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Science

Gravitation Anomaly Measured 540

Posted by michael
from the everything-you-know-is-wrong dept.
Rob Riggs writes "Is there a hole in Einstein's Theory of Relativity? A story in The Economist talks about an apparent gravitation anomaly recorded during solar eclipses. According to Chris Duif at the Delft University of Technology, the 'Allais effect' is real, unexplained, and could be linked to another anomaly involving a the Pioneer spacecraft. More detailed information can be found in the paper he has just posted on arXiv.org."
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Gravitation Anomaly Measured

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  • by freedom_india (780002) on Friday August 20, 2004 @06:04PM (#10028107) Homepage Journal
    This confirms the existence of Subspace and we're waiting for the Bord to open up a Subspace Tetrion Matrix Wormhole to assimilate us.

    Where is Capn' Picard when he is needed

  • by Anonymous Coward on Friday August 20, 2004 @06:04PM (#10028111)
    My wife had one of these after she went in for breast augmentation...
    • My wife had one of these after she went in for breast augmentation...

      "They swing lower because you are getting old, honey; not because of the ecli...*WHACK*
  • You mean that the sun and the moon together pull stronger than the sun alone?
    • by Anonymous Coward on Friday August 20, 2004 @06:08PM (#10028151)
      Yes. Syzygy is when the Earth, moon, and the sun are all lined up. Spring tides occur at this time. Spring tides are unusally high tides that occur during syzygy.
    • No, the solar eclipse just allows you to measure the positions of stars which are very close to the Sun in the sky. Light from these stars is bent as it passes the Sun on its way to the Earth, due to the Sun's gravitational field.

      Ironically, this was hailed as a proof of Einstein's relativity in the early 20th century, since the angle of deflection observed is much closer to the relativistic prediction, than to the Newtonian prediction.
    • as i understand it it's the other way round - one of the possibilities mentions the moon "blocking" gravitation from the sun during an eclipse.
    • by Anonymous Coward
      You mean that the sun and the moon together pull stronger than the sun alone?

      Nope, exactly the opposite.

      Not to mention that the article suggests that the effect occurred just as the alignment took place, not slightly before or after, when the summed effects of the Sun and Moon's gravity should have been nearly the same as during the alignment.
    • by Ancient_Hacker (751168) on Friday August 20, 2004 @06:27PM (#10028309)
      Havent we had objects in orbit for 40+ yrs now, many positioned in just the right orbits to transit thru the moon's shadow? Satellites like the GPS series, whose positions are known and tracked to the centimeter?

      Why hasnt this effect, if it exists, been noticed 1000's of times?
      • by mangu (126918) on Friday August 20, 2004 @07:09PM (#10028661)
        I work in satellite control systems. Satellites not only go through the moon's shadow, but through the earth's shadow as well. Geostationary satellites, such as most of the commercial communications satellites, go through eclipse periods twice each year, when for several weeks they cross the earth's shadow every day.


        To answer your question, the effect, if it exists, hasn't been noticed because there are many other perturbing effects on the orbit. The most important, by decreasing magnitude, are: earth's gravitational attraction, moon attraction, oblateness of the earth (that is, the flattening at the poles), sun gravitational attraction, solar radiation pressure, tri-axiality of the earth (that is, the east-west irregularity in the gravitational attraction), albedo (that is, the pressure exerted by the sunlight reflected by the earth), dynamic solid tide (the gravitational effect of the earth's deformation caused by the moon's attraction), gravitational attraction by venus, gravitational attraction by jupiter, relativistic effects caused by the earth's gravitation.


        So, you can see that there are so many other effects that it's pretty hard to separate each one. In particular, the effects of solar radiation and albedo change more or less randomly, so in the end, whatever cannot be explained otherwise in a satellite's orbit is normally attributed to "solar radiation".


        It's only when a probe goes so far from the sun as Pluto that solar radiation becomes small enough for other perturbations to be measured.

