The most intriguing, the most inspiring and the most elusive thing in the entire universe known to mankind is the Black Hole. There are hundreds of questions about Black Holes that are yet to be answered. Some of them have been answered while some others are still within theoretical frameworks and remaining keep giving birth to numerous science fictions we encounter on a day-to-day basis. So, what exactly are these Black Holes? What do we know about these entities? Here are 30 interesting facts about Black Holes that will make your jaws drop but before we give you the rundown, it is necessary that we start with the basic question of ‘what is a Black Hole?’
Black Hole Explained!
Black Holes are nothing but remnants of dead stars. Not all stars convert into Black Holes. Our sun will never become one! Only stars those are 10 to 15 times bigger than sun become Black Holes. We will not really attempt to explain what really happens but we will only say that bigger stars explode at the end of their life (that is, when the burn out all the fuel they have) and this phenomenon is known as Supernova Explosion. When a star dies and this explosion occurs, the majority of the total mass of star is thrown out into the void of the space while only a cold remnant stays back. This remaining part of the star does not experience any fusion reaction that used to give it life.
In a typical star, nuclear fusion is responsible for generation of energy and pressure. This is an outward pressure that neutralizes the gravitational pull created by the star’s own mass. After the supernova explosion, fusion reaction is completely absent. This means no outward pressure is created. As a result, the cold remnant starts collapsing on itself because of its own mass. Because there is nothing that opposes this gravitational pull, the cold remnant eventually collapses on itself and becomes infinitely dense. At this point the gravitational pull becomes so intense that even light fails to escape from it. Because light cannot escape, it becomes completely dark and invisible, giving rise to what we call Black Hole.
Now that we have a fair idea of how a Black Hole is formed, it is time that we learn some interesting facts about Black Holes. Are you ready? Let’s go for a ride.
Black Hole Facts: 1-10
1. The force of gravity is so high in Black Holes that it leads to gravitational time dilation. This is a phenomenon where time slows down because of gravitational pull. Interesting fact is that time dilation can also occur when velocity increases. This is known as velocity time dilation and is generally experienced by astronauts. We will cover this in some other list. Coming back to Black Holes, time completely stops at the center of Black Holes.
2. Black Holes have something known as event horizon! There is some heavy scientific explanation behind this but let us put it in simple words. Event horizon refers to a ‘point of no return’. Every Black Hole has a boundary. Any object outside that boundary is perfectly safe. But if, an object crosses the event horizon, it will have no other option but to fall into the Black Hole. Once sucked in, that object can never reappear.
3. Black Holes are literally the densest objects to live in universe (at least that’s what is known to humans). So, how dense can a Black Hole get? Imagine what kind of density you will get if you try to squeeze in the entire mass of Earth in a small (we mean miniscule) sphere with a DIAMETER of 9 millimeters! That’s the type of density we are talking about.
4. Black Holes can keep growing because anything (gas, liquid or solid matter) that enters the event horizon gets sucked in. Thus, Black Holes can grow infinitely large and they are known as supermassive Black Holes.
5. Stephen Hawking theorized that even Black Holes emit something and that they emit radiation. This radiation is emitted by the mass of the Black Holes. According to Hawking, Black Holes keep losing their mass in form of radiations and eventually they evaporate!
6. Black Holes eventually shrink down to the size smaller than the size of an electron (a sub-atomic particle). At this stage it reaches a size what is known as Planck Length. This length is actually the quantum size limit. Theoretically nothing can become smaller than this and there is actually no instrument available that can measure Planck Length. The value of Planck Length is 1.61619926 x 10-35 meters.
7. The event horizon is just the beginning of the Black Hole. It is not the core of the Black Hole. The core of the Black Hole is called Singularity. This point of Singularity is the ultimate destruction point. Absolutely nothing can survive at that point.
8. Closer to a Black Hole, things simply get distorted. The immense gravitational pull of the Black Holes have the ability to distort even space. This distortion gets profound because Black Holes spin rapidly. This distortion is nothing but an infinite regression of distortions.
9. Stars spin and they continue doing so even after their death. This means they keep spinning even when they become Black Holes and these Black Holes in turn keep spinning faster and faster as they keep evaporating and eventually shrink to Planck Length. Even when they achieve the Planck Length, they keep spinning. Along with this spin and their gravitational force, they distort everything around them (actually within their event horizon).
10. If something travels faster than light, it can actually escape Black Hole. Unfortunately, there is no such thing known to mankind.
Black Hole Facts: 11-20
11. At the point of Singularity, laws of Physics don’t exist because it is literally not possible to conceive anything that will have infinite density but zero volume.
12. Size and mass of a Black Hole are directly proportional. The size of a Black Hole is not really measurable. But there is an alternate way of measuring that. It is known as Schwarzschild Radius. This is the radius of the event horizon of a Black Hole. The bigger the radius, the bigger is the Black Hole. The bigger the Black Hole, the denser it is. Which means that the point of Singularity of a bigger Black Hole has more mass than a Black Hole that is comparatively smaller (that is one with smaller Schwarzschild Radius).
