A black hole is a region of spacetime from which gravity prevents anything, including light, from escaping.[1] The theory of general relativity predicts that a sufficiently compact mass will deform spacetime to form a black hole. Around a black hole, there is a mathematically defined surface called an event horizon that marks the point of no return. The hole is called "black" because it absorbs all the light that hits the horizon, reflecting nothing, just like a perfect black body in thermodynamics.[2][3] Quantum field theory in curved spacetime predicts that event horizons emit radiation like a black body with a finite temperature. This temperature is inversely proportional to the mass of the black hole, making it difficult to observe this radiation for black holes of stellar mass or greater.
Objects whose gravity fields are too strong for light to escape were first considered in the 18th century by John Michell and Pierre-Simon Laplace. The first modern solution of general relativity that would characterize a black hole was found by Karl Schwarzschild in 1916, although its interpretation as a region of space from which nothing can escape was first published by David Finkelstein in 1958. Long considered a mathematical curiosity, it was during the 1960s that theoretical work showed black holes were a generic prediction of general relativity. The discovery of neutron stars sparked interest in gravitationally collapsed compact objects as a possible astrophysical reality.
Black holes of stellar mass are expected to form when very massive stars collapse at the end of their life cycle. After a black hole has formed it can continue to grow by absorbing mass from its surroundings. By absorbing other stars and merging with other black holes, supermassive black holes of millions of solar masses may form. There is general consensus that supermassive black holes exist in the centers of most galaxies.
Despite its invisible interior, the presence of a black hole can be inferred through its interaction with other matter and with electromagnetic radiation such as light. Matter falling onto a black hole can form an accretion disk heated by friction, forming some of the brightest objects in the universe. If there are other stars orbiting a black hole, their orbit can be used to determine its mass and location. These data can be used to exclude possible alternatives (such as neutron stars). In this way, astronomers have identified numerous stellar black hole candidates in binary systems, and established that the core of our Milky Way galaxy contains a supermassive black hole of about 4.3 million solar masses.
Showing posts with label Michio Kaku. Show all posts
Showing posts with label Michio Kaku. Show all posts
Sunday, December 21, 2014
Wednesday, September 10, 2014
Michio Kaku: The Universe in a Nutshell
What if we could find one single equation that explains every force in the universe? Dr. Michio Kaku explores how physicists may shrink the science of the Big Bang into an equation as small as Einstein's "e=mc^2." Thanks to advances in string theory, physics may allow us to escape the heat death of the universe, explore the multiverse, and unlock the secrets of existence. While firing up our imaginations about the future, Kaku also presents a succinct history of physics and makes a compelling case for why physics is the key to pretty much everything.
The Universe in a Nutshell: The Physics of Everything
Michio Kaku, Henry Semat Professor of Theoretical Physics at CUNY
The Floating University
Originally released September, 2011.
Directed / Produced by Jonathan Fowler, Kathleen Russell, and Elizabeth Rodd
The Universe in a Nutshell: The Physics of Everything
Michio Kaku, Henry Semat Professor of Theoretical Physics at CUNY
The Floating University
Originally released September, 2011.
Directed / Produced by Jonathan Fowler, Kathleen Russell, and Elizabeth Rodd
Monday, June 17, 2013
Einstein [History Channel]
Video
Einstein, History Channel, documentry of Einstein, science, math, genius, Michio Kaku, Dr. Kaku
Einstein, History Channel, documentry of Einstein, science, math, genius, Michio Kaku, Dr. Kaku
Saturday, February 9, 2013
Space Bubble Baths and the Free Universe
How can you create a universe from nothing? Well if you calculate the total matter of the universe it is positive. If you calculate the total energy of the universe it is negative because of gravity. Gravity has negative energy. When you add the two together what do you get? Zero, so it takes no energy to create a universe. Universes are for free. A universe is a free lunch.
Michio Kaku -- We have found the Higgs boson. So then the next question is what's next? Well the Large Hadron Collider, this machine that is 27 miles in circumference, costing 10 billion dollars is big enough to create the next generation of particles. So the Higgs boson in some sense is the last hurrah for the old physics, the old physics of what is called the standard model, which gives us quarks and electrons. The new theory is going to take us into dark matter. Now we know dark matter exists. Dark matter is invisible, so if I held it in my hand you wouldn't see it. In fact, it would go right through my fingers, go right through the rock underneath my feet and go all the way to China. It would reverse direction and come back from China all the way here to New York City and go back and forth.
So dark matter has gravitational attraction, but it is invisible and we are clueless as to what dark matter really is. The leading candidate for dark matter today is called the sparticle. The sparticle is the next octave of the string. Now look around you. Everything around you, we think, is nothing but the lowest vibration of a vibrating string, the lowest octave in some sense, but a string of course has higher octaves, higher notes. We think that dark matter could in fact be nothing but a higher vibration of the string. So we think that 23% of the universe, which is the dark matter's contribution to the universe, comes from a higher octave of the string. Now the standard model which we have ample verification of only represents four percent of the universe. So the universe of atoms, protons, neutrons, neutrinos - that universe only represents four percent of what there is. 23% is dark matter, which we think is the next vibration up of the string and then 73% of the universe is dark energy.
