Black Hole - A point of no return
What is a black hole?
A black hole is a place in space wherein anything can get swallowed up and no substance (including light) can escape from it. In fact, any type of matter that goes into a black hole increases its mass. Matter is present in almost everything like air, pillows, water, etc. Some examples of things that are not matter are sound and light. Read my ‘States of Matter’ blog to find out more about matter.
How are black holes formed?
There are 4 ways in which a black hole can be formed:
A black hole is formed at the end of a star’s lifetime. The star has to be more than 10 times bigger than our sun to become a black hole. Normally, there are forces inside the core that keeps it from collapsing due to its own gravity. Simply put, the core of a big star has hydrogen atoms which collide to form helium which have energy that balances the core. These helium atoms turn into other elements which again creates energy. This process happens until all the hydrogen in a star turns into iron which doesn’t give out any energy This causes the gravity of the star to pull the core inwards, making the core smaller and denser. This process continues until the core can no longer support itself against gravitational collapse. When this happens, the star undergoes an explosion called a supernova. The result of this explosion is that a star has become a black hole. The smaller or denser a black hole the stronger its gravitational pull. Hence, a small black hole is actually more powerful than a larger one.
A black hole is formed when 2 stars collide which called a kilonova explosion.
A black hole is formed through a binary star system (a binary star system is when 2 stars rotate each other). One star starts to take the mass of the other star. It eventually takes so much mass (and hence gravity) that its core can't hold itself and goes supernova! This finally forms a black hole which obviously absorbs the rest of the star’s mass.
Supermassive black holes (read more on the next section of the blog) form from clouds of gas and dust: the same way stars are formed.
Trivia facts:
Trivia question:
A star the size of our Sun manages gravity by combining hydrogen atoms into helium. In contrast, a star 2.5 times larger than our Sun handles gravity by combining hydrogen atoms into helium and then repeatedly using helium causing oxygen, continuing this process until iron is formed. Since iron does not produce energy, the accumulation of iron in the star's core eventually leads to gravitational collapse. As the core contracts it becomes so small that the entire star implodes and after it touches the core it causes a supernova explosion.
Parts of a black hole: The Singularity and the Event horizon
Event horizon: The event horizon of a black hole is like the entrance to an inescapable prison and whatever crosses it, can never escape not even light. The event horizon is the part of the black hole that you can see, everything inside is invisible and unknown. It’s kind of a like a dome of a black hole which covers it and you cannot see through it.
Singularity: when you are inside the black hole you enter a singularity. The singularity is wherein space and time switch their roles. This means that space becomes infinite while time is finite so in theory when you are inside a singularity you can walk or move through space forever but after sometime time you will be stretched so long (this process is called spaghettification). This is because time is finite, it’s basically the end of time. This theory only works in a giant black hole. This is because a small black hole would spaghettify you even before reaching the event horizon
Can you remove the event horizon of a black hole
Before we find out the answer, we need to find out why scientists theorize that you can remove the event horizon of a black hole. When an object spins, it makes energy. This energy can push on the sides of the object, which happens to all planets (including earth). So, in theory, if we increase the rotation of the black hole, it will remove the event horizon. To do this, we have to throw something that is already spinning into the black hole. So, if you just put a lot of very fast spinning matter into the black hole it will result in the removal of the event horizon.
Trivia fact: black holes can also increase their rotation by merge with another Spinning black hole.
Characteristics of a black hole
A black hole is similar to elementary particles (ex: electron). Before we find out the reason to it, let’s understand what is an elementary particle. The world around us, including atoms and molecules, is made up of these particles. An elementary particle is a very simple object which depends on 3 things: mass, spin and charge. How is a black hole similar to an elementary particle? It’s because just like an elementary particle depends on mass, spin and charge; black holes also have mass, can spin and carry an electric charge.
Now let’s do some simulating by changing a black hole’s mass, spin and charge to check if a black hole really is like an elementary particle.
