Gravity detector could provide clues to the shape of the universe

St. Louis Post-Dispatch ^ | Monday, January 8, 2007 | Eric Hand

[SunkenCiv]

Ramanath Cowsik, a Washington University physicist, will poke and prod at some of the most daunting problems remaining in physics:

• What is causing the universe to fly apart, faster and faster each year?
• Why is gravity so weak and so different from the other basic forces in the universe? And what is the true shape of the universe?

In an era of big science -- billion-dollar space telescopes and atom smashers -- Cowsik's approach is refreshingly small. The apparatus, called a torsion balance, is cheap and based on a centuries-old idea. He says the torsion balance will cost about $100,000. When complete, it could measure gravitational forces as small as the weight of a bit of a salt grain cut into 60 billion pieces... Late in his career, Cowsik, 66, is joining a handful of laboratories around the country that are chasing gravity down to small spaces. In those spaces, the scientists suspect, the formula for gravity might not hold.

[SunkenCiv]

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Washington University physicist Ram Cowsik, left, and Kasey Wagoner discuss the mirrors they are testing with a high-precision camera that will be part of a force detector. (Noah Devereaux/P-D)

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[SunkenCiv]

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[pissant]

[martin_fierro]

[camle]

I got me qa gravity detector - If I drop an apple, and iit falls to teh ground, yep. there's gravity.

all kidding aside, gravity is faster than light.

[SunkenCiv]

I have one of those. I get the weight, then step off before it completes the "per cent of body fat" exam.

[SunkenCiv]

Wow, that was a trip into the Wayback Machine...

[SunkenCiv]

http://www.metaresearch.org/cosmology/speed_of_gravity.asp
http://www.metaresearch.org/cosmology/gravity/speed_limit.asp
http://www.metaresearch.org/home/Viewpoint/Kopeikin.asp
http://www.metaresearch.org/media%20and%20links/press.asp

[camle]

thanx.

[lesser_satan]

bump

[azhenfud]

What is causing the universe to fly apart, faster and faster each year?

Republicans caving to Democrats.

[EarthBound]

all kidding aside, gravity is faster than light.

Know its been over a week since you posted this, but I'll bite. How is gravity faster than light?

[camle]

if gravity was lightspeed or slower, then the gravitational pull of the sun on the earth would be slightly out of sync with the earth's location, and our orbit would be a outward spiral. we'd be long gone.

[Larry Lucido]

So, do we fall at the speed of gravity? :-)

[camle]

nope. we fall at a rate determined by atmospheric conditions, limited by resistance, terminal velocity, etc..

[TheyConvictedOglethorpe]

The Theory of Gravitation Made Simple:
Everything in the universe sucks.

[EarthBound]

if gravity was lightspeed or slower, then the gravitational pull of the sun on the earth would be slightly out of sync with the earth's location, and our orbit would be a outward spiral. we'd be long gone.

Experiments suggest that the abberation you allude to is resolved by electromagnetic forces in the system. Evidence suggests that the speed at which gravity propogates is between 80% and 120% of c. Indeed experimentations suggest the number is equal to c within 1%. Link below.

Link

[SunkenCiv]

Sure seems that way some times. :')

[SunkenCiv]

Thanks for that link. Here's something else from that site:

Is gravity itself a fictitious force?

A few lines up, I wrote that the force we feel when the bus is braking, is weird in that its strength is proportional to our own mass. But what about gravity? That also has a strength that is proportional to our mass! Could gravity be a fictitious force too?

Yes, that's exactly how gravity is viewed these days. This is the content of Einstein's General theory of Relativity. Einstein conjectured that perhaps we've been looking at things in the wrong way. Newton viewed the orbit of a satellite, or the parabolic flight of a projectile, or the fall of an apple, to be complicated motions caused by the action of this mysterious force called gravity. But Einstein turned the problem on its head, and decided that satellites, projectiles, and apples are all following a motion that is as simple as any motion can be, provided they are viewed on the stage of a curved spacetime.

[EarthBound]

Hmm, interesting. I did a quick search of the "speed of gravity" in wikipedia to back up my assertion that gravity, such as it is, propogates at c.

Thanks for the pings, I love theoretical physics... too bad I never could handle the math.