Gravitational Waves May Have Been Detected In 1987

KentuckyFC writes "In 1987, a physicist called Joe Weber claimed to have detected gravitational waves at the same time that other scientists spotted a supernova called SN1987A. His claims were largely ignored because of calculations showing that gravitational waves could not be strong enough to be picked up by Weber's equipment, a set of giant aluminium cylinders designed to vibrate as the waves passed by. But these calculations were based on first order effects in the way spacetime can be distorted. Now a new analysis shows that second order effects can enhance gravitational waves by four orders of magnitude, but only when certain asymmetries are present. It turns out that SN1987A possesses just the right kind of asymmetries to make this enhancement possible because the supernova wasn't entirely spherical. Which means that Weber, who died in 2000, may have been the first to see gravitational waves after all."

Comments

Nobel prize

[Alain Williams]

Can this be awarded posthumously ?

Some more info

[photonic]

I don't know the fine details of Weber's experiments, but I believe his 2 meter metal bar was operating at room temperature, so he was severely limited by thermal noise. His claimed strain sensitivity (delta L / L) was on the order of 1e-16. There are currently a small number of resonant bars operational which are kept at just a few Kelvin. They reach a sensitivity around 1e-21 in a narrow band and have not measured anything during the last ~5 years, so Weber's claim is highly unlikely. I am involved with one of the big interferometric detectors, which use vacuum tubes of several kilometers and reach sensitivities at the 1e-22 level over a broad bandwidth. If the astrophysical models are right we should be able to detect something within the next 5 years.

As already mentioned in a previous comment, the article is somewhat speculative and it is a little bit late to verify the experiment. The standard accepted practice for claiming the detection of a GW is to observe the event with at least 2 detectors which are separated far enough to not measure the same external disturbances (but preferably 3 or more spread around the world so that you can do proper triangulation of the source). One single glitch might be a cosmic ray, lightning, dust falling before your detector, an earthquake, an instrumental error, anything. We see more of those than we like. One glitch measured at different observatories within the time it takes to travel at lightspeed (a few ms) at different observatories around the world might give you a nobel prize.

One book that is high on my 'to read' list is Gravity's shadow, which supposedly describes not only Weber's experiments, but also its reception by the scientific community and the eventual downfall of Weber's reputation.

I saw the setup

[io333]

I saw the setup in the winter of late 1986. It was deep (many levels) under the physics department's machine shop, deep underground, at the University of Maryland & you had to go down several ladders to get there. It was hanging from the ceiling, big giant (I thought hollow, but apparently solid) cylinders of what looked like aluminum, hanging from thin wires. Does anyone know if it is still there?