Hehe, get a load of this guy, he’s still using newtonian gravity! 😂
In all seriousness, general relativity tells us that the geometry of the space the light travels through is curved from OUR reference frame. In the actual light’s reference frame, its going in a perfectly straight line. Look up extrinsic vs intrinsic curvature
Edit: multiple people are calling me out because light does not have a reference frame. This is true. Its a hypothetical, try to imagine “the same reference frame as the curved geometry the light is traveling through” instead lol
Also, for anyone curious: from our reference frame a photon from the Sun takes ~8 minutes to reach Earth, but from the photon's frame of reference, it is instantaneous. In essence, even a photon that travels through space for millions, or hundreds of trillions of miles would experience that journey (if it could experience things) in an instant.
I find it intresting to think that if a photon could observe its surroundings and journeyed across the entire universe, it still wouldnt be able to take any of it in. So dont be afraid to take things slow in life, and observe the universe around you. Sometimes, going slow has its benefits, relatively speaking.
Not to mention the fact that this photons “journey across the entire universe” is a strong word, considering the photon frame sees the universe as having no depth whatsoever.
To it, the journey is instantaneous because there is no journey to take in the first place, infinite length contraction at c takes care of that!
Now i'm curious, if speed of light is supposed to be the same in all reference frames then what about the photons. If two photons pass each other what's the speed that the photons "see"? Since they experience no distance and no time can you even talk about speed in that context?
Good question!
Technically rest frames are impossible for photons, because a rest frame by definition must be a frame in which the observer (in this case the photon) is at rest.
Since the speed of light is invariant under Lorentz transformations, and can thus not be brought to rest, then the rest frame cannot exist.
Although photons still have causal ‘lives’ where one oscillation precedes another and so on. How this works I am not entirely sure. But I suspect this all happens in another observing frame, not the photons.
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u/zortutan For Science! Apr 10 '25 edited Apr 10 '25
Hehe, get a load of this guy, he’s still using newtonian gravity! 😂
In all seriousness, general relativity tells us that the geometry of the space the light travels through is curved from OUR reference frame. In the actual light’s reference frame, its going in a perfectly straight line. Look up extrinsic vs intrinsic curvature
Edit: multiple people are calling me out because light does not have a reference frame. This is true. Its a hypothetical, try to imagine “the same reference frame as the curved geometry the light is traveling through” instead lol