When a star passes within a certain distance of a black hole, the stellar material gets stretched and compressed as the black hole swallows it, briefly releasing an enormous amount of energy as a flare. Astronomers have now observed infrared light echoes from these “stellar tidal disruption” events reflected by dust encircling a black hole.
Quasars are supermassive black holes that sit at the centre of enormous galaxies, accreting matter. They shine so brightly that they are among the most distant objects in the universe that we can currently study. New work from a team led by Carnegie’s Eduardo Bañados has discovered 63 new quasars from when the universe was just 7 percent of its present age.
Supermassive black holes do not give off any of their own light, hence the word “black” in their name. However, many black holes pull in surrounding material and emit powerful bursts of X-rays. Collectively, these active black holes can be thought of a cosmic choir, singing in the language of X-rays. Their “song” is what astronomers call the cosmic X-ray background.
Astronomers have discovered evidence for an unusual kind of black hole born extremely early in the universe. They showed that a recently discovered unusual source of intense radiation is likely powered by a “direct-collapse black hole,” a type of object predicted by theorists more than a decade ago.
Researchers at the University of Cambridge have developed a new method for detecting and measuring one of the most powerful, and most mysterious, events in the universe — a black hole being kicked out of its host galaxy and into intergalactic space at speeds as high as 5,000 kilometres per second (11 million miles per hour).
Some 3.9 billion years ago in the heart of a distant galaxy, the intense tidal pull of a monster black hole shredded a star that passed too close. After X-rays produced in this event first reached Earth on 28 March 2011, scientists concluded that the outburst, now known as Swift J1644+57, also represented the sudden flare-up of a previously inactive black hole.
A computer simulation of the powerful jets generated by supermassive black holes at the centres of the largest galaxies explains why some burst forth as bright beacons visible across the universe, while others fall apart and never pierce the halo of the galaxy. A jet’s hot ionised gas is propelled by the twisting magnetic fields of the central rotating black hole.
A matter of scientific speculation since the 1930s, dark matter itself cannot yet be detected, but its gravitational effects can be. Now, eight scientists from Johns Hopkins University consider the possibility that the first black hole binary detected by LIGO could be part of this mysterious substance known to make up about 85 percent of the mass of the universe.
LISA Pathfinder, a mission led by the European Space Agency with contributions from NASA, has successfully tested key technology needed to build a space-based observatory for detecting gravitational waves. These tiny ripples in the fabric of space, predicted by Albert Einstein a century ago, were first seen last year by the ground-based Laser Interferometer Gravitational-Wave Observatory (LIGO).
Astrophysicists have taken a major step forward in understanding how supermassive black holes formed. Using data from three of NASA’s space telescopes, Italian researchers have found the best evidence to date that the direct collapse of a gas cloud produced supermassive black holes in the early universe.
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