Bad Astronomy: Misconceptions and Misuses Revealed, from ...

114 SKIES AT NIGHT ARE BIG AND BRIGHT
A long exposure of the night sky
reveals the elegant motion of the
stars. From our vantage point on
the spinning Earth, the stars appear
to make circles in the sky. In this
picture, taken in Colorado and
facing north, the stars in the northern
hemisphere arc around Polaris.
Note that Polaris is not exactly on
the pole, so it too makes a short arc.
(Photograph courtesy of Jon Kolb,
Adventures in Astrophotography,
http://home.datawest.net/jkolb/.)
Now, as it happens, there is a middling bright star near the
NCP. You wouldn’t give it a second glance if it were anywhere else
on the sky, but since this one is near the NCP it never rises and it
never sets. All night long this star sits there while other stars get
higher or lower in the sky. Wouldn’t you think it’s important? Think
of it this way: before people had satellites, or airplane reconnaissance,
or handheld Global Positioning System (GPS) devices, they
had to know north from south and east from west. This star took
on great importance to them because it showed them which way
was north, all night long. Even today, if you get lost in the woods
without a compass you’ll be glad to see it.
This star has the somewhat unremarkable name of Alpha Ursa
Minoris, but due to its proximity to the NCP it has taken on the
popular name of Polaris. The star itself is actually rather interesting;
it’s really a multiple star consisting of at least six stars in orbit
around each other. They appear to be one star to us because they
are so far away—430 light-years—that all the stars merge into one