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Q & A: Galaxies and their properties

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Most recent answer: 03/04/2008
Q:
What exactly is a galaxy? How big is it? Are there any clones of us and earth found in the milky way?
- Anna (age 14)
Hong Kong
A:
A galaxy is a very large collection of stars, like our sun.  Our own galaxy is called the Milky Way which you can see on a clear night (perhaps not in Hong Kong due to lots of street lights). The size of our galaxy is enormous compared to distances we are familiar with, for example the distance from the earth to the sun. 
 Not only are there lots of stars in a galaxy, but there are lots of galaxies.  Astronomers have detected millions of them.    As to the possibility of clones of us and earth, astronomers have detected many stars that seem to have planets in orbit around them.  Whether or not they have an earth-like atmosphere or life sustainable conditions has not been determined yet.   Here are a couple of web sites that contain lots of galactic information:
  
An amusing tidbit I found while browsing the web is that the Greek word for milk is GALACTIA, hence the term for our own galaxy, The Milky Way.

LeeH 

(published on 03/04/2008)

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