M101: The Pinwheel Galaxy
Explanation:
Why do many galaxies appear as
spirals? A striking example is
M101, shown above,
whose relatively close distance of about 22 million light years
allow it to be studied in some detail.
Recent evidence indicates that a close gravitational interaction
with a neighboring galaxy created
waves of high mass and condensed gas which continue to circle the
galaxy. These waves compress existing gas and cause
star formation.
One result is that
M101, also called the Pinwheel Galaxy,
has several extremely bright
star-forming regions (called HII regions)
spread across its spiral arms.
M101
is so large that its immense gravity distorts smaller nearby galaxies.
Authors & editors:
Robert Nemiroff
(MTU) &
Jerry Bonnell
(USRA)
NASA Web Site Statements, Warnings,
and Disclaimers
NASA Official: Jay Norris.
Specific
rights apply.
A service of:
LHEA at
NASA /
GSFC
& Michigan Tech. U.
