Physicists sank a telescope 1.5 miles under the sea to put Einstein's relativity to the test

A half-built neutrino telescope on the floor of the Mediterranean Sea searched for cracks in one of physics' most basic invariances. It came up empty, but its limits rival those of detectors many times its size.

A particle-detecting telescope sunk more than a mile beneath the sea off the coast of France has tested a core principle of Einstein's relativity and found no cracks.

The detector, called Oscillation Research with Cosmics in the Abyss (ORCA), detects elusive particles called neutrinos.…