Black holes are among the most enigmatic features of the cosmos, even as we continue to unravel their mysteries. Although theorized mathematically for many years, the first confirmed black hole was identified in 1971, known as Cygnus X-1.
Today, we understand that black holes are quite common across the universe. For instance, a supermassive black hole named Sagittarius A* resides at the center of our galaxy, the Milky Way. In fact, NASA reports that most galaxies of a similar scale host gigantic black holes at their cores, with Sagittarius A* having a mass about four million times that of our Sun.
Interestingly, black holes aren’t literal holes in the universe. The term is used because their gravitational pull is so intense that even light cannot escape. In visual representations, they often appear as a ring of light orbiting around a dark center, resembling a donut. The central area represents the black hole itself. Similar to stars and planets, black holes spin as well. The ring of luminous material swirling around a black hole is known as the accretion disk, which becomes extremely hot and bright due to its rapid rotation.
It’s a common misconception that black holes are monstrous entities that devour everything in their vicinity. In reality, if our Sun were to be replaced by a black hole of equal mass, the orbits of the planets in our solar system would remain unchanged; they would simply be much colder.
We’re still in the dark when it comes to understanding the nature of matter inside a black hole. What we do know is that any substance crossing the Event Horizon—the boundary of a black hole—would undergo a process known as spaghettification. This bizarre phenomenon involves matter being stretched and compressed into elongated shapes, much like noodles.
NASA clarifies that black holes aren’t mere “cosmic vacuum cleaners.” Their gravitational pull is incredibly powerful, but celestial bodies can orbit black holes just as they do around other stars. While objects can fall in if they venture too close, from a safe distance, gravity operates just as we observe in our own solar system. It’s also understood that some black holes form from the explosive deaths and collapses of stars.
As NASA research astronomer Varoujan Gorjan explains, “Black holes don’t suck. You can orbit a black hole just as you can orbit any other massive object.”
Nonetheless, stars that come near a black hole can face destruction from its immense gravitational forces. This phenomenon is known as a tidal disruption event, where a star may be torn apart or have parts of its material consumed by the black hole, all while it continues its orbit. If any remnants of the star survive, they may continue to be drawn in during subsequent orbits.
Various imaging techniques, including x-ray and ultraviolet detection, are employed to identify black holes. Gravitational wave observatories also monitor the ripples in spacetime generated during the collisions of two black holes. Researchers are actively investigating how the colossal black holes at galaxy centers formed in the first place.
Finding black holes requires ingenuity. One effective method involves observing the rapid orbits of stars around an unseen object—the only explanation for these fast-moving stars is a black hole exerting enough gravitational influence to hold them in place. For instance, Cygnus X-1 was discovered by detecting its accretion disk, formed from material it siphoned off a nearby companion star, which emitted x-rays due to its extreme temperature.
Although there’s no need to fear the black hole at the center of our galaxy expanding to consume everything, scientists are able to track rogue black holes as they drift through the cosmos. The upcoming Nancy Grace Roman Space Telescope, set to launch in 2027, aims to identify black holes by observing the bending of starlight as it passes nearby, an indication of a black hole’s presence.
