[ars]

> but what if time travel is not a fast-forward?

That's my point - it kind of has to be, otherwise you violate conservation of momentum, energy, and gravity.

Violating those would be a bigger deal than time travel itself.

Incidentally that's why wormholes can't actually exist - they violate all of the above.

[kijin]

Could a time machine redirect, dissipate, or convert most of that energy into another form, such as a massive explosion in the middle of Siberia, leaving the traveler with very little momentum to worry about?

[maxerickson]

Maybe your time machine uses a bad design.

Which is a bit tongue in cheek, but I don't see how you can speak so concretely about it without having a working time machine.

[ars]

> but I don't see how you can speak so concretely about it without having a working time machine

Because the laws of physics are what they are. A time machine would have to fit inside those laws.

This constrains the design of the time machine - you can't just do anything you want.

Because of that, it's possible to narrow down how a time machine would work, if it could work.