PUMP DOWN Hydraulic fracturing operations pump a mix of water, sand and other materials into the ground to ease the retrieval of oil and gas from the rock layers. New research is looking into the link between fracking and earthquakes.
BEE COLD CASE Just what caused sudden disappearances of honeybees (a worker bee shown) about a decade ago is still a matter of scientific debate.
USGS Bee Inventory and Monitoring Lab/Flickr
SKY GLOW This panoramic view of the night sky from Meteor Crater in Arizona shows how light from Winslow, Phoenix and Flagstaff (left to right, starting at 90°) makes it harder to see the stars.