" Over the past 40 years, a number of practical applications have been found for these remarkable manifestations of quantum sync. Josephson’s superconducting sandwiches, now known universally as “Josephson junctions,” have spawned the most sensitive detectors known to science. For instance, a device called a SQUID (for superconducting quantum interference device) takes advantage of the extreme sensitivity of a supercurrent to a magnetic field. A SQUID can measure a displacement a thousand times smaller than an atomic nucleus, or a magnetic field 100 billion times weaker than Earth’s. SQUIDs are used in astronomy, to detect faint radiation from distant galaxies; in nondestructive testing, to spot hidden corrosion beneath the aluminum skin of airplanes; and in geophysics, to help locate sources of oil deep underground. "

― Steven H. Strogatz , Sync: The Emerging Science of Spontaneous Order