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Q & A: Do stars move at all ?

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Most recent answer: 06/14/2009
do stars move at all ?
- Celicaa (age 13)
Melbourne, Vic, Australia
Hi Celica,
You bet they do.  Although you can't see them move with your eye, they have large velocities with respect  to each other and to us. This movement is called 'proper motion' in the astronomy literature.  The problem is that since they are so far away it is difficult to detect the motion.  One needs a very good telescope and lots of patience to measure it.  The standard way is to record the relative positions of stars, wait for six months then record them again.  In six months time the earth has moved about 300 million kilometers around to the opposite side of the sun.  This gives a long base line which you can compute both the distance to the nearest stars as well as their relative motion. 
Here is a nice web site to visit:  


(published on 06/14/2009)

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