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Locrian

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Posts posted by Locrian

  1. That's your suggestion - not mine.

     

    No. Your suggestion is that our observations over a great deal of time have demonstrated that there is a pattern over a long period of time even up until recently, and yet we cannot assume that it is ongoing. This is the only interpretation that can be made from your posts.

     

    To establish the constancy of a redshift at a given distance would require observations over a long period of time.

     

    And all that requires it to view at farther distances. Since we have made observations at high distances - and that is what the study on supernovae was about, determining distances - we have also made observations over long periods of time.

  2. Note that this electromagnet you've created will generate a magnetic field similar to the bar magnet, and that the two fields can add to be a bigger one. However, this isn't making the bar magnet permanently stronger. You have to melt it and expose it to a magnetic field to do that.

  3. "Dark matter" and "dark energy" is nonsense. Sounds like astrophysics has gone over to science fiction these days.

     

    Gosh yea, its so crazy. They see evidence that something is pulling gravitationally on something else, and they have the audacity to suggest that there's matter there that isn't emmiting light and is difficult to observe - dark matter.

     

    Then we observe that the universe is accelerating. Since acceleration occurs because of a force, those crazy astronomers suggest that this acceleration is due to a force, and call the energy involved dark energy.

     

    Those kooky astronomers have just gone way off the deep end.

  4. That's Olber's paradox. One reason we wouldn't be blinded by the light from trillions of stars is due to redshifting. It is worth noting that if you look at the milky way band in the sky, it appears as a diffuse band of light. This is probably a fair example of what the universe might look like with out redshifting, except it would be even brighter.

     

    Of course, it isn't just red shifting that blocks light. Dark matter may block some light, but it would be little. The major interstellar component that blocks light is the interstellar medium. This reddens (not to be confused with red shifting) the light a great deal, and blocks quite a bit. This is why our milky way band isn't brighter. Note that interstellar medium is not considered a part of "dark matter" because it is observable and accounts for very little mass.

     

    On another note, this initial paper C.P Luke cited has generated a lot of interest. People seem to not note that there are already papers arguing against it, though they are not considered definitive.

  5. My point is that without evidence we can only assume[/i'] that the present state of (distant) events is like their past states. This may or may not be a reasonable assumption.

     

    Of course it is. The primary evidence was observations of type Ia supernovae at various distances. These observations combined with the redshifting of the light demonstrate a difference in velocity based on distance and time. The results show very consistent patterns over time. To suggest that we cannot assume this pattern continues today is to suggest that the universe operated under very straight forward laws for billions of years and then suddenly stopped and is operating under different ones, for no reason.

  6. So basically' date=' you have a new theory; you demand respect for it; you refuse to explain your theory.

     

    Great.[/quote']

     

    After seeing alexross post about this so many times I can't help but agree with drochaid. I am underwhelmed by the conversation and am tired of seeing the same shallow nothing repeated over and over.

  7. hmm I suppose I am just ignorant of what its hook is.

     

    I know how you feel! I used to think every part of physics was boring except astrophysics. That was my love. However, I took a class as an undergrad in lasers intending to learn more about spectroscopy - I found it absolutely fascinating. Every bit as much as astrophysics, or more. I was entirely ready to ditch my old crush for a new one. I never got the chance though, because I was taken away to something entirely different.

     

    Luckily, this process has repeated itself for everything I've worked in: materials sciences, crystal growth, cutting tools and most areas I touched on along the way. Recently I've started just randomly looking up physics departments, finding something that sounds boring and studying up on it. So far they've usually ended up interesting. I've done this with quantum dots, decoherence, superconductivity and more.

     

    So maybe me and you just need to spend a bit more time with the fundamentals in this case.

  8. The two papers of theirs I believe were so exciting were:

     

    Riess et al. “SNAPSHOT DISTANCES TO TYPE Ia SUPERNOVAE: ALL IN “ONE NIGHTS WORK.” Astrophysical Journal, 504 935-944 (1998)

     

    Schmidt et al. “THE HIGH-Z SUPERNOVA SEARCH: MEASURING COSMIC DECELERATION AND GLOBAL CURVATURE OF THE UNIVERSE USING TYPE Ia SUPERNOVAE.” Astrophysical Journal, 507 46-63 (1998)

     

    I'm pretty sure the first is the printing of the preprint you linked. Of course Schmidt actually published three papers on those experiments, of which that one is just the first. These two people are distinguished because they were first; those two papers were the first very definitive evidence of cosmic acceleration. You can see that in the title of Schmidt's paper - they intended to measure the deceleration, and just ended up with a very different result than they expected. (However, I'd like to say that I don't mean to only include those two; there might be another that deserves it with them.)

     

    I think those two groups are also distinguished because their work was very good. It was not a simple experiment and it wasn't accident they produced the data first. I find Schmidt's work on the implications of his findings to be good, though I admit I did not keep up with it much after the first few papers.

