The 4 Dimensional Space Time

Brian Greene the American theoretical physicist, mathematician, and string theorist explains the bizarre nature of the fabric of space-time which is a conceptual model combining the three dimensions of space with the fourth dimension of time.

The famous physicist Albert Einstein helped develop the idea of Spacetime as part of his theory of relativity. Brian Greene also credits Newton for his vision of the nature of space and time, although much of what Newton thought to be true about Spacetime is now considered to be wrong.

Brian Greene studies string cosmology which could explain why the space around us has three large dimensions.

Albert Einstein revolutionized our understanding of gravity and laid the foundation for the many scientific and technological breakthroughs that came after him.

The stronger the gravity, the more spacetime curves, and the slower time itself proceeds.

Time goes faster the farther away you are from the earth's surface compared to the time on the surface of the earth. This effect is known as "gravitational time dilation".

To describe the gravitational field of a black hole and the physical quantities such as the spacetime curvature which diverge at the center of the black hole, we need a theory that goes beyond general relativity into the quantum mechanics. Such a theory should allow the description to be extended closer to the center and might even allow an understanding of physics at the center of a black hole.

There are many proposed theories that attempt to explain what gravity is. String theory and Loop quantum gravity are the most popular among these theories. Currently, there is still no complete and consistent quantum theory of gravity, and the candidate models still need to overcome major formal and conceptual problems. They also face the common problem that, as yet, there is no way to put quantum gravity predictions to experimental tests, although there is hope for this to change as future data from cosmological observations and particle physics experiments becomes available.