[[Gravitationsbølger]] fra to pulsarersneutronstjerners spirallering mod hinanden (se rumtidsillustration) er observeret. Bølgerne passer meget nøjagtig med [[Generel relativitetsteori|Einsteins ligninger]]s forudsigelser (indenfor 99,95%).<ref>[http://www.sciencedaily.com/releases/2006/09/060914094623.htm Particle Physics & Astronomy Research Council (2006, September 14). General Relativity Survives Gruelling Pulsar Test: Einstein At Least 99.95 Percent Right. ScienceDaily] Citat: "...the double pulsar system should lose energy, causing the two neutron stars to spiral in towards each other by precisely the amount that we have observed -- thus our observations give an indirect proof of the existence of gravitational waves (as predicted by Einstein)..."</ref>
