It was the Apollo group of asteroids, which circle the sun in oblong orbits, that occasionally cross Earth's.

CNN: Planet of sound: Meteor blast resonated around Earth

His finding that the planets circle the sun underpins much of modern science.

BBC: New element named 'copernicium'

Here's the explanation: If the Earth made a perfect circle round the sun, the seasons would be almost exactly equal.

NPR: Not All Seasons Are Created Equal

"It's reminiscent of the model they had of the Earth going around the sun in a circle, " he says.

FORBES: Mandelbrot: A Math Maverick Takes Stock

This is the vicious circle for Mr Blair to ponder as he basks in the Tuscan sun.

ECONOMIST: Peer pressure

These days Mr Mandelson's circle save much of their vitriol for their old broadsheet friends, and pal up with former enemies at the Sun and the Daily Mail.

ECONOMIST: From Beaverbrook to Blair