Ring Around the Galaxy
Explanation:
It is difficult to hide one galaxy far behind another.
The closer galaxy's gravity will act like a
huge lens, pulling images of the
background galaxy around both sides.
This is just the case observed in the
above recently released image from the
VLT: the red galaxy
in the middle is in the foreground,
lensing the image of the
background green galaxy into
surrounding contorted arcs.
These images are more than
sideshows,
since the distance between background images
increases with the mass of the lens.
This lens mass turns out to be much greater than
the sum of all its stars - indicating the presence of
dark matter.
The
distorted galaxy
is said to appear as an
Einstein ring, named after
Albert Einstein
who accurately predicted many attributes of the
gravitational lens effect -- although
he also guessed that such an effect was
unlikely to be seen in practice.
Tomorrow's picture: On The Road Again
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.
