Summarize two observations that are contrary to the predictions based on Newton’s laws but that confirm Einstein’s explanation of gravity. Indicate how the predictions based on Newton’s theory differ from Einstein’s.
Two observations that are contrary to Newton's laws but confirm Einstein's explanation of gravity are the precession of Mercury's orbit and the deflection of light passing near massive objects.
1. Precession of Mercury's orbit: According to Newton's laws of gravity, the orbit of a planet should remain fixed and in a constant plane. However, scientists observed that Mercury's orbit gradually shifts over time, known as its precession. This discrepancy between theoretical predictions and actual observations could not be explained by Newton's theory. Einstein's theory of General Relativity, on the other hand, accurately predicts and explains this phenomenon. It takes into account the curvature of space-time caused by the massive Sun, which affects the orbit of Mercury, causing it to precess.
2. Deflection of light near massive objects: Another observation contrary to Newton's laws is the deflection of light when it passes near massive objects. According to Newton, light should travel in straight lines regardless of the presence of massive objects. However, during a solar eclipse in 1919, Sir Arthur Eddington confirmed Einstein's prediction that light would indeed be bent when passing near the massive Sun. This observation provided empirical evidence supporting Einstein's theory of General Relativity. The deflection is caused by the curvature of space-time around massive objects, which influences the path of light.
The predictions based on Newton's theory of gravity differ from Einstein's theory in terms of the concept of gravity itself. Newton's theory explains gravity as a force acting instantaneously between two objects, dependent solely on their masses and distance. It does not account for the curvature of space-time.
Einstein's General Theory of Relativity, on the other hand, describes gravity as the result of the curvature of space-time caused by the presence of mass and energy. According to Einstein, massive objects curve the fabric of space-time around them, and other objects, such as planets or light, move along these curves. This curvature of space-time accounts for the observed phenomena that deviate from Newton's predictions, like the precession of Mercury's orbit and the deflection of light.
Overall, Einstein's theory of General Relativity provides a more comprehensive and accurate description of gravity, incorporating the concept of space-time curvature, which explains the observations that contradict Newton's theories.