13. There are some scientific equations which end up suggesting that every Black Hole contains one universe. If that is true (this hasn’t been proven yet), everything we know about Black Holes will change. AND, if that is true, we are right now living inside a Black Hole. ‘We’ here refers to the entire universe that keeps eluding us!
14. It is very likely that supermassive Black Holes exist at the center of almost every galaxy. Now that galaxies have a nasty habit of colliding with each other occasionally, even Black Holes do the same! When two Black Holes bump into one another, one of these two gets kicked out of its galaxy.
15. The Black Hole that is closest to our Earth is 16 quadrillion kilometers away from our planet. This is actually 1,600 light years (one light year is the distance traveled by light in one year).
16. Our Milky Way galaxy (the galaxy of which our Solar System is a part) has a supermassive Black Hole at its center. It is known as Sagittarius A* (‘*’ stands for Star) How big is it? Well, its point of Singularity has a mass equivalent to the mass of 4 million solar masses! One solar mass is the total mass of our good old Sun. This behemoth and gigantic sucker is at a very safe distance from us. It is approximately 30,000 light years away from us.
17. The Black Hole at the center of our Milky Way has, according to the scientists, came to life after a star exploded 2 million years ago! That event is termed as Seyfret Flare.
18. The radiation from the Seyfret Flare 2 million years ago was a 100 million times more powerful than the remaining radiation we experience today. Scientists say that so big was the explosion that it was actually visible from Earth!
19. According to scientists, Black Holes don’t just suck, they also emit material. The speed of this emission is nearly the same as the speed of the light. Is it just a theory? Actually some scientists have really found a Black Hole emitting material. This Black Hole is at a distance of 1.5 billion light years from our Earth and is located in a different galaxy. This discovery was made using an array of advanced radio telescopes. So powerful is the jet that material emitted by the Black Hole is blown right out of the galaxy.
20. Recent studies have revealed that even the supermassive Black Hole living at the heart of our galaxy, the Milky Way, emits material. These materials are nothing but energetic particles that are shot out in space along the spin axis of the Black Hole creating an impression of a straight beam right through the center of the Black Hole.
Black Hole Facts: 21-30
21. Black Holes are very much like spheres and not funnels as illustrated in many text books.
22. If a human is dropped in a Black Hole, the person will not likely get crushed to death. He or she will more likely stretch to death. Why? That’s because, whatever part of the person’s body enters the event horizon first will experience immense gravitational pull that will accelerate the speed with which that part falls compared to the speed of the remaining part of the body. This will lead to stretching and hence, death!
23. According to many modern astronomers, not all Black Holes are similar. As a matter of fact, these astronomers actually came up with three distinct classifications (based on the amount of energy put out by the Black Holes when then distort space) which are: Simple spinning Black Holes, Electrical Black Holes and Spinning electrical Black Holes.
24. Black Holes are terribly noisy. It is true that sound waves cannot travel through space vacuum. So, how can one claim that Black Holes are noisy? Scientists say that use of special instruments (we don’t really know what kind of instruments) will reveal staticky sound inside the event horizon. This sound appears when the immense gravitational pull increases the speed of the particles (that appear once the object is broken down into sub-atomic particles after entering the event horizon) nearly to the speed of light. Particles traveling at that speed produce the staticky sound.
25. Any matter that enters the event horizon of a Black Hole is broken down into subatomic particles. These particles, according to scientists, have the ability to create life-supporting elements like carbon and iron.
26. Because gravitational time dilation takes place near Black Holes, if anyone can take a spaceship and orbit around the Black Hole (of course along the event horizon) and then travel back to Earth, the person will actually see future. This happens because time close to the Black Hole passes very slowly compared to that on Earth and by the time the person travels back to Earth, he or she will actually outlive his or her present (the time when the person left Earth)!
27. It is not necessary that only stars will give birth to Black Holes. Any object that can shrink endlessly on itself into a point that is infinitesimally small, it will eventually get a gravitational pull that is ridiculously high and hence, become a Black Hole. Look carefully at your car keys, even they can qualify for this!
28. Some scientists say that Black Holes actually limit the number of stars present in the whole universe. This theory pops out from the fact that Black Holes actually suck in gas and every other known matter and because gas is vital for the formation of stars, the number of Black Holes limit the number of stars.
29. Now, Black Holes are suckers and they are very very real. Some scientists believe that if there are Black Holes that suck, there can be something exactly opposite that will endlessly spew or spurt out matter into this universe. These objects are known as white holes. There was a time when white holes were pure myth and 100% hypothetical. In 2006 however, scientists observed unusual bursts of gamma rays from an object somewhere in our universe. This object may be the first evidence of a real white hole.
30. Albert Einstein didn’t really discover Black Holes. In 1916, Einstein only revived a theory that was developed long ago a scientist by the name John Mitchell. In 1783, Mitchell actually gave the theory of Black Holes after he started wondering whether there could be a gravitational force that could prevent even light particles from escaping the pull.