AWeber bar is a device designed todetect gravitational waves, first devised and constructed byphysicistJoseph Weber at theUniversity of Maryland. The device consisted ofaluminium cylinders, 2 meters in length and 1 meter indiameter,antennae for detectinggravitational waves.[1]
These massive aluminium cylinders vibrated at aresonance frequency of 1660hertz and were designed to be set in motion by gravitational waves predicted by Weber. Because these waves were supposed to be so weak, the cylinders had to be massive and thepiezoelectric sensors had to be very sensitive, capable of detecting a change in the cylinders' lengths by about 10−16 meters.[1]
Around 1968, Weber collected what he concluded to be "good evidence"[1] of the theorized phenomenon. However, his experiments were duplicated many times, always with a null result.
Such experiments conducted by Joseph Weber were very controversial, and his positive results with the apparatus, in particular his claim to have detected gravitational waves fromSN1987A in 1987, were widely discredited. Criticisms of the study have focused on Weber's data analysis and his incomplete definitions of what strength vibration would signify a passing gravitational wave.
Weber's first "Gravitational Wave Antenna" was on display in theSmithsonian Institution as part of "Einstein: a Centenary Exhibit" from March 1979 to March 1980.[2] A second is on display at theLIGO Hanford Observatory.[3]
Weber Memorial Garden was dedicated 2019 at theUniversity of Maryland, where Weber was a faculty member. The garden contains eight of the cores of Weber's bar detectors.[4]