A Beautiful Mind.
In 1947, John Nash (starring Russell Crowe) arrives at Princeton University. He is co-recipient, with Martin Hansen , of the prestigious Carnegie Scholarship for mathematics. At a reception, he meets a group of other promising math and science graduate students, Richard Sol, Ainsley, and Bender. He also meets his roommate Charles Herman, a literature student.
Nash is under extreme pressure to publish, but he wants to publish his own original idea. His inspiration comes when he and his fellow graduate students discuss how to approach a group of women at a bar. Hansen quotes Adam Smith and advocates "every man for himself", but Nash argues that a cooperative approach would lead to better chances of success. Nash develops a new concept of governing dynamics and publishes an article on this. On the strength of this, he is offered an appointment at MIT where Sol and Bender join him.
Some years later, Nash is invited to the Pentagon to crack encrypted enemy telecommunication. Nash can decipher the code mentally, to the astonishment of other decrypters. He considers his regular duties at MIT uninteresting and beneath his talents, so he is pleased to be given a new assignment by his mysterious supervisor, William Parcher (Harris) of the United States Department of Defense. He is to look for patterns in magazines and newspapers in order to thwart a Soviet plot. Nash becomes increasingly obsessive about searching for these hidden patterns and believes he is followed when he delivers his results to a secret mailbox.
Meanwhile, a student, Alicia Larde , asks him to dinner, and the two fall in love. On a return visit to Princeton, Nash runs into Charles and his niece, Marcee . With Charles' encouragement, he proposes to Alicia and they marry.
Nash begins to fear for his life after witnessing a shootout between Parcher and Soviet agents, but Parcher blackmails him into staying on his assignment. While delivering a guest lecture at Harvard University, Nash tries to flee from people he thinks are foreign Russian agents, led by Dr. Rosen. After punching Rosen in an attempt to flee, Nash is forcibly sedated and sent to a psychiatric facility he believes is run by the Soviets.
Dr. Rosen tells Alicia that Nash has paranoid schizophrenia and that Charles, Marcee, and Parcher exist only in his imagination. Alicia investigates and finally confronts Nash with the unopened documents he had delivered to the secret mailbox. Nash is given a course of insulin shock therapy and eventually released. Frustrated with the side-effects of the antipsychotic medication he is taking, which make him lethargic and unresponsive, he secretly stops taking it. This causes a relapse and he meets Parcher again.
Shortly afterward, Alicia discovers Nash is once again working on his "assignment." Realizing he has relapsed, Alicia rushes into the house to find her baby submerged in the tub. Nash claims that Charles was watching the baby. Alicia calls Dr. Rosen, but Nash believes Parcher is trying to kill her. He rushes in to push Parcher away, and accidentally knocks Alicia and the baby to the ground. As Alicia flees the house with their baby, Nash jumps in front of Alicia's car and begs her to stay. Nash tells her that he realizes that he's never seen Marcee age, even though he's known her for three years. He finally accepts that Parcher and other figures are hallucinations. Against Dr. Rosen's advice, Nash decides not to restart his medication, believing that he can deal with his symptoms himself. Alicia decides to stay and support him with this.
Nash returns to Princeton and approaches his old rival, Hansen, now head of the mathematics department. He grants Nash permission to work out of the library and to audit classes. Over the next two decades, Nash learns to ignore his hallucinations. By the late 1970s, he is allowed to teach again.
In 1994, Nash wins the Nobel Memorial Prize in Economics for his revolutionary work on game theory, and is honored by his fellow professors. The movie ends as Nash, Alicia, and their son leave the auditorium in Stockholm; Nash sees Charles, Marcee, and Parcher standing to one side and watching him.
Wednesday, February 8, 2017
Black Hole 2- History
The idea of a body so massive that even light could not escape was briefly proposed by astronomical pioneer John Michell in a letter published in 1783-1784. Michell's simplistic calculations assumed that such a body might have the same density as the Sun, and concluded that such a body would form when a star's diameter exceeds the Sun's by a factor of 500, and the surface escape velocity exceeds the usual speed of light. Michell correctly noted that such supermassive but non-radiating bodies might be detectable through their gravitational effects on nearby visible bodies. Scholars of the time were initially excited by the proposal that giant but invisible stars might be hiding in plain view, but enthusiasm dampened when the wavelike nature of light became apparent around the early eighteenth century; if light were a wave rather than a "corpuscle", it became unclear what, if any influence gravity would have on escaping light waves. In any case, thanks to modern relativity, we now know that Michell's picture of a light ray shooting directly out from the surface of a supermassive star, being slowed down by the star's gravity, stopping, and then free-falling back to the star's surface, is fundamentally incorrect.
