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Author Topic:   Did the expansion rate of the universe exceed lightspeed?
Rahvin
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Posts: 4042
Joined: 07-01-2005
Member Rating: 7.7


Message 75 of 86 (460383)
03-14-2008 3:44 PM
Reply to: Message 72 by ICANT
03-14-2008 12:48 PM


Re: acceleration
If expansion is true and expansion it taking place at light speed and is accelerating, they would never be able to collide.
You're also perpetuating this little myth, in addition to the rather glaring mathematical mistake Percy and Cavediver pointed out.
If the Unvierse were "expanding at light speed," you'd never be able to read this message - the space between your eyes and the monitor would increase at the same speed the light travels, so the light would never reach you.
The expansion of the Universe can't really be described as a "speed." There is a rate to the expansion, but as I recall it's expressed in (Distance/time/parsec). That means the farther away an object is, the faster it will be moving away from you. Close-together objects will barely be moving apart at all relative to each other - the expansion is insignificant at scales like the distance between you and your monitor, the distance between the Earth and the Sun, and even the distance between the Milky Way and Andromeda galaxies. As cavediver explained, the expansion is only significant at extreme distances, a the scale of galactic clusters.
Basically, the expansion of space is occurring for all units of distance, so the rate of expansion is additive. The rate of expansion for objects two feet apart is twice the rate of expansion between objects one foot apart. The rate of expansion between you and your computer monitor is imperceptibly small. The rate of expansion between you and an object 100 billion (not million) lightyears away would be relatively "fast."
Think of the balloon analogy again. All of the surface area on the balloon is expanding at the same rate. The distance between two mites an inch apart will be increasing slowly. The distance between two mites 6 inches apart on the balloon will be increasing 6 times "faster," even though they aren't actually moving at all. They can also have their own real motion in addition, but the expansion of space is not real motion with inertia or anything else we're used to.
Cavediver explained all of this at the start of the thread. Stop repeating the smae misconception 5 pages later, please.

This message is a reply to:
 Message 72 by ICANT, posted 03-14-2008 12:48 PM ICANT has replied

Replies to this message:
 Message 78 by ICANT, posted 03-14-2008 4:31 PM Rahvin has replied

  
Rahvin
Member
Posts: 4042
Joined: 07-01-2005
Member Rating: 7.7


Message 79 of 86 (460394)
03-14-2008 4:56 PM
Reply to: Message 78 by ICANT
03-14-2008 4:31 PM


Re: acceleration
I was quite satisfied with the answers I got from Percy and cavediver. And Percy pointing out my blunder. Too bad you had to waste a rant.
Apparently you didn't actually read my post, at all. I didn't talk about your mathematical error (others had done that adequately, as I said). I talked about your continued misconception regarding the rate of expansion, which you would know if you had read the post. It was also not a "rant." The only parts that could give you that idea would be the very beginning and the last line.
I am still waiting for information from you.
Here
Which is irrelevant to this thread. Perhaps, rather than attacking me, you could try to address my argument?

This message is a reply to:
 Message 78 by ICANT, posted 03-14-2008 4:31 PM ICANT has not replied

  
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