Does Gravity Expand Space? Einstein's Theory Explained

In summary, when observing a video explanation of Einstein's theory of General Relativity, we can see a star or planet causing a distortion in the fabric of space. This distortion is represented as a 2D plane in the x-axis, causing objects to "roll" around inside it due to gravity. However, this distortion actually occurs in all dimensions and orientations, making it appear as though gravity is expanding space. The popular representation of this phenomenon as a "curvature" is not entirely accurate, as it is a result of Riemann Geometry and not Euclidean Geometry.
  • #1
pforeman
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When watching a video of an explanation of Einstein's theory of General Relativity, you will see a star or planet distorting the fabric of space. This is always a 2 dimensional plane oriented in the x-axis that gets "dished" by the larger star or planet and the satelite will then roll around inside this dished out area (gravity).
However, this distortion of space would be in all dimensions and orientations, and when you look at it with all the distorted planes in view, it would seem that gravity has expanded space.
Thanks.
Paul
 
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  • #2
pforeman said:
When watching a video of an explanation of Einstein's theory of General Relativity, you will see a star or planet distorting the fabric of space. This is always a 2 dimensional plane oriented in the x-axis that gets "dished" by the larger star or planet and the satelite will then roll around inside this dished out area (gravity).
However, this distortion of space would be in all dimensions and orientations, and when you look at it with all the distorted planes in view, it would seem that gravity has expanded space.
Thanks.
Paul
No, the "distortion" that you see in pop-sci is really just a "curvature" when represented in Euclidean Geometry that does not exist in the actual Riemann Geometry of space-time, where the path is NOT "curved" but is a straight line (formally, a "geodesic"). What you see in pop-sci is the best that can be done with a 2D representation of something that really can't be truly represented well in 2D, and pop-sci isn't likely to bring reality into the picture by talking about Riemann Geometry.
 

1. Does gravity really expand space?

According to Einstein's theory of general relativity, gravity does indeed expand space. This is known as the "curvature of spacetime" and it explains how massive objects like planets and stars create a curvature in space, causing other objects to move towards them.

2. How does gravity expand space?

Gravity expands space by creating a curvature in spacetime. This curvature is caused by the presence of massive objects, which bend the fabric of spacetime. The more massive the object, the greater the curvature and the stronger the gravitational pull.

3. Does this mean that space is constantly expanding?

No, the expansion of space caused by gravity is not the same as the expansion of the universe. The expansion of the universe is a separate phenomenon and is caused by dark energy, not gravity. However, the expansion of space due to gravity can play a role in the overall expansion of the universe.

4. How does Einstein's theory explain this expansion of space?

Einstein's theory of general relativity explains the expansion of space by describing gravity as a curvature in spacetime. This means that the presence of massive objects causes a bending of the fabric of spacetime, which in turn affects the motion of other objects in the vicinity.

5. Is there any evidence to support this theory of gravity expanding space?

Yes, there is strong evidence to support Einstein's theory of general relativity, including the expansion of space caused by gravity. This has been observed in the bending of light around massive objects, the motion of objects in space, and the gravitational waves detected by LIGO. Additionally, many phenomena in our universe, such as the orbits of planets and galaxies, can be accurately explained by this theory.

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