Gravitational time dilation is a phenomenon that occurs due to the influence of gravity on time. It's a concept derived from Einstein's theory of general relativity, which describes the nature of gravity and its effect on space and time.
To understand gravitational time dilation, let's imagine a scenario where you have two observers, let's call them Alice and Bob. Alice is located on a massive celestial object like a planet or a star, while Bob is situated far away in empty space, away from any significant sources of gravity.
Gravity is caused by the presence of mass or energy, and it curves the fabric of space-time itself. In this case, the celestial object where Alice is located creates a gravitational field around it. This gravitational field affects the passage of time near it.
According to general relativity, time flows differently in regions with different gravitational potentials. Near a massive object, the gravitational potential is higher, and as a result, time runs slower compared to regions with lower gravitational potential.
So, when Alice and Bob compare their clocks, they would notice that time appears to pass more slowly for Alice on the celestial object compared to Bob, who is far away from any significant gravitational fields.
In other words, the closer you are to a massive object, the stronger the gravitational field, and the slower time moves for you compared to an observer in a weaker gravitational field.
This phenomenon has been observed and confirmed through various experiments and observations, such as the gravitational time dilation experienced by clocks on GPS satellites relative to clocks on Earth's surface.
In summary, gravitational time dilation is the effect of gravity on the passage of time. The stronger the gravitational field, the slower time moves relative to regions with weaker gravitational fields. It's a fascinating consequence of Einstein's theory of general relativity and has been experimentally validated.