The Apollo 17 crew caught this breathtaking view of our home planet as they were traveling to the moon on Dec. 7, 1972. NASA hide caption
An artist rendering of a sail propelled by a laser. Q. Zhang/Courtesy of UCSB Experimental Cosmology Group hide caption
The first issue of Animal Sentience looks at the question of whether fish can feel pain. iStockphoto hide caption
Saturn's rings cut across this view of the planet's largest moon, Titan, in this image taken by the Cassini spacecraft on May 12, 2011. NASA/JPL-Caltech/Space Science Institute hide caption
The Kavli HUMAN Project aims to capture data over 20 years based on the lives of 10,000 people, centered in New York. Ferran Traité Soler/iStockphoto hide caption
Big Fish Petroglyph by Kevin Sudeith was created in October 2013 in Smelt Brook, Cape Breton, Nova Scotia in Canada. "All the fish on this rock are carved at life size, and most originate in the story of a local fisherman," says Sudeith. Kevin Sudeith/Courtesy of Petroglyphist.com hide caption