All known black holes fall into two categories: small, stellar-mass black holes weighing a few Suns, and supermassive black holes weighing millions or billions of Suns. Astronomers expect that intermediate-mass black holes weighing 100 – 10,000 Suns also exist, but so far no conclusive proof of such middleweights has been found. Astronomers have announced new evidence that an intermediate-mass black hole (IMBH) weighing 2,200 Suns is hiding at the center of the globular star cluster 47 Tucanae.
Monster black holes sometimes lurk behind gas and dust, hiding from the gaze of most telescopes. But they give themselves away when material they feed on emits high-energy X-rays that NASA’s NuSTAR mission can detect. That’s how NuSTAR recently identified two gas-enshrouded supermassive black holes, located at the centers of nearby galaxies.
Emergent gravity is a new theory that might explain the curious motions of stars in galaxies. It predicts the exact same deviation of motions that is usually explained by invoking dark matter. Professor Erik Verlinde, renowned expert in string theory, publishes a new research paper today in which he expands his groundbreaking views on the nature of gravity.
Investigating the millions of missing stars from the centres of two big galaxies, researchers say they may have solved this cosmic whodunit — and the main culprits are not the usual suspects. While the astronomers confirm that one of the depleted cores is the largest ever detected, they report that it may not have formed in the manner previously thought.
It is only as recently as 2013 that astrophysicists found individual black holes in globular clusters via rare phenomena in which a companion star donates material to the black hole. New research by the University of Surrey on a globular cluster known as NGC 6101 shows that it could host several hundred black holes — a phenomenon that until recently was thought impossible.
The laws of physics as we know them cease to apply to black holes in their deepest regions. Large quantities of matter and energy concentrate in a gravitational singularity, where space-time curves towards infinity and all matter is destroyed. Or is it? A recent study suggests that matter might in fact survive its foray into these space objects and come out the other side.
Japan’s doomed Hitomi observatory peeled back a veil on the inner workings of the Perseus cluster of galaxies before the satellite spun out of control earlier this year, revealing in unprecedented detail how gas heated to millions of degrees behaves around an unseen supermassive black hole, scientists said.
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.