In a tour de force of technology and just plain stubbornness spanning half a century and costing more than $750 million, a team of experimenters from Stanford University reported on Wednesday that a set of orbiting gyroscopes had detected a slight sag and an even slighter twist in space-time.

The finding confirms some of the weirdest of the many strange predictions — like black holes and the expanding universe — of Albert Einstein’s theory of gravity, general relativity.

“We have completed this landmark experiment of testing Einstein’s universe,” Francis Everitt, leader of the project, known as Gravity Probe B, said at a news conference at NASA headquarters in Washington. “And Einstein survives.”

Image An artist’s conception of Gravity Probe B orbiting Earth to measure space-time. Credit... NASA

That was hardly a surprise. Observations of planets, the Moon and particularly the shifting orbits of the Lageos research satellites had convinced astronomers and physicists that Einstein’s predictions were on the mark. Nevertheless, scientists said that the Gravity Probe results would live forever in textbooks as the most direct measurements, and that it was important to keep testing theories that were thought to be correct.