Sun’s hidden twin is hurling killer comets at Earth — and may have wiped out dinosaurs: expert

A physicist has revived the idea that the Sun may have a faint red-dwarf companion, nicknamed Nemesis, whose periodic passes could send comets towards Earth. The theory offers a possible explanation for a proposed cycle of mass extinctions, including the event that wiped out the dinosaurs, but the star has not been detected and the idea remains disputed.

Richard Muller of the University of California, Berkeley, suggests Nemesis passes through the Oort Cloud every 26 million years, potentially triggering comet showers lasting up to a million years; he estimates the next pass is about 12 million years away. The hypothesis followed a 1982 study reporting marine extinctions on a roughly 26-million-year cycle. A 2014 analysis of data from NASA’s WISE telescope found no evidence of a companion star, and scientists have not established whether the object linked to the dinosaurs’ extinction was an asteroid or a comet.