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quote:Originally posted by rosyI understand this:Whilst the siren thing works because if the source is moving away from you the distance successive peaks have to travel between the source and your ear is equal to the wavelength of the sound emitted plus the change in distance between start and end points during the period of the note.So the new wavelength is now wavelength(1) = wavelength(0) + T * velocity of sound source (velocity measured in the frame of the observer)So as the source moves away pitch goes down.But my problem is this:Red shift is supposed to be due to the expansion of the universe, right? And this universe expansion is happening everywhere all the time but we don't notice because, essentially, it's happening sort-of between atoms so a metre is in some way getting longer but we can't tell because everything's getting longer/bigger?Or have I misunderstood that?Anyway, if I am right about the first bit, how come it's being observed in the red shift? How come that isn't just lost in the general everything-getting-bigger and not actually observed?
quote:Originally posted by rosy(---)But my problem is this:Red shift is supposed to be due to the expansion of the universe, right?
quote:Originally posted by mtheoryIt's the actual fabric of space that's moving (...) as the balloon is blown up.
quote:Originally posted by siaquote:Originally posted by mtheoryIt's the actual fabric of space that's moving (...) as the balloon is blown up. You are right, the matter does not fly apart.But!The universe is not an expanding ballon.It is the radiation that is "expanding" by wave-elongation.This is called redshift, which no-one has found any empirical explation for, until now.It is called entropy, the (lost) energy that is propelling the radiation forward. Ingvar, Sweden
quote:Originally posted by ukmickyThe reason why matter within galaxies and solar systems dosent fly apart from each other as the universe expands is because the force which is expanding space is a weaker force than gravity and therefore within areas of high mass like within our galaxy/local cluster gravity is able to overcome the force's causing the universe to expand and holds everything together.Michael
quote:Originally posted by mtheorySorry, either I don't understand your point or I don't agree. The expansion of the universe doesn't cause a repulsive force on matter or energy within the universe. The expansion of the universe is the expansion of space and time. It only 'drags' the matter and energy contained within it.Can you be more specific, or give an example of, the effect you are referring to?
quote:Originally posted by harryneildI have a question about red shift. The expanding universe is causing the light rays to 'stretch' into lower wavelength wave with less energy. Where does this energy go?"Knowledge has to be improved, challenged, and increased constantly, or it vanishes." Peter F. Drucker
quote:Originally posted by harryneildI have a question about red shift. The expanding universe is causing the light rays to 'stretch' into lower wavelength wave with less energy. Where does this energy go?