Sunday, 10 April 2011

Standing on a shore

It?s like when you stand at the seashore at one end of a wide bay,
looking across the sea at the other side of the bay, a thin strip of
land in the distance.

Our galaxy, the Milky Way, is a spiral galaxy. It has a fiery bright
core with several tendril-like arms radiating out from it in a flat
plane. They curl round, streamers whose tips drag behind as the
galaxy rotates, almost wrapping themselves back on the centre. Our
world lies at the far end of one of the arms and from our fabulous
vantage point, we look out onto a bay of empty space and directly
across the bay to the centre of our galaxy.
In the bay between us and the galaxy?s bright centre drift massive
clouds of gas. They shadow the hub, and show up as black, wide
streaks and patches imposed on the middle of the galaxy, apparently
splitting it into two separate lines of colour. In fact they simply
hide some of the majesty of the Milky Way?s core.
This is why, when we look up at the milky way, we see it as an
apparently distant strip across the sky, an unconnected thing, rather
than something that we are part of. We can?t see the arm we are in,
any more than you could see the outline of a forest when standing
inside it. We see the stars that make up the arm with us, surrounding

I took this photo of our galaxy on the roof of the base at 2am, on the
4th of april, in absolute temperature of -67 and a windchill of -87,
with a self-timer so I could be in the picture. You see the milky way
as an almost vertical green cloud, with the streaks of dark gas cloud
shadowing the middle of it. The light across the foot of the sky is a
faint aurora.

Sadly it is forever impossible to see the colour of the milky way with
the naked eye. You only see it when your eyes have adapted to the
dark. Dark-adapted eyes are about 10,000 times more sensitive than in
daylight, but the price is that a completely different set of light
receptors do the work, and they only see in black and white. So we
have to rely on cameras to see the colour for us. But by eye here at
Dome C you can see the shape of the galaxy and the outline of the gas
clouds with about the same clarity as in the photo. I?ve never seen
anything like it. The view from the shore is just magnificent.

Concordia station 75°06'06''S - 123°23'43''E
Satellite uploads at: 02.30, 09.00 and 14.00 UTC
Local time UTC + 8

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