Black Hole

A black hole is an infinite gravitational collapse within the fabric of spacetime. Space collapses towards what is called a singularity, with an event horizon around the object beyond which is ongoing gravitational collapse.

Formation of Black Holes

Black holes originate from massive stars that collapse under their own gravity after exhausting their nuclear fuel.

This leads to a temporary cooling of the interior of the star, which has run out of fuel, thus it is not undergoing the same rates of thermonuclear fusion as before. Causing the outer mass of the star to collapse in on itself, leading to a supernova explosion.

A great deal of the heaviest elements that form our known periodic table are forged in the hearts of stars, in this fashion.

During the collapse, if the core’s mass is sufficient, it can form a black hole, while lighter remnants may become neutron stars .

Structure of Black Holes

Event Horizon — is the boundary around a black hole beyond which nothing can escape, appearing as a black sphere.

The event horizon of a black hole is the limit of its gravitational collapse. Beyond the event horizon, the gravity would be the same as that of a star with the same mass as the black hole — albeit significantly smaller.

Beyond the event horizon, on the outside looking in, the gravity of the black hole behaves like any normal celestial object. When you cross the event horizon, you are in an infinite gravitational collapse.

The Singularity — At the center of a black hole, the object is theorized to be infinitely dense. However, at present its exact nature remains unknown. The singularity is an emerging property from Einstein’s Field Equations.

After Einstein first published his field equations in the early 20th century, Karl Schwarzschild was the first physicist to solve them. From his work is derived the Schwarzschild Radius of a Black Hole, for example, which defines an approximation of the radius a mass would have to be compacted to create a black hole singularity — for the object to be a black hole.

Essentially what this says is that there is a specific density that a mass — a mass of any size — to be compressed enough that it obeys the Schwarzschild condition for the formation of a black hole. Evidently, there is a limit on density in the universe, beyond which an event horizon and singularity are created. A black hole.

Supernova explosions are one way we believe black holes to be formed. The collapse of the interior of the star pounds in like a spherical anvil, all at once in the core of the star, which appears to exceed that density limit in the core, causing a black hole to be formed.

Interestingly, the conditions for an infinite gravitational collapse are not infinite in themselves.

Misconceptions about Black Holes

Contrary to popular belief, black holes do not “suck” objects like a vacuum cleaner; if the Sun were replaced by a black hole of equal mass, Earth’s orbit would remain unchanged.

Experience of Falling into a Black Hole

As one approaches the Event Horizon, time appears to slow down, creating a visual effect where the outside universe seems to speed up .

Two potential outcomes exist for someone crossing the Event Horizon: being stretched into a stream of plasma due to extreme gravitational forces or encountering a “firewall” that terminates them instantly .

Types and Sizes of Black Holes

Black holes vary in size, from Stellar Mass black holes to Supermassive black holes found at the centers of galaxies, with the largest known being 40 billion times the mass of the Sun .

Hawking Radiation and Black Hole Evaporation

Black holes can evaporate over time through Hawking radiation, a process where virtual particles near the Event Horizon are emitted into space. These virtual particles are energy, and thus result in the loss of mass of the black hole.

This evaporation is extremely slow, with the largest black holes potentially taking up to a googol years to completely dissipate. [1] Black holes might exist long after a universe itself has become no longer habitable.