Chelyabinsk 10 years on

From strange lights in the sky to rocks that spontaneously glide across the ground, the mysteries scientists are trying to finally crack

COLOURFUL CHEMISTRY

The worst time to look at the Moon is when it’s full, right? Not necessarily. It’s true that at full Moon, sunlight hits the surface head-on, flattening the appearance of its rugged landscape of deep

Yes. On cosmic timescales, comets hit Earth frequently, but because they’re largely made of ice rather than solid rock, they tend not to leave obvious craters. A small comet is more likely than an asteroid to break up as it plunges into Earth’s atmosphere and heats up, often resulting in an explosion called an airburst that can devastate large areas of the landscape but doesn’t leave a crater. Perhaps the most famous such event happened over the Russian region of Tunguska in 1908, when an exploding comet flattened some 770 square miles of Siberian forest. A comet would have to be pretty big in order to hit the ground intact.

GLOBAL EYE

This October marks 50 years since a heavily shielded spacecraft, the Soviet Union’s Venera 9, parachuted into the atmosphere of Venus. Then, having landed, it did something extraordinary: it beamed ba