Dark energy is the energy of nothing. It's the energy of the vacuum. Between two objects in outer space there is nothing, nothing except dark energy, dark energy, which is pushing the galaxies apart. So when people say if the universe is expanding they say two things, what's pushing the galaxies apart and what is the universe expanding into. Well what's pushing the galaxies apart is dark energy, the energy of nothing. Even vacuum has energy pushing the galaxies apart. And then what is the universe expanding into? Well if the universe is a sphere of some sort and we live on the skin of the sphere and the sphere is expanding what is the sphere expanding into? Well obviously a bubble, a balloon expands into the third dimension even though the people living on the balloon are two dimensional.
So when our universe expands what does it expand into? Hyperspace, a dimension beyond what you can see and touch. In fact, string theory predicts that there are 11 dimensions of hyperspace, so we're nothing but a soap bubble floating in a bubble bath of soap bubbles and so in some sense the multiverse can be likened to a bubble bath. Our universe is nothing but one bubble, but there are other bubbles. When two bubbles collide that could merge into a bigger bubble, which could be the big bang. In fact, that is what probably the big bang is or perhaps a bubble fissioned in half and split off into two bubbles. That could be the big bang. Or perhaps the universe popped into existence out of nothing. That is also a possibility.
And so the universe could essentially be nothingness, which was unstable and created a soap bubble Now you may say to yourself well that can't be right because that violates the conservation of matter and energy. How can you create a universe from nothing? Remainder of transcript - http://bigthink.com/ideas/49273
Directed / Produced by Jonathan Fowler & Elizabeth Rodd
Michio Kaku -- We have found the Higgs boson. So then the next question is what's next? Well the Large Hadron Collider, this machine that is 27 miles in circumference, costing 10 billion dollars is big enough to create the next generation of particles. So the Higgs boson in some sense is the last hurrah for the old physics, the old physics of what is called the standard model, which gives us quarks and electrons. The new theory is going to take us into dark matter. Now we know dark matter exists. Dark matter is invisible, so if I held it in my hand you wouldn't see it. In fact, it would go right through my fingers, go right through the rock underneath my feet and go all the way to China. It would reverse direction and come back from China all the way here to New York City and go back and forth.
So dark matter has gravitational attraction, but it is invisible and we are clueless as to what dark matter really is. The leading candidate for dark matter today is called the sparticle. The sparticle is the next octave of the string. Now look around you. Everything around you, we think, is nothing but the lowest vibration of a vibrating string, the lowest octave in some sense, but a string of course has higher octaves, higher notes. We think that dark matter could in fact be nothing but a higher vibration of the string. So we think that 23% of the universe, which is the dark matter's contribution to the universe, comes from a higher octave of the string. Now the standard model which we have ample verification of only represents four percent of the universe. So the universe of atoms, protons, neutrons, neutrinos - that universe only represents four percent of what there is. 23% is dark matter, which we think is the next vibration up of the string and then 73% of the universe is dark energy.
Dark energy is the energy of nothing. It's the energy of the vacuum. Between two objects in outer space there is nothing, nothing except dark energy, dark energy, which is pushing the galaxies apart. So when people say if the universe is expanding they say two things, what's pushing the galaxies apart and what is the universe expanding into. Well what's pushing the galaxies apart is dark energy, the energy of nothing. Even vacuum has energy pushing the galaxies apart. And then what is the universe expanding into? Well if the universe is a sphere of some sort and we live on the skin of the sphere and the sphere is expanding what is the sphere expanding into? Well obviously a bubble, a balloon expands into the third dimension even though the people living on the balloon are two dimensional.
So when our universe expands what does it expand into? Hyperspace, a dimension beyond what you can see and touch. In fact, string theory predicts that there are 11 dimensions of hyperspace, so we're nothing but a soap bubble floating in a bubble bath of soap bubbles and so in some sense the multiverse can be likened to a bubble bath. Our universe is nothing but one bubble, but there are other bubbles. When two bubbles collide that could merge into a bigger bubble, which could be the big bang. In fact, that is what probably the big bang is or perhaps a bubble fissioned in half and split off into two bubbles. That could be the big bang. Or perhaps the universe popped into existence out of nothing. That is also a possibility.
And so the universe could essentially be nothingness, which was unstable and created a soap bubble Now you may say to yourself well that can't be right because that violates the conservation of matter and energy. How can you create a universe from nothing? Remainder of transcript - http://bigthink.com/ideas/49273
Directed / Produced by Jonathan Fowler & Elizabeth Rodd
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