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)