Created when an aging star blew off its outer layers, planetary nebula PN A66 33 is, by chance, aligned with a foreground star, and bears an uncanny resemblance to a diamond engagement ring. This cosmic gem is unusually symmetric, appearing to be almost circular on the sky.
An unusual structure with a hexagonal shape surrounding Saturn's north pole was spotted on the planet for the first time thirty years ago. Nothing similar with such a regular geometry had ever been seen on any planet in the Solar System.
Astronomers from the Sloan Digital Sky Survey have used 140,000 distant quasars to measure the expansion rate of the Universe when it was only one-quarter of its present age. This is the best measurement yet of the expansion rate at any epoch in the last 13 billion years.
Mapping flood events, observing oil slicks in the oceans, detecting ice distribution in the sea and measuring ground movements with millimetric precision - just some of the tasks of Sentinel-1A, the new flagship in European Earth observation.
NASA's Cassini spacecraft and Deep Space Network have uncovered evidence Saturn's moon Enceladus harbors a large underground ocean of liquid water, furthering scientific interest in the moon as a potential home to extraterrestrial microbes.
A new study of gamma-ray light from the center of our galaxy makes the strongest case to date that some of this emission may arise from dark matter, an unknown substance making up most of the material universe.
College and university students have an opportunity to help design systems for future space habitats and exploration systems through NASA's Exploration Habitat (X-Hab) Academic Innovation Challenge. Applications for the fifth annual challenge will be accepted through April 30.