Space-time itself is curved, therefore there is no such thing as a straight line.
If anyone wants to grasp the basics: here is some fun reading (leading on to some beautiful math). Changing the idea of parallelity leads to hyperbolic geometry and other fun stuff. :)
Please correct my layman understanding if I’m wring here. But isn’t everything traveling in a straight line until an external force is applied. For example the earth orbiting the sun is traveling in a straight line in a curved apacetime. Also if you jump, the moment you leave the ground until you touch it again coming back down you were traveling in a straight line.
Also if you jump, the moment you leave the ground until you touch it again coming back down you were traveling in a straight line.
relative to the body of earth, including its rotation it would be an arc path, and including it’s tilt it would be 3d, if we also include the travel around the sun in orbit, that elongates it around the orbit, so uh.
In my understanding, since gravity is acting on us, an external force is applied when we jump. That’s why a jump is a parabola. “Gravity’s Rainbow”
What they are getting at is that gravity is not a force so much as your mass trying to travel in a straight line through curved spacetime. The weight you feel is because the surface of the earth is in your way.
Get into low earth orbit and that straight path has you going in apparent circles around the planet. You are very much within the earth’s gravity but you don’t feel “weight” because the surface of the earth is no longer blocking your path. You still have mass and inertia and all that, of course.
