Quote from: pasala on 02/10/2019 15:35:08"In space, it is possible to create "artificial gravity" by spinning your spacecraft or space station. When the station spins, centrifugal force acts to pull the inhabitants to the outside. This process could be used to simulate gravity. It wouldn't be exactly the same, though, because large Coriolis forces would also be present, and things would fall in curves instead of straight lines".
In case, let us assume that if cylindrical carnival “that accelerated motion” warps the space time.
The spin of an object can warp space-time (this is called frame dragging), but a non-spinning object will warp space-time as well.
Well, it is surprise, how a space station, by spinning on its axis creates Gravity.
I think for this theory, cylindrical carnival ride example of Einstein is base:
“To extend this further, let’s imagine a cylindrical carnival ride where you and your fellow passengers are pinned to the outer surface. The cylinder is rotated faster and faster until the acceleration eases and the movement stays constant. But even once the speed is constant, you still feel the accelerated motion—you feel yourself being pinned to the outer edge of the ride. cylindrical ride, that accelerated motion can warp space and time. It is here that Einstein connected the dots to suggest that gravity is the warping of space and time”.
First of all we have to remember that things on Earth are different, there is strong Gravity.
When a cylindrical carnival is rotated, the passengers are pinned to the edges. Here we are forgetting one important point that:
“Gravity is equal to acceleration”.
For the person at the center, there is no acceleration at all. Whereas the person at the edges travels full circumference. As the carnival picks up, Gravity weakens. The person, say ‘X’, is now gravity free. Now he carries only original Mass weight and due to air and other forces, he will be moved to the edges and warped at the edges.
The relevance to the carnival ride example is Earth. It is true that Earth is spinning against its axis with lot of speed. So, Einstein might have thought that similarly things at the edges of the carnival are being warped. But he forgot his own theory that “Gravity is equal to acceleration”.
If this is true:
“In 1632, even before Newton published his now-famous work, Galileo Galilei wrote about the relative motion of objects familiar in his time: ships. If you are in a closed room on a ship sailing at a constant speed and the ride is perfectly smooth, objects behave as they would on land. There’s no physical experiment you could conduct to tell whether you’re moving or stationary (assuming you’re not peeking out of a porthole). This is the core idea behind relativity, and is the same reason why we don’t feel our planet’s movement around the sun, or our solar system’s movement through the galaxy.
Is there any physical experiment you could do within the confines of your spaceship to tell whether you really were accelerating through space (assuming there were no windows to look out from), or if, instead, you were inside a spaceship stationary on the surface of Earth? Einstein said no—just as Galileo imagined the in distinguishability between a person inside a smooth-sailing ship (confined without windows) and a person on land, Einstein realised that the effects of acceleration and gravity were indistinguishable too”.
“This is called the equivalence principle”,
If the spinning alone is responsible for warping than Galileo’s idea must be wrong and if you are in a closed room of a ship, one must be free from Gravity. But there is Gravity. The person inside a closed room, if the ride is smooth will not be in a position to distinguish in between in a closed room and on Earth.
Einstein extended this to Spaceship. If you are in a spaceship and if it is accelerating through space, you will not be in a position distinguish, on Earth to cabin of spaceship.
Basic idea is that, in distinguishability, closed room of a ship, cabin of space ship to Earth. Things continued to be same.
What this indistinguishability tells us, Gravity can be packed. In a closed room of a ship Gravity is packed. Inside the spaceship also Gravity is packed.
The difference is that travelling from Gravity to Non-gravity area. When the spaceship started accelerating through space, inside the spaceship gravity is packed. When the spaceship reaches, non-gravity area, slowly gravity disappears.
Thing that is present on Earth is not there in space. Even if you pack it, it is moving out.
So, warped space time is present on the Earth.
This is of course not created due to spinning of Earth,. It is already created and present in the space surrounding Earth, which can be packed or moved.
Suppose if it is on Moon, weak gravity and thus your spaceship can only pack weak gravity.
The space station or space craft is already in inertial position. There is strong curvature against the space station. But it is not being warped.
If we rotate the space station or space craft, curvature weakens, mass gains weight. Since gravity is equal to acceleration.