'Great Dimming' of Betelgeuse star is solved
Astronomers say they've put to bed the mystery of why one of the most familiar stars in the night sky suddenly dimmed just over a year ago.
But a team using the Very Large Telescope (VLT) in Chile say the cause was almost certainly a giant dust cloud between us and the star.
Even if you can't name many points in the sky, you'll definitely know Betelgeuse by sight. It's the orange dot in the top-left corner of Orion - or bottom-right, if you're viewing the constellation in the Southern Hemisphere.
Close to Earth, relatively speaking, at a distance of about 550 light-years, Betelgeuse is what's known as a semi-regular variable star. It naturally brightens and darkens over a period of roughly 400 days.
But what happened 18 months ago was out of the ordinary. The loss of brightness was far greater than anything previously recorded.
Astronomer Miguel Montargès and colleagues investigated the event with the European Southern Observatory's VLT, one of the most powerful telescopes on Earth. It has the resolution to directly image the surface of Betelgeuse.
