'Putin cannot be seen to look weak'.

It has been described as the 'the worst day in the history of the Russian air force'.

Dinosaur fossils could be invaluable for cancer research - and better treatment.

We hold robots to higher moral standards, a study found.

The light is too dim for humans to see (Picture: Getty) All living things – from humans to mice and plants – emit a ghostly glow up until they die.