Eli5 How exactly does mass warp the fabric of the universe?

Question

I understand the concept of spacetime being warped (I’ve seen the rubber sheet analogy a thousand times), but does that mean that everything is *technically* always traveling in a straight—albeit warped—line?

In: 2

Answer 1

Yes. If you could somehow ask a fundamental particle the speed and direction that it was traveling in, *from its own perspective*, the answer would always be “straight forward at the speed of light.”

What the different forces in the universe do is to alter what that particle’s definition of “straight forward at the speed of light” looks like *from the perspective of every other fundamental particle in the universe*.