20 SCIENCE NEWS | February 13, 2021FEATURE | OUR WILD UNIVERSEat the centers of most if not all galaxies, where
they generate outflows of energy that affect how
and where stars form. “At the center of the galaxy,
they define everything,” she says.
Though visual confirmation is recent, it feels as
though black holes have long been familiar. They
are a go-to metaphor for any unknowable space,
any deep abyss, any endeavor that consumes all
our efforts while giving little in return.
Real black holes, of course, have given plenty
back: answers about our cosmos plus new ques-
tions to ponder, wonder and entertainment for
space fanatics, a lost album from Weezer, numer-
ous episodes of Doctor Who, the Hollywood
blockbuster Interstellar.
For physicist Nicolas Yunes of the University
of Illinois at Urbana-Champaign, black holes and
other cosmic behemoths continue to amaze. “Just
thinking about the dimensions of these objects,
how large they are, how heavy they are, how dense
they are,” he says, “it’s really breathtaking.”Spacetime waves
When general relativity’s behemoths collide, they
disrupt the cosmic fabric. Ripples in spacetime
called gravitational waves emanate outward, a call-
ing card of a tumultuous and most energetic tango.
Einstein’s math predicted such waves could be
created, not only by gigantic collisions but also by
explosions and other accelerating bodies. But for
a long time, spotting any kind of spacetime rip-
ple was a dream beyond measure. Only the most
dramatic cosmic doings would create signals that
were large enough for direct detection. Einstein,
who called the waves gravitationswellen, was
unaware that any such big events existed in the
cosmos.
Beginning in the 1950s, when others were still
arguing whether gravitational waves existed in
reality, physicist Joseph Weber sunk his career
into trying to detect them. After a decade-plus
effort, he claimed detection in 1969, identifying
an apparent signal perhaps from a supernova orQuasars (one illustrated)
are so bright that they
can outshine their home
galaxies. Though baffling
when first discovered,
these outbursts are
powered by massive,
feeding black holes.MARK GARLICK/SCIENCE SOURCECLOCKWISE FROM TOP: PICTORIAL PRESS LTD/ALAMY STOCK PHOTO;
NASA/COBE SCIENCE TEAM; AIP EMILIO SEGRÈ VISUAL ARCHIVES/RUBIN COLLECTIONuniverse.indd 20universe.indd 20 1/27/21 9:37 AM1/27/21 9:37 AM