July eclipse is best chance to look for gravity anomaly

[n2doc]

18:00 19 July 2009 by Phil McKenna
From remote observatories on the Tibetan plateau to a cave in a Shanghai suburb, Chinese researchers are poised to conduct an audacious once-in-a-century experiment. The plan is to test a controversial theory: the possibility that gravity drops slightly during a total eclipse.

Geophysicists from the Chinese Academy of Sciences are preparing an unprecedented array of highly sensitive instruments at six sites across the country to take gravity readings during the total eclipse due to pass over southern China on 22 July. The results, which will be analysed in the coming months, could confirm once and for all that anomalous fluctuations observed during past eclipses are real.

"It sounds like what is really necessary to break the uncertainty," says Chris Duif of Delft University of Technology in The Netherlands. "I'm not really convinced the anomaly exists, but it would be revolutionary if it turned out to be true," he says.

more:

http://www.newscientist.com/article/dn17481-july-eclipse-is-best-chance-to-look-for-gravity-anomaly.html

[Tikki]

1. Thank you for posting this....

I love this kind of stuff....SCIENCE rules.


Tikki

[qazplm]

2. why would gravity drop during an eclipse?

Gravity isn't "blocked" by an interceding object.

[Towlie]

3. Also, why would the effect only be detectable in a place where you can watch the eclipse?

If the effect exists, it should be possible to detect it anywhere on Earth.

[starroute]

4. It has to do with electromagnetic forces

A solar eclipse does have powerful electromagnetic effects. And though nobody has yet been able to successfully combine gravitation and electromagnetism into a unified field theory, there's a widespread expectation that they are related.

So it's not about the eclipse somehow "blocking" gravity but about gravitation itself being affected by unusual electromagnetic conditions.

There are a lot of fringe theories online that confidently assert the author knows exactly what the connection is between gravitation and electromagnetism. Some of them might even be correct -- after all, continental drift was a fringe theory for a long time -- but there's no scientific rigor behind them.

That is why these eclipse measurements are so important. If they show that *something* is going on, it makes it possible for respectable scientists to start looking into the question without looking like kooks.

[qazplm]

5. You said

A solar eclipse does have powerful electromagnetic effects.

Evidence for this? I may just not know, so maybe there is but I wasn't aware that simply blocking light would engender EM effects.

If so then why wouldn't a passing plane do so within it's shadow? Why not under any area that blocks the sunlight from reaching a certain spot?

[starroute]

8. That's a good question

Checking around, I find that aside from fringe sites, the only places the topic seems to be discussed is in technical papers that go well over my head.

For example, there's a pdf at http://www.ann-geophys.net/23/3487/2005/angeo-23-3487-2005.pdf titled "Solar eclipse effect on geomagnetic induction parameters," which says things like "Bencze et al. (2005) studied Pc3 pulsations during the 1999 eclipse. They found a localised decrease in their activity, concentrated at the dark spot. The amplitude decrease amounted to about 50 percent. Leaving the totality zone, the effect disappeared rather quickly. Moreover, the decrease moved in the same direction as the dark spot, and the velocities were similar, too. This effect was interpreted as a switch-off of the FLR mechanism due to a change in the eigenperiod of the geomagnetic field lines in consequence of a loss of charged particles along the field line. Since without solar electromagnetic radiation, the electron density decreases in the lower part of the ionosphere and consequently upward transport of charged particles weakens and the density of charged particles decreases both in the upper ionosphere and plasmasphere."

I also found an abstract at http://scitation.aip.org/getabs/servlet/GetabsServlet?prog=normal&id=APCPCS000899000001000345000001&idtype=cvips&gifs=yes of a paper titled "HF Propagation Measurements During the 29 March 2006 Total Solar Eclipse in Turkey."

As nearly as I can make out, the idea seems to be that the sudden cutting off of solar radiation during an eclipse affects the earth's ionosphere and magnetosphere, and that those changes in turn have an impact on the earth's magnetic field which is "concentrated at the dark spot."

Linking that to gravitational anomalies is something else again, though -- which is why it's important to find out first whether those gravitational anomalies are real or not, and therefore whether it's worth scientists spending time trying to figure them out.

I should say, by the way, that I typically read fringe scientific theories the same way I read most conspiracy theories -- as stuff that's interesting even if not yet ready for prime time. The failure of 20th century science to actually explain gravitation in any meaningful way is one of those major, potentially paradigm-shifting problems lurking out there at the margins, which is why there's interest in anything that promises to offer fresh clues.

[qazplm]

9. not busting your chops

but that still doesn't do it for me.

Understand that we would see a decrease in particle interactions from the sun with the upper atmosphere and magnetosphere and certainly that would probably have some effect on the Earth's magnetic field, but again not sure it would be concentrated at the dark spot, as opposed to simply a net overall decrease, or how it would be different from solar minimums versus solar maximums as I would guess a Sun at maximum versus minimum is probably a greater variation overall than a 10 minute eclipse.

I would also think that again at best this would be a minimization of magnetic energy, so why wouldn't we see gravity behave different on say Mars or the Moon which has little to no magnetic fields surrounding them?

If changing magnetic fields somehow affected gravity, you'd think it would be increased fields, not decreased.

I don't think 20th Century Science has failed to explain gravitation in any meaningful way. In fact, we've narrowed it down either to the property of mass in space-time (Einstein's balls on a rubber sheet thing) or, much like light, due an as yet undiscovered carrier, a Graviton, or even both.

[Festivito]

7. Or, Coriolis effect versus moon's gravitational pull.

Coriolis will depend on latitude north or south of equator. It can then be affected by an angular eclipse pulling to a side in combination with the sun rather angularly opposing it, again depending on the relative pull of these forces.

I'd think.

[Orsino]

6. Dowsing.

A pendulum that swings oddly once for one experimenter, in a way that hasn't been duplicated during twenty other eclipses? I think I'm gonna have to bet against rewriting gravitational theory.