269
See also: Gravitational theory 66–73 ■ Gravitational disturbances 92–93 ■ The shape of the Milky Way 164–65 ■
Supernovae 180–81 ■ The Oort cloud 206 ■ Dark energy 298–303
matter exists. Thanks to Rubin, the
general public learned that most of
the universe appears to be missing.
Throughout the 1960s and
1970s, the science of astronomy
was dominated by projects on a
grand scale, as researchers used
massive instruments, often in
remote parts of the world, to search
for exotic objects, such as black
holes, pulsars, or quasars. By
contrast, Rubin was looking for
a research area that would allow
her to stay in her home city of
Washington, D.C., and raise her four
children. She chose to study the
rotation of galaxies, specifically
looking at the anomalous behavior
of the outer regions of galaxies.Spinning spirals
The problem Rubin tackled was
the fact that huge disks of stars
in nearby galaxies did not move
in a way that was consistent with
Newton’s law of gravity: their
outer regions moved too quickly.
This curiosity was not new, but it
had previously been largely ignored.
Since the 1920s, when Bertil
Lindblad and others showed that
the Milky Way—and by extension
many other galaxies—were disks
of stars moving around a central
point, it was assumed that galaxies
were orbital systems just like any
other. In the solar system, near
objects orbit at a faster speed than
distant ones, so Mercury is moving
much more rapidly than Neptune.
This is because, following Newton,
gravity decreases with a square of
the distance. When the velocities ❯❯THE TRIUMPH OF TECHNOLOGY
We became astronomers
thinking we were studying the
universe, and now we learn
that we are just studying the
5 percent that is luminous.
Vera RubinVera Rubin Born Vera Cooper in Philadelphia,
Rubin earned her first degree from
Vassar College in upstate New
York, and then applied to go to
Princeton. Her application was
ignored because women were
barred from joining the university’s
graduate astronomy program until- Instead Rubin pursued her
studies at Cornell University,
where she studied under greats
such as Richard Feynman and
Hans Bethe. She subsequently
earned a Ph.D. from Georgetown
University in Washington, D.C.,
supervised by George Gamow.
Her thesis, published in 1954,
concluded that galaxies would
clump together, a fact that was
not fully explored until the work
of John Huchra in the late 1970s.
After teaching at a college in
Maryland, Rubin returned to
Georgetown, and then moved
to the Carnegie Institution of
Washington in 1965. It was here
that she conducted her work on
galactic rotation, and she has
remained there ever since.Key work1997 Bright Galaxies,
Dark MattersThe outer regions of
galaxies move much more
quickly than expected.To stop spinning
galaxies from disintegrating,
they must contain a lot more
mass than can be seen.This mass comes from
invisible dark matter—
there is six times more dark
matter in the universe than
ordinary matter.Most of
the universe
is missing.