Nell GreenfieldboyceNell Greenfieldboyce is a NPR science correspondent.
NASA astronaut Scott Kelly is seen inside a Soyuz simulator at the Gagarin Cosmonaut Training Center on March 4 in Star City, Russia. Kelly, along with Russian cosmonaut Mikhail Kornienko of the Russian Federal Space Agency, are scheduled for launch Friday aboard a Soyuz TMA-16M spacecraft from the Baikonur Cosmodrome in Kazakhstan.
Mars, anyone? Six researchers from the Mars Society sport their best space duds during this 2014 simulation of the conditions that explorers of the Red Planet might face. (From left) Ian Silversides, Anastasiya Stepanova, Alexandre Mangeot and Claude-Michel Laroche.
Micke Sebastien/Paris Match via Getty Images
The size of the brain of a chimpanzee (right) is considerably smaller than that of a human brain. Probably multiple stretches of DNA help determine that, geneticists say.
Science Photo Library/Corbis
The eruption of Mount Pinatubo in the Philippines in 1991 spewed almost 20 million tons of sulfur dioxide into the atmosphere, causing worldwide temperatures to drop half a degree on average.
Arlan Naeg/AFP/Getty Images
Stars over the Cerro Tololo Inter-American Observatory in Chile. Sheppard and Trujillo used the new Dark Energy Camera (DECam) on a telescope there to find the distant dwarf planet 2012 VP 113.
An example of a human precision grip — grasping a first metacarpal from the thumb of a specimen of Australopithecus africanus that's thought to be 2 to 3 million years old.
T.L. Kivell & M. Skinner
The newly described L. larvaepartus (male, left, and female) from Indonesia's island of Sulawesi. Odd, sure, but at least they don't use their stomachs as breeding chambers, as some other frogs do.
Jim McGuire/UC Berkeley