FTL Paradox: Grandfather Paradox Explained

In summary, the conversation discusses the concept of a superluminal object that emits photons as it moves from point A to B. Depending on the position of the observer, the order in which they detect the photons may appear to break causality. However, this is due to the limitations of detecting light and does not actually break causality. The speaker also mentions the famous grandfather paradox and concludes that it is based on a false premise of faster-than-light travel. They suggest looking into the "tachyonic antitelephone" for a more striking example of logical inconsistency in this scenario.
  • #1
MysticWizard
8
2
So here it goes:

2 points in space A & B.
1 superluminal object (fixed at 10c, no acceleration) that periodically transmits photons as soon as it starts moving.
1 observer with a very high accuracy photon counter removed a sufficiently large distance from the 2 points for light to take a small while to arrive but the distance between A & B is 10 times as large.

Now things are going to be set in motion: The superluminal object moves from A to B. In my view the observer detects the following depending on where he is:

1) If the observer (indicated by X) is positioned as follows:

X----A--------------------------------B

he will detect photons from A, then a trail of photons between A and B and finally detect photons from B

2) If the observer (indicated by X) is positioned as follows:

A--------------------------------B----X


he will detect photons from B, then a trail of photons from B to A and finally photons from A.

Now in situation 2 one could state causality is broken to the observer, but in reality no causality has been broken, we just don't have the means to detect the proper order of events using fotons. I'd also like to state that any human being would just see 1 small flash of light since the timescale is so small that we can't distinguish anything more, nothing close to seeing my grandfather, unless perhaps he lived in a different galaxy but then he'd be dead already.

Now what am I missing in this famous grandfather paradox. Thanks for your time :D
 
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  • #2
You aren't missing anything, but as you started with a false premise (that there is faster than light travel) the conclusions drawn from that premise need not be either correct or consistent. When you're reasoning about the behavior of light emitted by an object moving faster than light, you're basically saying: "let's apply the laws of physics to a situation in which they do not apply"

For an example of a more striking logical inconsistency that results from assuming faster-than-light travel, google for "tachyonic antitelephone".

This thread is closed, as the issue has been discussed in many previous threads.
 

What is the FTL Paradox?

The FTL Paradox, also known as the Grandfather Paradox, is a thought experiment that explores the consequences of time travel. It involves a hypothetical situation where a person travels back in time and kills their own grandfather before their parent is born, thus preventing their own existence.

How is the FTL Paradox resolved?

The resolution to the FTL Paradox is still a topic of debate among scientists and philosophers. Some propose the idea of parallel universes, where the time traveler would create a new timeline by changing the past. Others suggest that the time traveler would simply be unable to change the past, as it has already occurred and is therefore unchangeable.

What is FTL and how does it relate to the paradox?

FTL stands for Faster-Than-Light, which refers to any method of travel or communication that is faster than the speed of light. The FTL Paradox arises when considering the possibility of traveling faster than the speed of light, as it raises questions about the nature of time and causality.

Is the FTL Paradox scientifically possible?

Currently, there is no scientific evidence or technology that supports the possibility of time travel, let alone FTL travel. The FTL Paradox remains a thought experiment and is not considered scientifically possible at this time.

What are the implications of the FTL Paradox for the concept of free will?

The FTL Paradox raises questions about the concept of free will, as it suggests that the actions of a time traveler could potentially change the course of history and alter the choices and outcomes of individuals. However, if the past cannot be changed, then the concept of free will remains intact. This is a philosophical question that has yet to be definitively answered.

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