The CMB is the light that was finally allowed to spread out across space once the Universe had cooled sufficiently to permit the formation of hydrogen atoms - about 380, 000 years into the life of the cosmos.

BBC: Planck satellite: Maps detail Universe's ancient light

The company is also experimenting with a new way of storing the hydrogen that will fuel its cells a fabric made of fibres of activated carbon that can (when cooled with liquid nitrogen) soak up the same amount of energy per kilogram as petrol.

ECONOMIST: Clean living in Iceland