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# [sci.astro] Stars (Astronomy Frequently Asked Questions) (7/9)Section - G.12 Do star maps (or galaxy maps) correct for the motions of the stars?

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Top Document: [sci.astro] Stars (Astronomy Frequently Asked Questions) (7/9)
Previous Document: G.11 How far away is the farthest star?
```Author: Joseph Lazio <jlazio@patriot.net>

In general, no.

The reason is that stellar distances are so large.  Over human time
spans, the typical velocity of a star is so low that its distance does
not change appreciably.

Let's consider a star with a velocity of 10 km/s, typical of most
stars.  In 1000 yrs, this star moves about 300 billion kilometers (or
3E11 km).  Suppose the star is 100 light years (about 1E15 km or 1
quadrillion kilometers) distant.  Thus, in 1000 yrs, the star moves
about 0.03% of its distance from the Sun.  This is such a small
change, it's not worth worrying about it.

The situation is even more extreme in the case of galaxies.  Typical
galaxy velocities might be hundreds to thousands of kilometers per
second.  However, their distances are measured in the millions to
billions of light years.

```

## User Contributions:

Apr 27, 2016 @ 10:22 pm
The URL for the University of Adelaide CANGAROO project has changed. The updated URL is

- Remove the .html from the end
- Append /index.html

Top Document: [sci.astro] Stars (Astronomy Frequently Asked Questions) (7/9)
Previous Document: G.11 How far away is the farthest star?