The idea of a body so massive that even light could not escape was briefly proposed by astronomical pioneer John Michell in a letter published in 1783-1784. Michell's simplistic calculations assumed that such a body might have the same density as the Sun, and concluded that such a body would form when a star's diameter exceeds the Sun's by a factor of 500, and the surface escape velocity exceeds the usual speed of light. Michell correctly noted that such supermassive but non-radiating bodies might be detectable through their gravitational effects on nearby visible bodies. Scholars of the time were initially excited by the proposal that giant but invisible stars might be hiding in plain view, but enthusiasm dampened when the wavelike nature of light became apparent around the early eighteenth century; if light were a wave rather than a "corpuscle", it became unclear what, if any influence gravity would have on escaping light waves. In any case, thanks to modern relativity, we now know that Michell's picture of a light ray shooting directly out from the surface of a supermassive star, being slowed down by the star's gravity, stopping, and then free-falling back to the star's surface, is fundamentally incorrect.
Black Hole 1
A black hole is a region of spacetime exhibiting such strong gravitational effects that nothing—not even particles and electromagnetic radiation such as light which can escape from inside it. The theory of general relativity predicts that a sufficiently compact mass can deform spacetime to form a black hole. The boundary of the region from which no escape is possible is called the event horizon. Although the event horizon has an enormous effect on the fate and circumstances of an object crossing it, no locally detectable features appear to be observed. In many ways a black hole acts like an ideal black body, as it reflects no light. Moreover, quantum field theory in curved spacetime predicts that event horizons emit Hawking radiation, with the same spectrum as a black body of a temperature inversely proportional to its mass. This temperature is on the order of billionths of a kelvin for black holes of stellar mass, making it essentially impossible to observe.
Objects whose gravitational 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. Black holes were long considered a mathematical curiosity; it was during the 1960s that theoretical work showed they 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 visible light. Matter that falls onto a black hole can form an external accretion disk heated by friction, forming some of the brightest objects in the universe. If there are other stars orbiting a black hole, their orbits can be used to determine the black hole's mass and location. Such observations 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 radio source known as Sagittarius A*, at the core of our own Milky Way galaxy, contains a supermassive black hole of about 4.3 million solar masses.
On 11 February 2016, the LIGO collaboration announced the first observation of gravitational waves; because these waves were generated from a black hole merger it was the first ever direct detection of a binary black hole merger. On 15 June 2016, a second detection of a gravitational wave event from colliding black holes was announced.
A black hole is a region of spacetime exhibiting such strong gravitational effects that nothing—not even particles and electromagnetic radiation such as light which can escape from inside it. The theory of general relativity predicts that a sufficiently compact mass can deform spacetime to form a black hole. The boundary of the region from which no escape is possible is called the event horizon. Although the event horizon has an enormous effect on the fate and circumstances of an object crossing it, no locally detectable features appear to be observed. In many ways a black hole acts like an ideal black body, as it reflects no light. Moreover, quantum field theory in curved spacetime predicts that event horizons emit Hawking radiation, with the same spectrum as a black body of a temperature inversely proportional to its mass. This temperature is on the order of billionths of a kelvin for black holes of stellar mass, making it essentially impossible to observe.
Objects whose gravitational 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. Black holes were long considered a mathematical curiosity; it was during the 1960s that theoretical work showed they 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 visible light. Matter that falls onto a black hole can form an external accretion disk heated by friction, forming some of the brightest objects in the universe. If there are other stars orbiting a black hole, their orbits can be used to determine the black hole's mass and location. Such observations 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 radio source known as Sagittarius A*, at the core of our own Milky Way galaxy, contains a supermassive black hole of about 4.3 million solar masses.
On 11 February 2016, the LIGO collaboration announced the first observation of gravitational waves; because these waves were generated from a black hole merger it was the first ever direct detection of a binary black hole merger. On 15 June 2016, a second detection of a gravitational wave event from colliding black holes was announced.
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