Two massive black holes have astronomers on edge this Halloween season. One of them has devoured its second star in five years, while the other is part of a mysterious three-body system that challenges standard astrophysics.
According to Einstein’s theory of general relativity, there are millions of black holes in our galaxy alone, formed when stars collapse under their own gravity. These supermassive black holes reside at the centers of galaxies, including our own Milky Way.
One such black hole is notorious for its “tidal disruption event” (AT1910qix), where a star’s gravitational pull was disrupted by the strong gravitational forces near the black hole. The star was torn apart and its material fell into the black hole, but half of it escaped in an expanding disc.
Now, this debris is interfering with another nearby star, causing violent X-ray flashes every 48 hours as the star crashes through the remnant disc. An international team of astronomers has been tracking the phenomenon using a range of space telescopes.
Meanwhile, another mysterious black-hole triple, V404 Cygni, has sparked debate about how these massive objects form. Astronomers have long assumed that black holes are created when stars explode as supernovae, but this system suggests an alternative explanation.
Researchers propose that the black hole in V404 Cygni could have formed without a supernova explosion. This theory challenges conventional models of black-hole creation and highlights the complexity of these cosmic phenomena. As astrophysicist Daniel Holz noted, “Nature decides what can and can’t be done.”
Source: https://www.nytimes.com/2024/10/30/science/space/astronomy-black-holes.html