    • by mikael (484) on Friday August 20, 2004 @07:59PM (#10029039)
      The individual effect of each of the Sun or the Moon on the Earth is to cause two tidal bulges of the oceans/lakes/rivers of the Earth
      (one facing the object, and the other on the opposite side). These lead to diurnal (24 hour cycle) and semi-diurnal (12 hour cycle) tides.

      When the Moon and Sun are aligned together, you have Spring tides. Neap tides are caused when th e Moon and Sun are perpendicular to one another. There is also the Proxigean Spring Tide, when the moon is at its closest point to the Earth (perigee). This time is known as the "proxigee", and causes even higher tides than ordinary Spring Tides. Fortunately, these only occur once every 1.5 years.

      The gravitational acceleration at the Earth's surface is 9.8 metres/second per second (towards the centre of the Earth).

      The gravitational acceleration on Earth due to the Sun is 0.0059 metres/second per second.
      Or about 5.9 millimetres/second.

      The gravitational acceleration on Earth due to the Moon is 0.000033 metres/second per second.
      Or about 0.033 millimetres/second.

      Source: Space Talk Forum [space-talk.com]

      These amounts are small, but research groups at one of the particle accelerator rings actually noticed a distortion in the targeting of the beams due to the stretching/squashing of the surrounding land caused by the changing positions of the Sun and Moon. This caused the beam to periodically go off target.

      Intuitively, one would assume that gravity would be less when the Sun and Moon were overhead, and the pendulum would swing slightly higher and slower. Plus the behavior of the pendulum should vary according to the positions of the Sun and Moon.

      If the "shielding effect" occurred with large objects, then it would also apply to Earth's ocean tides. The closest side of the Earth one should shield the opposite side, but the bulging effect can be explained by simple vector addition/subtraction [uoregon.edu].
  • by raider_red (156642) on Friday August 20, 2004 @06:05PM (#10028124) Journal
    Remember: there is no gravity. The Earth sucks.
    • by the eric conspiracy (20178) on Friday August 20, 2004 @06:17PM (#10028235)
      Indeed. In fact there is no light either. The Sun sucks dark. In fact it sucks dark so hard that the friction of the dark moving to the Sun causes the Sun to be very hot. The flow of dark towards the Sun interrupted by the Earth causes the side of the Earth away from the Sun to accumulate dark, thus causing Night. As the Earth rotates the dark caught on the night side can then be pulled off, this causing the absence of dark known as Day.

      What we call light bulbs are truly dark suckers as well. That is why light bulbs are hot, just like the Sun. When a light bulb is full of dark and won't suck dark any more, it cools off. If you look in old light bulbs you can even seen the accumulation of dark.

      Dark is also heavier than water. This can be seen in the oceans where the deeper you go the darker it gets.

      • by Nos. (179609)
        We know the speed of light, but what is the speed of dark?
      • I'm sure I'm not the only thinking, "If this guy ever writes an Encyclopaedia of Everthing, I'd be the first to buy a copy. If he doesn't, I hope he at least tells us what kind of drugs he's using."
      • by gregmac (629064) on Friday August 20, 2004 @07:06PM (#10028631) Homepage
        For years, it has been believed that electric bulbs emit light, but recent information has proved otherwise.

        Electric bulbs don't emit light; they suck dark. Thus, we call these bulbs Dark Suckers.

        The Dark Sucker Theory and the existence of dark suckers prove that dark has mass and is heavier than light.

        First, the basis of the Dark Sucker Theory is that electric bulbs suck dark. For example, take the Dark Sucker in the room you are in. There is much less dark right next to it than there is elsewhere. The larger the Dark Sucker, the greater its capacity to suck dark. Dark Suckers in the parking lot have a much greater capacity to suck dark than the ones in this room.

        So with all things, Dark Suckers don't last forever. Once they are full of dark, they can no longer suck. This is proven by the dark spot on a full Dark Sucker.

