Sun’s lost twin gets blame for extinction

UNITED STATES: The Solar System once had two suns, scientists believe, and one of them may have helped to wipe out the dinosaurs.

A theoretical physicist at the University of California and an astronomer from Harvard University have discovered that most stars are born with a ‘‘brother’’, and our own Sun is likely to be no exception. In fact, this twin, called a Nemesis, may have been responsible for forcing an asteroid into Earth’s orbit, leading to the extinction of the dinosaurs.

In the 1980s, two palaeontologists from the University of Chicago suggested that the regular rate of mass extinctions on Earth every 26 million years - was caused by a mysterious ‘‘second Sun’’. But, despite years of searching, nobody could ever find it.

Now the new study suggests that the Sun did have a companion star billions of years ago, but it probably escaped the Solar System and is now lost in the Milky Way.

‘‘We are saying, yes, there probably was a Nemesis, a long time ago,’’ said study author Professor Steven Stahler, of UC Berkeley. ‘‘It was supposed to send comets crashing into the Earth, thus explaining mass extinctions, like those of the dinosaurs.

‘‘It would now be thousands of light years distant, and impossible to find.’’

Scientists believe the Nemesis must have existed after studying a giant cloud of recently formed stars in the constellation Perseus, which is about 600 light years from Earth. They found 55 baby stars in 24 multiple-star systems, and all but five of them had companion stars.

The team concluded that all stars like the Sun start off with a twin, and some 60 per cent split up over time. - Telegraph Group