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Yes.
You have. Repeatedly claiming that Time must expand if Space expands. I'm just curious- are you really forgetful or are you having as much trouble keeping up with your many posts, threads and questions as I am considering how scattered they seem to be...? |
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I am simply trying to explain the scientific method, the invariance that is, by definition, required for a frame of reference, and you cannot seem to make sense of it. But it is not nonsense. Did you not read that last post?
"The definitions of length and time are not changing in the standard model." The universe expands and so distances increase. 1 lightyear does not become a larger lightyear as time goes on. 1 meter does not become a larger meter as time goes on. Lightyears (and therefore meters) are, and always have been, the same length. Lightyears (and therefore meters) do not expand with the universe, distances increase with the expansion. You start off with 100,000,000 meters and you end up with 200,000,000 meters if the universe doubles in size. Did the universe expand? Yes. Did the distance in between objects increase? Yes. Did a meter expand? No, it stayed as a meter and the number of meters increases with the expansion. More meters are introduced by the expansion. If you want to think of it as space stretching, then what was once 1 meter has now stretched to become 2 meters. You now have more meters. What part of this very simple principle do you not understand? (This is what happens when people say things like "Meter sticks grow longer relative to the past as space expands while clocks simultaneously run faster", we have to be very careful with terminology - I myself said something similar in another post and regret it ever since!) |
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I don’t understand how stretching space can make two meters from one unless time expands (quickens, runs faster, however…) as space expands. Our clocks tell us that it now takes light twice as long to get from point A to point B when space stretches from one meter to two. Either our clocks are running faster or our light is moving slower. The length of a meter is defined as the distance light can travel in a given length of time so, if c is a constant, then the difference must be in the clocks. |
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If you drive at the (UK) speed limit to a town 70 miles away and it takes an hour, you'll be unsurprised when it takes two hours at the same speed to reach a town 140 miles away. You won't blame your watch or your car, you'll blame the distance. Why do you think light will behave any differently? Grant Hutchison |
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But more space appears: you can imagine existing space stretching, you can imagine new space "welling up" from an unknown source, you can even imagine space-time fairies if you really want to. All the mathematical description of the expanding universe tells us is that the distance increases, so light takes longer to cross it. That's all there is to it. You might as well get used to the idea, to quote Pat Benatar. Grant Hutchison |
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Grant Hutchison |
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Grant Hutchison |
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If a beam of light was traveling through space and reached a part of space that was expanding at C would that light be deemed to be traveling no distance, but taking infinite time or would it be deemed fixed at that spot? looking at it from 3 perspectives- away from the observer, towards the observer, adjacent to the observer? I guess this is really a SR, Question ![]() |
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![]() Cosmic microwave background photons, for instance, started off in our direction 13.7 billion years ago, from a proper distance of about 40 million lightyears, in a region of space that was moving away from us at 50 times lightspeed. So those photons were propagating at lightspeed in their own frame, but were moving away from us (in terms of proper distance) at 49 times lightspeed. But the expansion of space was slowing, and the photons were propagating constantly into regions that were receding from us more slowly than their point of departure. So eventually they arrived in a region that was moving away from us at lightspeed. As viewed from their emission point, they were receding at some multiple of lightspeed, because the emission point was expanding away from their current location. As viewed from their local space, they were moving at lightspeed. As viewed from our location, they were making no progress towards us. That's a temporary state of affairs, though, because they continued to propagate into regions of space that were moving more slowly relative to us, and so they began to make progress towards us, until they eventually arrived (at lightspeed) in our local space. Grant Hutchison |
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I realize that the original 40 million light years took 13.7 billion but at greater than light speed how would we determine the time dilation and length contraction? how would this be applied to space-time? |