Friday, March 16, 2012

The stars like dust

When I look out in the city-dimmed sky at night I can see Jupiter and Venus leaving conjunction, and maybe 60 stars.

It is hard to remember how thickly spread the sky is with not just stars, but galaxies: so thickly spread that there are even some galaxies behind quasars.

The Sloan Digital Sky Survey sounds almost a little dull: catalog the stars and then, masking them off, systematically look for galaxies. But it has been a hugely powerful tool for discovery.

2 comments:

Texan99 said...

I grew up in the suburbs of Houston, where stargazing almost always is impossible. Now I'm an hour north of Corpus Christi and can see the Milky Way on almost any cloudless night, though the low elevation and humid atmosphere are less than ideal.

james said...

I grew up in the tropics, and I don't remember a lot of cloudless nights, but in between clouds you could see stars. Now I live near Madison, and even on clear nights the city glow dims the sky. If there's going to be a good meteor shower we have to travel out into the hinterlands to get a good look.