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> Since they contain energy, they in turn have mass, That is not true... > and a gravitational field of their own. ... although this is. It's energy that cr
by drjesusphd 11y ago
> Since they contain energy, they in turn have mass,
That is not true...
> and a gravitational field of their own.
... although this is.
It's energy that creates a gravitational field, of which mass is a (usually dominant) subset. It does not mean anything with energy has mass. See: light.
Edit: also, the basic theory of gravitional waves is "linearized", which means that this kind of self-interaction is weak. That doesn't mean it doesn't happen, but it wouldn't resemble radiation if the effect is strong.
- ars 11y ago> It does not mean anything with energy has mass We are using different definitions of mass. I'm calling invariant energy mass, you are calling rest energy mass. > but it wouldn't resemble radiation if the effect is strong The wave does have a frequency though, which must blueshift as it interacts with matter.
- tfgg 11y ago> We are using different definitions of mass. I'm calling invariant energy mass, you are calling rest energy mass. Modern physics only refers to rest mass [1] as 'mass', otherwise people tend to get confused about how 'relativistic mass' (γm) affects gravity. [1] E/c^2 in a centre of momentum frame, which doesn't exist for an object travelling at c
- ars 11y agoYou misunderstand the difference between rest mass, invariant mass, and relativistic mass. Invariant mass is the same in all reference frames, so light can possess it (if there are multiple photons, or they are in a box). That is my preferred mass. Rest mass excludes photons, but there is no reason to do so most of the time, since the mass of the photon acts exactly like mass in most things except when dealing with change in velocity. Relativistic mass is special and depends on the relative motion between the objects. In any case gravitational waves posses invariant mass, so essentially they do have mass, and if you could hold them you could weigh them on a scale.
- deleted 11y ago[deleted]
- drjesusphd 11y agoNothing you're saying makes any sense. > since the mass of the photon acts exactly like mass in most things except when dealing with change in velocity Right: inertia. Funny that. The fact that photons are affected by gravitational fields, even though they're massless, was a major victory for the theory of general relativity. It wouldn't be a big deal if you could just say the photon has mass. Because it doesn't. A photon is massless. Fullstop. To say otherwise is to use a nonstandard definition of "mass". At best, people won't know what you're talking about. At worst, they will assume you don't. You should be more specific next time.
- jeff_tyrrill 11y agoThe parent comment's explanations and terms match the explanations throughout https://en.wikipedia.org/wiki/Mass–energy_equivalence https://en.wikipedia.org/wiki/Mass–energy_equivalence. Is the Wikipedia article all wrong?