# Speculative Time Jump Question

• Alvinho!
In summary, the conversation discusses the concept of time travel and its potential effects on an object's position and velocity. The participants consider factors such as the Earth's movement and the need for a teleportation feature or a spaceship to successfully travel through time. They also mention the importance of understanding the theoretical physics behind time travel before attempting to build a time machine. The conversation concludes with a reminder of the forum's guidelines regarding discussions of new or non-mainstream theories.
Alvinho!
I'm sure this has been asked 1000 times before, but here's my shot:

If I had a time machine and intantaneously 'jumped' 1 hour in the future, would I lose all my kinematic vector (velocity, acceleration) during my time jump?

I read on another thread on PF that the Earth is moving roughly 390 km/s considering motion around sun, sun's motion around galaxy, galaxy rotation through whatever. So it seems that after my time jump the Earth will have moved 1,404,000 km and I will be hopelessly adrift in space.

It would seem that I should build my time machine with a very elaborate teleportation feature, or else do it in a spaceship which means I would be spending a lot of time catching up to the Earth. 390 km/s is really, really fast!

I'm curious about what the theoretical folks think, and yes, I have lost sleep over this!

A time machine hasn't been invented, so speculating as to its properties seems kind of pointless.

It's hard to say what would happen because you haven't described how the time machine does it.

Seems to me your machine needs to specify your 4-coordinates for where you're going as well as your rest frame upon your arrival.

Try it on a little lizard before you step through yourself.

Antiphon said:
Try it on a little lizard before you step through yourself.

You owe me a new keyboard!

Yes, the trouble is that how it is operated will depend entirely on the physics by which it hypothetically works. The method by which the device reaches into the future and establishes a point the will dictate the freedoms by which that point can be placed.

You must first invent a plausible way time travel can occur at all, then invent a plausible way of engineering that to come about. By then, you will know what happens to its target location - there will be no choice.

By a similar example, if you were to build a wormhole, it would be you who would place the target end of it. You could only go to where you were able to place the target.

With some time machine, you would probably need a receiver at each end with a bridge between them. So your end location would be wherever you put the receiver.

Without the story line (time machine, etc) my question really boils down to this: How would the position and velocity vectors be impacted by an instantaneous change in time?

I know from calculus that the derivatives for velocity and acceleration depend on continuous time, so this is really the speculative part of the question. If a particle is moving smoothly and then the independent variable is suddenly discontinuous what would happen to the position and velocity? Mathmatically I would assume they would simply be 'not defined' but to me this is a cop out, because in physics I don't think things simply disappear.

I love the lizard suggestion, but I'd better put a little beacon on him so I can find where he went.

alvin

PF Rules said:
Overly Speculative Posts:

One of the main goals of PF is to help students learn the current status of physics as practiced by the scientific community; accordingly, Physicsforums.com strives to maintain high standards of academic integrity. There are many open questions in physics, and we welcome discussion on those subjects provided the discussion remains intellectually sound. It is against our Posting Guidelines to discuss, in the PF forums or in blogs, new or non-mainstream theories or ideas that have not been published in professional peer-reviewed journals or are not part of current professional mainstream scientific discussion. Non-mainstream or personal theories will be deleted. Unfounded challenges of mainstream science and overt crackpottery will not be tolerated anywhere on the site. Linking to obviously "crank" or "crackpot" sites is prohibited.

## 1. What is a speculative time jump question?

A speculative time jump question is a hypothetical scenario where one imagines the consequences of altering a past event or making a different decision in the past. It involves speculating about what the present would look like if the past had been different.

## 2. Why is speculative time jump important in science?

Speculative time jump allows scientists to explore different possibilities and outcomes in a controlled way. It helps to understand cause and effect relationships and how changes in the past can shape the present and future.

## 3. Can speculative time jump be tested or proven?

No, speculative time jump is purely hypothetical and cannot be tested or proven. It is a thought experiment used to explore different scenarios and possibilities.

## 4. How is speculative time jump different from time travel?

Speculative time jump involves only imagining the consequences of changes in the past, while time travel involves physically traveling to the past or future. Time travel is currently not possible according to our understanding of physics, while speculative time jump is a theoretical concept.

## 5. What are the potential ethical implications of speculative time jump?

Speculative time jump raises ethical concerns as it can lead to moral dilemmas and paradoxes. It also brings up questions about free will and the responsibility of individuals for their actions. However, since it is only a thought experiment, these ethical implications are not real and do not have any consequences in the physical world.

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