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Posts posted by NowThatWeKnow

  1. ...the early expansion was happening at many times the speed of light so that at that time

    you probably could not have seen any light all ? Even the light

    coming from your own sun ????? I gotta tell ya, I start to get

    real skeptical when theories require that kind of speed...


    ...Are we sure that the red-shift method is really giving us the

    right numbers...


    ...I posted a blog on this forum about 2 months ago concering light.

    It was titled "Is there more to light than meets the eye"...


    ...I also wondered if light itself is the driver for universe expansion....

    Martin is the expert and I am far from one but I would like to comment on a couple of things you said. The z=1090 I used in the morgan calculator took us back to the big bang when it was thought the expansion was at it's greatest.


    It very quickly fell off to a much lower speed when the universe was still starless dust and not transparent. I think the largest Redshift seen now is 8.2. Play with the calculator to get a feel for how they think it all went down. I agree with you that the jury is still out.


    I am not sure exactly how they use the cosmological red shift to determine expansion speed but there are a couple of different methods to cross check the results. The duration of an initial bright phase of a supernova is also used to determine distance and expansion.


    I often thought that light itself could be the energy responsible for the universe expansion but I have been told there is not enough energy there to produce the results we observe. It made more sense to me then dark energy/matter that we can not detect except for the results it produces. Almost like saying God did it. I will also not be surprised if there is a, yet to be defined, ether discovered with light playing some role.

  2. If you take the master clock with you on a trip it seizes to be a master clock...unless it worked on something outside of known physics...

    Our thought experiments have unlimited technology. The master clock is hooked to CMB speedometer and gravitonometer to stay synchronized to Earth time. :eek: The GPS satellites are synchronized to Earth clocks so it isn't impossible.

  3. They would both agree that the master clock had slowed the same amount relative to their own.


    But even after accounting for the time for transmission of the signals ...


    But that is why we have a master clock. So we do not have to wait for the time of transmission. Just because we see the lightning before we hear the thunder does not mean they were not simultaneous or synchronized.

  4. From swansont's post I seem to have it backwards. If the length contraction is observed by the spaceman it occurs in his frame and he could be injured.
    The space mans frame is his rocket ship and all that is in it. It all looks normal to him. He is not hurt. When the space man looks out the window, he is looking at a different frame that is contracted from ONLY his point off view.


    Edit - I think your problem is where to place the borders of each frame.

  5. Earth would judge them to be in the same time frame. They each would each consider the Earth's time frame to have slowed the same amount, relative to their own, but they would not agree at all that they were in the same time frame.

    How can all that be true? It sounds like a contradiction. I gave the two twins a master clock slaved to Earth's time frame and can not see how they would differ. And I thought I had those d@mned twins figured out. :embarass:

  6. ...(and possible injured) .... What I can’t comprehend is how the single body of the spaceman can be both compressed and not compressed...
    I know that many will argue that length contraction is not an illusion but maybe the distorted mirror may be the best way for some to look at it. :P
  7. I asked this in a thread in the relativity forum and it got buried and never got answered.


    Does the separation of matter caused by the expansion of space experience the same time dilation and length contraction as a similar distance change and speed from a rocket ride?


    I am thinking that if two galaxies are at rest with the CMB but are separating at relativistic speeds due to a increase in distance from expansion, they will share the same time frame.


    I am thinking that if the two twins blasted off from Earth experiencing equal acceleration but in opposite directions, They also would experience the same time frame. Despite there increasing separation speed.


    Anyone have the answer and where am I going wrong?

  8. Thanks! Tell me how you do it, please, if it's simple to do.

    In this case there was a typo: the lambda term should be 0.73. ...


    Can you believe all the mind power necessary to come up with the knowledge to make this calculator accurate, and I had a typo that made it all worthless. :eek:


    Well I fixed it. :D

    I will PM you.

  9. ..I wish I could show you Morgan's calculator with the input of z = 1090, the redshift of the CMB. It gives the distance then, distance now, recession rate then, recession rate now. (Recession rate is not a motion speed it is a distance expansion rate.)...
    I had a couple of extra minutes.



    Edit - Fixed typo on attached image.


