The discussion centers on the nature of gravitational waves and the concept of curvature in spacetime versus space. It establishes that gravitational waves are not purely temporal and emphasizes that gravity is a result of spacetime curvature, not just spatial curvature. The conversation clarifies that all objects possess temporal extent, which influences their interaction with gravity. The distinction between four-velocity and traditional velocity is highlighted, asserting that they are fundamentally different concepts.
PREREQUISITESPhysicists, students of general relativity, and anyone interested in the fundamental principles of gravity and spacetime dynamics.
Nidhi1007 said:temporal velocity
It is curvature of spacetime, not curvature of space. Even a point particle has temporal extent.Nidhi1007 said:Summary:: An object moving in a straight line appears to be attracted to a massive body due to the curvature of space, this gives the appearance of gravity attracting the body. But why does a body at rest tend to move along the curvature of space?
No, but the four-velocity is timelike.weirdoguy said:There is no such thing as temporal velocity.
Thank youDale said:It is curvature of spacetime, not curvature of space. Even a point particle has temporal extent.
Because it isn't the curvature of space, it's the curvature of spacetime. The curvature of space really isn't important for gravity except for the most precise measurements or in really extreme circumstances. It's actually the curvature in space-time planes that is important for gravity, and objects have an extent in time.Nidhi1007 said:But why does a body at rest tend to move along the curvature of space?
Better to say that it is because all objects have an extent in time. There is a kind of meaning to "velocity in a timelike direction" and you do see this written in popsci, but it's a kind of misdirection to associate four velocity with the more familiar velocity from school physics. They are rather different things.Nidhi1007 said:An object with no spatial velocity experiences gravity due to temporal velocity?
Gravitational waves have nothing to do with this. Gravity as we experience it every day and gravitational waves are related phenomena, but they are not the same thing.Nidhi1007 said:Are gravitational waves purely temporal?
We can say each object is represented in spacetime by a worldtube.Ibix said:It's actually the curvature in space-time planes that is important for gravity, and objects have an extent in time.