70 sextillion stars in 'known universe'

Ever tried to count the number of stars on a clear night?

According to a study by a team of stargazers based at the Australian National University, there are 70,000,000,000,000,000,000,000 (70,000 million million million, or 70 sextillion) stars in the known universe.

That is about 10 times more than the grains of sand on earth.

At the General Assembly of the International Astronomical Union meeting in Sydney, Dr Simon Driver, who headed the team, said the number was drawn up based on a survey of one strip of sky.

Within the strip of sky some 10,000 galaxies were pinpointed and their brightness was measured to figure out how many stars they contained.

That number was then multiplied by the number of similar sized strips needed to cover the entire sky, Dr Driver said, and then multiplied again out to the edge of the visible universe.

Two telescopes, one at the Anglo-Australian Observatory in northern New South Wales state and one in the Canary Islands, were used to carry out the survey.

According to him, it is likely that there are many more million stars, but 70 sextillion was the number visible within range of modern telescopes.

The universe is so big that light from the other end of the universe 'hasn't reached us yet', Australia's The Age newspaper quoted him as saying.

Asked if he believed there was other intelligent life out there, he said: "Seventy thousand million million million is a big number... it's inevitable."