I am new to General Relativity, so please excuse my ignorance ahead of time. :)(adsbygoogle = window.adsbygoogle || []).push({});

While attempting to grasp the concept of bending spacetime I was stumped by the concept of continual gravitational forces and how they exist in the concept of GR. To clarify I understand the following as reasonable to say, that given the bending of spacetime the moon orbits about the earth not because it is actually rotating about, but rather because the definition of the straight line path that the moon was taking has been redefined due to a bending of spacetime by the earth. However where I am having trouble is the concept of a book on a table. Gravity is not pushing on the book downward but rather the table is pushing up on the book due to the books original path of travel being redefined to point to the center of the earth (the table is just in the way). Sounds good, however why is the force continual. Meaning why does the book not decelerate by the table and then float off, to illustrate, if I threw the book at the wall in a straight line it would hit the wall and then bounce, not stick to it and stay there with a force based on its weight. To follow that same point if there is no motion of either body in the depths of space would the two attract? Given Newton the answer is yes, however with neither body moving irregardless of straight line definitions it would seem (by my limited understanding) that with GR the answer would be no. Again sorry for the lame question, however I am really stumped by this.

By the way I am currently reading Spacetime and Geometry (Carroll) and using Gravity (Hartle) as a reference. If you have recommendations for any GR books I would be interested.

Thanks

**Physics Forums | Science Articles, Homework Help, Discussion**

The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

# Why are gravity forces on going in the context of GR

**Physics Forums | Science Articles, Homework Help, Discussion**