, but the astronomer is inspired by it: he knows how lucky he is, at this time in the evolution of the Universe, to be here at all, here, under this eternal night, under this ancient light. We are not unimportant, lowly beings, cowering from an infinite sky: for all we know, the Universe might never have produced anything like us before, and may never do again. We are lords of creation and we have vanquished the vagaries of chance just to be.
A female voice screams, cutting the air like a shrill blade. Somewhere off in the night, a drunken couple is arguing. He seems to be accusing her of something. I didn’t, she yells, as another meteor falls in the east. You did, he shouts, I was told, as Vega’s icy brilliance looks down. Their slurred voices shatter the silence of the stars. The astronomer feels annoyed that people could steal this moment from him, that they could spoil this silent night, his communion with the universe. But then he feels a sense of sadness that the couple, like the vast majority of humans, will probably never stand and look up at the sky as he does, they will never see what he sees, they would probably live their whole lives without knowing who and where they were. Nobody had ever shown them the majesty of the night sky, or taught them of its treasures. They had been robbed of the chance of feeling truly human, which, felt the astronomer, was something which could only ever be felt through contemplating a starry sky on a night such as this.
The couple’s angry voices recede; the glorious silence is restored; ancient photons fall like dust.
Birds start to chatter from the trees. There is a glow in the east. Preoccupied with observing Jupiter, which has not long risen, at first the astronomer doesn’t pay much attention. But very soon the glow begins to fill the eastern sky. The astronomer suddenly realises it’s morning: eight hours have passed like minutes. He’s spent the whole night under the stars, yet he does not feel at all tired. He feels renewed, reinvigorated, refreshed, as he always does after nights like this. Nights under the stars, looking up.
End of podcast:
365 Days of Astronomy
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