The Universe is a strange place. It’s so mysterious and beautiful. Sometimes people fall in love with its beauty. But once a wise man said, “Love is a dangerous thing” and the universe is full of dangerous things.
|INTERSTELLAR / R. HURT / CALTECH|
Sometimes scientists discovered something so strange that makes us think, How little knowledge about the universe we have. The more we know about the universe, the more we realize that we know nothing about it. Well, that’s how people felt when science confirms that black holes really exist.
What Is a Black Hole
The black hole is a very massive and approximately infinitely dense object. The black hole’s gravity is so high even the light itself can’t escape from its gravitational field. The black hole has so much mass in a tiny area that the gravity produced by it becomes stronger than any other force.
The idea of a black hole is proposed in the 18th century based on the laws of gravity known by that time. According to these gravitational laws, the more mass an object has, the more small & dense it became. Also, the more gravitational force the surface of that object will feel.
Both John Michel and Pierre Simon Laplace separately said that it is impossible to avoid the effects of gravity of an object who possessed extreme high mass and too small size, Even light will not be able to escape from it.
But In Reality, Albert Einstein was the first who predicted the existence of black holes in 1916, with his general theory of relativity. A few years later, In 1967, John Archibald Wheeler was the one who gave the name black hole to these extremely highly massive objects in which light can’t escape.
Physicists and mathematicians have found out that near the black hole spacetime act in a strange way, and because of these strange properties, black holes have been the favorite thing for science fiction writers. But a black hole isn’t a fantasy. Whenever an extremely massive star died, then it collapses inside itself because of its gravity, and a black hole is born.
After decades of black holes being known only as theoretical objects, the first physical black hole ever discovered in 1971. Then, in 2019, the Event Horizon Telescope (EHT) collaboration released the first image ever recorded of a black hole.
Do The Black Holes Follow The Laws Of Physics?
You may say black holes don’t follow the current laws of physics. The current physical laws can’t explain them. Black holes are the challenge for the laws of physics as we know them but nothing can defy the laws of physics.
Something is inconsistent with the laws of physics, then they need to be modified to accommodate the inconsistency. Black holes are extreme objects. They were first predicted from the Schwarzschild solution to Einstein’s theory of relativity.
Many people had thought, black holes don’t exist until evidence was found. Few theories suggested that the black hole breaks the laws of physics.
One is that there is a singularity that exists inside a black hole. A singularity is a point of infinite density and infinite curvature of spacetime. Physicist Kip Thorne described singularity as a point where every law of physics got destroyed.
Another one is the information paradox. If the particle falls into a black hole, information about its state got lost. This is a complete violation of the law of conservation of energy.
Dr. Stephen Hawking published his theory to explain the information paradox. According to his theory, when a particle entered into the region of the event horizon, the energy of the particle eventually evaporates, leaving the quanta of Hawking radiation in space.
From this perspective, Maldacena‘s insight holds, and there is no information loss in the process. And that makes people think that we need new laws of physics. Yes, black hole defies the laws of physics as we know them, and that means our current laws of physics are incomplete, or we need new laws of physics.
What Is The Size Of a Black Hole?
The size of a black hole’s radius is determined by the radius of the event horizon or Schwarzschild radius. Schwarzschild radius is the region in space around a black hole where even light can’t escape from its gravitational effects. People gave it a dramatic name “The point of no return”.
There are two different ways to explain how big something is. The first one is “how much mass an object contains” and the second one is “how much space an object takes”.
As we know already know, black holes are singularities that have an infinitely dense form of matter and energy. We can’t explain what infinite density looks like and the infinite density causes infinite curvature in spacetime.
The radius of the black hole directly depends on its mass, so we can answer the question, “What is the size of a black hole?” Based on the size and amount of mass, scientists have divided black holes into four categories.
Type Of Black Hole
The mass of the black hole is measured into the solar mass. The solar mass is a standard unit of mass in astronomy, which is equal to approximately 2×1030 kg.
- Stellar-mass black hole- The black hole has a mass under 10 to 100 solar masses is categorized under a stellar-mass black hole.
- Supermassive black hole- These black holes present in the centre of a galaxy. Such one also presents in our Milky Way’s center, called “Sagittarius-A” which has 4.3 million solar mass.
- Intermediate black hole- Because of the vast gap in size of stellar-mass and supermassive black holes, astronomers also believed that Intermediate black holes also exist in the universe and the belief got real when the black hole name HLX-1 discovered which estimated to be around 20,000 solar masses.
- Miniature black hole- These are the tiny black holes whose minimum mass would be equal to plank mass. These are related to quantum mechanics. They formed during the early universe when density fluctuations were too high. These are short-lived black holes and evaporate too quickly through Hawking radiation.