Tiny specks of cosmic dust which are left over from the formation of our solar system have been discovered on the rooftops of three European cities.

The space debris, which is falling constantly through the atmosphere, has previously only been found in Antarctica and the deep ocean.

It was thought that it would never be found in cities because it would be so difficult to detect it amid the pollution, dust and grime in urban areas.

But scientists at Imperial College have confirmed that particles have been found on the rooftops of Paris, Oslo and Berlin.