        A candle is a primitive Dark Sucker. A new candle has a white wick. You can see that after the first use, the wick turns black, representing all the dark that has been sucked into it. If you put a pencil next to the wick of an operating candle, it will turn black. This is because it got in the way of the dark flowing into the candle. One of the disadvantages of these primitive Dark Suckers is their limited range.

        There are also portable Dark Suckers. In these, the bulbs can't handle all the dark by themselves and must be aided by a Dark Storage Unit. When the Dark Storage Unit is full, it must be either emptied or replaced before the portable Dark Sucker can operate again.

        Dark has mass. When dark goes into a Dark Sucker, friction from the mass generates heat. Thus, it is not wise to touch an operating Dark Sucker. Candles present a special problem as the mass must travel into a solid wick instead of through clear glass. This generates a great amount of heat and therefore it's not wise to touch an operating candle.

        Also, dark is heavier than light. If you were to swim just below the surface of the lake, you would see a lot of light. If you were to slowly swim deeper and deeper, you would notice it getting darker and darker. When you get really deep, you would be in total darkness. This is because the heavier dark sinks to the bottom of the lake and the lighter light floats at the top. The is why it is called light.

        Finally, we must prove that dark is faster than light. If you were to stand in a lit room in front of a closed, dark closet, and slowly opened the closet door, you would see the light slowly enter the closet. But since dark is so fast, you would not be able to see the dark leave the closet.

        Next time you see an electric bulb, remember that it is a Dark Sucker.

    • by ynotds (318243)
      Proponents of Process Physics [flinders.edu.au] claim that Einstien's original case for general relativity was built on a misinterpretation of critical 19th century experimental data and contend that the consequential abandonment of the ancient notion of Æther was wrong headed.

      From their perspective, gravity should not be seen as a force field but rather as the cummulative effect of all massive bodies continuously absorbing/dissipating Æther. Locally the earth sucks most of the Æther and we experience the
  • 3rd body problem? (Score:5, Interesting)

    by Bill, Shooter of Bul (629286) on Friday August 20, 2004 @06:07PM (#10028147) Journal
    My limited understanding of interstellar phsyics is that einstins equations have never really been solved for the third body problems. Am I wrong? If I remeber correctly we can only aproximate third body forces (tidal forces) even when using the newtonian model.
    • Re:3rd body problem? (Score:3, Interesting)

      by Anonymous Coward
      Einstein's equation hasn't even been exactly solved for two-body problems; that's why black hole and neutron star collisions are such a hot topic in numerical relativity.

      Nevertheless, for solar system dynamics, this is irrelevant. Newtonian gravity works quite well, and even if you did need to go to relativistic corrections, you can do that within the perturbation scheme of linearized gravity to more than sufficient accuracy.
    • Re:3rd body problem? (Score:2, Interesting)

      by aeroegnr (806702)
      I've heard from multiple sources that n-body (with n > 2) problems are unsolvable exactly with current techniques. For instance, we can predict the motion of all the planets of the solar system for a certain length of time by only considering the sun's gravity, and once that prediction goes bad we use new boundary conditions for another estimate that will last a length of time. But we have no way of predicting what planetary motion will look like millions of years from now with much accuracy. (I coul
      • Re:3rd body problem? (Score:3, Interesting)

        by bluephone (200451)
        Well, we _can_ but the interactions of 9 planets, a hundred moons, thousands of asteroids, etc., becomes so complex that our ability to accurately model it for (cosmically) significant periods of time is limited by computational power, thus we have to simplify the equations, and get accuracy to a more limited extent. Essentially, it's Hard(tm).
    • Re:3rd body problem? (Score:3, Interesting)

      by Thagg (9904)
      As I recall (and I'm certain that others will correct you further) there is no closed-form solution for the three-body problem. The shapes of the orbits cannot be written down as a simple equation -- where (neglecting relativity) two orbiting bodies trace perfect ellipses.

      On the other hand, you can calculate a solution to the three-body problem to any level of accuracy that you are interested in, without much effort. Yes, it's an approximation, but so is any calculation.

