Feasibility of measuring the Shapiro time delay over meter-scale distances

S. Ballmer, S. Márka, P. Shawhan

Research output: Contribution to journalArticlepeer-review

11 Scopus citations


The time delay of light as it passes by a massive object, first calculated by Shapiro in 1964, is a hallmark of the curvature of spacetime. To date, all measurements of the Shapiro time delay have been made over solar-system distance scales. We show that the new generation of kilometer-scale laser interferometers being constructed as gravitational wave detectors, in particular Advanced LIGO, will in principle be sensitive enough to measure variations in the Shapiro time delay produced by a suitably designed rotating object placed near the laser beam. We show that such an apparatus is feasible (though not easy) to construct, present an example design, and calculate the signal that would be detectable by Advanced LIGO. This offers the first opportunity to measure spacetime curvature effects on a laboratory distance scale.

Original languageEnglish (US)
Article number185018
JournalClassical and Quantum Gravity
Issue number18
StatePublished - Sep 21 2010

ASJC Scopus subject areas

  • Physics and Astronomy (miscellaneous)


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