When a photon approaches a massive object, such as one with a mass of 10^10 solar masses (Msun), its speed remains constant at the speed of light. However, as the photon enters the gravitational potential well of the mass, its energy increases, resulting in a decrease in wavelength, known as blue shifting. This phenomenon is a direct consequence of general relativity and the interaction between light and gravity.
PREREQUISITESAstrophysicists, physicists, and students studying the effects of gravity on light, as well as anyone interested in the principles of general relativity and photon behavior in strong gravitational fields.
surajc0504 said:imagine a photon (travelling with the speed of light) is moving straight towards a huge mass say 10^10 Msun. what will happen to its speed/energy as it comes closer to it?