Hoags Object: A Strange Ring Galaxy
Explanation:
Is this one galaxy or two?
This question came to light in 1950 when astronomer
Art Hoag
chanced upon this unusual
extragalactic object.
On the outside is a
ring dominated by bright blue stars,
while near the center lies a ball of much redder stars
that are likely much older.
Between the two is a
gap that appears almost completely dark.
How
Hoag's Object
formed remains unknown, although similar objects
have now been
identified and collectively labeled
as a form of
ring galaxy.
Genesis hypotheses include a
galaxy collision
billions of years ago and the gravitational affect of a
central bar that has
since vanished.
The
above
photo taken by the
Hubble Space Telescope
in July 2001 reveals unprecedented details of Hoag's Object and may yield a
better understanding.
Hoag's Object spans about 100,000
light years and lies about 600 million
light years away toward the
constellation of the Snake
(
Serpens).
Coincidentally, visible in the gap
(at about one o'clock) is yet another
ring galaxy that likely lies
far in the distance.
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.
