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Fraser
2003-Jul-08, 10:09 PM
SUMMARY: Theorized by Einstein for almost a century, physicists have found evidence to support the theory that the force of gravity moves at the speed of light. The speed was measured by physicist Sergei Kopeikin by watching how light from a distant quasar was bent by Jupiter's gravity. Variations in how the image of the quasar was bent accounted for this speed of gravity.


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jkmccrann
2005-Dec-12, 05:02 PM
Gravity moves at the speed of light?!? So does that mean we're all being gravitationally effected by looking up at the night sky and seeing all those magnificent points of light?

trinitree88
2005-Dec-12, 06:27 PM
SUMMARY: Theorized by Einstein for almost a century, physicists have found evidence to support the theory that the force of gravity moves at the speed of light. The speed was measured by physicist Sergei Kopeikin by watching how light from a distant quasar was bent by Jupiter's gravity. Variations in how the image of the quasar was bent accounted for this speed of gravity.


What do you think about this story? Post your comments below.

This thread is similar to Speed of Gravity...can of worms by Slywester Kornowski. However, I am quite pleased that this result is in concordance with the results of SN1987a. There the arrival was less than 2 seconds separation after 160,000 years of travel time. Pete

jkmccrann
2005-Dec-12, 06:37 PM
This thread is similar to Speed of Gravity...can of worms by Slywester Kornowski. However, I am quite pleased that this result is in concordance with the results of SN1987a. There the arrival was less than 2 seconds separation after 160,000 years of travel time. Pete

How was the gravitational effect of SN1987a measured?

swansont
2005-Dec-12, 06:56 PM
SUMMARY: Theorized by Einstein for almost a century, physicists have found evidence to support the theory that the force of gravity moves at the speed of light. The speed was measured by physicist Sergei Kopeikin by watching how light from a distant quasar was bent by Jupiter's gravity. Variations in how the image of the quasar was bent accounted for this speed of gravity.


What do you think about this story? Post your comments below.

There has been some controversy (http://www.space.com/scienceastronomy/gravity_speed_030116.html) about the measurement. I'm not an expert in GR by any stretch of the imagination, but I found his presentation compelling when I attended a colloquium he gave a while back.

jkmccrann
2005-Dec-12, 07:33 PM
Interesting article, cheers. :)

Dragon Star
2005-Dec-12, 08:58 PM
Heh, just made a reference to this just the other day here (http://www.bautforum.com/showthread.php?t=35485)

trinitree88
2005-Dec-13, 12:57 AM
How was the gravitational effect of SN1987a measured?

At the time of SN1987a, the gravity wave detectors were large aluminum cylinders, suspended by wires. Piezoelectric sensors mounted on them searched for a pattern whereby the bar changed dimensions sequentially in two orthogonal directions...signaling a gravitational wave passing. Joseph Weber (Univ. of Maryland) was the American group leader. Rome was a similar set-up. Results were reported at Neutrino 88, the conference at Tufts Univ., Medford, MA by Guido Pizella. You can find him at NASA Astrophysics Database. It was later republished by Larry Sulak et al (head of the IMB neutrino detector)...also in Il Nuovo Cimento C....circa 1993. . confidence level 99.99 %.:wall:

Remember, proponents of the next experimental design...the LIGO, laser interferometric gravitational-wave observatory, are hardly likely to see funding, if the contemporary design is already seeing these effects. So those scientists are going to be particularly doubtful of the legitimacy of the initial detections by bar detectors. As I am not an experimental physicist, I'm not going to get into it in a big way, but in my personal conversation with Professor Sulak, he was, without doubt, sure they(gravitational waves ) had been seen. Pete.

P.S. My conversation with Prof. Sulak involved the piezoluminescence sometimes seen in salt mines when the lights are out. Shifting salt crystals under stress/strain conditions flash weakly. I was curious if the walls were moving. He commented that the floors of the IMB...once machined flat...seemed to be buckling up. "Do you mean they're moving?" he asked. (salt domes are considered very geologically stable). "Yes, Scientific American ran an article called Salt Tectonics...they move." I replied. He was curious, so a few months later I chased down the article for him, and personally delivered it to Boston Univ. (I had business there also). Prof. Sulak wasn't around that day. Three months later the roof of the IMB fell in......just like inflationary spacetime models of the BB will with the WMAP 2nd year data release. Ciao. Pete

jkmccrann
2005-Dec-13, 05:05 AM
Very interesting Pete, Cheers. Interesting anecdote regarding the `Salt Tectonics' as well.