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AviSchiffmann

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  1. Hi so I don't know too much, but I was watching a video and it talked about how scientists have trouble unifying gravity with quantum physics. So I was wondering, maybe we have to take gravity out of the question because all these super tiny things are just too small for gravity to have an affect? I don't know much but just a random thought...
  2. Hi guys I am writing a speech for a school video and I have a maximum of 3 minutes, but I've written 4 minutes and 17 seconds worth of stuff. I need help cutting the fat away giving me around 2 minutes and 45 seconds worth of stuff so that I can have some quick experiments and speak slower so it's easier to understand. If you guys could help me on cutting it down a bit that would be super helpful! Thanks! Speech: What are Black Holes? The information paradox is something that took scientists tens of years to understand, so let’s understand it in 3 minutes. Before we go deeper we need to understand what hawking radiation and a black holes are. Black holes are regions in spacetime with a core called a singularity with infinite density and virtually zero volume. The sphere that surrounds a black hole has a radius that can be calculated if you know the mass of the black hole. This is called the Schwarzschild radius, and surface area that surrounds the sphere is called the event horizon. Hawking Radiation. Another key concept we need to understand is Hawking Radiation, and how it causes black holes to “evaporate.” Over time, the mass of a black hole decreases as it emits particles in the form of radiation. When a pair of virtual particles appear next an event horizon, one particle crosses and the other particle escapes. Therefore, to ensure that conservation of energy is conserved, a black hole loses some of its mass in exchange for the virtual particle. What is information? So what is this “information”? In quantum mechanics, information is basically the arrangement of particles in a specific way. For example, if you arrange carbon atoms in a certain order, you get graphite. If you arrange those same atoms in a different way, you get diamonds. This is stored as what we call information, it’s kind of like if our universe was a giant computer storing everything as 1’s and 0’s. Picture a book. Now picture throwing it into a fire. It’s gone, right? Actually not really. If you could get back all the ashes and collect all the light and heat you could theoretically rebuild the book. The information of the book is not gone, it’s just hard to read. The Information Paradox. Suppose say there was a black hole, and I threw a fish inside it. According to our understanding of the universe, the fish’s information should come out as hawking radiation, but instead we get nothing. Hawking radiation is like a giant cosmic eraser that wipes out information as the black hole evaporates, and when it finally dies it leaves no trace that any information was ever there. Sounds like we got an information paradox, and the journey for an answer has come up with numerous solutions, including that our universe may actually just be a hologram. The Holographic Principle. The Holographic Principle is the idea that the information that falls into a black hole becomes plastered along the event horizon, and imprinted on the hawking radiation. This idea came from the fact that if someone fell into a black hole, an outside observer would never see the person cross the event horizon, and that their information would be smeared across the horizon. So the information is technically still there. But there's a problem. For starters, would the falling object have enough information to affect the hawking radiation, and even if it did have enough, wouldn’t that break the laws of quantum mechanics and create just another information paradox? Well yeah, it turns out that transferring information onto hawking radiation breaks the law of conservation of information just as much as if a black hole were to destroy it. If you were to fall into a black hole, you wouldn’t be frozen at the event horizon like what an outside observer were to see, you would fall right into the black hole with all your information. Once you are inside, your information would radiate out as hawking radiation AND be plastered along the event horizon, so isn’t duplicating? The answer is yea, it violates the quantum “No-cloning theorem” but a Stanford Physicist called Leonard Susskind thinks otherwise. He thinks that the two sources of information are separate, and that it does not violate the no-cloning theorem because of black hole complementarity. So what does this have to do with holograms? Another physicist named Gerard T’ Hooft realized that the falling information might actually clump together and create a bulge on the event horizon, adding more mass to the black hole. These bulges could then interact with the hawking radiation, allowing them to hitch a ride away. So then the information is not destroyed by the black hole. It is but rather a 2-dimensional representation of an object’s information imprinted on the surface of the event-horizon as a kind of indecipherable hologram. This led Gerard T’Hooft to realize that maybe our entire 3D universe is just a projection on a 2D structure. All of this is what is known as the Holographic Principle. Thank you for watching!
