The CRISPR enzyme (green and red) binds to a stretch of double-stranded DNA (purple and red), preparing to snip out the faulty part. Illustration courtesy of Jennifer Doudna/UC Berkeley hide caption

itoggle caption Illustration courtesy of Jennifer Doudna/UC Berkeley

One of 30 copies of the first protoype meter made by the International Bureau of Weights and Measures (BIPM) in Sevres, France. 1875-1889 NIST Museum Collection hide caption

itoggle caption NIST Museum Collection

The Z machine is located in Albuquerque, N.M., and is part of the Pulsed Power Program, which started at Sandia National Randy Montoya/Sandia National Laboratory hide caption

itoggle caption Randy Montoya/Sandia National Laboratory

Current water-filtering technology is costly, but MIT scientists are testing a simpler and cheaper method that uses wood from white pine trees. Wikimedia Commons hide caption

itoggle caption Wikimedia Commons

About 50,000 years ago, a meteorite struck earth east of present-day Flagstaff, leaving this crater as its calling card. Shane.torgerson/Wikimedia Commons hide caption

itoggle caption Shane.torgerson/Wikimedia Commons

A nurse attaches the low-cost breathing machine (far left) to an infant at The Queen Elizabeth Central Hospital in Blantyre, Malawi. Jocelyn Brown/Rice University hide caption

itoggle caption Jocelyn Brown/Rice University