Time Travel and Conservation Laws

In summary, the conversation discusses the compatibility of time travel and the laws of conservation. While sending an object back in time may seem to violate the conservation of energy, some sources suggest that this may not be the case due to the local nature of conservation laws. However, there are still many questions and uncertainties surrounding the idea of time travel and its potential impact on conservation laws.
  • #1
TheBaker
19
0
I'm doing some research into time travel for a presentation I have to give in a month or so, and I'm currently looking at the compatibility of Time Travel and the Laws of Conservation.

Sending an object back in time would increase the mass - and hence the energy - in the Universe at this time, and would therefore appear to violate the conservation of energy.

However, I found http://www.weburbia.com/physics/time_travel.html" that says that in fact the conservation laws may not violated because conservation laws are local, whereas there may not be a global conservation law.

I've tried to find more information on this, but couldn't nothing obvious came up, so I was wondering what people here thought of the idea.

Assuming that there are no other objections to time travel, do conservation laws necessarily rule out time travel? Or can the two be compatible (even if it requires something strange to be happening)?
 
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  • #2
TheBaker said:
However, I found http://www.weburbia.com/physics/time_travel.html" that says that in fact the conservation laws may not violated because conservation laws are local, whereas there may not be a global conservation law.
Here's a good page on the problems with defining what "energy conservation" means globally in general relativity (and general relativity does allow for the possibility of backwards time travel in certain unusual spacetimes):

http://math.ucr.edu/home/baez/physics/Relativity/GR/energy_gr.html
 
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  • #3
It would have more mass i think when it speeds up to allow it to go back in time but as soon as it stops it would have the same mass. Asumeing nothing interfears. If it did make it back in time we wouldn't see it because events in time would change it. But it would have more mass at the objects initial entry in time.
 

Related to Time Travel and Conservation Laws

1. What are conservation laws and how do they relate to time travel?

Conservation laws are fundamental principles in physics that state that certain physical properties, such as energy, momentum, and mass, remain constant in a closed system. In the context of time travel, these laws suggest that any changes made in the past would have a ripple effect on the present and future, potentially violating these conservation laws.

2. Can time travel be achieved without violating conservation laws?

Currently, there is no scientific evidence or technology that supports the possibility of time travel. However, some theories, such as the concept of wormholes, propose that time travel may be possible without violating conservation laws. Still, these theories are purely speculative and have not been proven.

3. How does the concept of causality play a role in time travel and conservation laws?

Causality refers to the principle that an event must have a cause, and that cause must come before the effect. In the context of time travel, causality becomes complicated as changes made in the past could potentially create paradoxes and violate conservation laws. Many theories, such as the Novikov self-consistency principle, attempt to explain how causality could be preserved in a time-travel scenario.

4. Are there any real-life examples of time travel and conservation laws being observed?

No, there are no confirmed instances of time travel being observed or proven, and thus, no instances of conservation laws being violated. However, some phenomena, such as the twin paradox, have been theorized to potentially have time-travel-like effects on a smaller scale.

5. What are some ethical and philosophical considerations surrounding time travel and conservation laws?

Time travel raises many ethical and philosophical questions, such as the potential for altering the course of history and the implications of changing one's own past. Additionally, the concept of free will and determinism may come into play when considering the possibility of changing the past and its impact on the present and future. These are complex and ongoing debates in the scientific community.

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