BEIJING, Jan. 8 (Xinhuanet) -- Astronomers have
created the first three-dimensional map of the large-scale distribution of
dark matter in the universe, according to the journal Nature on Monday.
team led by the British scientist Richard Massey, of the California Institute of
Technology, has used NASA's Hubble Space Telescope, mapping its presence by the
way it bends light coming from stars that lie behind.
This new map provides the best evidence to date that normal matter, largely in
the form of galaxies, accumulates along the densest concentrations of dark
matter. The map reveals a loose network of filaments that grew over time and
intersected in massive structures at the locations of clusters of galaxies.
The map stretches halfway back to the beginning of
the universe and shows how dark matter has grown increasingly "clumpy" as it
collapses under gravity.
For astronomers, the
challenge of mapping dark matter in the universe has been similar to mapping a
city from nighttime aerial snapshots showing only streetlights. Dark matter is
invisible, so only the luminous galaxies can be seen directly. These new map
images are equivalent to seeing a city, its suburbs and country roads in
daylight for the first time. Major arteries and intersections become evident,
and a variety of neighborhoods are visible.
Mapping dark matter's distribution in space and time
is fundamental to understanding how galaxies grew and clustered over billions of
years. Tracing the growth of clustering in dark matter may eventually also shed
light on dark energy, a repulsive form of gravity that would have influenced how
dark matter clumps.
The research results is consistent with predictions
that a hidden scaffold of dark matter orchestrates the distribution of visible,
bright matter such as galaxies and stars.