      Thad
      • Re:3rd body problem? (Score:3, Interesting)

        by Mukaikubo (724906)
        In fact, it's been shown that it is impossible to solve it analytically, for any level of technology you care to name. It's too easy to tip into chaos.
    • Re:3rd body problem? (Score:5, Informative)

      by Carnildo (712617) on Friday August 20, 2004 @06:15PM (#10028215) Homepage Journal
      The "three-body problem" is that there is no known general closed-form solution to Newton's laws if more than two gravitating bodies are involved. In short, you can't derive an equation that will give you the positions of all three objects at any arbitrary point in time.

      Instead, iterative solutions are used: given the current masses, positions, and velocities of the objects involved, figure out where they'll be a short time from now. Lather, rinse, repeat. The problem with this is that over long timespans (tens of millions of years), errors build up.
    • by totoanihilation (782326) on Friday August 20, 2004 @07:54PM (#10029014)
      I've asked my girlfriend many times about involving a third body, but she consistently refuses.
  • The Economist? (Score:5, Insightful)

    by raider_red (156642) on Friday August 20, 2004 @06:09PM (#10028161) Journal
    Why is this being carried in the Economist? Shouldn't it be picked up by New Scientist or some other scientific (or pseudo-scientific) publication?
    • by raider_red (156642) on Friday August 20, 2004 @06:13PM (#10028193) Journal
      Never mind. I RTFA, and now I know that it was an economist who first discovered the effect. (Which in my mind only casts doubt on its existance.)

    • > Why is this being carried in the Economist? Shouldn't it be picked up by New Scientist or some other scientific (or pseudo-scientific) publication?

      FWIW, this is really old news. The others have probably already covered it.

    • Re:The Economist? (Score:5, Informative)

      by Anonymous Coward on Friday August 20, 2004 @06:45PM (#10028458)
      The Economist is probably the best source of general news available. It is in the same category as Time, Newsweek, US News & World Report, except that where those magazines tend to be 10-20% real news and 80-90% pab, the Economist is the inverse with 80-90% real hard news.

      They know it too, and consequently it is very hard to find much of a discount on subscription pricing -- if you can pick it up for under $100/yr you are doing very well. All those other rags can typically be found for pennies on the dollar if you look.

      In case you can't tell, I get all my news online - no tv news, no newspaper, maybe a dab of NPR when I'm tired of listening to my music in the car and no magazines, except the Economist. Which I get full access to online by virtue of paying for a paper subscription.
    • Re:The Economist? (Score:5, Informative)

      by Voivod (27332) <cryptic@gmail.cGAUSSom minus math_god> on Friday August 20, 2004 @09:20PM (#10029490)
      You obviously aren't a subscriber or a regular visitor to their website. The Economist is simply the best weekly news print magazine in the world. For example, it's the only news magazine which never makes me cringe when they cover technical subjects I know well like Linux or computing. Same with their culture section, world news, etc. They've been doing this since 1843 and they are bad ass. I highly recommend it to anyone looking to read just one print magazine a week to learn about world news.

      And no I don't work for them. :-)

  • by Artifakt (700173) on Friday August 20, 2004 @06:16PM (#10028222)
    According to the article, earlier results include those measured with "so called paraconical pendula". It's shocking to think that we have allowed ersatz paraconical pendula to be used in place of the genuine articles.
    Mr. President, we must spend whatever is necessary to close the paraconical pendula gap.
  • by tarranp (676762) on Friday August 20, 2004 @06:17PM (#10028230)
    Einstein once said something along the following lines:

    Testing theories is a very thankless task, because nature never says "yes." Usually nature says "no," meaning that a measurement contradicts a theories predictions.
    Sometimes, nature says, "maybe," indicating that while the measurements are consistent with the theory.
    But nature never says "yes," because your theory could be incomplete or erroneous but your instruments are either too inaccurate to detect the error, or you are not doing the right experiment.