     

    The measurement of cosmic acceleration has had a huge impact on astrophysics, cosmology and even high energy theoretical physics. While I don't claim to know enough about every area of physics to say those two deserve to win the nobel prize, I would be very disappointed if their names didn't at least come up from time to time within the committee.

     

    As you pointed out the winner, it seems this discussion is rather moot for the period of about 360-364 days ;)

  9. Bodies of mass have a gravitational constant. With earth, it is aproximatly 9.8m/s squared acceleration force.

     

    9.8m/s^2 is not the gravitational constant. The gravitational constant is the same everywhere. 9.8m/s^2 is the acceleration on a body near the surface of the earth. It differs far from the surface.

     

    I beleive in theory since the gravitational constant changes as you increase the distance between two objects that the speed of the 2 apples would be equal at the 1 mile mark.

     

    Countless experiments on gravity have been done, and they disagree with you. Just sum up the work done by gravity over those distances and convert it from kinetic energy to velocity. You'll see that the speed would be different.

  10. To clarify, it isn't money that prevents us from using limestone for fission energy; the fact is that fissing atoms that limestone is made out of requires more energy than it produces. Roughly speaking the lighter the element the more energy produced by fusing it, and the heavier element the more energy produced by fissing it. You have losses in any energy production process, so when it comes to fusion and fission you use elements at far ends of the weight spectrum for good reason.

     

    I would also highly object to your characterization of matter as tightly compacted energy. I don't feel that phrase has much meaning.

  11. I would just think that physics as a whole should be more concerned with why things work the way they do, as opposed to simply predicting outcomes.

     

    When you propose an idea that is why something works, how will you show it's correct? You'll show that it predicts things that are observed. If it predicts nothing that wasn't already predictable, then there is no reason for it to exist, and we'll just use occams razor to eliminate it.

     

    You are creating a false dichotomy that isn't philosophically sound. Ontop of that, I'm not sure you are really fully aware of what physics as a whole does.

  12. Suggesting that relativity is "a curve fit" doesn't make much sense. The only way I can interpret that is to say that the theory is built off large numbers of experimental results in such a way that it predicts them and all new ones.

     

    Which is about the nicest thing you can say about any theory.

     

    Yet, by your paragraph, it didn't sound like you were trying to give it a grand compliment. I'm afraid your meaning is eluding me.

  13. No, traveling faster than forces travel creates causation issues all by its lonesome.

     

    Also, swansont didn't say that traveling faster than the speed of light is mathematically impossible because that makes no sense at all. Mathematics don't determine how the universe operates; instead, we use how the universe operates to produce mathematics that predict observation. The special theory of relativity is well-tested and known to correspond to physical results. This includes the limitation on relative velocity.

  14. swansont, last time I read anything on QM (it was a real text book) it taled extensively about the uncertainty relationship. How could you ssay an electron has 0 angular momentum without saying that it could be anywhere in the universe?

     

    First, look at the total angular momentum operator in spherical coordinates. Now, see if it commutes with the spherical coordinate r. You'll see that they commute just fine.

  15. This is from my blog, entitled "Physics Riddle." Of course all the big-wigs in the thread will know the answer immediately, but I remember finding it suprising way back when I was an undergrad, so maybe someone here will find it amusing as well. In any case, the information is on topic:

     

    -------------------

     

    One of the predictions of the special theory of relativity is that when two observers have a velocity with respect to each other, they percieve time as passing differently for each other. This is not just an optical trick; consider the infamous “twin paradox,” where one twin leaves planet earth traveling very, very quickly and then later returns. The one that left and returned would find themselves younger than the other.

     

    Consider this experiment*: In 1972 two men took three atomic clocks to an airport. One left traveling east completely around the world on multiple flights. Another left traveling west and traveled around the world. A third atomic clock was left at the airport.

     

    Based on the twin paradox, what do you think should happen? You might think those who are in motion have clocks that count slower. The results might (or might not) be suprising. The man traveling eastward was about 60 nanoseconds younger than the reference clock. The man traveling westward was 273 nanoseconds older than the reference clock.

     

    And this is exactly what special relativity predicts.

     

    So what gives?

     

    *See Science 177, 166-170 (1972)

  16. Good question. Historically this was to avoid solutions which had negative energy. If you can derive the relativistic form (as I suggested) you will see what I mean....

     

    I admit I haven't done that yet. That is certainly a mark against me.

     

    However, I believe your answer affirms a point I'd like to make: while the SE may be considered derivable in retrospect (knowing what we know now), it wasn't at the time. In fact, I suggest it should really be considered an assumption that has just been repeatedly validated by theoretical and experimental tests.

  17. We all know that electron is negative and the nucl is positive and that they attract to each other. My question is why the electron ORBITS the nucl? What are the fources influencing that behavior of the electron?

    Thank you

     

    This will be almost entirely answered in your first quantum mechanics class. Get excited!

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