A question about a hypothetical time travel device utilizing rotation

a reply to: aethertek

No information is lost in the universe. Other than that

a reply to: TerryDon79

Would not the conservation of angular momentum provide an equal but opposite force to counter the exponential increase in mass?

a reply to: Pirvonen

see above post (negative energy)

Thank you I had never heard of that but it provides for a mightily interesting thought experiment!

a reply to: Arbitrageur

I LOVE Richard Feynman..... but you are absolutely correct about his misinterpretation.

Now how has it been shown that this would fly apart, much less at such a low speed as sound travels?

I do believe time would stop at C, but what happens after the threshold is broken? The end of Matrix Revolutions?

But seriously, would you have a good talking to by the creator, or would time truly cease to have any effect in the device?

a reply to: drphilxr

So, wormholes? Or does that depend on the existence of white holes?

a reply to: Justoneman

Parallel universe access is what I would be trying to accomplish with this if it were doable, and not cost more than all the gold on earth.

originally posted by: mbkennel
a reply to: Arbitrageur

I'm sure that Feynman would have said that E = gamma(v) * m0 * c^2, with gamma(v) tending to infinity as v->c .

He says a lot about the topic in "The Feynman Lectures", but here's an excerpt from the bottom of Volume 1, page 16-9:

It is not convenient and often not possible to separate the total mc² energy of an object into rest energy of the inside pieces, kinetic energy of the pieces, and potential energy of the pieces; instead, we simply speak of the total energy of the particle. We "shift the origin" of energy by adding a constant m0c² to everything, and say that the total energy of a particle is the mass in motion times c², and when the object is standing still, the energy is the rest mass times c²

So he's not following Einstein's advice to use the momentum term for the object in motion, and instead is creating an "apparent mass" different from rest mass against Einstein's advice.

originally posted by: SharonGlass
a reply to: Arbitrageur

I LOVE Richard Feynman..... but you are absolutely correct about his misinterpretation.

Now how has it been shown that this would fly apart, much less at such a low speed as sound travels?

Let's say the disc is made of steel, with speed of sound in steel being 13,600 miles per hour, do you really think that's "low speed"? The explanation including the math is given in your link, though I too would like to see the experiments supporting that. It would be interesting to watch a steel disc spinning up to where the outer edge exceeds 13,600 mph and thus flies apart, though it would have to be done in a vacuum since air friction at that speed would probably melt the steel.

I do believe time would stop at C, but what happens after the threshold is broken? The end of Matrix Revolutions?

But seriously, would you have a good talking to by the creator, or would time truly cease to have any effect in the device?

You're chasing an impossible thought experiment but why, when there's a more realistic scenario? Just think of approaching the event horizon of a supermassive black hole, where time won't stop for you but you could watch 10 billion years pass by in the outside universe if you're really close to the event horizon. Once you reach the event horizon your clock would appear to stop to an outside observer, but to you it would keep going normally, so remember that your clock speed is relative to who is observing it and from what reference frame. Time doesn't stop in any absolute sense in the black hole scenario nor in your impossible thought experiment. Time is relative, so even if one observer sees a clock falling into a black hole stop, the clock falling into the black hole doesn't really stop if it's a large enough supermassive black hole so it's not destroyed by tidal forces at the event horizon. As it keeps falling and reaches the center of the black hole, then it will stop but because the clock is destroyed, and we don't really understand what goes on there since our math breaks down at the singularity.

I exaggerated slightly saying you'd see the clock falling into a black hole stop when it reaches the event horizon. You can't actually see that because by that point any light from the clock is so red-shifted you couldn't see it.

originally posted by: TerryDon79
a reply to: Arbitrageur

So mass doesn't increase with speed? I thought that was a commonly accepted thing? I'll have to look into that later so I get my facts straight.

Damn you making me do research

There is true mass ( rest mass )which doesn't change at all. And relativistic mass which does. People get these two confused and that's why you believed mass increases. Think of it as inertial mass like a spinning object. Relativistic mass takes the body's speed, and the angle between its direction of motion and the applied force and gives us an energy value. Also the same reason you can't make an object that can spin at the speed of light by the way. The energy needed increases with the energy requirements of the sustem. Its relativistic mass eventually becomes so great that you simply can't put enough energy in to get it to spin faster. And your thinking the wrong way when trying to reach light speed smaller is better. O can get a small object like an electron to spin closet to the speed of light with less energy than it would require to spin the earth. The bigger you make it the more energy needed.

Now things like planets can steal energy from the sun by using gravity. An example is spacecraft we will send them near Jupiter for example to steal orbital energy making our probe go faster. Think of it as starting a go cart on top of a hill you can get moving really fast by the time you get to the bottom.

a reply to: SharonGlass

I know many of you have seen rotating space stations in science fiction movies and television programs. This is used to simulate gravity in most cases.

yup, that imo is so silly. Rotating the hall of space ship will not make gravity, it will not even simulate it. Astronaut would simply hang in mid air and the 'floor' would 'run' beneath his feet))) making his travel even more annoying.(like trying to catch that coffee machine...."..lets wait for another round for it to pass by, Nick")))

just my 2 cents.))

originally posted by: aethertek
a reply to: Justoneman

OFFS, That "Time Line"? that you speak of is every creation,orbit, decay & destruction of every speck of everything that would need be undone to go "back in time".

Why is this such a hard concept for people to grasp?

How would any "machine" that you could manufacture undo every physical event in time & space of matter & energy that has already happened & no longer exists.

K~

indeed, that only way to go back in time would be to have some sort of 'time recorder' with all events 'recorded'. Then within that simulation you can travel back to the moment the recording started. If time travel ever possible it would be going back only to the point of when 'time machine' went online and only in virtual world setup.

No travel to the future tho))) no recording yet of those events). IMO.

cheers)

originally posted by: greenreflections
a reply to: SharonGlass

I know many of you have seen rotating space stations in science fiction movies and television programs. This is used to simulate gravity in most cases.

yup, that imo is so silly. Rotating the hall of space ship will not make gravity, it will not even simulate it. Astronaut would simply hang in mid air and the 'floor' would 'run' beneath his feet))) making his travel even more annoying.(like trying to catch that coffee machine...."..lets wait for another round for it to pass by, Nick")))

just my 2 cents.))

Have you ever been on a ride in tour life or driven a car?? Centrifugal force can exactly mimic gravity here you can see for your self.

a reply to: greenreflections

You are only right if the astronauts are not touching anything when they start to spin the ship. However, as soon as they grab on to something and start spinning with it, then the centrifugal force will kick in, and it will feel like gravity to them. It's not gravity, but it acts like it.

a reply to: WeAre0ne
Yes, that's right, though if the ship has air in it instead of a vacuum, the astronaut wouldn't even need to grab onto anything.

The air would start moving with the ship due to friction, and then the air would start pushing on the astronaut, so he too would start moving with the ship, even if he didn't grab anything.

It would take a complete vacuum inside the spaceship for GreenReflection's scenario to pass where the astronaut didn't feel the effects of the rotation, so you'd have bigger problems than not feeling pseudo-gravity if that was the case, you couldn't breathe!