  3. Hi, I am working on a video, and I was wondering if any of you knew of some real-life demonstrations I can do about black holes? So far I have the gravity well, and the balloon covered by foil that you crush to show same mass but denser. My video is about the anatomy of a black hole, so I cover all the parts from photon spheres to singularities. Do any of you know of some interesting and or funny demonstrations I can do in real life? Limited visual effects because I want less animation and more me actually doing stuff. Thank you!
  4. Hey guys I have 3 minutes max to make this presentation. How are the facts in this? It's about how black holes work. Also if anyone has any cool ideas on how I can visually do an experiment relating to black holes or anything in the video please tell me. Also should I get rid of the part about field equations and replace it with hawking radiation or the photon sphere? Thanks! (Black solid with text saying 40 billion M☉) 40 billion solar masses. (Cut to me) That’s the size of the S5 0014+81, the largest known black hole in the universe. But did you ever wonder how they work? It all begins with Stars. In their core, nuclear fusion combines four hydrogen nuclei into one helium nucleus, releasing an enormous amount of energy in the form of radiation. This energy pushes against the gravity on the star, maintaining a balance between forces. The energy from the fusion allows stars to fuse heavy elements until it reaches iron. Iron does not release any energy when it is fused, so gravity gains the upper hand, breaking the equilibrium. When a very massive star uses the rest of its nuclear fuel, and there are no more reactions to fight the gravity, it explodes as a supernova. If the core remaining is at least 2.5 times the mass of the sun, gravity will eventually collapse the core into a singularity. A singularity is a mathematical point with virtually zero volume and infinite density. When this happens, it would require a velocity greater than the speed of light to escape the singularity’s gravity. According to Einstein's Theory of Relativity, it is impossible for any object to reach a speed faster than light. Therefore any matter or radiation, including light, that passes within the event horizon of a black hole is trapped forever. Wait. What was that about the Einstein? (Maybe wear a cutout photo of Einstein as a mask? Or have Einstein as a green screen standing next to me) In the early 20th century, Albert Einstein published two theories of relativity. The Special Theory of Relativity, and the General Theory of Relativity. But we only care about the general one right now. According to the general theory of relativity, matter and energy bend space and time. Also known as gravity. This is why objects that travel near a large mass will appear to move along a curved path in space-time. Why do we care? To do this theory, Einstein needed a set of formulas called the field equations. This is where Karl Schwarzschild comes in with a solution. The field equations state that an extremely dense ball of matter create a spherical region in space where nothing can escape. Sound familiar? That’s because it is. Using the field equations we know that if we have the mass of a black hole, we can determine the size of the sphere that surrounds the black hole. This is where Karl comes in. The radius of that sphere is called the Schwarzschild radius, and the surface area that surrounds that sphere is called the event horizon. And as we know from earlier, once something enters the black hole, it’s not coming back. Is there only one type of black hole? Nope! There are three main types that are classified based on their size and mass. The smallest ones are known as Primordial black holes, and are believed to be as small as an atom, but have have the mass of a mountain. Next there are medium-sized black holes. These are called Stellar black holes because their mass can be up to 20 times greater than the mass of our sun and fit into a radius of 8 km. Then we have the champion of all black holes. Supermassive black holes have masses that are greater than 1 million suns and are about as big as our own solar system. Scientists believe that a supermassive black hole resides in the center of all galaxies, including the milky way.
