Category Astronomy/Space

Credit: Jean Lachat/University of Chicago Nicolas Dauphas, the Louis Block Professor in Geophysical Sciences, holds a chondrite meteorite that contains a puzzling mismatch in isotopic composition with Earth’s crust. The mismatch puzzles scientists because they long believed that Earth formed from planetary objects similar to meteorites. Dauphas and his colleagues present research this week in Nature that explains how this mismatch could have come about.

Chondrite meteorites contain a puzzling mismatch in isotopic composition with Earth’s crust. The mismatch puzzles scientists because they long believed that Earth formed from planetary objects similar to meteorites. For the past 10 years, scientists have been trying to understand why...

Valleys much younger than well-known ancient valley networks on Mars are evident near the informally named “Heart Lake” on Mars. Image credit: NASA/JPL-Caltech/ASU

Lakes and snowmelt-fed streams on Mars formed much later than previously thought possible, according to new findings using data primarily from NASA’s Mars Reconnaissance Orbiter. The recently discovered lakes and streams appeared roughly a billion years after a well-documented, earlier era of wet conditions on ancient Mars. These results provide insight into the climate history of the Red Planet and suggest the surface conditions at this later time may also have been suitable for microbial life.

“We discovered valleys that carried water into lake basins,” said Sharon Wilson of the Smithsonian Institution, Washington, and the Uni...

This illustration shows a glowing stream of material from a star as it is being devoured by a supermassive black hole in a tidal disruption flare. Credit: NASA/JPL-Caltech

When a star passes within a certain distance of a black hole, the stellar material gets stretched and compressed – or “spaghettified” – as the black hole swallows it. A black hole destroying a star, an event astronomers call “stellar tidal disruption,” releases an enormous amount of energy, brightening the surroundings in an event called a flare. In recent years, a few dozen such flares have been discovered, but they are not well understood. Astronomers now have new insights into tidal disruption flares, thanks to data from NASA’s Wide-field Infrared Survey Explorer (WISE)...

Visualization of Chariklo and its rings ( left; ESO/L. Calçada/M. Kornmesser/Nick Risinger). Visualization of the rings as seen from Chariklo’s surface (right ESO). Credit: ESO/L. Calçada/Nick Risinger (skysurvey.org)

A team of researchers has clarified the origin of the rings recently discovered around 2 minor planets known as centaurs, and their results suggest the existence of rings around other centaurs (minor planets that orbit between Jupiter and Neptune, their current or past orbits crossing those of the giant planets). It is estimated that there are around 44,000 centaurs with diameters >1 km.

Until recently it was thought that the 4 giants such as Saturn and Jupiter were the only ringed celestial bodies within our solar system...