Types of black holes
They are 4 types of black holes. These include: Stellar black holes, Supermassive black holes, Intermediate black holes, and Primordial black holes / Miniature black holes. Let’s understand each of them:
Primordial black holes / Miniature black holes: Primordial black holes are very hypothetical which means scientists have no proof that they actually exist. This is because a black hole is formed from something quite small and as we already know when an object becomes a black hole it actually becomes smaller which makes a primordial black hole super small. The size of the primordial black hole is about the size of a nucleus (to know more about nucleus, read my ‘states of matter’ blog). This also makes them hard for scientists to find. In recent times, only stars and gas clouds have the gravity to collapse upon its own gravity. So, scientists theorize that they were formed just a couple million years after the big bang. If this theory is true, they might be one of the oldest objects in the universe.
Stellar black holes: Unlike miniature black holes, they are not theoretical. In fact, they are the most common – and they are millions of them in the galaxy. They have a mass of 5-20 solar masses, not very big compared to other black holes. Also, the closest black hole to earth, Gaia-BH1, is a Steller black hole.
Intermediate black holes: They are also not theoretical. They might form when 2 Steller black holes collide. They have a mass of 100 to 100,000 solar masses! They also have a diameter of approximately 60,000 km
Supermassive black holes: Supermassive black holes are gigantic, formed from merging of intermediate black holes and the collapse of gas clouds. They are so big that the black hole at the center of the galaxy is 14.6 million miles. In fact, a supermassive black hole is the biggest black hole in the universe.
What is the largest black hole in the universe?
Before understanding the largest black hole in the universe, we have to get an idea of the size of these black holes. Let’s take the largest black hole in our galaxy. It is the supermassive black hole: Sagittarius A-star. It has a diameter of 23 million kms.
This might sound big but it is small compared to the biggest black hole in the universe. It is the supermassive black hole: Ton 618. Which has a diameter of 389.64 billion kms. This is about 19590 times bigger than Sagittarius A-star.
Quasars
Before finding out about quasars let’s find out about accretion disk. When you throw something like a ball into a black hole, it gets squashed and goes inside in a spiral but something is different when you put a star into it. Suddenly, the star also gets squashed but after sometime the material slowly becomes a spiral ring. This ring is called an accretion disk. As the material of the accretion disk collides with each other, they heat up to lacs and lacs of degrees celsius. In the case of supermassive black holes, it absorbs so much material that some of the light and radiation goes into space like a super-powered laser! This light and radiation comes out via the black hole’s poles. This is called a quasar.
What are worm holes and white holes?
Worm holes are hypothetical, just like miniature black holes. There is a theory that states that if you enter a worm hole, you can go to any place in the universe. A wormhole is like a tunnel between two far places in our universe that cuts the travel time from one point to the other. Instead of traveling for many millions of years from one galaxy to another, under the right conditions one could theoretically use a wormhole to cut the travel time down to hours or minutes. While, a white hole is also a hypothetical object but it is the opposite of a black hole. This means instead of taking matter in, it lets matter out. It is also impossible to go inside one. Some scientists find a similarity between the three. When you go into a worm hole you go in through one way. Similarly, you go out via the other way. This sounds suspiciously like getting sucked in by a black hole and coming out via a white hole. This is called the Black Hole-White Hole model.
Is a black hole a threat to our solar system?
There is no evidence or even a remote possibility that a black hole can be a threat to our solar system. The reason for this is that the nearest black hole is about 1,560 light years* away. This means that the minimum number of years for a black hole to crash into our solar system is 1.428 million years. Despite the occurrence of this event being extremely low, it is important to know the impact it can have on a likelihood of such an event. To explain this further, it can be very dangerous to our solar system because of its tendency to absorb anything and everything in its path, and also because it travels through space.
* A light year means the distance light takes to travel in one year.
How to destroy a black hole
Black holes can absorb nearly everything that you throw at it, be it a bomb or any type of explosive. In fact, it actually becomes bigger even if you put energy into it as energy =mass. Even if the black hole collides with another one it won’t be destroyed. To explore more, please read the next section of the blog.
So, how do you destroy it? Well, it is really hard but it is possible. Stephen Hawkings cracked this mystery.
According to Stephen Hawkings, in space there are particles and antiparticles. If the particles and antiparticles collide, they will release a tremendous amount of energy. If an antiparticle or a particle gets absorbed in by a black hole its antiparticle will come out as radiation. This is the only possible way that it gets destroyed. This process, though, can take billions and billions of years.
Trivia fact: The time it takes for a supermassive black hole to evaporate is a number with 100 zeros number of years or 10100 years
What happens if one black hole collides with another black hole?
There is no exact answer to this question, as we need to check the speed at which they are moving, how fast they are rotating and the angle at which they have collided but there are only 2 things that could happen.
Giant black hole: In this scenario the 2 black holes will not be able to escape each other’s gravitational pull. This will cause them to orbit each other. In such an event, they will come closer and closer. After several billion years, they will crash into each other and release a huge amount of energy. If this happens anywhere near our solar system it could destroy it. Fortunately, the closest black hole is too far away to cause any damage.
Floating black hole: In this scenario the bigger black hole will send the smaller black hole floating uncountably into the vast space.
How to take the energy of a black hole
The reason why it is it is possible to take the energy of a black hole is because black holes spin there are 2 results of this.
So, if you throw a rocket into a spinning black hole we can go into it, give it some of the weight of the rocket and a bit rocket fuel to change the direction and use the rotation energy of the black hole to completely escape. So, it is basically a trade, meaning it’s just that the black hole loses more spin. The best option for stealing energy is a fast-spinning black hole, as not only will it give more energy it will also give it faster.
Trivia fact: As black holes can suck up anything including mass and energy, it will also suck up the little invisible energy that the rocket had used to escape. Also, because E=mc2 which means energy is equal to mass, the black hole will become bigger.
Can you become a black hole?
Yes, you can and not only you but anything can become a black hole. This is because a black hole is actually formed when any type of matter (like you) is crushed so hard that it becomes a black hole! Luckily, right now it is impossible for anyone to create a force so powerful that you become a black hole. In fact, if a star 10 times bigger than our sun (14 million km in diameter) became a black hole it would be only 34 km in diameter. The only reason a star can become a black hole is because gravity is the strongest force in the universe and also the only force strong enough to make matter a black hole.
How effective is a black hole at creating energy?
It is very good at this! In fact, it is 100 times better than nuclear fission (the process that generates energy for most factories). This means that black holes are like machines that suck up material, convert it into energy, and store it. To understand this better, let’s imagine black holes as banks. In this scenario, if you throw 1 kg of garbage into a black hole, it can produce nearly enough energy to power the entire United Kingdom for a whole year!
Now, let’s consider how much energy it loses. This loss depends on how long the matter has been inside the black hole and how much mass it has. Let’s go back to the black hole bank analogy. Imagine you deposit a mass equivalent to a number with 1 followed by 171 zeros (10^171) kg into it and leave it there for a billion years (I know, it sounds crazy). After all that time, when they finally check how much energy has been lost, they find that only 3 joules have escaped—just enough to power an average LED for only 3 seconds.
Credit:
https://youtu.be/ulCdoCfw-bY
https://youtu.be/fHQq2Hc7fDM
https://youtu.be/gTsYN2txgAE
https://youtu.be/V4Z8EdiJxgk
https://youtu.be/cFslUSyfZPc
https://youtu.be/e-P5IFTqB98
A black hole is a place in space wherein anything can get swallowed up and no substance (including light) can escape from it. In fact, any type of matter that goes into a black hole increases its mass. Matter is present in almost everything like air, pillows, water, etc. Some examples of things that are not matter are sound and light. Read my ‘States of Matter’ blog to find out more about matter.
How are black holes formed?
There are 4 ways in which a black hole can be formed:
A black hole is formed at the end of a star’s lifetime. The star has to be more than 10 times bigger than our sun to become a black hole. Normally, there are forces inside the core that keeps it from collapsing due to its own gravity. Simply put, the core of a big star has hydrogen atoms which collide to form helium which have energy that balances the core. These helium atoms turn into other elements which again creates energy. This process happens until all the hydrogen in a star turns into iron which doesn’t give out any energy This causes the gravity of the star to pull the core inwards, making the core smaller and denser. This process continues until the core can no longer support itself against gravitational collapse. When this happens, the star undergoes an explosion called a supernova. The result of this explosion is that a star has become a black hole. The smaller or denser a black hole the stronger its gravitational pull. Hence, a small black hole is actually more powerful than a larger one.
A black hole is formed when 2 stars collide which called a kilonova explosion.
A black hole is formed through a binary star system (a binary star system is when 2 stars rotate each other). One star starts to take the mass of the other star. It eventually takes so much mass (and hence gravity) that its core can't hold itself and goes supernova! This finally forms a black hole which obviously absorbs the rest of the star’s mass.
Supermassive black holes (read more on the next section of the blog) form from clouds of gas and dust: the same way stars are formed.
Trivia facts:
- A supernova can result in a black hole (if it is 10 times bigger than our sun), or a neutron star (if it is 2.5 times bigger than our sun). This because a star is 2.5 times bigger than our sun has less mass.
- When hydrogen turns into helium, oxygen, etc. the process is called nuclear fusion
- A binary system is called a binary star system as binary means 2, star system means a system made of just stars
Trivia question:
Why a star has to be 2.5 or more times bigger than our sun to result in a supernova?
A star the size of our Sun manages gravity by combining hydrogen atoms into helium. In contrast, a star 2.5 times larger than our Sun handles gravity by combining hydrogen atoms into helium and then repeatedly using helium causing oxygen, continuing this process until iron is formed. Since iron does not produce energy, the accumulation of iron in the star's core eventually leads to gravitational collapse. As the core contracts it becomes so small that the entire star implodes and after it touches the core it causes a supernova explosion.
Parts of a black hole: The Singularity and the Event horizon
Event horizon: The event horizon of a black hole is like the entrance to an inescapable prison and whatever crosses it, can never escape not even light. The event horizon is the part of the black hole that you can see, everything inside is invisible and unknown. It’s kind of a like a dome of a black hole which covers it and you cannot see through it.
Singularity: when you are inside the black hole you enter a singularity. The singularity is wherein space and time switch their roles. This means that space becomes infinite while time is finite so in theory when you are inside a singularity you can walk or move through space forever but after sometime time you will be stretched so long (this process is called spaghettification). This is because time is finite, it’s basically the end of time. This theory only works in a giant black hole. This is because a small black hole would spaghettify you even before reaching the event horizon
Can you remove the event horizon of a black hole
Before we find out the answer, we need to find out why scientists theorize that you can remove the event horizon of a black hole. When an object spins, it makes energy. This energy can push on the sides of the object, which happens to all planets (including earth). So, in theory, if we increase the rotation of the black hole, it will remove the event horizon. To do this, we have to throw something that is already spinning into the black hole. So, if you just put a lot of very fast spinning matter into the black hole it will result in the removal of the event horizon.
Trivia fact: black holes can also increase their rotation by merge with another Spinning black hole.
Characteristics of a black hole
A black hole is similar to elementary particles (ex: electron). Before we find out the reason to it, let’s understand what is an elementary particle. The world around us, including atoms and molecules, is made up of these particles. An elementary particle is a very simple object which depends on 3 things: mass, spin and charge. How is a black hole similar to an elementary particle? It’s because just like an elementary particle depends on mass, spin and charge; black holes also have mass, can spin and carry an electric charge.
Now let’s do some simulating by changing a black hole’s mass, spin and charge to check if a black hole really is like an elementary particle.
- Spin: As we already know, in theory black holes can lose their event horizon via rotation. We also think that if a black hole is rotating fast, a person going into it would feel as if he were going into a drain – rotating around the center while also going closer to it. While a slow rotating black hole would feel less like a drain and more like a tunnel. So, spin is very important.
- Charge: As, we already know as same charges repel each other (known as electrostatic repulsion) causing something to get repelled by the black hole instead of getting attracted. This makes charge also important.
- Mass: If you increase the mass of a black hole, it might stretch and spaghettify you (stretch you a lot). This makes mass also important.
Types of black holes
They are 4 types of black holes. These include: Stellar black holes, Supermassive black holes, Intermediate black holes, and Primordial black holes / Miniature black holes. Let’s understand each of them:
Primordial black holes / Miniature black holes: Primordial black holes are very hypothetical which means scientists have no proof that they actually exist. This is because a black hole is formed from something quite small and as we already know when an object becomes a black hole it actually becomes smaller which makes a primordial black hole super small. The size of the primordial black hole is about the size of a nucleus (to know more about nucleus, read my ‘states of matter’ blog). This also makes them hard for scientists to find. In recent times, only stars and gas clouds have the gravity to collapse upon its own gravity. So, scientists theorize that they were formed just a couple million years after the big bang. If this theory is true, they might be one of the oldest objects in the universe.
Stellar black holes: Unlike miniature black holes, they are not theoretical. In fact, they are the most common – and they are millions of them in the galaxy. They have a mass of 5-20 solar masses, not very big compared to other black holes. Also, the closest black hole to earth, Gaia-BH1, is a Steller black hole.
Intermediate black holes: They are also not theoretical. They might form when 2 Steller black holes collide. They have a mass of 100 to 100,000 solar masses! They also have a diameter of approximately 60,000 km
Supermassive black holes: Supermassive black holes are gigantic, formed from merging of intermediate black holes and the collapse of gas clouds. They are so big that the black hole at the center of the galaxy is 14.6 million miles. In fact, a supermassive black hole is the biggest black hole in the universe.
What is the largest black hole in the universe?
Before understanding the largest black hole in the universe, we have to get an idea of the size of these black holes. Let’s take the largest black hole in our galaxy. It is the supermassive black hole: Sagittarius A-star. It has a diameter of 23 million kms.
This might sound big but it is small compared to the biggest black hole in the universe. It is the supermassive black hole: Ton 618. Which has a diameter of 389.64 billion kms. This is about 19590 times bigger than Sagittarius A-star.
Quasars
Before finding out about quasars let’s find out about accretion disk. When you throw something like a ball into a black hole, it gets squashed and goes inside in a spiral but something is different when you put a star into it. Suddenly, the star also gets squashed but after sometime the material slowly becomes a spiral ring. This ring is called an accretion disk. As the material of the accretion disk collides with each other, they heat up to lacs and lacs of degrees celsius. In the case of supermassive black holes, it absorbs so much material that some of the light and radiation goes into space like a super-powered laser! This light and radiation comes out via the black hole’s poles. This is called a quasar.
What are worm holes and white holes?
Worm holes are hypothetical, just like miniature black holes. There is a theory that states that if you enter a worm hole, you can go to any place in the universe. A wormhole is like a tunnel between two far places in our universe that cuts the travel time from one point to the other. Instead of traveling for many millions of years from one galaxy to another, under the right conditions one could theoretically use a wormhole to cut the travel time down to hours or minutes. While, a white hole is also a hypothetical object but it is the opposite of a black hole. This means instead of taking matter in, it lets matter out. It is also impossible to go inside one. Some scientists find a similarity between the three. When you go into a worm hole you go in through one way. Similarly, you go out via the other way. This sounds suspiciously like getting sucked in by a black hole and coming out via a white hole. This is called the Black Hole-White Hole model.
Is a black hole a threat to our solar system?
There is no evidence or even a remote possibility that a black hole can be a threat to our solar system. The reason for this is that the nearest black hole is about 1,560 light years* away. This means that the minimum number of years for a black hole to crash into our solar system is 1.428 million years. Despite the occurrence of this event being extremely low, it is important to know the impact it can have on a likelihood of such an event. To explain this further, it can be very dangerous to our solar system because of its tendency to absorb anything and everything in its path, and also because it travels through space.
* A light year means the distance light takes to travel in one year.
