Stclaim Posted November 8, 2017 Share Posted November 8, 2017 Is there (or rather, what is) a maximum distance that light can travel? Surely there is. Can anything travel forever, infinite energy? If we think of light in a way similar to batteries. A rough similarity I am afraid. Then we could (possibly) explain the problem of the universe not having enough matter/energy, as we can only see part of it. The light from the rest of the universe not reaching us because it exceeds the maximum distance light can travel. Thus there is more universe out there that we cannot, and never will, see unless we travel to another galaxy. Link to comment Share on other sites More sharing options...
swansont Posted November 8, 2017 Share Posted November 8, 2017 It doesn't require infinite energy to travel forever. There's no dissipation of the energy it has, if traveling in flat spacetime. Light does not behave like a battery. Link to comment Share on other sites More sharing options...
Strange Posted November 8, 2017 Share Posted November 8, 2017 10 minutes ago, Stclaim said: The light from the rest of the universe not reaching us because it exceeds the maximum distance light can travel. Actually, just because it hasn't had time to reach us yet. Link to comment Share on other sites More sharing options...
swansont Posted November 8, 2017 Share Posted November 8, 2017 1 hour ago, Strange said: Actually, just because it hasn't had time to reach us yet. And some will never reach us because of expansion. Link to comment Share on other sites More sharing options...
Raider5678 Posted November 8, 2017 Share Posted November 8, 2017 2 hours ago, swansont said: It doesn't require infinite energy to travel forever. There's no dissipation of the energy it has, if traveling in flat spacetime. Light does not behave like a battery. Well, there are random atoms floating around in space. Wouldn't that theoretically eventually absorb the rays of light? Link to comment Share on other sites More sharing options...
swansont Posted November 8, 2017 Share Posted November 8, 2017 5 minutes ago, Raider5678 said: Well, there are random atoms floating around in space. Wouldn't that theoretically eventually absorb the rays of light? That will attenuate light, yes — you will lose some photons. But not all of them, and the light isn't continually losing energy as it travels. Link to comment Share on other sites More sharing options...
Strange Posted November 8, 2017 Share Posted November 8, 2017 And this doesn't just apply to photons. A golf ball would fly through empty space without losing energy as well. (Of course, interstellar space is not completely empty so there would be a minute amount of drag from the interstellar medium which could slow it down.) Link to comment Share on other sites More sharing options...
Itoero Posted November 8, 2017 Share Posted November 8, 2017 2 hours ago, Stclaim said: The light from the rest of the universe not reaching us because it exceeds the maximum distance light can travel. The light from the rest of the universe hasn't reached us because there is a limit to its speed...c. This is called the particle horizon or cosmic light horizon. It represents the furthest distance from which we can retrieve information from the past, and so defines the observable universe. https://en.wikipedia.org/wiki/List_of_cosmological_horizons Link to comment Share on other sites More sharing options...
Mordred Posted November 8, 2017 Share Posted November 8, 2017 (edited) As a stable mean lifetime massless particle the photon has an effective infinite range. See http://hyperphysics.phy-astr.gsu.edu/hbase/Forces/exchg.html Edited November 8, 2017 by Mordred Link to comment Share on other sites More sharing options...
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