OPINION
DOCTORS' Lounge
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THE DIVINE IS in the Details
Mary G. Barry, MD
Louisville Medicine Editor
[email protected]
T
he signal from outer space came
at last, and it came from a billion
years ago. At the time, gazillions
of galaxies away, there were two
black holes that had been spin-
ning in orbit around each other for millions
of years. They were drawing ever closer, in
tighter and tighter circles, like twin sumo
wrestlers stomping ‘round the ring, pulsing
out huge forces, their gravitational ener-
gies banging and crackling and crashing
between them - and all while zooming at
the speed of light. Finally their combined
gravities overcame even that speed. They
collided, and boom! They merged into one
giant black hole, so dense with gravity that
no light could escape. But the shockwaves
that exploded out from this massive colli-
sion did escape, and bloomed out into the
void. Two years ago, they finally came to
Earth.
Nicola Twilley wrote all about them in
The New Yorker, Feb. 11, 2016. Albert Ein-
stein first imagined these energy ripples, and
called them “gravitational waves” in 1915.
Scientific interest grew over time, but only
in certain circles. Many people thought it
was a crackpot idea that gravitational waves
could prove the theory of relativity, itself a
concept too big to grasp. Einstein’s great
theory stated that “Space and time curve in
the presence of mass, and that this curvature
produces gravity.”
That is the sort of statement that we En-
glish-major types strain our brains on. The
unbelievably gargantuan gravity of the black
hole sucks in all the light waves. None can
generate the speed to evade: the light dies
there, so to speak. I think of black holes as
Hell, in space. Ms. Twilley comes to our aid.
“Imagine,” she says, “when two black holes
orbit each other, they stretch and squeeze
space and time like two children running in
circles on a trampoline, creating vibrations
that travel to the very edge. These vibrations
are gravitational waves.” Apparently, they
bombard us from all over the universe, but
are so weak they have not yet had an effect
we could measure.
Dr. Rainier Weiss of MIT and Dr. Kip
Thorne of Caltech believed they were real
and that they would be able to measure
them. With the Scottish scientist Ron
Drever, they convinced the National Sci-
ence Foundation to give them nearly $300
million, despite vociferous opposition. With
that, in about 1990, the scientific team led
by Dr. Barry Barish and Dr. Weiss began to
construct Dr. Weiss’ design of the Laser In-
ferometer Gravitational Laboratory (LIGO),
whose detecting devices are so unimagin-
ably fine that they measure “a vibration of
less than a trillionth of an inch.” Yet these
devices are laser beams that are 4 km long,
arranged in an L shape. We have two, one
in Louisiana and one in Washington. The
lasers live in steel vacuum tubes that re-
quired 40 days of pumping to empty out
every particle of air and dust. They are tuned
and balanced and shielded to perfection to
filter out interference from the wind, the
trucks, the ocean, the movement of wildlife.
Dr. Weiss explained that if a gravitational
wave hit one of the L arms, it would instan-
taneously register as longer than the other
(mass curving space), and then the second
L-arm would register as shorter than the
other (to every action there is an equal and
opposite reaction).
On 9/24/15, after hundreds of thousands
of minute adjustments, that signal sent a
billion years ago arrived. It caused a sensa-
tion. The LIGO had just hours before gone
back online after five years of $200 million
(continued on page 28)
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