New measurements of the Lense-Thirring effect

Ignazio Ciufolini (with Erricos Pavlis) has a paper out in Nature (see also the news and views item by Neil Ashby) on "A confirmation of the general relativistic prediction of the Lense-Thirring effect". According to Ciufolini,

...this paper describes a measurement of the Lense-Thirring effect, accurate at the 5% to 10% level, using observations of the nodes only of the two LAGEOS satellites. This experimental determination of the Lense-Thirring effect agrees 99% with the theoretical prediction of general relativity.

The basic idea is the same as in the original 1984-86 proposal, using two laser-ranged satellites with supplemenatary inclinations satellites (PRL 56, 278, 1986) in order to eliminate the gravitational perturbations. This idea was analyzed in a large number of papers and official review studies by NASA, ASI, etc., (establishing an error of about 10 % in the measurement of the Lense-Thirring effect). The only difference here is that the two inclinations of the LAGEOS satellites have
now an offset from the ideal supplementary configuration of about 18 degrees and not some 0.1 degree (to allow for injection error) as in the original proposal.

However, thanks to the NASA space mission GRACE (two satellites ranging to each other to accurately measure Earth's gravity field) we now have models of the field that are several orders of magnitude better than those at the time of the 1984-86 proposal. Thereby making possible the result we obtained.

An important technical note on the error analysis of this measurement: In regards to the effect of the Earth gravitational
perturbations, even if one considers an error three times larger than the published GRACE model errors (which already include systematic errors), you are still left with a measurement of the Lense-Thirring effect at an accuracy level of about 10%! As far as the nongravitational perturbations, the total uncertainty of these perturbations has been studied in a large number of papers and in the already mentioned 1989 official review study of NASA and ASI, as reported in the supplementary information section.

Let me be a bit naughty, and suggest that Ciufolini's results may have so far been underreported in the U.S. (perhaps because of GPB's competing interests?) until GSFC joined into the fray (with Pavlis). However, Lorenzo Iorio has a different opinion on the precision of this determination.