|
Credit & Copyright: Steve Cullen
Explanation:
When did you first learn to identify this group of stars?
Although they are familiar to many people around the world,
different cultures have associated this
asterism with
different icons
and folklore.
Known in the
USA as the
Big Dipper, the stars are part of a constellation designated
by the
International Astronomical Union in 1922 as the Great Bear
(Ursa Major).
The recognized star names of these stars are
(left to right)
Alkaid,
Mizar/Alcor,
Alioth,
Megrez,
Phecda,
Merak, and
Dubhe.
Of course, stars in any given
constellation
are unlikely to be physically
related.
But surprisingly, most of the Big Dipper stars do seem to
be headed in the same direction as they
plough through
space, a property they share with other stars spread out
over an even larger area across the sky.
Their
measured common motion suggests that they all belong
to a loose, nearby
star cluster, thought to
be on average only about 75
light-years away and up to 30 light-years across.
The cluster is more properly known as the
Ursa Major
Moving Group.
The
featured
image captured the iconic stars recently above
Pyramid Mountain
in Alberta,
Canada.
Free APOD Lectures:
January 5 in NYC & January 9 in DC
|
January February March April May June July August September October November December |
| ||||||||||||||||||||||||||||||||||||||||||||||||
NASA Web Site Statements, Warnings, and Disclaimers
NASA Official: Jay Norris. Specific rights apply.
A service of: LHEA at NASA / GSFC
& Michigan Tech. U.
Based on Astronomy Picture
Of the Day
Publications with keywords: Ursa Major - star cluster
Publications with words: Ursa Major - star cluster
See also: