Blackholes - Blind love of astrophysicists.
There are many interesting facts, many are observed phenomena and many other are purely theoretical as we cannot go and experiment near a blackhole.
1. Nothing can escape
The very famous thing about blackholes which everyone knows is the fact that,nothing can escape the gravity of blackholes, not even light. Thoughphotons are massless, but it is the bend in space time curve (General Relativity) caused by blackhole, which forces the light to travel through the bent space inside blackhole.
2. Singularity
Singularity is a point which doesn't contain any spatial dimension, means that point doesn't contain any height length or breadth. It is just asingular point with no shape and size, and infinite density. Singularity point was also the starting point of Big Bang.
My other answer on singularity is here.
3. Mystery beyond Event Horizon
Event horizon is the boundary line of blackhole. Anything which crosses event horizon cannot return back, hence it is also called point of no return. It is called as event horizon because whatever events occurs beyond that boundary line, it cannot affect an outside observer. Rotating blackholes can havedistorted and non spherical event horizons.
4. Really, are blackholes really black? Hawking Radiation.
Blackhole sucks up everything, even light, then how it can emit anything? Thanks to Sir Hawking for finding out the answer to this mystery.
Due to quantum fluctuations, pair of virtual particle appear in space and then they disappear almost immediately.
What is Hawking Radiation?
Imagine a pair of virtual particles, say A and B gets created at the event horizon, and before they disappear, particle A enters the event horizon while particle B goes away in opposite direction. Hawking has considered these quantum fluctuations and quantum corrections at the event horizon for black hole, and found that the blackholes emits these non cancelled particles (like particle B), known as Hawking Radiation.
5. Nothing is forever, not even blackholes.
Who can destroy the most massive and powerful object in the universe?Blackholes evaporates over time, and thus one day the black hole willcompletely disappear. We know that blackholes emits Hawking radiation, and that Hawking radiation carries away some mass and energy along with it. Thus blackholes gets evaporated slowly over time in the form of Hawking Radiation.
6. Death of a massive star - Birth of a Blackhole.
Blackholes are created as a result of most violent events in the universe -Supernova. When the fuel of star gets over, the star tries to fuse heavier atoms in it's core. Based on the size and mass of star, either it will die a slow death and become a neutron star, or the star will explode with a very bigexplosion called as supernova. Once the star has exploded into supernova, it will leave behind a blackhole, which is so massive that it curves spacetime in itself.
Source: Home - remnant of supernova 1E 0102.2-7219, about 190,000 light-years.
7. Whiteholes - Opposite of blackholes.
It was said that at the core of blackhole lies singularity. Recent studies suggests that a black hole might vomit up all the matter and energy at the other end of it, resulting in white hole. Black hole curves space time and thus emits massive energy to somewhere else, as a whitehole. One such whitehole we know BIG BANG, who knows may be the big bang is a white hole of a giant black hole.
8. Blackhole also gives rise to most brightest object in the universe - Quasars.
Blackholes possess mass billions of times the mass of the Sun. Due to it's immense gravity, the matter around around the blackholes also gets attracted by it. When the matter gets too close, it forms an accretion disk around the black hole. Due to immense gravity and collision of matter particles, thematerial heats up to millions of degrees, blasting out an enormous amount of radiation. The magnetic environment around the black hole forms twin jets of material which could be many light-years long.
9. Blackholes - The Architect of Universe.
It was discovered that almost every galaxy has a massive blackhole at it's center. It is this center galactic black hole, around which the entire galaxy rotates. Our own milky way is also having a massive blackhole, which isbillions of times more massive than sun. It is blackholes which shapedthe galaxies, and shaped the universe the way we observe it today. Infact quasars are generally formed by center galactic black holes.
10. Gravitational waves are caused by blackholes.
When two massive object moves around space in some kind of harmony, then it may cause gravitational wave. Imagine two blackholes dancing salsa. There are two black holes which are rotating around each other. Their gravity will bend the fabric of space-time, and thus the continuous rotating motion will create a wave in ripple form.
My detailed answer on Gravitation Wave is here.
11. Black holes freezes time
Blackholes freezes time beyond event horizon. As per general relativity the clock will tick slower at higher gravity than at lower gravity. This phenomena is also known as gravitational time dilation.
Please read my detailed answer on this Vivek Keshore's answer to Does time depend on gravity?
11. Black holes and Theory of Everything (TOE)
Theory of Everything is like holygrail for physicists. String theory is one of the solid contender which can lead to the ultimate theory - Theory of Everything. String theory is not proved till now experimentally. But we know blackholes are out there in universe, and string theory predicts supersymmetric black holes. Thus making string theory a more strong theory which is like one step closer towards TOE.
Please read more about string theory, black holes and TOE in my other answer here.
12. Blackholes, holograms and Information paradox
Taking a snippet of my other anwser.
What is information paradox?
Imagine this, you are preparing a milk shake in a blender. While blending a piece of paper from your pocked falls inside blender and the paper gets ripped off and gets mixed with the shake. As per quantum mechanics the information written on your paper is still inside the blender, though you cannot recognize it in normal way, but it is there. Information is not lost, it is in some other form inside blender. Quantum mechanics says the information cannot be lost.
The information stored in a black hole is proportional to its surface area (in two dimensions) rather than its volume (in three dimensions). This could be explained by quantum gravity, where the three dimensions of space could be reconstructed from a two-dimensional world without gravity – much like a hologram. String theory was shown to be holographic in this way.
Using holography we can describe the evaporation of the black hole in the two-dimensional world without gravity. So holography tells us thatinformation is not lost in black holes.
Also it leads to a very fascinating question, are we all just a hologram on the surface of this universe?
13. Blackholes are the future of the universe.
We know that stars die after they burn all their fuel. So, after few billion years when all the stars would have burned their fuel, only black holes will remain in the universe. The black universe, where there will be no light. Soon, blackholes will also evaporate over time, and there will be nothing in this universe. Not a single ray of light. As the universe started with a big bang, it will one day end with either big crunch or big rip.
There are many interesting facts, many are observed phenomena and many other are purely theoretical as we cannot go and experiment near a blackhole.
1. Nothing can escape
The very famous thing about blackholes which everyone knows is the fact that,nothing can escape the gravity of blackholes, not even light. Thoughphotons are massless, but it is the bend in space time curve (General Relativity) caused by blackhole, which forces the light to travel through the bent space inside blackhole.
2. Singularity
Singularity is a point which doesn't contain any spatial dimension, means that point doesn't contain any height length or breadth. It is just asingular point with no shape and size, and infinite density. Singularity point was also the starting point of Big Bang.
My other answer on singularity is here.
3. Mystery beyond Event Horizon
Event horizon is the boundary line of blackhole. Anything which crosses event horizon cannot return back, hence it is also called point of no return. It is called as event horizon because whatever events occurs beyond that boundary line, it cannot affect an outside observer. Rotating blackholes can havedistorted and non spherical event horizons.
4. Really, are blackholes really black? Hawking Radiation.
Blackhole sucks up everything, even light, then how it can emit anything? Thanks to Sir Hawking for finding out the answer to this mystery.
Due to quantum fluctuations, pair of virtual particle appear in space and then they disappear almost immediately.
What is Hawking Radiation?
Imagine a pair of virtual particles, say A and B gets created at the event horizon, and before they disappear, particle A enters the event horizon while particle B goes away in opposite direction. Hawking has considered these quantum fluctuations and quantum corrections at the event horizon for black hole, and found that the blackholes emits these non cancelled particles (like particle B), known as Hawking Radiation.
5. Nothing is forever, not even blackholes.
Who can destroy the most massive and powerful object in the universe?Blackholes evaporates over time, and thus one day the black hole willcompletely disappear. We know that blackholes emits Hawking radiation, and that Hawking radiation carries away some mass and energy along with it. Thus blackholes gets evaporated slowly over time in the form of Hawking Radiation.
6. Death of a massive star - Birth of a Blackhole.
Blackholes are created as a result of most violent events in the universe -Supernova. When the fuel of star gets over, the star tries to fuse heavier atoms in it's core. Based on the size and mass of star, either it will die a slow death and become a neutron star, or the star will explode with a very bigexplosion called as supernova. Once the star has exploded into supernova, it will leave behind a blackhole, which is so massive that it curves spacetime in itself.
7. Whiteholes - Opposite of blackholes.
It was said that at the core of blackhole lies singularity. Recent studies suggests that a black hole might vomit up all the matter and energy at the other end of it, resulting in white hole. Black hole curves space time and thus emits massive energy to somewhere else, as a whitehole. One such whitehole we know BIG BANG, who knows may be the big bang is a white hole of a giant black hole.
8. Blackhole also gives rise to most brightest object in the universe - Quasars.
Blackholes possess mass billions of times the mass of the Sun. Due to it's immense gravity, the matter around around the blackholes also gets attracted by it. When the matter gets too close, it forms an accretion disk around the black hole. Due to immense gravity and collision of matter particles, thematerial heats up to millions of degrees, blasting out an enormous amount of radiation. The magnetic environment around the black hole forms twin jets of material which could be many light-years long.
9. Blackholes - The Architect of Universe.
It was discovered that almost every galaxy has a massive blackhole at it's center. It is this center galactic black hole, around which the entire galaxy rotates. Our own milky way is also having a massive blackhole, which isbillions of times more massive than sun. It is blackholes which shapedthe galaxies, and shaped the universe the way we observe it today. Infact quasars are generally formed by center galactic black holes.
10. Gravitational waves are caused by blackholes.
When two massive object moves around space in some kind of harmony, then it may cause gravitational wave. Imagine two blackholes dancing salsa. There are two black holes which are rotating around each other. Their gravity will bend the fabric of space-time, and thus the continuous rotating motion will create a wave in ripple form.
My detailed answer on Gravitation Wave is here.
11. Black holes freezes time
Blackholes freezes time beyond event horizon. As per general relativity the clock will tick slower at higher gravity than at lower gravity. This phenomena is also known as gravitational time dilation.
Please read my detailed answer on this Vivek Keshore's answer to Does time depend on gravity?
11. Black holes and Theory of Everything (TOE)
Theory of Everything is like holygrail for physicists. String theory is one of the solid contender which can lead to the ultimate theory - Theory of Everything. String theory is not proved till now experimentally. But we know blackholes are out there in universe, and string theory predicts supersymmetric black holes. Thus making string theory a more strong theory which is like one step closer towards TOE.
Please read more about string theory, black holes and TOE in my other answer here.
12. Blackholes, holograms and Information paradox
Taking a snippet of my other anwser.
What is information paradox?
Imagine this, you are preparing a milk shake in a blender. While blending a piece of paper from your pocked falls inside blender and the paper gets ripped off and gets mixed with the shake. As per quantum mechanics the information written on your paper is still inside the blender, though you cannot recognize it in normal way, but it is there. Information is not lost, it is in some other form inside blender. Quantum mechanics says the information cannot be lost.
The information stored in a black hole is proportional to its surface area (in two dimensions) rather than its volume (in three dimensions). This could be explained by quantum gravity, where the three dimensions of space could be reconstructed from a two-dimensional world without gravity – much like a hologram. String theory was shown to be holographic in this way.
Using holography we can describe the evaporation of the black hole in the two-dimensional world without gravity. So holography tells us thatinformation is not lost in black holes.
Also it leads to a very fascinating question, are we all just a hologram on the surface of this universe?
13. Blackholes are the future of the universe.
We know that stars die after they burn all their fuel. So, after few billion years when all the stars would have burned their fuel, only black holes will remain in the universe. The black universe, where there will be no light. Soon, blackholes will also evaporate over time, and there will be nothing in this universe. Not a single ray of light. As the universe started with a big bang, it will one day end with either big crunch or big rip.
No comments:
Post a Comment