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The infiniteness of Light?

Imagine there's nothing else in the whole universe except for a big sun and you, an observer at a very long distance away. Let's say a very long amount of time passes and light from this sun theoretically should have reached you. My puzzlement arises. If light originates from an infinitesimal point such as the sun relative to the rest of the universe, that should mean that all the rays coming from it should radiate at an angle outwards meaning eventually these rays would diverge so much that there would be blind spots forming everywhere after a point where the light density is less and this light can literally pass you by without you seeing anything. Do you think this is possible? I don't understand how or believe parallel rays of light can radiate outwards from a point. It also suggests light is infinite (or rather, radiation). Which is another story on its own.

What's your take on this?

Note by Olawale Olayemi
2 years, 6 months ago

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The wave-particle duality of electromagnetic radiation is at play here. If we were to look at light as being quantized, (i.e., as photons), then I suppose at a great distance there is a not insignificant probability that the particles will "miss" you. However, since the photons are constantly streaming from the sun, the probability that you would be missed for an extended period of time would diminish greatly.

If we were to look at light in the form of spherical wavefronts, however, there is no chance that you will avoid receiving the light, (even if it becomes increasingly dim over great distances according to the inverse-square law). The same would hold true if we saw light as rays, since at the source the rays would have infinite density. The dual nature of light means that we use one perspective or the other to theoretically explain observable phenomena. If we were to conduct an experiment as you describe and found that there were "gaps" in our reception of light then we might be tempted to explain this by using the particle model, but i suspect that the wave model would win the day here. So to answer your question succinctly - it is possible, but not probable. Brian Charlesworth · 2 years, 6 months ago

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@Brian Charlesworth Wow, great stuff. Thanks for commenting. What do you do for a living, may I ask? Or rather, what do you do that makes you know stuff like this? I have been watching a lot of YouTube videos that explain the multitude of things that the atom (and the universe as a whole) contain: quarks, neutrinos and what have you. It's a really mind-boggling world out there. Further to your explanation, I think it is probable that to detect such a 'gap', we might need to be ridiculously small and therefore not able to. The concept of light is one concept that always amazes me. I could sit still looking at a flame in wonder to no end. Olawale Olayemi · 2 years, 6 months ago

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@Olawale Olayemi Yes, the quantum "world" is quite mind-boggling and we'll never understand everything, but a world with a few mysteries is preferable to a world without any. I agree that any 'gap', if it existed, would probably be miniscule and fleeting. We would need a very large array of sensitive photoreceptors oriented in a plane perpendicular to the light source, monitored over a vast stretch of time, to see if there were any variations, i.e., 'gaps', in the incoming radiation. Of course, there would also be different frequencies, (energies), to monitor, so the array would have to include receptors of different sensitivities to see if the gaps showed up in some energy ranges and not others. Experimental physics involves a great deal of money and patience. :) Brian Charlesworth · 2 years, 6 months ago

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