Scottish stargazer looks to find the real size of universe

Published on Monday 13 April 2009 22:08

AN ASTRONOMER from Scotland will use a powerful new telescope to try to find out the true size of the universe.

Dr Alan Penny from the University of St Andrews believes data from Nasa's Kepler satellite, launched last month, will show that current estimates of the size of the universe are not accurate.

Although the satellite's main purpose is to hunt for new planets, he will use it to examine the brightness of certain stars.

Dr Penny, member of a 200-strong global team, will examine six stars known as Cepheids.

By studying the brightness of these stars, they will be able to calculate the distance to galaxies. This enables them to estimate the size of the universe.

Dr Penny said that it is likely that scientists' understanding of how these stars vary in brightness is incomplete.

He believes that current estimates of the size of the universe, at 93 billion light years, might change by up to a few per cent.

He said: "These Cepheid stars which get brighter and fainter by some tens of per cent every ten to a hundred days are mostly understood.

"But recently it has become clear that our theories of what happens in the outer layers of these stars which cause the variations in brightness do not totally agree with what we see.

"The exquisite accuracy of Kepler in measuring star brightness, 100 times better than we can do from the ground, means we can get such good measurements that we should be able to match theory with observation."

He added: "Resolving the issue may only change estimates of the size of the universe by a small amount, but we won't rest easy until the problem is solved."