Universe is twice as bright as previously thought 5/16/2008 1:02:00 PM
London,
May 16 (ANI): Astronomers from UK Universities working with colleagues
from Germany and Australia have calculated that the Universe is actually
twice as bright as previously thought. The
team of astronomers has come up with this theory after finding how dust
is obscuring approximately half of the light that the Universe is
currently generating.
For
nearly two decades we've argued about whether the light that we see
from distant galaxies tells the whole story or not, said lead author Dr
Simon Driver from the University of St Andrews. It
doesn't; in fact only half the energy produced by stars actually
reaches our telescopes directly, the rest is blocked by dust grains, he
added. While
astronomers have known for some time that the Universe contains small
grains of dust, they had not realised the extent to which this is
restricting the amount of light that we can see. The dust absorbs
starlight and re-emits it, making it glow. They
knew that existing models were flawed, because the energy output from
glowing dust appeared to be greater than the total energy produced by
the stars. You
can't get more energy out than you put in so we knew something was very
wrong. Even so, the scale of the dust problem has come as a shock
appears that galaxies generate twice as much starlight as previously
thought, said Dr Driver. For
their research, the team combined an innovative new model of the dust
distribution in galaxies developed by Dr Cristina Popescu of the
University of Central Lancashire and Prof Richard Tuffs of the Max Plank
Institute for Nuclear Physics. Using the new model, the astronomers could calculate precisely the fraction of starlight blocked by the dust. The
results demonstrate very clearly that interstellar dust grains have a
devastating effect on our measurements of the energy output from even
nearby galaxies, said Professor Richard Tuffs. With the new calibrated
model in hand, we can now calculate precisely the fraction of starlight
blocked by the dust, he added. After
carefully measuring the brightness of thousands of disc-shaped galaxies
with different orientations, the astronomers matched their observations
to computer models of dusty galaxies. From
this, they were able to calibrate the models and, for the first time,
determine how much light is obscured when a galaxy has a face-on
orientation. This then allowed them to determine the absolute fraction
of light that escapes in each direction from a galaxy. (ANI)
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