22 SCIENCE NEWS | February 13, 2021THE VIRGO COLLABORATIONFEATURE |OUR WILD UNIVERSEfrom a newly discovered type of rapidly spinning
star called a pulsar. In the few years after report-
ing the initial find, Science News published more
than a dozen stories on what it began calling the
“Weber problem” (SN: 6/21/69, p. 593). Study
after study could not confirm the results. What’s
more, no sources of the waves could be found. A
1973 headline read, “The deepening doubt about
Weber’s waves” (SN: 5/26/73, p. 338).
Weber stuck by his claim until his death in
2000, but his waves were never verified. Nonethe-
less, scientists increasingly believed gravitational
waves would be found. In 1974, radio astronomers
Russell Hulse and Joseph Taylor spotted a neu-
tron star orbiting a dense companion. Over the
following years, the neutron star and its com-
panion appeared to be getting closer together
by the distance that would be expected if they
were losing energy to gravitational waves. Scien-
tists soon spoke not of the Weber problem, but of
what equipment could possibly pick up the waves.
“Now, although they have not yet seen, physicists
believe,” Dietrick E. Thomsen wrote in Science
News in 1984 (SN: 8/4/84, p. 76).It was a different detection strategy, decades
in the making, that would provide the needed
sensitivity. The Advanced Laser Interferometry
Gravitational-wave Observatory, or LIGO, which
reported the first confirmed gravitational waves
in 2016, relies on two detectors, one in Hanford,
Wash., and one in Livingston, La. Each detector
splits the beam of a powerful laser in two, with
each beam traveling down one of the detector’s
two arms. In the absence of gravitational waves,
the two beams recombine and cancel each other
out. But if gravitational waves stretch one arm of
the detector while squeezing the other, the laser
light no longer matches up.
The machines are an incredible feat of engi-
neering. Even spacetime ripples detected from
colliding black holes might stretch an arm of the
LIGO detector by as little as one ten-thousandth
of the width of a proton.
When the first detection, from two colliding
black holes, was announced, the discovery was
heralded as the beginning of a new era in astron-
omy. It was Science News’ story of the year in
2016, and such a big hit that the pioneers of theGravitational waves ripple away
from two black holes that orbit
each other before merging (shown
in this simulation). The merging
black holes created a new black
hole that’s much larger than those
found in previous collisions.DEBORAH FERGUSON, KARAN JANI, DEIRDRE SHOEMAKER AND PABLO LAGUNA/GEORGIA TECH, MAYA COLLABORATIONuniverse.indd 22universe.indd 22 1/27/21 9:53 AM1/27/21 9:53 AM