Quote:
Originally Posted by peacegirl
If the sun were to explode while we were
looking at it we would see it the instant it happened, not 8 minutes
later.
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peacegirl, I'm going to explain the problem with this according to relativity. Please read it carefully.
In relativity, there is no 'instant' that is the same for everyone. Whether or not two things happen 'at the same time' is a matter of
perspective based on relative velocities. This is called
relativity of simultaneity.
In your example, if one person
really did see the Sun explode the instant it happened, another person (travelling with a different velocity relative to the Sun) would see the Sun explode after it happened. And another person with a different velocity would see the Sun explode
before it happened! All of them are 'correct'; there is no 'right' or 'wrong' answer. It's a matter of perspective, not fact. It is
relative to the observer, hence why the theory has its name.
This is why instantaneous vision is problematic in relativity.
Do you understand why this is a problem?