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Thread: Speed of light

  1. #1 Speed of light 
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    Something that's been on my mind from time to time is the speed of light, it's often referred to as a constant.

    The escape velocity of a black hole is greater than the speed of light, so light can't escape it. In my mind, this means that light is travelling at zero mps because it's trapped within the event horizon.

    The escape velocity of a neutron star is less than the speed of light, so light can escape it at it's normal constant velocity.

    After a supernova from a star with enough mass to become a black hole, as the dust collapses on itself, there is a point where the gravity exceeds the escape velocity of light. At that point, does the speed of light change make a sudden change or is it gradual?


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  3. #2 Re: Speed of light 
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    Quote Originally Posted by mjr150
    Something that's been on my mind from time to time is the speed of light, it's often referred to as a constant.

    The escape velocity of a black hole is greater than the speed of light, so light can't escape it. In my mind, this means that light is travelling at zero mps because it's trapped within the event horizon.

    The escape velocity of a neutron star is less than the speed of light, so light can escape it at it's normal constant velocity.

    After a supernova from a star with enough mass to become a black hole, as the dust collapses on itself, there is a point where the gravity exceeds the escape velocity of light. At that point, does the speed of light change make a sudden change or is it gradual?
    The speed of light is a constant. It does not change, even in a black hole. Light is prevented form crossing the enent horizon from inside to outside by the extreme curvature of spacetime, not by being slowed down.


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  4. #3  
    Moderator Moderator Janus's Avatar
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    The remaining posts have been moved to New Ideas and Hypotheses as they involve a unsupported personal theory of an individual poster.
    "Men are apt to mistake the strength of their feelings for the strength of their argument.
    The heated mind resents the chill touch & relentless scrutiny of logic"-W.E. Gladstone


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  5. #4  
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    How do you know that light can't escape a black hole? No one even knows fro certain if black holes even exist. have you ever been in one? has anyone on this planet ever been in one? Do we have any factual knowledge of even black holes exist as mankind as postulated? No, we have not. Science has moved away from facts these days to postulation.
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  6. #5  
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    Einstein predicted the existence of black holes. And many of his predictions have been proven. For example, Einstein predicted that a large body of mass bends light and that was proven to be true like a decade ago.

    I see articles pop up all the time from individuals claiming that they have found Relativity to be flawed, but time and time again, they are proven to be wrong. What this man did on paper a long time ago seems to stand firm.

    We have never observed a black hole directly your right, but we have observed it's affect on surrounding material.
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  7. #6  
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    Einstein was a brilliant man, but is he a GOD? No, he got his knowledge from previous physics professors over 200 years before his time. He did not know everything and no one does.

    I am right as no one has ever seen a black hole up front. No one has ever sent a probe into one, we do not even know if they are what we think they are. For all we know it may just be a dead star with alot of dense mass and it shoots the mass out faster than we can see. Did you ever think about that. I seriously doubt that we have a washing machine in space sending things into Peter Pan's never never land. Thats doesn't make any logical sense....period....

    I love science, but I will not follow hypothetical what if's.
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  8. #7  
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    We can't see and electron or a photon and we've never sent a probe into a neutron star or a pulsar. Do you doubt these as well?

    Synchronized atomic clocks becomes out of sync if one of them is on an air plain proving that time does slow down with speed.

    If your climbing a set of stairs with your eyes closed, eventually, you being to trust where to position your foot on your next step. This is known as a pattern.

    If the theories of relativity are proven one after the other, eventually, you being to trust that the rest of it accurate.
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  9. #8  
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    Quote Originally Posted by mjr150
    If the theories of relativity are proven one after the other, eventually, you being to trust that the rest of it accurate.
    It's even more solid than that. There's only two theories (special and general relativity). Over their domain of validity, both haven repeatedly been proven to be extremely accurate. If the theory is accurate, predictions made from that theory, within its domain, (such as black holes) are necessarily accurate.
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  10. #9  
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    Quote Originally Posted by MagiMaster
    Quote Originally Posted by mjr150
    If the theories of relativity are proven one after the other, eventually, you being to trust that the rest of it accurate.
    It's even more solid than that. There's only two theories (special and general relativity). Over their domain of validity, both haven repeatedly been proven to be extremely accurate. If the theory is accurate, predictions made from that theory, within its domain, (such as black holes) are necessarily accurate.
    The only one of these two that is a fundamental theory is general relativity.

    Special relativity is really only a local approximation to general relativity, basically GR on the tangent space. Another way to say that is that SR is GR in the absence of gravity, in which case spacetine is flat.

    So in reality there is only one theory. The reason that you hear of them separately is that SR was discovered first and is so much easier to handle that SR is still taught first, and to more people than the much more difficult general theory. Also SR is a very good approximation in many situations.
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