How to destroy a black hole
Black holes can absorb nearly everything that you throw at it, be it a bomb or any type of explosive. In fact, it actually becomes bigger even if you put energy into it as energy =mass. Even if the black hole collides with another one it won’t be destroyed. To explore more, please read the next section of the blog.
So, how do you destroy it? Well, it is really hard but it is possible. Stephen Hawkings cracked this mystery.
According to Stephen Hawkings, in space there are particles and antiparticles. If the particles and antiparticles collide, they will release a tremendous amount of energy. If an antiparticle or a particle gets absorbed in by a black hole its antiparticle will come out as radiation. This is the only possible way that it gets destroyed. This process, though, can take billions and billions of years.
Trivia fact: The time it takes for a supermassive black hole to evaporate is a number with 100 zeros number of years or 10100 years
What happens if one black hole collides with another black hole?
There is no exact answer to this question, as we need to check the speed at which they are moving, how fast they are rotating and the angle at which they have collided but there are only 2 things that could happen.
Giant black hole: In this scenario the 2 black holes will not be able to escape each other’s gravitational pull. This will cause them to orbit each other. In such an event, they will come closer and closer. After several billion years, they will crash into each other and release a huge amount of energy. If this happens anywhere near our solar system it could destroy it. Fortunately, the closest black hole is too far away to cause any damage.
Floating black hole: In this scenario the bigger black hole will send the smaller black hole floating uncountably into the vast space.
How to take the energy of a black hole
The reason why it is it is possible to take the energy of a black hole is because black holes spin there are 2 results of this.
- Ringularity: The singularity is a point and a point cannot spin so it is a ringularity which is like a ring.
- Ergosphere: We already know about accretion disks, event horizons and singularities. Yet, there is one more part of a black hole: the Ergosphere. This is where it is possible to enter it and come out. This means it is like going into a drain.
So, if you throw a rocket into a spinning black hole we can go into it, give it some of the weight of the rocket and a bit rocket fuel to change the direction and use the rotation energy of the black hole to completely escape. So, it is basically a trade, meaning it’s just that the black hole loses more spin. The best option for stealing energy is a fast-spinning black hole, as not only will it give more energy it will also give it faster.
Trivia fact: As black holes can suck up anything including mass and energy, it will also suck up the little invisible energy that the rocket had used to escape. Also, because E=mc2 which means energy is equal to mass, the black hole will become bigger.
Can you become a black hole?
Yes, you can and not only you but anything can become a black hole. This is because a black hole is actually formed when any type of matter (like you) is crushed so hard that it becomes a black hole! Luckily, right now it is impossible for anyone to create a force so powerful that you become a black hole. In fact, if a star 10 times bigger than our sun (14 million km in diameter) became a black hole it would be only 34 km in diameter. The only reason a star can become a black hole is because gravity is the strongest force in the universe and also the only force strong enough to make matter a black hole.
How effective is a black hole at creating energy?
It is very good at this! In fact, it is 100 times better than nuclear fission (the process that generates energy for most factories). This means that black holes are like machines that suck up material, convert it into energy, and store it. To understand this better, let’s imagine black holes as banks. In this scenario, if you throw 1 kg of garbage into a black hole, it can produce nearly enough energy to power the entire United Kingdom for a whole year!
Now, let’s consider how much energy it loses. This loss depends on how long the matter has been inside the black hole and how much mass it has. Let’s go back to the black hole bank analogy. Imagine you deposit a mass equivalent to a number with 1 followed by 171 zeros (10^171) kg into it and leave it there for a billion years (I know, it sounds crazy). After all that time, when they finally check how much energy has been lost, they find that only 3 joules have escaped—just enough to power an average LED for only 3 seconds.
Credit:
https://youtu.be/ulCdoCfw-bY
https://youtu.be/fHQq2Hc7fDM
https://youtu.be/gTsYN2txgAE
https://youtu.be/V4Z8EdiJxgk
https://youtu.be/cFslUSyfZPc
https://youtu.be/e-P5IFTqB98
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