000004957 001__ 4957
000004957 005__ 20200831131513.0
000004957 037__ $$aPERIO-2020-0003
000004957 100__ $$aVan Camp, Michel
000004957 245__ $$aIAG Newsletter
000004957 260__ $$c2020
000004957 310__ $$aMonthly
000004957 500__ $$aIAG Newsletter 253 (August 2020)
000004957 520__ $$a25 years of continuous measurements of gravity in Membach On August 4, 2020, the superconducting (or cryogenic) gravimeter has been measuring for 25 years the variations of gravity with a precision of one-hundredth of a billionth (10-11) of g (g = 9.81 m/s²).  Since September 18, 2017, this instrument holds a double world record, in gravimetry and physics:     1. Record of the cryogenic gravimeter that has operated the longest at a given location.     2. It is also, as far as we know, the longest levitation of a superconducting artefact in a magnetic field. This field is generated by persistent currents, which were injected in 1995 into superconducting coils, where they circulate since then without any resistance and therefore, without ever having been dissipated. Although this record does not contradict what physicists specializing in persistent currents expect – in theory, a superconducting current can flow forever –, it is at least worthy of a place in a "cabinet of curiosities".
000004957 594__ $$aNO
000004957 6531_ $$aMembach
000004957 6531_ $$aSuperconducting gravimeter
000004957 6531_ $$a25 years
000004957 6531_ $$aWorld record
000004957 8560_ $$fmichel.vancamp@observatoire.be
000004957 85642 $$ahttps://www.iag-aig.org/iag-newsletters/253
000004957 980__ $$aNEWSLETTER