johan01 Posted January 20, 2009 Posted January 20, 2009 Hi All its been a while since i thought about this so i need some insight.Here goes. If the furthest galaxies are receeding at nearly the speed of light, then for them we are receeding at the same speed. True or false? So then every body in space is actually moving APART " close to the speed of light " relative to any other body , PROVIDED IT IS FAR FAR AWAY" For me its strange that , this law " hubble's law " , that implies dark matter/energy, has no inverse law or observations. Why are there no galaxies moving toward each other at close to the speed of light. " In our Local near proximity" or even "far proximity" for that matter. Or has this been observed , if so how fast are they approching eachother at. Just another stupid thought. Further more , are all galaxies , say 14 billion light years from our galaxy , moving away from US at the same speed , how constant is this recession. Are all galaxies at 7 billion light years away also moving away from us at a constant velocity. how accurate are all these redshift measurments. Could gravitational lensing and "tired light theories " not play a part.
swansont Posted January 20, 2009 Posted January 20, 2009 Hi All its been a while since i thought about this so i need some insight.Here goes. If the furthest galaxies are receeding at nearly the speed of light, then for them we are receeding at the same speed. True or false? So then every body in space is actually moving APART " close to the speed of light " relative to any other body , PROVIDED IT IS FAR FAR AWAY" For me its strange that , this law " hubble's law " , that implies dark matter/energy, has no inverse law or observations. Why are there no galaxies moving toward each other at close to the speed of light. " In our Local near proximity" or even "far proximity" for that matter. Space is expanding, which is why the general motion is that of receding rather than approaching. There is local motion on top of this, of course. Hubble's law say that the speed of recession is proportional to the distance, which is why it's galaxies far apart that have the highest speeds.
johan01 Posted January 21, 2009 Author Posted January 21, 2009 This i understand. I you say space is expanding , are the galaxies stretching or expanding as well, since they occupy space as well.
Baby Astronaut Posted January 21, 2009 Posted January 21, 2009 From what I understand, the expansion doesn't occur in places where local forces (i.e. gravity, electromagnetism) are stronger and thus overcome it.
NowThatWeKnow Posted January 21, 2009 Posted January 21, 2009 Martin has a sticky on "Cosmo Basics" with several good links in it. I liked this one and it answers many questions and is a fun read. http://www.mso.anu.edu.au/~charley/papers/LineweaverDavisSciAm.pdf Local gravity keeps the galaxies and even galaxy clusters from expanding but the space in between expands. As Baby Astronaut pointed out.
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