Jeff Wilson / Sun Dog, or Parhelion, caused by refraction of the sun's rays, more commonly seen in Antarctica, above glacier, Dry Valleys, Antarctica, December 2009. Taken on location for the BBC series, Frozen Pla...

Philippe Clement / Photovoltaic solar panels on roof of house inside incandescent lamp / bulb against black background Digital composite

Jeff Wilson / 'Sun Dog', or Parhelion, caused by refraction of the sun's rays, more commonly seen in Antarctica, above glacier, Dry Valleys, Antarctica, December 2009. Taken on location for the BBC series, Frozen P...

Juergen Freund / Traditional home with solar panel, Chea Village, Marovo Lagoon, Solomon Islands, Melanesia, Pacific, July 2010, a politician donated a solar panel for each household providing light for those living i...

Juergen Freund / Floating cages for Coral trout (Plectropomus leopardus) with solar powered light for night security to protect from poachers, Live Reef Fish Trade, Palawan, Philippines, May 2009.

Aflo / Y-11904 Andromeda galaxy, otherwise known as M31, the nearest galaxy to our own - the Milky Way

Aflo / Y-1002 Cumulonimbus clouds in blue sky with sun shining above sea

Aflo / Y-9902 Bright sun rays above cloud line, Hawaii, USA

Nick Garbutt / Beginning of total solar eclipse. 21st June 2001 Morombe, Madagascar

Jose B. Ruiz / Solar powered street light, Alicante, Spain.