Does Light Have Mass or Not?

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    Light Mass
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Discussion Overview

The discussion centers around the question of whether light, specifically photons, has mass. Participants explore the implications of gravity on light, particularly in the context of black holes, and the relationship between mass and the behavior of light in gravitational fields. The conversation includes theoretical considerations and interpretations of Einstein's theories.

Discussion Character

  • Debate/contested
  • Conceptual clarification
  • Exploratory

Main Points Raised

  • Some participants argue that since photons move at the speed of light, they must have no mass, while others suggest that their behavior in a black hole implies they possess mass.
  • One participant asserts that gravity affects light, countering the claim that gravity only affects matter.
  • Another participant explains that gravity is the curvature of space-time, which light follows, regardless of whether it has mass.
  • A participant challenges the inference that photons have mass based on their paths bending in a gravitational field, referencing a FAQ from a relativity forum.
  • There is a mention of photons having zero rest mass and a discussion about their mass while moving, referencing de Broglie's relation.
  • A link is provided for a longer explanation regarding how gravity affects light without requiring rest mass.

Areas of Agreement / Disagreement

Participants express differing views on whether photons have mass, with some asserting they do not and others suggesting that their behavior in gravitational fields indicates otherwise. The discussion remains unresolved with multiple competing views present.

Contextual Notes

Participants reference various interpretations of Einstein's theories and the nature of gravity, indicating a reliance on specific definitions and theoretical frameworks that may not be universally agreed upon.

adimantium
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Einstein said it would take an infinite amount of energy to move something at the speed of light. Photons move at the speed of light every day, so we can infer that photons have no mass. However, a black hole has so much gravity (gravity only affects matter) even light is sucked in. Because light is sucked into a black hole, we can infer that photons have mass. WHAT? how can this be?
I assume either some how photons can be propelled without an infinite amount of energy (very unlikely). Or light is sucked into a black hole for another reason besides gravity.
 
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adimantium said:
However, a black hole has so much gravity (gravity only affects matter)

This is not true. Gravity affects light too.

I assume either some how photons can be propelled without an infinite amount of energy (very unlikely). Or light is sucked into a black hole for another reason besides gravity.

Nope, it's just gravity.
 
It's because gravity isn't just a field force; it's the curvature of space-time, according to Einstein. When light is traveling across space-time, it must follow this curvature whether or not it has mass, and the curvature is caused by objects with mass/a gravitational force.
At least, that's how I interpret it.
 
depends on question also
what i know is that light is made of photons and mass less electric and magnetic fields.


photons have zero rest mass and its masswhile moving = h/λc (by the de brogle)
mind me to saying it may be wrong
 
Last edited:
Do photons have mass?
https://www.physicsforums.com/showthread.php?t=511175
 
Last edited:

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