The authority said it was using clay to plug the 13ft (4m) wide hole, caused by the collapse of a mine shaft.

BBC: Stoke-on-Trent mine collapse drains lake

Authorities say they worry the hole is still spreading and the house could collapse at any time.

CNN: A loud crash, then nothing: Sinkhole swallows Florida man

That's why an event such as GRB130427A probably signals the collapse of a massive star into a black hole.

CNN: Why gamma-ray burst shocked scientists

In part, the decline was down to the collapse of trade with the Soviet block: new trade with China filled only part of the hole.

ECONOMIST: Nomadism in Mongolia

It was that pulsars are rotating neutron stars, the super-dense last stage of collapse of a star not quite heavy enough to form a black hole.

ECONOMIST: Obituary

If you were to assume that every point in the universe contained some information, then even a small office would be so densely packed with particles that it would collapse in on itself like a black hole, says Raphael Bousso, a physics professor at the University of California, Berkeley.

FORBES: Flatland?