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Gravitation Anomaly Measured
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."
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?
It's good to use your head, but not as a battering ram.
I would highly doubt that Einstein's theory is flawed, but then again, they did not study the effects of gravity during a solar eclipse back then.
Not only is this comment not "insightful" but it is just plain wrong. One of the original PROOFS for relativity involved measuring the amount that light is bent during a -- pay attention now -- solar eclipse. To quote the article you so carefully did not read, it was "observations taken during a solar eclipse (of the way that light is bent when it passes close to the sun) which established General Relativity in the first place."
Next.
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.
"They redundantly repeated themselves over and over again incessantly without end ad infinitum" -- ibid.
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.
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.
I wonder if Gravity Probe B 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?)
MOND evidently has problems; while dark matter can explain both galactic rotation curves and cosmological behavior, MOND is hard to make consistent with both. (And it's also, I've heard, extremely hard to make consistent with any relativistic theory of gravity.)
As for the "apparent need" for FTL expansion in the early universe, by which I assume you mean inflation, some very specific predictions of inflation are now verified by WMAP, including the structure of the acoustic peaks in the CMBR angular power spectrum.
Wacky as they may seem, dark matter, dark energy, and inflation are the mainstream theories right now for a reason: the alternatives so far simply don't work as well.
African or European?
The easy explanation as I was given to understand is that the photons propagate in spacetime, ie the wave that they are does. Spacetime is curved by gravity, hence the photons/waves curve with them. According to General relativity, they cannot have mass since they propagate at light speed. Any object with mass obtains infinite mass upon attaining lightspeed, which is impossible. Hence a photon has no mass. Of course, solar sails work so photons can exert pressure which might lead one to suppose they have mass. In sense they do, as energy and matter are equivalent. In the case of a solar sail, it is impulse that is being transferred. It depends on how you measure the presence of the photon. By the way, note that Duif does not cast doubt upon Einstein's theories per se. Rather, he invokes the presence of dark matter (although no one has ever demonstrated its presence unequivocally).
----- One learns to itch where one can scratch.
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.
We are Bord. Prepare to be athimilated. Rethithtanth ith futile.
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.
Speak before you think
waiting for the Bord
We are the Bord.
Ennui will envelope you.
Existence is futile.
I watched C-beams glitter in the dark near the Tannhauser gate.
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.
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.
Squirrel!
I've asked my girlfriend many times about involving a third body, but she consistently refuses.