A Galaxy Gravitational Lens
Credit & Copyright: NASA,
HST, K. Ratnatunga. Myungshin Im
(JHU)
Explanation:
Sometimes it takes a keen eye to see a good mirage. Around the center of
the red
galaxy image in the
above photograph
lie four blue "smudges." Each smudge is actually a different image of
the same background
quasar. The central galaxy happens to fall
directly in the light path of the
quasar. Consequently, the huge mass of
the galaxy is able to pull separate images of the quasar around it - an
effect called
gravitational lensing.
Hence we see a gravitational mirage!
Astronomers have hopes of using light differences between these quasar images
to not only "weigh" the central galaxy but even provide clues about the
expansion rate and
composition of the
universe.
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.
