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Debate:If the universe is young and it takes light millions of years to reach us from far off stars, how can we see them? (view source)
Revision as of 18:41, July 2, 2007
, 18:41, July 2, 2007→Theory 3
:Oh, theory is out - of course, should have realised earlier. If C is altered, the knock-on effect ould include a shift in emmission spectrum. That would be very easily observed in distant stars. As it isn't observed, that means C must be constantish. Perhaps just a little variation, but not a 1.67-million-times factor. I think that just about kills the 'C is faster elsewhere' idea. - Suricou
:Oh, theory is out - of course, should have realised earlier. If C is altered, the knock-on effect ould include a shift in emmission spectrum. That would be very easily observed in distant stars. As it isn't observed, that means C must be constantish. Perhaps just a little variation, but not a 1.67-million-times factor. I think that just about kills the 'C is faster elsewhere' idea. - Suricou
=== Signs of C changing ===
If the speed of light had changed in the past, would we not see some evidence of it today? I'm no physicist, but I do know one thing about light: when light particles collide with matter they impart energy to that matter, making it warmer. Now, from what I do know of physics it seems to me that the warming effect of light on matter should have something to do with the speed at which said light is travelling. My point is this: if light once travelled much faster than it does today, would that light not also have had a much greater warming effect on matter that it collided with? Would you not, then, expect that modern science would have at least some ability to observe the evidence of light's changing speed. I could only imagine that examples of such evidence might include planets that are completely scorched, or have been scorched in the past, without any current explanation as to why such scorching could have occurred. If light was travelling at faster speeds while there was life present on earth, I can only imagine that some of those creatures would've been getting one heck of a sunburn! [[User:Simple|Simple]] (14:31 GMT-5) 2 July 2007
If the speed of light had changed in the past, would we not see some evidence of it today? I'm no physicist, but I do know one thing about light: when light particles collide with matter they impart energy to that matter, making it warmer. Now, from what I do know of physics it seems to me that the warming effect of light on matter should have something to do with the speed at which said light is travelling. My point is this: if light once travelled much faster than it does today, would that light not also have had a much greater warming effect on matter that it collided with? Would you not, then, expect that modern science would have at least some ability to observe the evidence of light's changing speed. I could only imagine that examples of such evidence might include planets that are completely scorched, or have been scorched in the past, without any current explanation as to why such scorching could have occurred. If light was travelling at faster speeds while there was life present on earth, I can only imagine that some of those creatures would've been getting one heck of a sunburn! [[User:Simple|Simple]] (14:31 GMT-5) 2 July 2007
:Good shot at it--but the energy of light does not depend on its speed. Light imparts its energy to any object it strikes, in discrete packets tentatively called [[photon]]s, the energy of which depends solely on the [[frequency]] of the light. The function is a linear one and depends on [[Planck's constant]].
:Indeed, part of the problem with light is that its speed ''does not even relate to any frame of reference''. The speed of light in any medium depends solely on the [[electrical permittivity]] and [[magnetic permeability]] of that medium. (In fact, the speed of light is the [[reciprocal]] of the [[geometric mean]] of these two quantities.)
:Thus for c to change, the permittivity and permeability of vacuum must also have changed. And the only way to determine that is to examine previous records--and even ''that'' will fail if those records are not sufficiently precise.--[[User:TerryH|TerryH]]<sup>[[User talk:TerryH|Talk]]</sup> 14:41, 2 July 2007 (EDT)
== White-hole Cosmology ==
== White-hole Cosmology ==