Thread: Is this really true or it's just science fiction?

  1. #121
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    um no offense but isn't sean a boys name?

    my sister is called seana

    [its pronounced sean - ah not sea - anna or shoan - ah ]

  2. #122
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    passing thought:

    Quantum singularity means all the rules of physics break down,

    Where do you want to go today?

    <---:-(

    does santa claus travel faster than light, and if so he must be einstein?

  3. #123
    The Earth is not flat. Clyde's Avatar
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    "whats light propulsion ?? light having no mass, how does it work ?? your not talking about the solar wind ???"

    Light doesn't have "rest-mass" ie. if it stopped moving it wouldnt have a mass and it would cease to exist, however whilst its moving it does have a mass.

    All energy has a mass accosicated with it: E=MC^2

    If light is shone at a suspended mirror, the mirror can be (very slightly) deflected.

    I think the term "solar wind" refers to light, though i may be mistaken.

  4. #124
    The Earth is not flat. Clyde's Avatar
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    "Quantum singularity means all the rules of physics break down"

    There are hopes that quantum gravity will reveal the inner workings of singularities.

  5. #125
    My diaper's full....... stevey's Avatar
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    i think the solar wind is actually charged particles.

    and light doesn't have a mass even at light speed does it ????
    ow don't explain, i think i'll go back to my Stephen Hawking book.........
    Steve

  6. #126
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    Originally posted by brif

    does santa claus travel faster than light, and if so he must be einstein?
    No. Santa teleports. It's all about making atoms at different positions behave as if they were one.

  7. #127
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    Santa doesn't travel faster than light, he doesn't have to. Ever since the stanta act of 1943, kids only get presents from santa if they deserve them.
    That limits his list to about 3 kids up in greenland.
    If you own a piece of land and there is an volcano on it and it ruins a
    nearby town, do you have to pay for the property damage?

  8. #128
    Ethereal Raccoon Procyon's Avatar
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    Light does not have rest mass, though it does have "mass" associated with its energy (as usual, it depends on your definition of mass/energy). Its mass is not really the issue, though. Light particles (photons) do have momentum (in the amount hf/c), which can be conferred to anything they deflect off of. That's how a solar sail would work - every photon of light ricocheting off of it would confer twice its momentum to the sail, causing it to accelerate.

  9. #129
    It's full of stars adrianxw's Avatar
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    Hi Clyde:

    >>>
    I understand what you're saying. I've heard it many times before. Whenever science holds something up to be true, people say "But science has been wrong before, therefore you can't be sure".
    <<<

    Yes, that's true, however, I would not put myself in that category, (you might!). I accept as fact many things that are regarded as dubious by many others, indeed, on this very board I have defended a number of scientific explanations.

    My problem with relativity is as I have mentioned before, it tends to be self referential, (A because of B, B because of A). You did it yourself. Given time I'm quite sure I could come up with a self referential model of something stupid, that was quite internally consistent, but also obviously wrong.

    You mention "special magic particles" - well, what's wrong with that? If your familiar with Bondi, Winterberg, Forward etc., then negative mass, negative energy, negative timelines, a seemingly endless flock of hypothetical dark matter... who knows what else?

    Anyway, suprisingly perhaps, I do believe that relativity is currently the best model we have, but I have doubts, and say again, it is a model.

    You did not pick up my question about the FTL assertions of the cosmological inflation theory, I'd be interested in your answer, (Procyon, your's too, I know your more into this stuff then me!).
    Wave upon wave of demented avengers march cheerfully out of obscurity unto the dream.

  10. #130
    The Earth is not flat. Clyde's Avatar
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    "BTW, how do physicists feel about the faster than light problems associated with cosmologists inflation theory?"

    Hmm, well for a start all cosmologists are physists Since inflation theory came about as a direct consequence of relativity (although initially Einstein refused to believe his own equations and stuck in a constant so that they would show the universe to be static), I would have thought there were no faster than light problems associated with it.

    "You mention "special magic particles" - well, what's wrong with that? If your familiar with Bondi, Winterberg, Forward etc., then negative mass, negative energy, negative timelines, a seemingly endless flock of hypothetical dark matter... who knows what else"

    Ah you see there is no problem with particles with special properties, but they all obey the laws of physics: charged particles act like charged particles, and particles with mass act like particles with mass ie. can't travel faster than c.

  11. #131
    It's full of stars adrianxw's Avatar
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    >>>well for a start all cosmologists are physists

    Oooh, not to loud!

    >>> were no faster than light problems associated with it.

    I'll find and post a link.

    >>>
    and particles with mass act like particles with mass ie. can't travel faster than c.
    <<<

    That begs the question, would a particle with negative mass be able to travel slower than c?

    Another related problem I have with the universe, (as opposed to some of the people in it), is the need to constantly propose new exotic particles and so on, to make the observations fit the theories.

    The dark matter flock for example, okay, spiral galaxies rotate in such a way that they do not fit the model, so we need to add some matter to make them fit the model. Of course we can't see this new matter, but the model says that it must be there, so it is. (I am aware that people are looking for it, but not found it). It seems to be a "cart before the horse" situation.

    Information cannot be transmitted faster than light, (the theories say so), but then quantum entangling comes along.

    People cling to their theories, because it is the best they have, and solves some of their problems, ensures their research budgets are renewed and so on. I go on worrying about this.

    As a thought experiment, I wondered what would happen if you took a bunch of highly intelligent mathematically bent people but kept them away from relativity and so forth, then just gave them the observations as known, and ask them to come up with a model that fitted - would it look anything like what we use today?
    Wave upon wave of demented avengers march cheerfully out of obscurity unto the dream.

