Although Tethys and Janus both orbit Saturn and are both made of more or less the same materials, they are very different worlds. via NASA http://ift.tt/1RftqBR Amazing.
The distinctive blue bubble appearing to encircle WR 31a is a Wolf–Rayet nebula — an interstellar cloud of dust, hydrogen, helium and other gases. Created when speedy stellar winds interact with the outer layers of hydrogen ejected by Wolf–Rayet stars, these nebulae are frequently ring-shaped or spherical. via NASA http://ift.tt/1oEvGez Amazing.
NASA research mathematician Katherine Johnson is photographed at her desk at Langley Research Center in 1966. Johnson made critical technical contributions during her career of 33 years, which included calculating the trajectory of the 1961 flight of Alan Shepard. She was awarded the Presidential Medal of Freedom on Nov. 24, 2015. via NASA http://ift.tt/1QgSqsn Amazing.