第7章致密天体课件.ppt

* /headlines/y2003/04mar_xrayteachers.htm?list477791 !! Any mass causes the rubber sheet (space) to be curved. As people assemble at the appointed spot on the sheet the curvature grows progressively larger, as shown in frames (a), (b), and (c). The blue arrows represent some directions in which information can be transmitted from place to place. The people are finally sealed inside the bubble (d), forever trapped and cut off from the outside world. * /headlines/y2003/04mar_xrayteachers.htm?list477791 !! Any mass causes the rubber sheet (space) to be curved. As people assemble at the appointed spot on the sheet the curvature grows progressively larger, as shown in frames (a), (b), and (c). The blue arrows represent some directions in which information can be transmitted from place to place. The people are finally sealed inside the bubble (d), forever trapped and cut off from the outside world. * 度规（系数），它是一个张量，故又叫度规张量。给定度规张量，空间的度量性质就完全确定了。 * Fill in your favorite city map here. * This light source, moving closer and closer to a black hole, emits radiation in all directions. (a) At large distances from the hole, most of the light (marked in blue) escapes into space. (b) As the distance decreases, more and more of the radiation is deflected by the black holes gravity onto paths that intersect the event horizon, and this radiation is trapped (shown in red). (c) At a distance of 1.5 Schwarzschild radii, photons can orbit the hole on circular trajectories, which mark the photon sphere. (d) Eventually, when the source reaches the horizon, all the light it emits is destined to enter the hole. * Light emitted from the event horizon itself would be gravitationally redshifted to infinitely long wavelengths. * As a photon escapes from the strong gravitational field close to a black hole it must expend energy to overcome the holes gravity. This energy does not come from a change in the speed at which it travels (this is always 300,000 km/s, even under these extreme condi