    Newtonian dynamics makes good enough predictions for alot of phenomena.

    General Relativity is more precise in its predictions.

    Given our difficulties in unifying it with quantum mechanics, it is likely that we don't have the right theory. As our instruments get more precise and we conduct more experiments, eentually we'll get a hint as to where we are going wrong.
    • by Ignignot (782335) on Friday August 20, 2004 @06:31PM (#10028346) Journal
      Exactly. There are almost certainly missing elements in the model for gravity, for quantum mechanics, and so on. Maybe sometime in the future someone will come up with a quantum - relativistic super duper theory that brings disparate theories together. Yes, some of that is what string theory is trying to do. In the end though, it is going to take a LOOONG time before advances in science can be applied to engineering. Finding new particles, finding dark matter, and finding where missing socks go have no real life application right now - and I can't even imagine one. Just as math was (and still is) far ahead of where science can go, science is far ahead of where engineering can go. The missing elements of models would be useful for abstract knowledge, but have no practical use right now or probably in the next century.
  • by Engineer-Poet (795260) on Friday August 20, 2004 @06:17PM (#10028239) Homepage Journal
    If gravity is blocked by mass, this effect would be much easier to measure on the Moon during lunar eclipses than on Earth: the entire Moon is shadowed during many lunar eclipses whereas only part of the Earth is fully shadowed during even total eclipses, and the effect should be easier to measure against the smaller gravity of the Moon.

    For real confirmation, an experiment on one of the Jovian moons would do nicely.

    Yes, I'm serious about this. This is fundamental to our understanding of physics, which is in turn fundamental to our understanding of the origins, processes and fate of the universe. A billion to put a pendulum on the Moon would be money well spent.

    • Or, you could just do the test here on earth at night. Then the whole mass of the earth is between your apparatus and the sun.

      I guess the reason that doesn't work is that thermal effects (like those that may be causing the Allais results) change everything at night, and it's too hard to distinguish a legitimate anomaly from some-thermal-effect-we-didn't-think-of.

      Still, there's no need to go to Jupiter or even the moon; as a satellite in a higher and higher earth orbit checks the effect, the earth effects

    • by Louis Savain (65843) on Friday August 20, 2004 @06:46PM (#10028468) Homepage
      If gravity is (very slightly) blocked by mass, then one would expect to have a different weight on the dark side of the earth than on the light side. It this observed? After all, if you're on the dark side, the entire mass of the earth should be shielding you (ever so slightly) from the gravitational pull of the sun.
      • by Tired and Emotional (750842) on Friday August 20, 2004 @07:34PM (#10028873)
        A very nice point. However I am not sure it works. Some of the earth's own mass is shielded so the orbit is slightly larger than it ought to be, so the gravitational pull on the sun side is slightly lower and that on the shielded side slightly higher than it should be. This will at least reduce any effect.

        I see no discussion in the article of the fact that the moon distorts the space around it so that when it is between us and the sun we are slightly further away from the sun than when it is not in line. This effect has to be incredibly small but it appears the allais effect, if it exists at all, is quite small, so perhaps this is the cause. Somebody should at least calculate it out.

        I have seen this theory that they mention about gravity being less effective when weak. The usually more reliable Scientific American allowed an article on it to sneak in some months ago.

        Its a very silly idea because it breaks the principle of equivalence - you can now tell if you are in an elevator or a gravitational field by bringing a mass close to a test mass to almost cancel out the field and observing whether or not you see the weak gravity effect.

        This in turn means physics is not covariant and that there are preferred frames of reference. So its not a "small adjustment" but a total do-over of physics.

        • Its a very silly idea because it breaks the principle of equivalence - you can now tell if you are in an elevator or a gravitational field by bringing a mass close to a test mass to almost cancel out the field and observing whether or not you see the weak gravity effect.

          With sufficiantly accurate measurment devices (which we don't happen to have), you should be able to tell the difference between an elevator or a gravitational field anyways. Why? Gravity is a field. Therefore the force at your head is eve
    • by Grishnakh (216268) on Friday August 20, 2004 @07:20PM (#10028744)
      Yes, I'm serious about this. This is fundamental to our understanding of physics, which is in turn fundamental to our understanding of the origins, processes and fate of the universe. A billion to put a pendulum on the Moon would be money well spent.

      This is a total waste; the Republicans already know the origins of the universe. It's all written in the book of Genesis. The earth was created 6000 years ago, in 7 days. That billion dollars would be better spent on more military hardware for use in the US's next invasion, or better yet it could be given in a no-bid contract to Halliburton for some massively overpriced fuel and services.
  • This just makes me think that, however refined your theory gets, there is a deeper level of complexity. You can get infinitely close to the truth, but never quite there. Fortunately, in Real Life, small errors aren't that noticeable. Except, of course, things like the small fraction of mass that gets converted into a massive amount of energy in nuclear reactions.
  • Gravity Probe B (Score:5, Informative)

    by SamBeckett (96685) on Friday August 20, 2004 @06:23PM (#10028286)
    I wonder if Gravity Probe B [stanford.edu] will be able to measure this effect if it is still in working order next time an eclipse rolls around.

    (Side note-- I never heard of this probe until I saw it in a magazine. Why not?)
  • Possible explanation (Score:4, Interesting)

    by Cassander (251642) on Friday August 20, 2004 @06:41PM (#10028420)
    Let's assume for the sake of argument for a second that gravity is a wave...

    Could this be constructive interference caused by the collision of the gravity wavefronts from the sun and the moon when they are lined up just right?

    Just a thought, the real explanation is probably much crazier.
  • by dexter riley (556126) on Friday August 20, 2004 @06:56PM (#10028532)
    Although, despite all proposed conventional explanations fail to explain the observations either qualitatively or quantitatively, it is likely that the reported anomalies will turn out to be due to a combination of some of these effects and instrumental errors. The judgement of some of the experimental results is hampered by the lack of a statistical analysis and/or data of sufficient length. Nevertheless, there exist some strong data which cannot be easily explained away.

    And here's a point not covered in the paper: if these experimental effects occur when the moon is between the pendulum and the sun, then shouldn't they also occur every time the earth is between the pendulum and the sun...say, every night? If this effect is due to a large mass's ability to block gravity, then surely someone should have detected this effect from the earth blocking the sun's gravity by now!

    On the other hand, if the effect is because moon cheese acts as a form of Cavorite [wikipedia.org], well, then I can't help you with that.
    • by argent (18001) <peterNO@SPAMslashdot.2006.taronga.com> on Friday August 20, 2004 @07:36PM (#10028885) Homepage Journal
      shouldn't they also occur every time the earth is between the pendulum and the sun...say, every night

      Problem is, there is a known effect that would change the gravitation acceleration on an object as the Earth's orientation changes with respect to the sun. During the lunar eclipse, though, there's very little change in the relative positions and orientation of the earth, the moon and the sun.

      That is, I suspect it would be too hard to distinguish between any such Allias Effect from the Earth and solar (and in this case, lunar) tides.
    • ...shouldn't they also occur every time the earth is between the pendulum and the sun...?

      I've read many of the old (and new) 'push' gravity theories, the ones that theorize a particle carrier for gravity (I'll call them gravitons here). Where there are less gravitons, e.g. next to a body and more so between two bodies), you experience a lop-sided 'push' from areas of high graviton density.

      With two bodies, you wouldn't be able to tell the difference - the absorption of gravitons would be measurable as

  • A reminder (Score:5, Informative)

    by epepke (462220) on Friday August 20, 2004 @06:59PM (#10028557)
    The General Theory of Relativity consists of sixteen coupled differential equations that can be reduced to ten, which when just written out would take hundreds of pages. It is so complex that there are research programs just categorizing possible solutions.