  10. Admittedly, I am not convinced BBT is valid, no longer wish to argue the point ...

    Neither am I. Hence, my screen name. In actuality we don't know $h!t. Knowledge is changing quickly and that should continue. I suspect we will never be able to say "NowThatWeKnow". :) So, I am just attempting to relay what I think is mainstream today. Knowing that much of it will change tomorrow.


    ... How could the observation be the same from observations made from distant points. Regardless how you understand 'center' with regards to a self contained U in rapid expansion, said to be in all direction (not material) then the effects of expansion IMO cannot be equal in every quadrant of that object, sphere or other wise.

    As the balloon expands the distance between every dot (qalaxy) increases. Each specified distance will expand equally in all directions. The further the distance, the faster the speed. There is no center to the surface of the balloon.

    Light is sent out as a continuous beam over billions of years and not just a flash to be monitored at a particular time. As the distance of two objects separating increases, the light will redshift until it can no longer be seen.


    Just a few of my thought addressing what I think you were saying.

  11. Please follow the link. http://en.wikipedia.org/wiki/Ladder_paradox I'm not mixing reference frames. 1' is 1' for you, but your 1' is not my 1'.


    ...the Earth is moving at >0.999999999999999C. They just tend not to be very convenient...


    But it may interest you that there are, in fact, plenty of particles moving at more than half C relative to the Earth that collide with the Earth all the time. In fact, these allowed us to have some of the first direct observations of relativistic time compression.


    Sysyphus and swansont,

    The ladder paradox is interesting, I will try to think of a way my "master clocks" can simplify it. :) It seems I was confusing comparing different frames to mixing different frames. Sometimes I am not sure where to put that line.


    I wasn't thinking of minute particles everywhere traveling a high speeds relative to us and of course the particle accelerators where we can observe the results of relativistic speeds.


    This has been an educational thread for me and your tolerance to physics ignorance is admirable. Thank you.


    Now, on to the next problem. Does the separation of matter caused by the expansion of space and the movement through space relative to us, such as a rocket, both experience the same time dilation and length contraction from Earth's point of view?

  12. ...This is evidenced by the fact that you are traveling at 99% the speed of light relative to any countless arbitrary frames of reference,...


    This is mentioned a few times in this thread but afaik the only frames moving at relativistic speeds relative to Earth are because of the expansion of space and not motion. This brings us back to my question in the last paragraph in post 23. Unless we can say for sure that speed from space expansion causes time dilatation and length contraction and not just motion through space, should we use it as an example to prove a point?


    Last plug for my cause. :D I will start a new thread if it isn't resolved.

  13. If the light from a galaxy took 13.66 billion light years (almost the age of universe) to get here, it was emitted when it was 0.205525 billion light years away and is now 43.762 billion light years away. This is not because of the movement of galaxies but because of the expansion of space.


    The universe was more dense long ago but the big bang is currently looked at as not coming from a singularity. At the edge of the observable universe we would probably see a similar view in every direction as we do from the Milky Way.

  14. I'm sorry. Does Smoot actually say singularity? Maybe he did, so please let me know. ...If he said observable universe concentrated in volume the size of an atom, an atomic nucleus, or a proton, that's fine...

    I remember him saying

    "observable universe concentrated in volume the size of an atom,"

    To the layman that sounds like singularity.

    Good video but not pushing the agenda of this thread.

  15. Thanks again everyone but I understand this expansion of space, I think, say galaxyA 1mly away is moving away from us, galaxyB 2mly away is moving away,(but the galaxies arent moving just space in between is getting bigger) but also galaxy A would see both us and galaxyB moving away from it at the same rate. That is a shortened sorta version of whats in my head...


    Watch the Wright Balloon video as Martin suggested. A picture is worth a thousand words.


    Also, if you can visualize a balloon slowly filling up with air and the balloon has dots (dots are galaxies) all over it. No matter what dot you are on, all other dots are moving sway from you. The further away the dot is the faster it is moving away. Space is expanding between each dot. There is no center on the surface of the balloon and every location will yield the same view.



