Hubble: The Great Synthesizer
the breadth and birth of the universe
by Liza Gross
Hubble, visionary astronomer
and founder of modern cosmology, was a man of surprising
talents. He may be the only intellectual giant in history
to have had a shot at both the Nobel prize and the heavyweight
boxing title of the world.
Hubble was born in Marshfield, Missouri, in 1889, and moved
with his family to Chicago nine years later. He earned a
degree in mathematics and astronomy at the University of
Chicago in 1910, as well as a reputation as a gifted boxer.
While at Chicago, promoters courted him as the next "great
white hope"--their pick to dethrone controversial African-American
heavyweight champ Jack Johnson. Instead, Hubble accepted
a Rhodes scholarship to Oxford, earned a degree in law,
and ultimately turned to astronomy, a field he described
as "a calling."
When Hubble began working in astronomy in 1919, scientists
were still debating whether the Milky Way--earth's galactic
home--constituted the entire universe, or whether ours was
just one of many galaxies inhabiting a far larger space.
But they couldn't resolve the issue without better telescopes.
Hubble was lucky enough to start his career at California's
Mount Wilson Observatory, where the largest and most technologically
advanced telescope in the world had just been built.
From his mountain perch high above Los Angeles, Hubble set
his sights on fuzzy clouds of cosmic light called nebulas--and
hit the jackpot. Within one of those clouds, known as the
Andromeda nebula, he detected cepheids (pronounced CEE-feeds)--"variable
stars" that regularly change in luminosity.
Thanks to the pioneering work of Henrietta Leavitt, who
had developed a technique using variable stars as a measure
of distance, Hubble determined that his cepheids were much
too far away to be part of our own galaxy. He realized,
in fact, that the Andromeda nebula itself wasn't a nebula
at all, but a galaxy made up of billions of stars, just
like our own. His discovery proved that our Milky Way is
just one of many galaxies, settling the controversy once
and for all, and forever changing the way we view our place
in the universe.
Hubble at work.
shining moment was yet to come. The history of scientific
discovery is a history of the unexpected, and what Hubble
would soon reveal was no exception.
By the early 1900s, astronomy had taken some giant leaps
forward. Scientists could not only determine how far away
a galaxy was (using cepheids), but they had also figured
out a way to use the light from a galaxy to determine how
fast it was moving.
From our point
of view, the spectra of light emitted by celestial bodies
shifts depending upon whether they're moving toward or away
from earth. Galaxies moving toward earth shift toward the
blue end of the spectrum; those moving away shift toward
the red. By plotting the distance of eighteen galaxies against
their red shifts, Hubble
discovered a direct relationship: Galaxies were moving away
from earth at a rate proportional to their distance from
Hubble's discovery was not just unexpected, but monumental.
No one had thought to compare these data points before.
Using the ratios he observed, Hubble determined that the
farther the galaxy, the greater the red shift. In other
words, the greater the distance between a galaxy and the
earth, the faster that galaxy was moving away from us. (And
the greater the distance between galaxies, the faster they
were moving away from each other.) This phenomenon, known
today as Hubble's law, meant that the
universe was expanding.
From this realization, Hubble went one step further. If
galaxies that were twice as far away were moving away from
each other at twice the speed, he reasoned, they must have
begun their cosmic expansion from the same space at the
same time. Using his distance/speed ratio, Hubble fixed
that time at about two billion years ago. He was off by
some ten to thirteen billion years by today's estimates,
but he laid the foundation for the Big Bang
theory, providing evidence that the universe exploded
into existence with a furious burst of energy, and has been
expanding ever since. It was a shattering blow to the centuries-old
notion of a static universe.
Near the end of Hubble's career, around 1948, a BBC reporter
asked him what he hoped to find with the immense telescope
he'd helped develop for Mount Palomar in Southern California.
"We hope to find something we hadn't expected," Hubble replied.
While Hubble never did win the Nobel Prize (there was no
category for astronomy at the time), his legacy reaches
far beyond such temporal tokens of recognition. Stephen
Hawking, noted cosmologist and author of A Brief History
of Time, has hailed Hubble's expanding-universe discovery
as "one of the great intellectual revolutions in the twentieth
Today, it's only fitting that our most finely tuned eye
on the universe--the Hubble telescope--bears the name of
the man who pushed the limits of our understanding of the
nature and structure of space. It's surely just a matter
of time before Hubble takes his rightful place among the
astronomical heavyweights. Like Copernicus and Galileo,
Hubble was light-years ahead of his time, forever changing
our view of the heavens--and ourselves.