As we celebrate the Fourth of July by watching dazzling fireworks shows, another kind of fireworks display is taking place in a small, nearby galaxy.
Pancake-shaped clouds not only appear in the children's book "Cloudy With a Chance of Meatballs," but also 3 billion miles away on the gaseous planet Neptune. When they appeared in July 2015, witnessed by amateur astronomers and the largest telescopes, scientists suspected that these clouds were bright companions to an unseen, dark vortex. The dark vortex is a high-pressure system where the flow of ambient air is perturbed and diverted upward over the vortex. This forms huge, lens-shaped clouds, that resemble clouds that sometimes form over mountains on Earth.
LIGO detects whispers of another black-hole merger
Nature 534, 7608 (2016). http://www.nature.com/doifinder/10.1038/nature.2016.20093
Author: Davide Castelvecchi
After historic first discovery last September, twin observatories detected gravitational waves again on Boxing Day.
The first gravitational-wave source from the isolated evolution of two stars in the 40–100 solar mass range
Nature 534, 7608 (2016). doi:10.1038/nature18322
Authors: Krzysztof Belczynski, Daniel E. Holz, Tomasz Bulik & Richard O’Shaughnessy
The merger of two massive (about 30 solar masses) black holes has been detected in gravitational waves. This discovery validates recent predictions that massive binary black holes would constitute the first detection. Previous calculations, however, have not sampled the relevant binary-black-hole progenitors—massive, low-metallicity binary stars—with sufficient accuracy nor included sufficiently realistic physics to enable robust predictions to better than several orders of magnitude. Here we report high-precision numerical simulations of the formation of binary black holes via the evolution of isolated binary stars, providing a framework within which to interpret the first gravitational-wave source, GW150914, and to predict the properties of subsequent binary-black-hole gravitational-wave events. Our models imply that these events form in an environment in which the metallicity is less than ten per cent of solar metallicity, and involve stars with initial masses of 40–100 solar masses that interact through mass transfer and a common-envelope phase. These progenitor stars probably formed either about 2 billion years or, with a smaller probability, 11 billion years after the Big Bang. Most binary black holes form without supernova explosions, and their spins are nearly unchanged since birth, but do not have to be parallel. The classical field formation of binary black holes we propose, with low natal kicks (the velocity of the black hole at birth) and restricted common-envelope evolution, produces approximately 40 times more binary-black-holes mergers than do dynamical formation channels involving globular clusters; our predicted detection rate of these mergers is comparable to that from homogeneous evolution channels. Our calculations predict detections of about 1,000 black-hole mergers per year with total masses of 20–80 solar masses once second-generation ground-based gravitational-wave observatories reach full sensitivity.
Astrophysics: Recipe for a black-hole merger
Nature 534, 7608 (2016). doi:10.1038/534478a
Authors: J. J. Eldridge
The detection of a gravitational wave was a historic event that heralded a new phase of astronomy. A numerical model of the Universe now allows researchers to tell the story of the black-hole system that caused the wave. See Letter p.512
Giant SKA telescope rattles South African community
Nature 534, 7608 (2016). http://www.nature.com/doifinder/10.1038/534444a
Author: Sarah Wild
Struggle in Northern Cape province highlights a balancing act that scientists leading gigantic projects face.
Astronomy: Early galaxy has wisps of oxygen
Nature 534, 7608 (2016). doi:10.1038/534438c
Astronomers have detected oxygen in a 13-billion-year-old galaxy — the first time that the gas has been found at such an early stage of the Universe.A team led by Akio Inoue at Osaka Sangyo University in Daito, Japan, used the powerful Atacama Large Millimeter/submillimeter