College Physics II – Mechanics, Sound, Oscillations, and Waves
Definition
Einstein's theory of general relativity describes gravity as the curvature of spacetime caused by mass and energy. It extends the principles of special relativity to incorporate gravitational fields.
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General relativity predicts that massive objects cause a distortion in spacetime, which is perceived as gravity.
The theory explains the precession of Mercury's orbit better than Newtonian mechanics.
One of its key equations is the Einstein field equation: $$R_{\mu\nu} - \frac{1}{2}Rg_{\mu\nu} + \Lambda g_{\mu\nu} = \frac{8\pi G}{c^4} T_{\mu\nu}$$.
Predicted phenomena include gravitational time dilation, where time runs slower in stronger gravitational fields.
The bending of light around massive objects, known as gravitational lensing, was confirmed during a solar eclipse in 1919.
Review Questions
How does general relativity describe gravity differently from Newtonian mechanics?
What significant prediction about Mercury's orbit does general relativity explain?
Explain gravitational lensing and how it was confirmed.
Related terms
Spacetime: A four-dimensional continuum combining the three spatial dimensions and time into a single construct.
Gravitational Time Dilation: A difference in the elapsed time measured by two observers due to a difference in gravitational potential between their locations.
Einstein Field Equations: $$R_{\mu\nu} - \frac{1}{2}Rg_{\mu\nu} + \Lambda g_{\mu\nu} = \frac{8\pi G}{c^4} T_{\mu\nu}$$; these equations describe how matter and energy determine spacetime curvature.