Testing the gravitational inverse-square law

Physics World ^ | April 2005 | Eric Adelberger, Blayne Heckel and C D Hoyle

[<1/1,000,000th%]

Wow! Bump for later.

[Intolerant in NJ]

Bump.....

[Alamo-Girl]

Thanks for the ping!

[Doctor Stochastic]

Check the Einstein and Hilbert discussion here.

[Ichneumon]

"Geometry, Relativity and the Fourth Dimension " by Rudolf v. B. Rucker

Rudy Rucker has also written a number of science fiction stories, and they're *very* mindbending -- like taking a drug trip via text. Even calling them "science fiction" doesn't really capture their weirdness. Perhaps they're better described as "math fiction" or "physics fiction"...

[Bear_Slayer]

It's a start.

[ctdonath2]

Space is nothing more than 'space' the absence of objects.

Except that particles are popping in and out of existence within that "empty space". The energy potential in a vacuum is astounding.

Why is it that the last few years we have seen new, wierd 'dimensions'?

Because we're looking at reality close enough to notice things nobody noticed before.

[spintreebob]

This is ridiculous. Three dimensions are based on 90 degree angles. The choice of 90 degrees, rather than 60 degree or any other increment of angularity is strictly arbitrary. It is arbitrary in the same sense that the weight of a kilogram or the length of a foot is arbitrary.

[aruanan]

Einstein's radical new theory made gravity consistent with the two basic ideas of relativity: the world is 4D - the three directions of space combined with time - and no physical effect can travel faster than light.

In spite of the fact that the measured gravity of the sun points not toward its apparent position (if gravity moved at the speed of light) but toward its instantaneous position?

[doc30]

For example, what about "spooky action at a distance." Perhaps someone more intimate with physics can describe this apparent faster than light phenomenon.

[doc30]

And that is why physics should never be taught as a fact. It contains only theories and critical discussions involving the holes in these theories need to be discussed and alternative views must be expressed. - As per stickers in Georgia biology textbooks.

[<1/1,000,000th%]

This article didn't consider 2 pieces of data that I would have liked to see discussed. These are the seemingly contradictory mysterious attraction towards the sun (MATS) experienced by the Pioneer and Voyager spacecraft, and the acceleration of distant galaxies away from us.

Historically it reminds me of events like Boltzmann's estimate of the age of the earth using thermodynamic considerations. I didn't look up his answer but it was only on the order of 20-30 million years. Since no one was aware of radioactivity, he couldn't account for the heating that caused.

Another event was the cloud chamber experiments from the end of the 19th and beginning of the 20th centuries where discrepancies in particle velocities and masses kept popping up. Electrons looked like they had variable masses. This finally made sense in light of Special Relativity.

It makes me think there is another property or force that hasn't been discovered yet. There's probably several of them. And when will my warp drive be ready???

[PatrickHenry]

This article didn't consider 2 pieces of data that I would have liked to see discussed. These are the seemingly contradictory mysterious attraction towards the sun (MATS) experienced by the Pioneer and Voyager spacecraft, and the acceleration of distant galaxies away from us.

Those two spacecraft are a problem, but I don't think there's a general agreement yet about what's really being observed. The other item you mention is, I assume, the recently observed enhanced expansion of the universe. You're right, both of these could be manifestations of the ultimate nature of gravity -- whatever that turns out to be. But I think the authors of this paper are mostly focused on determining whether there are deviations from the inverse-square law at very small distances. There are serious theoretical consequences, depending on whether the answer is yes or no.

[Oberon]

And when will my warp drive be ready???

It's ready, but it requires a greater degree of warpedness than you now display in order to operate. Researchers hope to lower the warp requirement threshhold by a factor of five within the next two years.

[Bloody Sam Roberts]

Today, increasing numbers of physicists are seriously questioning whether we are like tightrope walkers, unaware of the true number of dimensions in space.

Just because an ant can walk around the circumference of a cable, does not mean it is aware of that being an additional dimension. By the same token, just because humans lack the proper equipment to eprform the same feat, does not mean we are unaware of that additional dimension.

[Bloody Sam Roberts]

If everything in the universe is attracted to everything else in the universe gravitationally, then all matter would soon be occupying the exact same space, a clear impossibility!

Why is that impossible? Is not the process carried out on a much samller scale everyday when stars are born? Couldn't the birth of a star be considered a model for the "end of the Universe"? Did not all matter in the Universe occupy the same space at the very beginning?

[<1/1,000,000th%]

LOL!

I can be more warped if I need to.

[PatrickHenry]

Warped pl_acemarker.

[spinestein]

Please recheck at the bottom of #4 to see this:

[BTW, satire alert]

and then if you reread the entire thing it will make more sense.

[X. OTerica]

This concept depends very much on what the definition of "travel" is.

Exactly. Do a Google on “quantum entanglement” to see how quantum effects can be instantaneously transmitted over a distance (i.e., there is no “travel” is involved).

Pretty rudimentary at present but could make Stargate a reality some day, who knows?