Fifty-five million light-years away, in the galaxy known as M87, lies a supermassive black hole. It is a powerfully active black hole with a mass of 6.5 billion Suns, and in 2019 it was the first black hole to be imaged directly. The radio image captured by the Event Horizon Telescope (EHT) shows a halo of ambient light warped by the black hole’s gravity and directed our way. On one side of the halo, the light is brighter, which according to general relativity is due to the rotation or spin of the black hole. It was the first direct confirmation that the black hole rotates. A new study published in Nature has given us more rotational evidence.
Continue reading “It's Confirmed. M87's Black Hole is Actually Spinning”Gluttonous Black Holes Eat Faster Than Thought. Does That Explain Quasars?
At the heart of large galaxies like our Milky Way, there resides a supermassive black hole (SMBH.) These behemoths draw stars, gas, and dust toward them with their irresistible gravitational pull. When they consume this material, there’s a bright flare of energy, the brightest of which are quasars.
While astrophysicists think that SMBHs eat too slowly to cause a particular type of quasar, new research suggests otherwise.
Continue reading “Gluttonous Black Holes Eat Faster Than Thought. Does That Explain Quasars?”Strong Evidence that Supermassive Black Holes Affect Their Host Galaxy’s Chemistry
Supermassive Black Holes (SMBHs) are impossible to ignore. They can be billions of times more massive than the Sun, and when they’re actively consuming stars and gas, they become luminous active galactic nuclei (AGN.) A galaxy’s center is a busy place, with the activity centred on the SMBH.
New research provides strong evidence that while going about their business, SMBHs alter their host galaxy’s chemistry.
Continue reading “Strong Evidence that Supermassive Black Holes Affect Their Host Galaxy’s Chemistry”The Closest Black Holes to Earth are Probably Hidden in This Nearby Star Cluster
In the constellation Taurus, there is a cluster of a few hundred stars known as the Hyades. The cluster is just 150 light-years away, and it could be harboring a stellar-mass black hole.
Continue reading “The Closest Black Holes to Earth are Probably Hidden in This Nearby Star Cluster”A Black Hole Nibbles on a Star Every 22 Days, Slowly Consuming it
Astronomers working with NASA’s Neil Gehrels Swift Observatory have spotted something unusual. The observatory’s X-Ray Telescope (XRT) has captured emissions from a supermassive black hole (SMBH) in a galaxy about 500 million light-years away. The black hole is repeatedly feeding on an unfortunate star that came too close.
Continue reading “A Black Hole Nibbles on a Star Every 22 Days, Slowly Consuming it”Astronomers are Hoping the Event Horizon Telescope saw Pulsars Near the Milky Way's Supermassive Black Hole
Millisecond pulsars are amazing astronomical tools. They are fast-rotating neutron stars that sweep beams of radio energy from their magnetic poles, and when they are aligned just right we see them as rapidly flashing radio beacons. They flash with such regularity that we can treat them as cosmic clocks. Any change in their motion can be measured with extreme precision. Astronomers have used millisecond pulsars to measure their orbital decay due to gravitational waves and to observe the background gravitational rumblings of the universe. They have even been proposed as a method of celestial navigation. They may soon also be able to test the most fundamental nature of gravity.
Continue reading “Astronomers are Hoping the Event Horizon Telescope saw Pulsars Near the Milky Way's Supermassive Black Hole”Astronomers Precisely Measure a Black Hole's Accretion Disk
When you think of a black hole, you might think its defining feature is its event horizon. That point of no return not even light can escape. While it’s true that all black holes have an event horizon, a more critical feature is the disk of hot gas and dust circling it, known as the accretion disk. And a team of astronomers have made the first direct measure of one.
Continue reading “Astronomers Precisely Measure a Black Hole's Accretion Disk”Could This Supermassive Black Hole Only Have Formed by Direct Collapse?
Nearly every galaxy in the universe contains a supermassive black hole. Even galaxies that are billions of light years away. This means supermassive black holes form early in the development of a galaxy. They are possibly even the gravitational seeds around which a galaxy forms. But astronomers are still unclear about just how these massive gravitational beasts first appeared.
Continue reading “Could This Supermassive Black Hole Only Have Formed by Direct Collapse?”Does the Milky Way's Supermassive Black Hole Have a Companion?
At the heart of our galaxy, there is a monster black hole. Known as Sagittarius A*, it has a mass of 4.2 million Suns, and it’s only about 27,000 light-years from Earth. Sag A* is the closest supermassive black hole, and one of only two that we’ve observed directly. It is so close that we can even see stars closely orbiting it. Some of those stars we’ve been observing for more than 20 years, which means we have a very good handle on their orbits. We’ve used those orbits to determine the mass of Sag A*, but a new study looks at a different question: does our galaxy’s black hole have a companion?
Continue reading “Does the Milky Way's Supermassive Black Hole Have a Companion?”How Did Supermassive Black Holes Grow So Quickly, So Early?
Supermassive black holes haunt the cores of many galaxies. Yet for all we know about black holes (not nearly enough!), the big ones remain a mystery, particularly when they began forming. Interestingly, astronomers see them in the early epochs of cosmic history. That raises the question: how did they get so big when the Universe was still just a baby?
Continue reading “How Did Supermassive Black Holes Grow So Quickly, So Early?”