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Jacques

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Posts posted by Jacques

  1. What would happen if in let say in a supernova explosion some of the matter somehow are pushed over the speed of light.

    My thinking is that to an outside observer that FTL matter will look like going back in time then instead of seeing that matter expanding we would see it contracting. Is it plausible that supernova remanant are such observationnal artifact ?

  2. why would there be a perfectly uniform contraction of matter

    Because of gravity.

     

    Yes Occam's razor.

    No need for a big bang :)

    Accelerated contaction because thing are getting closer. No need for dark energy to accelerate the expansion...

  3. I called neutronium the matter inside a neutron star.

    I was wondering if we could take a teaspon of neutronium, and bring it outside of the gravitationnal field of the star, what would happen ?

    I know that it would be almost impossible to do that, a teaspon would weight many tons here on earth and I have problem to imagine how it would weigth on the neutron star !

    Will the neutronium turn into a neutron soup and neutron decay into a proton and an electron and form hydrogene H1-1 ? Will it create super heavy hydrogen isotope like for example H1-10 ?

    Just curious :confused:

  4. No comment...

    Let me rephrase it:

    From the point of view of a gravitationnaly bounded galaxy cluster the universe is expanding.

    From the point of view of the universe, gravitationnaly bounded system contract.

    Is it equivalent ?

  5. Here is a foolish idea:

    What if the redshift of distant galaxy is not caused by the expansion of space, but by the contraction of matter ?

    Wouldn't it be equivalent ?

    Let me explain a little how the contraction of matter can give the redshift.

    At the time a galaxy 1 billion light year away, atom where a lot bigger and where emiting light with a lot bigger wave length. While it was traveling toward us our local group was contracting and now the same kinds of atoms are emitting at a much shorter wave length.

    I think that you can get it. I know I have nothing to support that hypothesis, but I am interested to know if it can explain all observations we have on the distant universe :doh:

  6. I found that and tought that you might be interested

    Astronomers' Doubts About the Dark Side:

     

    No more dark energy ???

     

    Prof. Shanks comments "CMB observations are a powerful tool for cosmology and it is vital to check for systematic effects. If our results prove correct then it will become less likely that dark energy and exotic dark matter particles dominate the Universe. So the evidence that the Universe has a 'Dark Side' will weaken!"

     

    What do you think of that ?:eek:

  7. Thanks I didn't saw abj link

    I copied the equation:

    [math]f_o = \frac{1}{t_o} = \gamma (1-v/c) f_s = \sqrt{\frac{1-v/c}{1+v/c}}\,f_s[/math]

    The wiki tell

    ( v is negative if the observers are moving toward each other).

    If it is correct when v is .995c then [math]f_o=\sqrt{\frac{1+.995}{1-.995}}\,f_s=20f_s[/math]

    OK:doh:


    Merged post follows:

    Consecutive posts merged

    Swansont

    The observer pops into his Gamma100 spaceship which travels at .995c (so gamma=100).

    I thinks there is an error: At .995 c I found gamma=10.

  8. mooeypoo:

    Visible light is an electromagnetic wave with a certain frequency. Increase that frequency, and you get radio waves.

    Radio waves have lower frequency than light

    Electromagnetic spectrum

     

    Also I want to add to Swanson reply that not only the Gamma100 passenger will need to tune is radio to 20 time the earth radio station frequency, but the information will comein 20 time faster.

     

    But he will experience Relatisvistic time dilatation that may cancel the Doppler blue shift (or add the Doppler blue shift I am not sure...)

  9. 246000 mm / 7200 sec = 34.17 mm/sec

    That the linear speed of the tape.

    34.17/45 = .76 rad/sec at the beginning when the reel is full

     

    the trick to find the radius when the angular speed is the same is to think in term of surface. The tape has a thickness and the area of the tape is constant.

    At half the tape the total area of the tape on the 2 reels is the same has the area of the tape on the big reel at the beginning.

    pi*R^2-pi*r^2=pi*(R^2-r^2)=pi*(45*45-12*12)=5909 mm^2

    Half that is 2954.5

    2954.5=pi*(x*x-12*12) where x is the radius of the reel half way

  10. First thing I would do to simplify the problem is to convert everything in the same units.

    For time you have hour and you have sec and minute. For the lenght you have meter and millimeter. I would suggest to convert every thing in millimeter and second.

    After I would do some exercise: What is the angular speed in rads/sec at the beginning of the tape ? at the end of the tape ?

    You will see that the angular speed depend on the radius of the reel.

    So the sub-question: What is the radius of the reels when they have the same angular speed ? Answer: When they have the same radius. What is that radius ?

    That were you need more thinking :)

  11. I don't know much about Telsa coil but with the description you gave of an aircoil transformer you need AC. But not so sure because the spark gap switch may do the job of creating an AC current in the transformer

  12. If we were at the location of a former supernovae we would see remnats of the cloud all around us, we don't.

    We don't because the cloud condensed back into the sun.

    Also what remains is a neutron star or black hole, neither of which are at the centre of the sun.

    How are you so sure that a neutron star is not at the center of our sun ? Heliosysmographie doesn't have the resolution to detect a few kilometers sphere.

    I don't tell that it is it, but just speculating

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