    Now put an ant on the balloon (Not sure why I use ants). Say his movement represents the speed of light. He can easily get to the dots near by but if the balloon is expanding fast his speed may not be enough to get to dots far away.


    I am tired of typing. Go watch the short video.


    Edit - http://www.astro.ucla.edu/~wright/Balloon2.html

  16. But with relativistic velocities, it does shrink, in the applicable reference frames. It's not just an illusion, as with a mirror. A twenty foot pole moving fast enough will fit inside a ten foot room, in the reference frame where the room isn't moving...

    I started a thread once called "Is relativistic mass an illusion" and got varied responses. What you observe from different frames will vary but no matter what frame your are in, 1' is 1' and you can not mix frames as you are suggesting above. I do agree the mirror may not have been the best analogy.


    Interesting. I don't know, but I'm thinking it can't work the same way as motion, if only because at some point they'd all have infinite momentum, and then beyond...


    Oh, and it's not caused by motion relative to the CMB. "At rest with respect to the CMB" is convenient but not privileged. It's caused by motion relative to whatever reference frame it's considered in.


    Yes, motion relative to the CMB was not a good example but at that moment it seemed right since galaxies are basically at rest with the CMB despite separating at relativistic speeds.


    Martin said any one at rest with the CMB, any where in the universe, would calculate the age of the universe the same. That indicates to me that there is no time dilation between separating galaxies (with the same background temperature). I would like someone with more knowledge then me to chime in here..................Please :embarass: Maybe the uniform expansion is acceleration equal in all directions with time dilatation being equal accross the universe. Hang on, time is slowing down and will soon stop. :D

  17. Making them the same frequency is syntonized, as I said earlier. If you synchronize clocks running at different rates they will lose synchronization, as with two clocks in different frames.


    GPS clocks are set to run at earth clock speeds by adjusting their frequency.

    Thank you for elaborating. I was trying to keep it simple and thinking of synchronized clocks in different frames as analogue hands moving over the same numbers simultaneously with no regard to how it was done.

    Merged post follows:

    Consecutive posts merged
    I see what you mean about the satellites. In that sense, yes, both twins could have their clocks synchronized (I personally wouldn't call them Master Clocks though)...

    Sometimes I think we are looking at the same thing from different angles and then arguing with ourselves. :D As far as "Master Clocks", swansont has convinced me to use it, at least until something better is suggested.

  18. That's it. To me, universal/absolute time implies that such a thing exists. A master clock, OTOH, is an agreed-upon reference, much like we agree to measure longitude starting at Greenwich. You can start anywhere and get consistent answers, but the problem arises when you try to talk to someone else.

    You make an excellent point and I have been converted. :) If there is some reason to use the words "universal time" in the future, I will define it.

    Merged post follows:

    Consecutive posts merged

    Is that what you're asking? I'm not familiar with using background temperature as a reference.


    A consistent background temperature in all directions will put you at rest with the CMB. Gravity will also have to be considered but it will help eliminate time dilation and length contraction issues when looking at simultaneous events. At Least that is the way I see it. I like your examples.


    Edit - I started to elaborate but seem to be brain dead at the moment.

  19. The spaceman has only one body and it either shrinks or does not. If it shrinks he may have problems.

    If you look in a distorted mirror you will look distorted but it doesn't mean you are distorted. It does not shrink.


    This brings up another question. I know there is red shift because of the expansion of space, but is there time dilation and length contraction because of the expansion of space? Or is time dilation and length contraction only caused by movement relative to the CMB.


    If the expansion of space does cause time dilation, what is time doing in galaxies so far away they are separating at MORE then the speed of light? :confused:

  20. I have to correct this. Synchronized means the same reading. The rates can be different if they are in different frames, so what I said above only applies in the same reference frame.

    The speed of a clock could be synchronized without the time being synchronized (in the same frame), right?


    I think you are saying that the GPS satellite clocks are synchronized to Earth clocks but running at different speeds and in different frames. Is that right?

  21. So does the fact that some bodily functions (let's say circulation, to keep it clean) are moving parallel to his direction of motion and others moving perpendicular matter?


    No, not any more then it would matter to you right here, right now. You are both at rest in your own frame.

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