Consider the following phenomena : 1. Light is affected by gravity. 2. The Universe is constantly expanding. 3. Matter warps its surrounding space-time. Which of the above is/are the prediction/predictions of Albert Einstein’s General Theory of Relativity, often discussed in media ?
- (a) 1 and 2 only
- (b) 3 only
- (c) 1 and 3 only
- (d) 1, 2 and 3 ✓ UPSC's answer
Why the answer is (d)
• General Relativity (1915) describes gravity as the curvature of space-time by mass and energy (3).
• A consequence is that light bends when passing near a massive body (1), confirmed by Eddington's 1919 eclipse observations.
• Einstein's field equations also implied a dynamic, non-static universe; Friedmann and Lemaître derived the expanding-universe solutions, confirmed by Hubble in 1929 (2) — the official key counts this as a prediction of the theory.
• Hence 1, 2 and 3, option (d).
Why the other options are wrong
- (a) 1 and 2 only
- Space-time warping is the core of General Relativity.
- (b) 3 only
- Light bending and expansion are also consequences of the theory.
- (c) 1 and 3 only
- The expanding universe also follows from Einstein's equations.
Asked in the GS Paper I of the UPSC Civil Services Preliminary Examination 2018, held on 3 June 2018. Question and answer key: Union Public Service Commission. Explanation: UPSC Answer Check.