Exploding supernova bursts into visibility

But there is no danger of the Earth being swept away by the cosmic concussion. The “nearby” supernova is 21 million light years away.

The stellar explosion is the closest of its type observed for 40 years and was spotted in the Pinwheel Galaxy, a spiral galaxy in the constellation of the Great Bear, by astronomers from Oxford University and in the US on Wednesday and reported in the journal Science.

Dubbed PTF11kly, the supernova is getting brighter and could be visible with good binoculars in the next 10 days.

“The best time to see this exploding star will be just after evening twilight in the Northern hemisphere in a week or so’s time,” said Dr Mark Sullivan, who led the Oxford team. “You’ll need dark skies and a good pair of binoculars, although a small telescope would be even better.”

He added: “The most exciting thing is that this is what’s known as a Type 1a supernova – the kind we use to measure the expansion of the Universe. Seeing one explode so close by allows us to study these events in unprecedented detail.”

The discovery came as scientists from the Australian Commonwealth Scientific and Industrial Research Organisation reported on a “diamond planet” located orbiting a tiny spinning star 4,000 light years away.

The density of a once massive star shows it must largely be made of crystalline carbon – or, to use another word, diamond.