Enrage
发表于 2025-3-23 13:08:48
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贪婪地吃
发表于 2025-3-23 15:26:09
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Demulcent
发表于 2025-3-23 21:32:06
Covariant Differentiation,We must have a method of differentiation that maintains the anti-symmetry, thus making sure that what we end up with after differentiation is still a form.
圆木可阻碍
发表于 2025-3-24 01:10:38
Curvature,The covariant directional derivative of a vector field . along a vector . was defined and interpreted geometrically in Sect. 5.2, as follows.
CRAMP
发表于 2025-3-24 04:38:03
,Einstein’s Field Equations,Energy–momentum conservation for a Newtonian fluid in terms of the divergence of the energy momentum tensor can be shown as follows.
Ceremony
发表于 2025-3-24 08:16:18
The Schwarzschild Spacetime,This is a solution of the vacuum field equations . for a static spherically symmetric spacetime. One can then . the following form of the line element (employing units so that c=1):
bronchodilator
发表于 2025-3-24 12:32:45
Black Holes,Surface gravity is denoted by . and is defined by where . is the horizon radius, . for the Schwarzschild spacetime, . is the time component of the 4-velocity. The 4-velocity of a free particle instantaneously at rest in the Schwarzschild spacetime: The only component of the 4-acceleration different from zero is .
使痛苦
发表于 2025-3-24 18:14:37
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可商量
发表于 2025-3-24 20:36:57
,Newton’s Law of Universal Gravitation,ties, i.e. velocities much smaller than the velocity of light and “weak” fields. Weak fields are fields in which the gravitational potential energy of a test particle is very small compared to its rest mass energy. (Note that here one is interested only in the absolute values of the above quantities
拱形大桥
发表于 2025-3-24 23:28:49
Cosmology,s reference particles. Then we introduce a “comoving coordinate system” in this frame of reference with spatial coordinates χ, θ φ. We use time measured on standard clocks carried by the galactic clusters as coordinate time (cosmic time).