So what is a black hole? A black hole is an object that has an absurd amount of mass crammed into a relatively tiny space. This creates an extreme amount of gravitational force towards the center of the black hole known as the singularity. Once something gets sucked into a black it is unlikely that it will escape since even light is unable to escape a black hole once it is trapped in it. There are five main parts that make up a black hole. These are event horizon, singularity, photon sphere, ergosphere, and innermost stable circular orbit (ISCO). The event horizon is the theoretical boundary around the black hole where matter and electromagnetic radiation, and light can only pass into the mass of the black hole but it cannot escape it. The singularity refers to the center or the eye of the black hole, and the curvature of the black hole becomes infinite at the singularity. The photon sphere is a spherical boundary that does not have a definite or classifies thickness. Photons move perpendicularly to the sphere and it is trapped in an elliptical orbit with respect to the black hole. The ergosphere is the area where things are always moving due to the phenomenon of frame dragging (Frame-dragging is an effect on space-time, predicted by Einstein’s general theory of relativity, that is due to non-static stationary distributions of mass and energy). The final part is the ISCO and this where objects orbit the black hole at certain distances from the singularity. Black holes fundamentally have three properties mass, electrical charge, and spin due to angular momentum. Due to the way black holes are formed, the electrical charge will be close to zero. Angular Momentum is the quantity of rotation of a body, which is the product of its moment of inertia and its angular velocity.
Black holes were first explained by Einstein’s theory of relativity. However, they were first theorized by eighteenth-century scientists John Michell and Pierre-Simon Laplace. Although this idea was ignored by most nineteenth-century scientists, there were some whose curiosity or even belief urged them to discover more. The first modern solution of general relativity that would characterize a black hole was found by Karl Schwarzschild in 1916, although its interpretation as a region of space from which nothing can escape was first published by David Finkelstein in 1958. There are 5 types of black holes. Primordial Black Holes, Miniature Black Holes, Stellar Black Holes, Intermediate Black Holes, and Supermassive Black Holes. Black holes can start small and by sucking in things from the universe around them such as dust and gas, they can grow to be larger and larger.
Primordial Black Holes:
This is the smallest classification of a black hole and is a hypothetical black hole that is thought to have been formed when and shortly after the big bang happened. Apart from being formed very early in the history of the universe, it is also theorized that primordial black holes might be the seeds to other more massive black holes. Scientist suspect that their physical size would be about as big as an atom but have a mass of a mountain.
Miniature Black Holes:
Miniature Black Holes also called quantum mechanical black holes are also theoretical black holes that are thought to have a mass smaller than our Sun and are also thought to be formed early in the history of the universe just like primordial black holes.
Stellar Black Holes:
Once the core of a high mass star completely burns to iron, the energy production, and reactions that have been taking place in the star come to a stop. Following that, the core of the star collapses on itself rapidly and explodes in what is known as a supernova explosion. If the core is greater than about 2-3 solar masses (the maximum mass of a neutron star), the pressure of neutrons is unable to stop the collapse and a stellar black hole is formed. Stellar black holes are thought to have the mass of about a 100 times greater than our Sun.
Intermediate Black Holes:
These mid-size black holes are also known as IMBH. These black holes usually form when two stars of a cluster of stars collide with one another in a chain reaction. Intermediate black holes can also form by a smaller black hole sucking in white dwarfs and other celestial objects. Scientists suspects that intermediate black holes are rare because most black holes have grown.
Supermassive Black Holes:
In 1971, Donald Lynden-Bell and Martin Rees hypothesized in that the center of the Milky Way galaxy would contain a supermassive black hole. Sagittarius A* was discovered and named on February 13 and 15, 1974, by astronomers Bruce Balick and Robert Brown using the Green Bank Interferometer of the National Radio Astronomy Observatory. They discovered a radio source that emits synchrotron radiation; it was found to be dense and immobile because of its gravitation. This was, therefore, the first indication that a supermassive black hole exists in the center of the Milky Way. Over time black holes trap more and more objects or huge supernovas or colliding of stars to become supermassive black holes. Since the universe is currently very old, many black holes have had enough time to grow to become larger and larger. They grow by accretion of matter and merging with other black holes. Accretion is when matter gets attracted to one center due to gravity, and the matter continues to accumulate at a greater rate as the force of gravity increases (gas accretion is one of the fastest ways a black hole grows). Therefore, most black holes in the universe are under the classification of supermassive black holes. Another possibility that had been theorized is that large gas clouds could collapse into a quasi-star. This quasi-star collapses to form a black hole. A quasi-star becomes unstable to radial perturbations because of electron-positron pair production in its core and the collapse into a black hole can occur without the need for a supernova explosion (which would eject most of its mass, preventing the black hole from growing as fast).
Two Interesting Facts About My Topic
- There are 5 main parts that make up a black hole. These parts are event horizon, singularity, photon sphere, ergosphere, and the innermost stable circular object or ISCO.
- There are different types of black holes. These types are primordial, miniature, stellar, intermediate, and supermassive. I also learned that supermassive black holes are thought to be the most abundant.
The Journey Through A Black Hole 