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Constants Not Constant?

grytpype writes: "According to this story, a team of astronomers have determined (based on their observations of distant quasars) that [certain physical constants] may have been different in the far past of the universe. The discovery (if validated) is said to be good news for string theorists."

12 of 494 comments (clear)

  1. Summary by tbo · · Score: 4, Informative

    Here's a quick summary, for those opposed to NYTimes registration (incidentally, feel free to use the login slashdot66, password slashdot):

    Astrophysicists have observed spectra from metallic atoms in gas clouds up to 12 billion light years away. Certain patterns in these spectra cannot be explained with current physics, and suggest that the fine structure constant (alpha) had a value slightly different in that place and time. From memory, I believe alpha is a dimensionless number with a value near (but not exactly) 137. The difference between alpha as we know it, and the apparent alpha in these gas clouds is about 0.001%. The observation was made from the Keck Telescope on Mauna Kea in Hawaii.

    Something like this, if confirmed, would almost certainly win the discoverers a Nobel Prize. Also, such a discovery would apparently also support string theory (although that's outside my area of research).

    I'll stop karma whoring now, and return you to your regularly-scheduled uninformed flamefest.

  2. Re:Evolution vs. Creation debate by alexjohns · · Score: 4, Informative

    Let's see. It's changed by 1 part in 100,000 over the last 12 billion years. So, we're dating fossil remains from about 100 million years ago. Assuming the same error, we'd be off by (hmm... carry the five, move the three, divide by pi, ignore the remainder, add 1 for good measure, and we get) about 1000 years. Gosh, yes, we 'evolutionists' are worried.

  3. You are confusing math constants with physic ones. by efuseekay · · Score: 5, Informative

    Mathematical constants are "constants" in the sense that it won't change whatever the universe's physics behave. Pi, for example, is always 3.14... in a flat euclidean space (which can be defined and have nothing to do with the real universe which may not be flat, nor is it euclidean).

    Physical constants, like Grav Constant (which by the way, is NOT a composite), however, are constants in the sense that they come out of a theory that needs MEASURED parameters to make it work.

    The "constant" in the article refers to the fine structure constant, is a quantity that is either a constant or not dependent on which theory you believe. Currently the Standard Model (which is believed to be wrong at some level) thinks it is. If it is varying with time, like the article says it is, then the interesting thing is that it allows to speculate what the real "underlying" theory is actually is (Not the Standard Model).

    YOur idea about the "Atomic constant" and "composite constant" are just plain misunderstanding of what a constant really is. There is no such jargon as "atomic constant". We use the word "fundamental constants of a theory", which is theory/physics dependent. The other constants, like Pi, are mathematical and has NOTHING to do with physics, for chrissake!

    So the Greeks cannot square the circle, ever.

    --
    Mode (3) smart-aleck mode. Press * to return to main menu.
  4. Re:Evolution vs. Creation debate by magi · · Score: 4, Informative
    It's pretty damn hard to think of how you could disprove evolution.

    Just look at the creationist sites and you'll find hundreds of attempts to disprove evolution, usually by demonstrating apparent impossibilities. For example, a whale buried vertically through several geological strata would be kind of impossible according to standard theories of stratification. Of course, the only instance the creationists have given, is a false one. However, were the case really what they claim it is, it would give a heavy blow to geology (and therefore to evolutionary theory). Similar claims would include combined dinosaur and human fossils, etc, etc.

    Just about anything you find, the biologists will make up an explanation for. Evolutionary theory also doesn't really make testable predictions.

    It does. Just consider the basic idea that all species have begun from a single cell. Therefore, a raise in complexity over time would be required. We can therefore predict, that the organisms in young strata are, on average, more complex than the ones in much older strata. This is, in fact, what we have observed. There are, for example, no complex animals (such as mammals) in 3 billion years old strata, and the fossils actually have a very rough ascending trend in complexity. (Assuming that fossilised skeletal complexity correlates with genetic complexity.) We can also roughly observe the birth of radically new features, which the older fossils didn't have, such as wings.

    Actually, the creationist hypothesis also makes a similar prediction; there would be no observable trend in the fossil record through the "apparent time". However, this hypothesis is in disagreement with the observations. Nevertheless, it's also testable in this way.

    I guess it's often though that evolutionary theory can't make predictions because we can't observe large-scale evolution right now. But that's not at all necessary. We don't have to do it right now. To give an analogy, we can't "test" a murder after it has happened. However, we can prove it with evidence. For example, we can have theories about the murder of JFK, but can't "test" it. However, if we found out that there had been a surveillance camera filming the apartment where the killer would have been according to a theory, we could make a prediction that the film shows him, and the film could provide the observation. So the idea is that historical events can be observed through the record of evidence they leave, just as a nuclear physics experiment might be analyzed from film plates later. Similarly, to test the astrophysical prediction that some stars blow up at some time in their life, we don't actually have to test it with our Sun, but we can observe the explosions that happened thousands or millions years ago.

