A Spiral Galaxy Gallery
Explanation:
A progression of beautiful spiral galaxies is illustrated above with three
photographs from NASA's Ultraviolet Imaging Telescope (UIT).
Flying above the Earth's obscuring layer of atmosphere on the
Space Shuttle Columbia during
the Astro-1 mission in 1990,
UIT's cameras were able to image these distant spirals in the ultraviolet
light produced by hot, young stars.
These bright stars, newly condensed from
gas and dust clouds, give away the location of the spiral arms
they are born in.
Because they are massive (many times the mass of the
Sun), they are shortlived.
Dying and fading before they move too far from their
birth place they make excellent tracers of spiral structure.
From left to right the galaxies are known as M33, M74, and M81 and
have progressively more tightly wound spiral arms. Astronomers would
classify these as Scd, Sc, and Sb type spirals using a
galaxy classification scheme first worked out by
Edwin Hubble.
Information:
The
Scale of the Universe Debate in April 1996
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.