    Analytical solutions only exist for two cases: the overall case that describes a homogeneous universe, and the Schwartzschild case that describes a spherical body. There is also a linear approximation that gets gravity waves.

    It's a bit premature to say that GR has a hole in it, because nobody has ever explored it fully. Perhaps this will lead to a solution of GR for this case, or perhaps not.
    • by Iainuki (537456)
      This is not quite accurate: there are analystic solutions for single-body cases more complicated than Schwarzschild (spinning black holes for instance), and for some exotica that may be physically uninteresting (Godel's rotating universes, for instance). The commmon feature of all analytic solutions is the high degree of symmetry they possess.
    • Another reminder (Score:3, Interesting)

      by bar-agent (698856)
      Don't forget, there is still the unexplained slowing down of extra-solar space probes. There are things going on; things we don't understand.

      Mys-TEER-i-ous things (with waggling fingers)...
  • by JavaNPerl (70318) on Friday August 20, 2004 @07:00PM (#10028564)
    I thought running Eclipse on my Sun workstation was just ironic.
  • by DM9290 (797337) on Friday August 20, 2004 @07:15PM (#10028701) Journal
    If gravity is blocked by mass, it would be a simple thing to simply observe a pendulum at night time and compare that to daytime.
    The earth would block much more solar gravity than the puny little moon.

    Then again, we would need a pendulum which is attracted to solar gravity because every pendulum on earth which swings, is doing so because of the gravitational attraction of the Earth.

    Pay attention... pendulums on earth fall towards the EARTH, NOT THE SUN.

    And another thing:

    if you allow a pendulum to swing freely for 24 hours, the reason its path will trace out a circle, is *because of inertia* and the earth is rotating. THE PENDULUM IS NOT SWINGING TOWARDS THE SUN'S GRAVITATIONAL FIELD.

    Are there any economists here who can explain this more clearly?

    • "Pay attention... pendulums on earth fall towards the EARTH, NOT THE SUN."

      Like hell they don't. The sun is the most massive hunk of anything in the star system and its gravity, by definition, has an effect on everything. Accurately measure the period of that pendulum and you will find that it has a tendency to move faster during the night (earth and sun pulling in the same direction) as it does during the day (earth and sun pulling in opposite directions). The question this anomally brings up is how mu
  • Proper peer review (Score:5, Informative)

    by adrianbaugh (696007) on Friday August 20, 2004 @07:18PM (#10028721) Homepage Journal
    I'm inherently skeptical of any paper first heard of via a website. Call me old fashioned, but I'd rather wait for peer review to run its course and read this in something like the Journal of the AAS. Having said that, I read the paper and it's considerably less sensational than the summary suggests. The author considers it possible, if not probable, that the effects can be ascribed to a combination of experimental error and theorists not having taken into account the circumstances of the situation. He suggests that further research would be useful, but I've never read a paper that didn't...
  • by unikron (524813) on Friday August 20, 2004 @07:34PM (#10028872)
    Well, in Penteli mountain, there are verified gravitational anomalies (there are also a hell lot more noted in the Hellenic space by physicists).

    For example, you put your car in neutral in the outskirts of the mountain and instead of gravity to pull it down, it is tractored upside. Expert physicists claim there is another energy in the mountain area that is more powerful than the gravity itself, thus creating the effect.

    NATO was interested (and presumambly is still) in that particular area. It's part of Greece's x-files :)

    • Well, in Penteli mountain, there are verified gravitational anomalies (there are also a hell lot more noted in the Hellenic space by physicists).


      Who mods this crap up? "NATO was interested" and "gravitational anomalies"?!? WTF!? I thought we were nerds here...

