Why does time slow down as you get closer to the black hole?

 In a video presented at the World Science Festival, Britannica's publishing partner Prian Greene revealed that the story of black holes originated with the meteorologist, mathematician, and astronomer. German Karl Schwarzschild.

During World War I, he was sent to the Russian front to help calculate bombing trajectories. "And somehow, in the middle of the battlefield, he got access to Einstein's theory of relativity and did some calculations based on it," Green said. Through those calculations, Schwarzschild realized that when spheres of considerable mass collapse and are crushed into very small pieces, the force of gravity will be so strong that nothing in the sphere of influence of a The black hole can escape its pull. Just like Einstein's theory predicted: black holes twist, bend, and distort space-time. 

Black holes twist, bend, and distort space-time.

To understand why time slows down as an object approaches a black hole, you need to understand what time dilation is. Einstein - obsessed with time and space - was the first to realize that time is only relative. After more than a decade of research, Einstein published his theory of relativity in 1915, shocking all Newtonian believers and ushering in a scientific revolution.

Einstein reasoned that although the laws of physics are invariant in the universe, the speed or motion of time and space are not constant but are relative. But relative to what? The answer is from the observer's point of view.

Einstein often talked about trains and the difference in time and speed perception of people above and below a moving train. For example, he showed that a speeding train would travel much faster for a person standing on the platform than for someone chasing that train on another train running parallel to it. This led to a series of experiments being carried out with clocks and atomic clocks, and the resulting answers proved that Einstein was right: time is not constant, and it can expand.

But scientifically speaking, time does not change according to an observer's position; it changes because of changes in gravity. Scientists have demonstrated these changes in time by measuring atomic clocks placed on top of buildings and on the ground, or on satellites in orbit and above Earth. So, if gravity can change time, what happens to time in the presence of the supermassive gravity of a black hole?

It takes an extremely large object, like a black hole, to make a noticeable difference in the timeline.

When it comes to the relationship between time and black holes, we have the most obvious example of time dilation, because black holes are the densest objects in the universe and have the greatest gravity. NASA JPL studied black holes to understand the interactions between space and time. The team explains that as an object approaches a black hole, the flow of time slows down from the perspective of the observer, who is experiencing the timeline when it is unaffected by the black hole.

For example, if a star comes close to a black hole and we can see that star from Earth with a telescope, we will see it slow down until it actually freezes in the timeline. space, and we'll never see it fall into a black hole! However, from the point of view of that star, time passed as usual.

Einstein's theory of relativity states that time will slow down near any large object due to its gravity. That's called time dilation because of gravity, which increases exponentially near black holes. Black holes were once dying stars, sometimes hundreds or thousands of times the mass of our Sun, but collapsed and compressed to a very small size. 'It takes an extremely large object, like a black hole, to make a noticeable difference in the timeline. There's still a lot to learn about what happens to time and space inside a black hole,' according to NASA JPL's Ota Lutz.