  5. Hey guys I updated my script and changed a bit, what do you think now? Black holes are one of the weirdest things in space. They can warp space and time, and even swallow up entire stars! But did you ever wonder how they created and work? Stars are massive collections of mostly hydrogen atoms. In their core, nuclear fusion combines 2 hydrogen atoms into 1 helium atom, releasing an enormous amount of energy. This energy pushes against the gravity on the star, maintaining a balance between those two forces and creating heat. All of the energy at the core allows the star to fuse heavy elements until it reaches iron. But iron is special, unlike the other elements it doesn’t release any energy when it is fused, so the iron builds up inside the core until the balance between gravity and energy is broken. In a fraction of a second the star collapses under gravity and explodes into a supernova. If the star is massive enough, the core will collapse into a singularity, the center of a black hole. But if the star is not big enough, it will instead turn into a neutron star. The boundary surrounding a black hole is called the event horizon, once you enter it, not even light can escape. You would need to have an escape velocity higher than the speed of light to break out, and according the Einstein's Theory of Relativity, that is impossible. The size of an event horizon is based upon the Schwarzschild radius, which states how much mass needs to be compressed for the gravitational effect of that mass to be so strong that even light can’t escape. For example, the sun would need to be compressed into 3 km, and for the earth, the Schwarzschild radius is even smaller at about 1 cm. Although, light doesn’t necessarily have to enter the event horizon. There is a really wonky place called the Photon Sphere, which is 1.5x the Schwarzschild radius, where light itself actually orbits a black hole. The gravity that pulls the light in is just as much as the momentum that carries it away from the black hole. If you were to find yourself in the photon sphere, you could look sideways and actually see the back of your head because the photons reflecting off the back of your head would travel all around the black hole right back to your eyes. But if photons have no mass, how do they orbit a black hole? Since gravity has an effect on space time, if a photon were to pass by the spacetime, it would be warped and enter the Photon Sphere. Black holes eventually die, just like most things in the universe. Spinning black holes evaporate due to a process called Hawking Radiation. To understand this we have to look at what is called “empty space”. Empty space isn’t really empty though, it is filled with virtual particles that pop into existence. In quantum mechanics, temporary violations of the conservation of energy can occur when one particle can become a pair of heavier particles, what we call virtual particles, that quickly rejoin the original particle as if they never existed. When this happens at the edge of the event horizon, one of the virtual particles will be drawn into the black hole, and the other one will be shot out and turned into a real particle. Therefore Hawking radiation causes the black hole to lose energy and mass, which ultimately causes it to evaporate. I have a speaking limit of 3 minutes btw
  6. Thanks so much this is really helpful! Do you recommend I talk about Spaggehtification at the end or more about the Schwarzschild's radius?
  7. Hey everyone, is anyone able to check the facts of this speech I wrote? It's about the Schwarzschild radius and Spaghettification. Thank you so much! Black holes are an extremely heavy region of space where all sorts of crazy things happen in physics. To make a black hole, you need a lot of mass crammed into a very small amount of space. Imagine cramming the entire Earth into a ball you could fit into your pocket. One of the essential ways a black hole can be formed, is by having an amount of mass, say a star, and compressing it until it reaches the tipping point, collapsing into a singularity, the center of a black hole. This is called the Schwarzschild radius, and it is the formula that explains how far you need to compress an object until it reaches its tipping point and collapses into a black hole. To find the tipping point we need the Schwarzschild's radius formula. The size of Schwarzschild's radius solely relies on the mass of the object, the rest of the numbers in the formula are all constants. So the more dense you make the object, the larger the Schwarzschild's radius will be. That means that if I were to compress the Earth to the size of a peanut, the Schwarzschild's radius would be quite small because a peanut is only a few centimeters large. But if you had a much bigger object, say an extremely dense star, the Schwarzschild's radius would be a lot bigger because the mass is much larger. You can figure out the tipping point of anything, even yourself. Our sun has a Schwarzschild's radius of about 3 km, our earth, just 1 cm. But what about you? Since the other numbers besides mass in the formula are constants, we can rewrite it as 1.49*10^-27. I weigh 54 kg, so if I plug my mass into the formula, I would need to be compressed into 8.02*10^-26 meters. That's 0.00000000000000000000000000802 meters. Because compressing something that small takes so much energy, it would be near impossible for this to ever happen, but not for stars with very large masses. When a very massive star collapses in upon itself, it causes a supernova. The massive amount of energy from the supernova causes stars to be compressed way past the Schwarzschild’s radius, causing them to form a singularity. The gravitational pull from the singularity is so great, that not even light can reach the escape velocity once it passes the event horizon. But what would you see if you fell into a black hole? As you are pulled in, space and time would warp around you, and by the time the black hole filled half your vision, you would be in the Photon Sphere. At this point, the photons in light actually orbit the black hole. When you finally cross the event horizon, things would begin to hurt. As you inch towards the singularity, parts of you that are closer would be pulled more strongly. This is because the closer you get to the singularity, the more the gravitational forces begin to have an effect on you. Your entire body would be stretched towards the singularity with extreme forces. The molecules inside of your body would be ripped and stretched apart until you are nothing but a string of atoms adding to the mass of the black hole. This is a process called Spaghettification because the forces pulling on the object would stretch it into long thin shapes that resemble spaghetti.
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