Category Astronomy/Space

Wandering Supermassive Black Holes in Milky-Way-mass Halos. The Astrophysical Journal, 2018; 857 (2): L22 DOI: 10.3847/2041-8213/aabc0a

Astronomers are beginning to understand what happens when black holes get the urge to roam the Milky Way. Typically, a supermassive black hole (SMBH) exists at the core of a massive galaxy. But sometimes SMBHs may “wander” throughout their host galaxy, remaining far from the center in regions such as the stellar halo, a nearly spherical area of stars and gas that surrounds the main section of the galaxy. Astronomers theorize that this phenomenon often occurs as a result of mergers between galaxies in an expanding universe. A smaller galaxy will join with a larger, main galaxy, depositing its own, central SMBH onto a wide orbit within the new host.

In a...

(Left) Galaxy cluster MACS J1206 observed with the Subaru Telescope. (Right) Magnified image of the left by the Hubble Space Telescope. Credit: NASA/ESA, Umetsu et al. 2012, ApJ, 755, 56

Analysis of gravitational lensing data by an international research team reveals that the evolution of galaxy clusters is dictated by a surprisingly simple law, which clearly shows that they are still growing. Using observational data from the Hubble Space Telescope and the Subaru Telescope, the size and mass of galaxy clusters have precisely been measured. The newfound law will serve as a tool to clarify the evolutionary history of clusters and the universe.

Galaxy clusters are the largest celestial body in the Universe...

Meteorite sample. Credit: © 2018 EPFL / Hillary Sanctuary

Using transmission electron microscopy, EPFL scientists have examined a slice from a meteorite that contains large diamonds formed at high pressure. The study shows that the parent body from which the meteorite came was a planetary embryo of a size between Mercury and Mars. The discovery is published in Nature Communications.

On October 7, 2008, an asteroid entered Earth’s atmospahere and exploded 37 km above the Nubian Desert in Sudan. The asteroid, now known as “2008 TC3,” was just over four meters in diameter. When it exploded in the atmosphere, it scattered multiple fragments across the desert. Only fifty fragments, ranging in size from 1-10 cm, were collected, for a total mass of 4.5 kg...