The Century that Defined Galaxy
Explanation:
As the
twentieth century dawned a
debate raged over whether the
Milky Way
was the entire universe.
The
1920s brought
observations of
spiral-nebulae
that housed familiar but faint
variable stars,
and hence placed these
nebulae much farther
than anything else ever found.
The Milky Way, apparently, is itself a
spiral nebula seen from the inside.
Soon
interstellar dust was
identified as the opaque material that blocks our view of distant
spiral arms, confirming that our
Sun was well away from the center.
As the
twentieth century closes, galaxies are seen
forming across the universe,
and our Milky Way is referred to as a spiral
galaxy quite similar to
NGC 1288, as
pictured above.
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.
