These mutant nematode worm embryos are genetically identical, but fluorescence imaging shows they are not exactly the same. The pink spots are mRNA molecules involved in gut development. Some twins have spots and some don't, which means some will develop guts and others won't. Arjun Raj hide caption

itoggle caption Arjun Raj

A technician works on a Toyota Prius hybrid at a production facility in Aichi Prefecture, Japan. According to experts, cars like the Prius are the next step in a future that's moving toward vehicles with more robotic-type control systems that can analyze driving conditions and act accordingly. Kyodo/AP hide caption

itoggle caption Kyodo/AP

A thin (0.1 mm) layer of water that is frozen and examined under polarized light. Courtesy of Rainer Stahlberg and Gerald H. Pollack, University of Washington hide caption

itoggle caption Courtesy of Rainer Stahlberg and Gerald H. Pollack, University of Washington

The bdelloid rotifer Philodina gregaria. Bdelloid rotifers are tiny invertebrates that reproduce asexually. Courtesy of Micrographia hide caption

itoggle caption Courtesy of Micrographia

An artist's rendering of a NASA Mars Exploration Rover on the surface of Mars. The robotic explorer Spirit has been stuck in sandy soil on Mars since April 2009. NASA/JPL-Caltech hide caption

itoggle caption NASA/JPL-Caltech

Researchers dyed sperm from each deer mouse a different color; in this case, red represents one male and green another. The sperm joined together with their own kind, as seen here, allowing them to swim faster than those that did not cluster together. Heidi Fisher hide caption

itoggle caption Heidi Fisher

A two-dimensional representation of E8 symmetry, the type of symmetry exhibited by particles in the study. John Stembridge hide caption

itoggle caption John Stembridge

Scientist turned director Valerie Weiss discusses a scene with cinematographer Jamie Urman on the set of her film, Losing Control. Courtesy of Richard Salazar hide caption

itoggle caption Courtesy of Richard Salazar