Monday, July 14, 2008

Planet: A self-gravitating body that is nearly round

The other day I was looking at the Sloan Digital Sky Survey (SDSS) database table on photometric classification. I needed to recall which type was a star and which was a galaxy. So I was interested to see the following two listings in this table buried deep in the SDSS information:
Galaxy: An extended object composed of many stars and other matter.
Star: A a self-luminous gaseous celestial body.
I guess I was just surprised at how pedantic it was.


Kayhan Gultekin said...

Looks like a brown dwarf is a star by their definition.

Becky said...

I guess they don't care why it's self-luminous. That makes life so much simpler.

Are planetary nebulae stars? Are globular clusters just many stars? This would make teaching intro astro so much easier.

Sarah said...

Guess that's solved. Next problem!