The European Space Agency (Esa) says its comet lander, Philae, has woken up and contacted Earth.

Philae was dropped on to the surface of Comet 67P by its mothership, Rosetta, last November.

It worked for 60 hours before going to sleep when its solar-powered battery ran flat.

BBC Science Correspondent Jonathan Amos says the comet has since moved nearer to the sun and Philae has enough power to work again.