People view the Northern Lights over Bamburgh Castle Beach Thursday in Northumberland, England. A powerful solar flare caused the aurora borealis to be visible farther south than usual. Josh Maidwell/Barcroft Media/Landov hide caption

itoggle caption Josh Maidwell/Barcroft Media/Landov

Images of Folsom Lake, a reservoir in Northern California, show the severity of the state's drought. The photo at left, taken on July 20, 2011, show the lake at 97 percent of total capacity and 130 percent of its historical average for that date. The photo at right shows the lake on Jan. 16, 2014, when it was at 17 percent of capacity and 35 percent of its historical average. California Department of Water Resources hide caption

itoggle caption California Department of Water Resources

The iconic "Earthrise" photo taken by astronaut Bill Anders through a window on the Apollo 8 command module on Dec. 24, 1968. Bill Anders/NASA hide caption

itoggle caption Bill Anders/NASA

KABOOM! A NASA illustration of a gamma-ray burst. They occur, the space agency says, when "a massive star runs out of nuclear fuel, collapses under its own weight, and forms a black hole. The black hole then drives jets of particles that drill all the way through the collapsing star." NASA.gov hide caption

itoggle caption NASA.gov