Joking about the universe, serious science popularization: Lecture by Liang Canbin on "Black Holes and Wormholes in "Interstellar""
w88 casino News Network (Reporter Ye Xiaoyun）What exactly is a black hole? How to travel through a wormhole? The wonders of the universe are fascinating yet puzzling.2015Year4month14日19:00, accompanied by the melodious and ethereal soundtrack of the movie "Interstellar", Liang Canbin, a famous physics professor at Beijing Normal University, was in the Shaw Research Building102The classroom took the audience on a journey through a wormhole to explore a black hole.
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Professor Liang Canbin, who is silver-haired and energetic, first reviewed basic astronomy knowledge such as the speed of light, light years, and galaxies for the audience, and then gave a series of popular science knowledge explanations based on the plot of the "Interstellar" movie.
Professor Liang Canbin
He first explained the wormhole, the way to achieve interstellar travel in the plot, and visually demonstrated the shape of the wormhole and the way to travel through the wormhole through slides. He compared the spool to a wormhole and led the audience to use the motion trajectory of a pole vault to understand the trajectory through the wormhole, and specifically clarified several common misunderstandings about wormholes. He explained that from a three-dimensional perspective, the mouth of a wormhole is actually spherical, and a spacecraft passing through a wormhole should sail around a spherical surface; a wormhole is a shortcut for interstellar navigation, not because of its short absolute distance, but because the space-time scale inside and outside the wormhole is very different. "The space-time scale inside the wormhole is much shorter than the space-time scale outside the wormhole."
“Black holes are so wonderful, you won’t know if you don’t listen!” Liang Canbin’s jingle led the topic to the mysterious world of black holes. He thinks,As a celestial body formed by the collapse of a large star under its own gravity, a black hole has two main characteristics: singularity and event horizon. The star collapses into a point under its own gravity, which is called a singularity. The singularity has an extremely strong gravitational force that can attract all surrounding particles, including photons, through a one-way film with no entry and no exit and enter the interior. The interior of the film is pitch black, so it is called a black hole. The one-way membrane that separates the invisible area inside the black hole and the visible area outside the black hole is called the event horizon. "The singularity is incredibly strange; the horizon is incredible!" Professor Liang summed it up wittily.
Subsequently, he used different theories to explain several special plot designs in "Interstellar".
Why in the movie, one hour on the giant wave star is equal to one hour on the earth7Year? Liang Canbin introduced two clock slowing effects in the theory of relativity: the clock slowing effect in the special theory of relativity, that is, clocks will run slower on high-speed moving objects; the gravitational field clock slowing effect in the general theory of relativity, that is, clocks will slow down when the gravitational field is strong. Because the giant wave star is close to the black hole, its gravity is extremely strong, so time passes slowly. Immediately afterwards, Professor Liang Canbin gave an example of the importance of relativity knowledgeGPSHelp for navigation system operation.GPSIn the early stages of operation of the system, there was a problem that error accumulation caused the inability to accurately position. This problem can be explained by two clock slow effects:GPSThe satellite rotates around the earth at a high speed, so the clock on the satellite slows down every day7Microseconds, the car on the earth is affected by the strong gravity of the earth, the clock on the car slows down every day45Microseconds, so generated relative to each day38Microsecond error. After the time microseconds are multiplied by the speed of light, the coordinate positioning error per day reaches11.4Kilometers. “The general public’s impression of the theory of relativity is ‘difficult! useless!’” Professor Liang Canbin joked, “In fact, the knowledge of relativity has already entered the mainstreameverybody’s everyday life". The mixture of English and Chinese dialects caused laughter from the audience.
Black holes attract photons, so why do black holes in movies still shine? Liang Canbin summarized two reasons: First, interstellar matter is attracted and rotates at high speed with the black hole as the center. During the rotation, the particles friction heats up and emits light outward, forming a brilliant "accretion disk" around the black hole; second, in the gravitational field, light propagates through curves, and the black hole forms a gravitational lens effect at the observation point. The light around the black hole is actually the light of distant stars.
"The boundary of the line is2points, the boundary of the surface is4lines, the boundaries of the cube are6faces...so, the boundary of the hypercube is8three-dimensional boundary volumes. "Through the detailed graphic presentation of the slides and clear and simple language, Professor Liang Canbin simplified the complex and understood the high dimensions from the low dimensions, and skillfully explained the stunning high-dimensional hypercube structure in the movie.
After the explanation, Professor Liang Canbin patiently answered the questions raised by the students.
Question session
This event is organized by the Academic Practice Department of the w88 casino student union.
