Dark Matter Map
Explanation:
The total mass within giant galaxy cluster
CL0025+1654,
about 4.5 billion
light-years away,
produces a cosmic gravitational lens --
bending
light as predicted
by Einstein's theory of gravity and forming detectable images
of even more distant background galaxies.
Of course, the
total
cluster mass is the sum of the
galaxies themselves, seen as
ordinary luminous matter, plus the cluster's
invisible dark matter whose
nature
remains unknown.
But by analyzing the distribution of luminous matter and the
properties of the
gravitational lensing
due to total cluster mass,
researchers have solved the problem of tracing
the dark matter layout.
Their resulting map
shows the otherwise invisible dark matter in blue,
and the positions of the cluster
galaxies in yellow.
The work,
based on extensive Hubble Space Telescope observations,
reveals that the cluster's
dark
matter is not evenly distributed, but
follows the clumps of luminous matter closely.
Authors & editors:
Robert Nemiroff
(MTU) &
Jerry Bonnell
(USRA)
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NASA Official: Jay Norris.
Specific
rights apply.
A service of:
LHEA at
NASA /
GSFC
& Michigan Tech. U.