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 the predictions based on Newton's laws but confirm Einstein's explanation of gravity are:
1. Gravitational Redshift: According to Newton's theory of gravity, the color of light emitted from a source should not be affected by gravity. However, Einstein's theory of general relativity predicts that the wavelength of light will be stretched, or redshifted, as it travels through a strong gravitational field. This prediction was confirmed through experiments that observed light from distant stars passing near massive objects like black holes or massive galaxies. The observed redshift of the light confirmed Einstein's explanation of gravity.
2. Gravitational Lensing: Newton's theory states that gravity does not affect the path of light. In contrast, Einstein's theory of general relativity predicts that gravity can bend the path of light when it encounters a massive object. This prediction was confirmed through observations of distant galaxies whose light was observed to be bent by the gravitational influence of a massive object in the foreground. This phenomenon, known as gravitational lensing, provides further evidence for Einstein's explanation of gravity.
The predictions based on Newton's theory of gravity differ from Einstein's explanation in several ways. Newton's theory assumes that gravity is a force acting instantaneously across distances, while Einstein's theory posits that gravity arises from the curvature of spacetime caused by the mass and energy of objects. Additionally, Newton's theory does not account for the effects of high velocities or strong gravitational fields, whereas Einstein's theory includes these effects in its predictions. Finally, Einstein's theory also predicts that time is affected by gravity, leading to phenomena like time dilation, which is not accounted for in Newton's theory. Overall, Einstein's theory of gravity, known as general relativity, provides a more comprehensive and accurate explanation of gravitational phenomena than Newton's theory.