Is Time Travel Possible?

[ajohn]

1) So your driving an F1 car. Your wearing a watch. How does lap time as measured by that relate to the one measured by the track as the start finish line is passed.
https://www.auto123.com/en/news/f1-...s-circuit-in-melbourne/35523/?folder=industry

2) While training to be a fighter pilot your left in a centrifuge for 24hrs by mistake set to produce 6g. The arm of the centrifuge is 10m long. Add 1m to where your watch is. What time in the centrifuge did your watch show compared with the one on the wall in the room. Your watch matched that exactly initially. You may assume that both are as accurate as an atomic clock.

Answers by noon 22 Mar 2022 showing your calculations.

 

[jeds]

Please get out of your head the "Star trek/Beano/Movies" version of time travel, where you pop in and out of a different time dimension.

?? Where did I say that?

 

[ajohn]

?? Where did I say that?

There are all sorts of problems with the spaceship speed time rate changes. One is achieving the speeds needed in a reasonable time without crushing the occupants. Same sort of problem slowing down again. Warp space or change dimension - no one has the remotest idea what would happen to time if it could be done.

I believe an ion drive can get near to the speed of light in theory eventually. You might find details about on the web on how long it would take.

 

[Alec_t]

Time travel must be possible. I've just bought a gizmo which clearly states on the packet "Battery charge time: ± 2.5 Hours."
No instructions as to how to charge it in negative time though

 

[JP_]

I believe an ion drive can get near to the speed of light in theory eventually.

even if we could travel at close to light speed, it would still take around 4.4 years to get to the nearest stars, although the time to accelerate then slow down would add to that time.

And there will probably be nothing at all there.

A small neighbourhood

 

[Justin Passing]

Th ergosphere of a spinning black hole goes faster than light. Something like 29% iirc. Faster if it's charged. I imagine you could slingshot something with it, but I don't know. If you fired a rocket inside it, you could go faster again.
I'll see if I've got one in the shed...

 

[ajohn]

From Earth's frame of reference, if you're accelerating at a constant rate of 1 g, then you'd reach near the speed of light in about a year, having covered about 0.5 light-years in distance.

Tidal effects get pretty dramatic on the way to black holes.
Stephen Hawking described the flight of a fictional astronaut who, passing within a black hole's event horizon, is "stretched like spaghetti" by the gravitational gradient (difference in gravitational force) from head to toe.[2] The reason this happens would be that the gravity force exerted by the singularity would be much stronger at one end of the body than the other.

Wiki link https://en.wikipedia.org/wiki/Spaghettification
Another

https://spacemath.gsfc.nasa.gov/blackh/4Page33.pdf