  5. Re:Evolving value of Pi by eXtro · · Score: 3, Informative

    It's not necesarily true, an infinitely long irrational number does not necessarily include every other possible number sequence. Go here for more info.

  6. the paper by bcrowell · · Score: 5, Informative
    The paper is here.

  7. Re:Evolution vs. Creation debate by tbo · · Score: 4, Informative

    I'm not sure what you mean by "observational science". All science is observational, in the science that observation and experiment is the ultimate test of theory. If it wasn't, it would either be math, philosophy, or just pure bullshit. I agree with you that evolutionary theory isn't a very good theory, but I hold that it's better than creationism.

    About your point that radioisotope dating methods may not be accurate due to changes in physical constants, please stop being ridiculous. Scientists have possible evidence for a 0.001% change in a physical constant unrelated to radioactive decay in a place 12 billion light years away and time 12 billion years ago. That's hardly reason to criticize radioisotope dating. You're obviously tremendously biased towards anything that might lend a shred of support to your theory. That's not objective science.

    As to why I have issues with evolutionary theory, here are my tests for a good scientific theory:

    1. Must be falsifiable. If there is no reasonable way it could be proved wrong, it's not science.

    2. Must make verifiable predictions. If a theory doesn't make any predictions that can be checked, it's not terribly useful.

    It's pretty damn hard to think of how you could disprove evolution. Just about anything you find, the biologists will make up an explanation for. Evolutionary theory also doesn't really make testable predictions. About all it's good for is explaining things after-the-fact. Of course, creationism fails both tests in an even worse manner. Thus, lacking a better alternative, I believe in evolution, but hold healthy doubts.

  8. Re:Reevaluation of constants.. by MindStalker · · Score: 3, Informative

    Actually if you understand that the hebrew language is mathematical, you get a much better value of PI from the bible. I used to have the explanation memorized (I love arguing random crap like that), but I don't anymore, but basically each letter/word of the alphabit of the hebrew language has a mathematical meaning and the word "line" is used twice in the setence, but a different word is used the second time. If you take the (second word/first word)*3 you get 3.14156 or something like that, which is even closer than the egyptians reportably knew of pi.
    (figured I'd do a google search for this before I submitted this, came up with this)
    http://www.yfiles.com/pi.html

  9. Let's get some perspective here by frankie · · Score: 5, Informative

    This is (quite literally) not the end of the world, and also not relevant to the evolution debate (although it will surely be blown out of proportion a billion-fold by shoddy journalists). Some info for the crowd:

    The fine structure constant (alpha) is found by combining several other "universal constants" in such a way that all of the units (such as meters per second) cancel out. You get a dimensionless number, like pi, whose particular value (about 137) is basically built in to the universe. One formula is:

    So if alpha is actually not constant, any one of those items may have changed while others remained constant. And more importantly, the research points to a change of only 0.001% over the past 12 billion years. In short, warp drive this ain't.

  10. alpha by Mercuria · · Score: 3, Informative

    alpha =(e^2)/((h-bar)*c)

    where e is the charge on an electron, h-bar (normally a lover case script h with a horizontal line through the stem just above the round part) is Plank's constant divided by 2*pi, and c is the speed of light. the answer is a dimensionless 1/137.036.

  11. Re:Reevaluation of constants.. by AUSketch · · Score: 3, Informative

    Will this myth never end?

  12. laboratory check; statistics; so what? by bcrowell · · Score: 3, Informative
    The change they claim to have detected, based on astronomical measurements, is about 1 part in 10**15 per year. At the end of their paper, they compare with various other methods, and say that the upper limit from laboratory measurements, carried out over a time period of a few months, is 1 part in 10**14 per year. Presumably the lab experiments can be improved with enough funding and motivation --- either the technique can be improved, or they can just take data for years instead of months, or both. I don't really trust the purely astronomical method, although it's true that the resolution of the solar neutrino problem did turn out to involve new physics, not misunderstood astronomy.

    You also have to realize they're only claiming a four-sigma result. Four sigma is very convincing if it's really four sigma, but experimentalists never really truly know their error bars that well --- four sigma could really be two sigma, which could be wrong.

    And anyway, say they're right. So what? It would be interesting, but I don't think it revolutionizes physics. The link to string theory suggested in the NY Times article is kinda silly, since string theory would only have produced significant effects at times a zillionth of a second after the Big Bang. Also, it's not news that the fine structure constant isn't constant. In quantum field theory, coupling constants are not absolute constants; they have different values on different distance scales. So yes, it's surprising if atomic spectra have changed, but it doesn't bring all of physics to its knees.