# Help with Topic on Causality and Speical relativity

1. Aug 31, 2008

### Chaste

Hi all, this is part of my assignment where I have to write an essay of a range of 6000-8000 words.
Here goes : Consider the concept of causality. Could a killer use the principle of
special relativity to argue that, in a certain reference frame, his/her victim
died before the killer fired the gun, thus avoiding a murder charge?

I need points to draft an outline of this topic

2. Aug 31, 2008

### LowlyPion

What are your thoughts on the topic?

3. Aug 31, 2008

### Chaste

Actually, I have no idea yet. Perhaps, defining SR principles and theory behind causality?
Besides, am I right to say that in a preferred reference frame, the victim may have died of shock even before the killer pulled the trigger?

4. Aug 31, 2008

### granpa

read up on time-like and space-like paths.

5. Aug 31, 2008

### LowlyPion

Anything is possible of course, but if your purpose is to use Special Relativity to postulate insufficient causal link between a defendant's actions and some criminal act, then for legal purposes (applying the laws of physics to the laws of Cesar), you have to demonstrate that it has a larger than a shadow of a doubt likelihood in order for it to be useful for the defendant to forward it.

In your example, will a victim dying of shock at the sight of the bullet in flight toward them be sufficient to argue defendant was not culpable?

6. Oct 13, 2008

### Chaste

Hi all, I'm back and need help for this topic.
Is there a specific reference frame such that the murderer's victim
died before the killer fired the gun, thus avoiding a murder charge?

Now we all know practically, it's impossible to beat the speed of light. However, according to our theoretical imagine, assume we can beat it...

I'm thinking of such a scenario:

Victim is on an automated vehicle travelling faster than speed of light. He is travelling towards the killer who shoots a laser beam at speed of light. There is a witness behind the murderer and all 3 of them are collinear. The order from left to right is the victim on the vehicle, then the murderer and lastly the witness.

From my judgement, when the murderer shoots laser gun, this is event 1. Event 1 propagates in both direction towards the witness and the victim coming towards it at faster than speed of light. The death of victim is denoted by event 2, which is travelling faster than speed of light. Therefore, theoretically speaking, event 2 will reach the witness first before event 1 does. That means, the witness actually witnessed the murder before he saw the laser gun was fired.

Am I right? Did I miss anything out? I know I have to take into account of length contraction... where the victim travelling faster than speed of light actually may be invisible to the witness as he passes by.