Category Astronomy/Space

Types of galaxies (Credit: NASA)

In the late 1970s, astronomers Vera Rubin and Albert Bosma independently found that spiral galaxies rotate at a nearly constant speed: the velocity of stars and gas inside a galaxy does not decrease with radius, as one would expect from Newton’s laws and the distribution of visible matter, but remains approximately constant. Such ‘flat rotation curves’ are generally attributed to invisible, dark matter surrounding galaxies and providing additional gravitational attraction. Now a team led by Case Western Reserve University researchers has found a significant new relationship in spiral and irregular galaxies: the acceleration observed in rotation curves tightly correlates with the gravitational acceleration expected from visible mass only.

“If you measure the...

These pseudotachylites — fine grained rocks — are from the British Isles. Credit: Image courtesy of Yale University

A new study shows that rocks formed by the grinding together of other rocks during earthquakes are rich in trapped hydrogen – a finding that suggests similar seismic activity on Mars may produce enough hydrogen to support life. Researchers from Yale, the University of Aberdeen, and Brock University studied rock formations around active fault lines in the Outer Hebrides, off the coast of Scotland. “Previous work has suggested that hydrogen is produced during earthquakes when rocks fracture and grind together. Our measurements suggest that enough hydrogen is produced to support the growth of microorganisms around active faults,” said Yale geologist Sean McMahon.

While humans an...

The spatial distribution of all PS1 detected Trojans. The solid triangles are the newly discovered Neptune Trojans, and open triangles are the known ones detected by PS1. The positions of Neptune Trojans correspond to their first detections of PS1. The blue circles show the locations of Neptune from 2010 to 2013, and the crosses show the corresponding Lagrange points. Notice that the Galactic Center (GC) overlapped with L5 during 2010 to 2012. Credit: Lin et al., 2016.

An international team led by Hsing-Wen Lin of the National Central University in Taiwan has detected 5 new so-called “Neptune trojans” – minor bodies sharing the same orbit as the planet Neptune. The discovery was made by Pan-STARRS 1 (PS1) survey...

© NASA/Johns Hopkins University Applied Physics Laboratory/Southwest Research Institute. The polar cap of « Sputnik Planum », in false colors, is surrounded by mountains which have been eroded and shaped by the glacial activity. The dark areas are covered by organic materials produced by the photolysis of methane by solar ultraviolet light.

What is the origin of the large heart-shaped glacier revealed in 2015 on Pluto by the New Horizons spacecraft? Two researchers show that Pluto’s peculiar insolation and atmosphere favor nitrogen condensation near the equator, in the lower altitude regions, leading to an accumulation of ice at the bottom of Sputnik Planum, a vast topographic basin...