The pair of stars in a system called HR 6819 is so close to us that on a clear night in the Southern Hemisphere, a person might be able to spot them without a telescope. What that stargazer wouldn’t see, though, is the black hole hiding right there in the constellation Telescopium. At just 1,000 light-years away, it is the closest black hole to Earth ever discovered, and it could help scientists find the rest of the Milky Way’s missing black holes. Continue reading Astronomers Discover the Closest Known Black Hole
At the center of the Milky Way galaxy, nearly 26,000 light-years away, a cluster of stars circles close to the supermassive black hole known as Sagittarius A*. As these few dozen stars, called S-stars, approach the black hole—which is about four million times more massive than the sun—its immense gravitational force whips them around faster than 16 million miles per hour. In fact, the gravitational pull of Sagittarius A* is so intense that it warps the light from these stars when they stray too close, stretching the wavelengths toward the red part of the electromagnetic spectrum. Continue reading A Star Orbiting in the Extreme Gravity of a Black Hole Validates General Relativity
Less than two weeks after the gravitational wave detectors turned back on, they’ve already seen evidence of two pairs of colliding black holes. Continue reading Gravitational Wave Detectors Spot Two Potential Black Hole Collisions in a Week
At the center of a galaxy called Messier 87, about 55 million light-years away, about which all of the matter of the galaxy orbits, there lies a monster: a supermassive black hole. With about 6.5 billion times the mass of the sun, the black hole at the center of M87 is so dense that its escape velocity, or the velocity needed to escape the object’s gravity, is more than the speed of light. Accordingly, not even photons of light can escape once they wander too close.
Albert Einstein’s theory of general relativity is magnificent. For a hundred years, it has consistently predicted all sorts of wacky phenomena scientists have later observed throughout space. One international team is now announcing that a 26-year-long observation campaign has once again confirmed the theory. Continue reading Supermassive Black Hole Stretches Starlight, Proving Einstein Right Again
At the core of each large galaxy lies a supermassive black hole with the mass of 1 million suns. New research shows that these celestial vacuum cleaners do more than just devour nearby objects—they also grow to a size that eventually suppresses a galaxy’s ability to churn out new stars, effectively rendering them sterile.
There was a bang. A big one. It was the beginning of everything, but for several hundred million years, all was darkness. Then, lights started flickering to life, stars and gases and galaxies all coming online.