TheQuestionGuy14 said:Recently I watched a video on Gravity according to General Relativity. The video shows that the Earth rises up to catch the apple, what does this mean? It also shows the time axis being curved as the apple falls. Doesn't this mean that with enough time falling, the time axis will curve into a circle, making a Closed Timelike Curve?
This is a good question. It shows that you are really thinking this through.TheQuestionGuy14 said:It also shows the time axis being curved as the apple falls. Doesn't this mean that with enough time falling, the time axis will curve into a circle, making a Closed Timelike Curve?
It has no physical meaning, it's just how the diagram is spread out in the plane. Look at the rolled up version at 1:10min in the video, where the lowest space coordinate (Earth's surface) is at the same height everywhere.TheQuestionGuy14 said:Recently I watched a video on Gravity according to General Relativity. The video shows that the Earth rises up to catch the apple, what does this mean?
No, to represent more time in the initial flat diagram, you would have to start a new layer every time you come around. This is a purely an illustration layout issue, and has nothing to do with the actual physics.TheQuestionGuy14 said:Doesn't this mean that with enough time falling, the time axis will curve into a circle, making a Closed Timelike Curve?
General Relativity (GR) is a theory developed by Albert Einstein in 1915 to explain the force of gravity. It is based on the idea that gravity is not a force between masses, but rather a curvature of spacetime caused by the presence of mass and energy.
In GR, the curvature of spacetime is responsible for the motion of objects in the presence of mass. In the case of the Earth rising, the curvature of spacetime caused by the Earth's mass causes objects to follow a curved path towards the Earth's surface, giving the appearance of Earth rising.
In GR, time is treated as the fourth dimension, along with the three dimensions of space. The presence of mass and energy causes the curvature of spacetime, which results in the time axis also curving. This means that time is not constant and can be affected by the presence of mass and energy.
No, there are other theories that attempt to explain gravity, such as Newton's theory of gravity and Quantum Mechanics. However, GR is the most widely accepted and successful theory for explaining gravity on a large scale, such as celestial bodies like planets and stars.
GR has had a significant impact on our understanding of the universe. It has allowed us to accurately predict and explain many astronomical phenomena, such as the bending of light by massive objects, the existence of black holes, and the expansion of the universe. It also plays a crucial role in modern technologies, such as GPS systems, which rely on the accurate measurement of time and the effects of gravity on time and space.