How Much Do You Know About Black Holes?

Black holes are extremely dense points in space that produce large gravity sinks. Even light cannot escape the strong pull of a black hole's gravity once it reaches a specific area. And in a theoretical process fittingly known as spaghettification, anything that ventures too close, be it a star, planet, or spaceship, will be stretched and squished like putty.

Black holes can be classified as stellar, moderate, supermassive, or small. Stellar death is the process that produces black holes the most frequently. The majority of dying stars will expand, lose mass, and then cool to produce white dwarfs. However, the most colossal of these flaming bodies—those at least 10–20 times as massive as our sun—are destined to either become stellar-mass black holes or very dense neutron stars.

Supernovae are gigantic explosions that occur when big stars reach the end of their lives. Such a burst leaves the central core behind but launches star stuff into space. When the star was still alive, nuclear fusion produced a steady outward push that counteracted the gravitational attraction of the star's own mass. But because there are no longer any forces to counteract that gravity, the star core starts to collapse in on itself in the stellar remnants of a supernova.

A black hole is born when a mass collapses into an incredibly small point. Black holes have extremely strong gravitational pulls because of how much mass they can fit into such a small space—many times the mass of our own sun. There could be thousands of these stellar-mass black holes in the Milky Way alone.

One black hole is not like the others

Einstein's general theory of relativity foresees supermassive black holes, which could have masses equivalent to billions of suns and are thought to reside at the cores of most galaxies. Sagittarius A* (pronounced "ay star"), a supermassive black hole that is more than four million times as massive as our sun, is located at the core of the Milky Way.

The smallest black hole family members are currently only speculative. It's possible that these tiny dark vortices began to exist shortly after the big bang, or 13.7 billion years ago, and then quickly dissipated. Although there is currently some debate about the evidence, astronomers also believe that the cosmos contains a type of objects known as intermediate-mass black holes.

Black holes can develop during the course of their existence regardless of their initial size, swallowing gas and dust from any nearby objects. Theoretically, due to a dramatic rise in gravity as one falls towards the black hole, anything that exceeds the event horizon, the point at which escape is impossible, is doomed to spaghettification. Astrophysicist Neil Degrasse Tyson once put it this way when he said that as you are being stretched, you are also being squeezed and being forced through space's fabric like toothpaste is forced through a tube.

Black holes, however, aren't quite "cosmic vacuum cleaners," as frequently portrayed in popular culture. To win this gravitational tug-of-war, objects must progressively get closer to one another. Our planetary family, for instance, would continue to circle unaffected even if our sun were abruptly replaced by a black hole of comparable mass. It would just be much less warm and lit.

Peering through the darkness

Astronomers cannot directly observe black holes like they do the myriad glittering cosmic objects in the sky because they swallow all light. But there are a few indicators that point to the existence of black holes.

For one, anything near a black hole feels the strong gravitational pull of the object. These erratic movements are used by astronomers to guess the presence of the nearby invisible monster. Alternatively, objects may orbit a black hole, and to find a likely candidate, astronomers might search for stars that appear to orbit nothing.

That's how astronomers finally identified Sagittarius A* as a black hole in the early 2000s .Black holes often betray their locations since they are messy eaters. Their powerful gravitational and magnetic forces superheat the infalling gas and dust, causing it to radiate radiation as they reach the nearby stars.A portion of this luminous debris swirls around the black hole in an accretion disk.

Even material that first enters a black hole may not remain there permanently. Stardust falling into black holes can occasionally be ejected by powerful radiation-filled burps.