“It’s burning helium in its core at the moment, which means it’s nowhere near exploding,” Dr. Joyce said. “We could be looking at around 100,000 years before an explosion happens.” Co-author Dr. László Molnár from the Konkoly Observatory?in Budapest says the study also revealed how big Betelgeuse is, and its distance from Earth. “The actual physical size of Betelgeuse has been a bit of a mystery — earlier studies suggested it could be bigger than the orbit of Jupiter. Our results say Betelgeuse only extends out to two thirds of that, with a radius 750 times the radius of the...