What Is The Energy of a Point In Space?

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SUMMARY

The discussion centers on the concept of energy at a point in spacetime, particularly in relation to electromagnetic radiation. Participants clarify that the energy of electromagnetic waves, such as light, is defined by the electromagnetic stress-energy tensor, which describes how energy and momentum density vary based on observation angles and reference frames. The energy of a photon is quantified by the equation E=hf, where h is Planck's constant and f is the frequency. The conversation emphasizes that while energy is conserved, it is not invariant and can appear differently based on the observer's reference frame.

PREREQUISITES
  • Understanding of electromagnetic radiation and its properties
  • Familiarity with the electromagnetic stress-energy tensor
  • Knowledge of Planck's constant and the equation E=hf
  • Basic grasp of reference frames in physics
NEXT STEPS
  • Study the electromagnetic stress-energy tensor in detail
  • Explore the implications of the Doppler effect on light perception
  • Learn about reference frames and their impact on energy measurements
  • Investigate the concept of zero-point energy in quantum mechanics
USEFUL FOR

Physicists, students of quantum mechanics, and anyone interested in the nature of energy and light in relation to spacetime and observation.

  • #31
How far is it from point A to point B?
 
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  • #32
gary350 said:
How far is it from point A to point B?

I've often thought about that. Seems to me you cannot have a 'point A and a point B' alone. Because as points there's no way to measure their separation.

A dimensionless point has no dimensions in itself. In a surroundings lacking dimensions there's nothing we can say in terms of dimension.

Given a third point we can start measuring. That third point could be part of the first point if it is given dimensions, thickness, height, width...

Then the distance from A to B becomes in terms of A the number of times you can divide the width of A into the interval.

Hence the need for three. Three is the smallest number.
 
  • #33
I think it's time to close this thread as the contributions become more and more meaningless and tend towards unsubstantial speculations.

Thread closed.
 
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