  12. #132
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    >>> I'll find and post a link.

    Here for example...

    http://imagine.gsfc.nasa.gov/docs/fe...inflation.html

    ... an extract...

    >>>
    Inflation is an extension of the Big Bang theory in which the Universe expanded from an atomic scale to a cosmic scale in a fraction of a second, making the Universe geometrically flat. This rapid expansion, as you can imagine, would leave its stretch marks on the cosmic microwave background. Inflation is one of the prime theories that MAP will test.
    <<<

    >>> atomic scale to a cosmic scale in a fraction of a second,

    ... i.e. faster than light.
    Wave upon wave of demented avengers march cheerfully out of obscurity unto the dream.

  13. #133
    The Earth is not flat. Clyde's Avatar
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    "Another related problem I have with the universe, (as opposed to some of the people in it), is the need to constantly propose new exotic particles and so on, to make the observations fit the theories.

    The dark matter flock for example, okay, spiral galaxies rotate in such a way that they do not fit the model, so we need to add some matter to make them fit the model. Of course we can't see this new matter, but the model says that it must be there, so it is. (I am aware that people are looking for it, but not found it). It seems to be a "cart before the horse" situation. "

    Dark matter is simple; can measure how fast the universe is expanding, and basically we can tell that the rate that its slowing down is much more than it should be given the observeable mass of the universe. Hence the conjecture that there is extra mass out there that we can't see accounting for the extra slow down: dark matter. -seems reasonable to me.

    "Information cannot be transmitted faster than light, (the theories say so), but then quantum entangling comes along"

    Quantum entanglement is an interesting dilemma, it appears to violate locaility, it's not understood well, but it does not nessesarily mean information is being transmitted faster than light.

    "People cling to their theories, because it is the best they have, and solves some of their problems, ensures their research budgets are renewed and so on. I go on worrying about this. "

    People might do but science does NOT, that is its greatest strength; whenever it is possible to modify or replace a theory with one that better fits the data, science does so.

    You worry, but you don't even have 100th of the picture, how can your conclusions possibly have any validity?

    "As a thought experiment, I wondered what would happen if you took a bunch of highly intelligent mathematically bent people but kept them away from relativity and so forth, then just gave them the observations as known, and ask them to come up with a model that fitted - would it look anything like what we use today?"

    They would get nowhere, they would be unable to produce a meaningful model (they would have too much information) or they would start producing a basic relativistic model.

    Remember relativity was NOT devised to "fit" observed phenomenon like time dilation/ the limit of light being c. Relativty DISCOVERED those properties, pretty much the only data relativity was based on was that light seemed to be measured at the same speed whether we were away from the sun or toward it.

    In much the same way that the only solution to an object accelerating is a force, the only solution allowing light to travel at the same speed from the point of all observers is to change the geometry of the universe ->relativity.

    "... i.e. faster than light"

    Well, in the first second of the universe the laws of physics were substancially different, the four forces were unified, and loads of other funky stuff was going on, so its not so unplausable that the absolute speed was different.

    Further more i don't think there is an absolute speed that space itself can travel at. Only an absolute speed for objects travelling through space.
    Last edited by Clyde; 04-09-2002 at 06:13 AM.

  14. #134
    It's full of stars adrianxw's Avatar
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    >>>
    Dark matter is simple; can measure how fast the universe is expanding, and basically we can tell that the rate that its slowing down is much more than it should be given the observeable mass of the universe. Hence the conjecture that there is extra mass out there that we can't see accounting for the extra slow down: dark matter. -seems reasonable to me.
    <<<

    Is "therefore our understanding of the situation is woefully inadequate" also not a viable conclusion - seems reasonable to me.

    >>> does not nessesarily mean

    Not necessarily, but it might. As you correctly state, it is not well understood.

    >>>
    whenever it is possible to modify or replace a theory with one that better fits the data, science does so.
    <<<

    Agree with that, I've been advocating an open minded position throughout the debate.

    >>>
    You worry, but you don't even have 100th of the picture, how can your conclusions possibly have any validity?
    <<<

    Naturally. The same can be said of anyone. People are either so expert in a field that they lose sight of the bigger picture, of have a broad enough overview to see the problems but not the details.

    >>> would start producing a basic relativistic model.

    (Information overload point accepted - it was just a thought experiment). I would suggest that you think that's what they would produce, because that is what you think. I am prepared to accept that they may, or possibly a completely different self consistent model might emerge.

    >>> Only an absolute speed for objects travelling through space.

    So we have two objects, stationary with respect to the space they occupy, but in two parts of space that are travelling above c relative to each other...

    We could go on, but I think in the end we would acheive little.

    I am not going to lose my doubts while there are so many fiddle factors added to make things look right. The genetic analogy you mentioned earlier does not do this. The flat Earth/round Earth does not. This stuff does. ( I was at a seminar a year back where two groups were presenting their work and arguing for a ressurrection of the "cosmological constant". Fun thing was, their estimates of it's value had opposite signs!)

    I'm not going to lose my doubts, and I suspect you are not going to accept them!
    Wave upon wave of demented avengers march cheerfully out of obscurity unto the dream.

  15. #135
    Funniest man in this seat minesweeper's Avatar
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    Just a small query:

    ...the four forces were unified
    Hasn't it now been reduced to just two? At least that is what I remember Stephen Hawking saying in "A Brief History of Time".

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