How does gravity affect time dilation?

Gravity affects time dilation by slowing down time in stronger gravitational fields compared to weaker ones.

In the realm of physics, particularly in Einstein's theory of General Relativity, gravity is not just a force but a curvature in the fabric of space-time caused by mass and energy. This curvature creates what we perceive as gravitational force. One of the most intriguing predictions of General Relativity is that time passes slower in stronger gravitational fields compared to weaker ones, a phenomenon known as gravitational time dilation.

Imagine a clock placed at a certain height above the Earth's surface. According to General Relativity, this clock will run faster than an identical clock placed on the Earth's surface. This is because the gravitational field is weaker at higher altitudes compared to the surface. The difference might be minuscule, but it is measurable with precise instruments. This effect has been confirmed by numerous experiments, including the famous Hafele-Keating experiment which involved atomic clocks flown around the world in commercial airliners.

The principle of gravitational time dilation also has practical applications. For instance, the Global Positioning System (GPS) has to take into account the time dilation effect. The satellites in the GPS system are in a weaker gravitational field compared to the receivers on Earth. Therefore, the clocks on the satellites run faster than the clocks on Earth. If this effect was not accounted for, the GPS system would quickly accumulate errors and become useless.

In essence, gravity affects time dilation by causing time to pass at different rates in different gravitational fields. This is a fundamental aspect of our universe, deeply rooted in the fabric of space-time itself. Understanding this concept is not just crucial for theoretical physics, but also for practical applications like satellite-based navigation systems.