      "Gravity hills" are nothing more than optical illusions, Penteli mountain included. Check out this link [ucr.edu] for more information. (shakes head at the state of "science" here on Slashdot... double shakes at the tin foil hat wearing mods...)
  • Einstein is safe (Score:5, Interesting)

    by TheLastUser (550621) on Friday August 20, 2004 @08:28PM (#10029225)
    The paper is talking about effects on the order of 0.5*10^-10 m/s^2. I don't know how anyone could measure this with a pendulum. Also, the paper doesn't show that this effect isn't accounted for by Einstein's theory. I think they need to solve the equations for the Earth/Moon/Sol system before saying that the effect disproves the theory. The only theory they talk about is Newton's theory, eg. a = gm/r^2, which we already know doesn't hold for the scales that they are talking about.

    Seems to me like the effect is most likely due to someone walking their dog a couple blocks away.

    More interesting is how everyone wants to prove that Einstein's theory is wrong. Seems to me like a bit of brain-envy.

    Nice try, but this article only goes about 0.5*10^-10 of the way to convincing me the chuck the field equations.
  • by Cyberllama (113628) on Friday August 20, 2004 @09:57PM (#10029656)
    You think of The Economist. Where else will you find the all latest scientific breakthroughs?
  • IANA physicist but the pdf is accessible to anyone with high school physics and some interest in physics news. More accessible references below.

    Most of the posts are supposing the physicists doing this are real dumb. That in itself, is stupid. I think one or two have interesting points (e.g. "Einstein is Saf e") and most of the others are way off base. The paper is a summary of research by other people. The problem being discussed was noticed by Allais 50 years ago when he ran a month long pendulum experiment (three drops per minute I believe) that happened to intersect the time of an eclipse. The paper goes over a number of possible reasons for error and includes some as yet unpublished data on experiments intended to uncover them. The possibilities are c reative and followed up scientifically, for example one is done in remote China with nobody within 200 meters. All tests showed the suggested errors to be miniscule, although the paper does suggest that a combination of them might just cover it.

    It would appear that a significant anomaly has been detected by various experiments and that professional scientists are taking it much more seriously than say cold fusion. It also is clear that there is a lot still to learn about gravity and that NASA is one of the groups that is working hard to figure out why its space probes don't move as expected. Some people even think gravity moves 20 times faster than light and other stories. It is not a shut case yet. In the paper mentioned in the post, they are saying that most people couldn't in the past solve the problem because they were thinking in terms of the Moon "shielding" the Earth from gravity, which the paper does not believe. They think it is more like an extra horizontal force that sometimes occurs during eclipses (of which there are different kinds including variations of angles). So all the posts about shielding are off base.

    NASA has suggested that if experimental error really can't be the culprit, it might be caused by the same thing that apparently is accelerating Voyager more than expected.

    I'd like to quote from a NASA article on the people who built Gravity Probe B [gravityprobeb.com].

    A National Research Council panel, among them Cliff Will, wrote in 1995, "In the course of its design work on Gravity Probe B, the team has made brilliant and original contributions to basic physics and technology. Its members were among the first to measure the London moment of a spinning superconductor, the first to exploit the su perconducting bag method for excluding magnetic flux, and the first to use a 'porous plug' for confining superfluid helium without pressure buildup. They invented and proved the concept of a drag-free satellite, and most recently some members of the group have pioneered differential use of the Global Positioning System (GPS) to create a highly reliable and precise aircraft landing system."

    I think that is cool. It says to me we have a good chance about learning a lot more about gravity and lots of other fundamental physics in the near to medium term future.

    The paper also notes that one more individual experiment will not solve it; many simultaneous and comprehensive experiements are needed over the next few eclipses. It also suggests that it might be interesting to investigate "gravitational lensing by relativistic dark matter" although I cannot tell if that suggests we are in the midst of a river of high speed dark matter or what, something invisible passing between the Earth and Moon? Somebody with astrophysics degree please finally step in. Sounds like it might be interesting to have the ISS get involved too!

    Links:

    NASA decrypting the eclipse ('99) [nasa.gov]
    Gravitational Anomalies - Literature List [space-time.info]
    In Search of Gravitomagnetism (NASA Gravity Probe B) [nasa.gov]

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