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Talk:Starlight problem (view source)
Revision as of 02:53, January 31, 2012
, 02:53, January 31, 2012→39 billion light years away?
::::::::::::::::::That's not a flat no, and that's why I asked "most probably"; some objects may be drifting further away with an expanding universe? [[User:RobSmith|Rob Smith]] 21:37, 30 January 2012 (EST)
::::::::::::::::::That's not a flat no, and that's why I asked "most probably"; some objects may be drifting further away with an expanding universe? [[User:RobSmith|Rob Smith]] 21:37, 30 January 2012 (EST)
:::::::::::::::::::I can give a flat no to that. Objects aren't drifting away; space is expanding between objects that aren't gravitationally bound. What that basically means is that unbound objects have two distances from us; comoving distance - how far away they actually are now, if they still exist - and light travel distance, which is how far the light from them has travelled to reach us and therefore how many years in the past we're seeing them. Gravitationally bound objects, though, basically have only one distance (it's not quite that simple, but it's close enough for government work) because the space in between is not expanding. --[[User:GeorgeLi|GeorgeLi]] 21:42, 30 January 2012 (EST)
:::::::::::::::::::I can give a flat no to that. Objects aren't drifting away; space is expanding between objects that aren't gravitationally bound. What that basically means is that unbound objects have two distances from us; comoving distance - how far away they actually are now, if they still exist - and light travel distance, which is how far the light from them has travelled to reach us and therefore how many years in the past we're seeing them. Gravitationally bound objects, though, basically have only one distance (it's not quite that simple, but it's close enough for government work) because the space in between is not expanding. --[[User:GeorgeLi|GeorgeLi]] 21:42, 30 January 2012 (EST)
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I sort of follow that -- and sort not. Space is expanding between unbound objects but distances are not? That's not exactly what you said, but it is what it sounded like. A moment ago you said lightyear is a measurement of distance, not time. Now you've basically inverted that saying lightyears are measurements of time. I don't wish to sound pedantic or critical, you really are helping sort this out. [[User:RobSmith|Rob Smith]] 21:53, 30 January 2012 (EST)
::::::::::Rachel, Aschalfly says that he saw "numerous references" to people talking about observable stars 39 billion light years away. I have an open mind, and want to be able to have him share his knowledge with me. [[User:ScottDG|ScottDG]] [[User talk:ScottDG|Talk]] <b>Is Gingrich an orphan? Conservapedia says yes. Why does nobody else? </b> 21:02, 30 January 2012 (EST)
::::::::::Rachel, Aschalfly says that he saw "numerous references" to people talking about observable stars 39 billion light years away. I have an open mind, and want to be able to have him share his knowledge with me. [[User:ScottDG|ScottDG]] [[User talk:ScottDG|Talk]] <b>Is Gingrich an orphan? Conservapedia says yes. Why does nobody else? </b> 21:02, 30 January 2012 (EST)
:::::::::::There most certainly are stars 39 billion light years away, or close to it. That's the cosmological principle in action. But, as Aschlafly pointed out, they're not going to be observable because light from those stars has not had time to get to us, and if we attempted to look back that far, we will eventually hit the "wall," so to speak, as a result of the opacity of the early universe. [[User:RachelW|RachelW]] 21:10, 30 January 2012 (EST)
:::::::::::There most certainly are stars 39 billion light years away, or close to it. That's the cosmological principle in action. But, as Aschlafly pointed out, they're not going to be observable because light from those stars has not had time to get to us, and if we attempted to look back that far, we will eventually hit the "wall," so to speak, as a result of the opacity of the early universe. [[User:RachelW|RachelW]] 21:10, 30 January 2012 (EST)