1889 - 1953
a vast universe beyond the Milky Way, then found the first hints
that it began with a Big Bang
By MICHAEL D. LEMONICK for Time Magazine
During the past 100 years, astronomers have discovered quasars,
pulsars, black holes and planets orbiting distant suns. But all
these pale next to the discoveries Edwin Hubble made in a few
remarkable years in the 1920s. At the time, most of his
colleagues believed the Milky Way galaxy, a swirling collection
of stars a few hundred thousand light-years across, made up the
entire cosmos. But peering deep into space from the chilly
summit of Mount Wilson, in Southern California, Hubble realized
that the Milky Way is just one of millions of galaxies that dot
an incomparably larger setting.
Hubble went on to trump even that achievement by showing that
this galaxy-studded cosmos is expanding — inflating majestically
like an unimaginably gigantic balloon — a finding that prompted
Albert Einstein to acknowledge and retract what he called "the
greatest blunder of my life." Hubble did nothing less, in short,
than invent the idea of the universe and then provide the first
evidence for the Big Bang theory, which describes the birth and
evolution of the universe. He discovered the cosmos, and in
doing so founded the science of cosmology.
Hubble's astronomical triumphs earned him worldwide scientific
honours and made him the toast of Hollywood during the 1930s and
1940s — the confidant of Aldous Huxley and a friend to Charlie
Chaplin, Helen Hayes and William Randolph Hearst. Yet nobody
(except perhaps Hubble) could have imagined such a future when
the 23-year-old Oxford graduate began his first job, in New
Albany, Ind., in 1913.
Hubble majored in science as an undergraduate at the University
of Chicago. A tall, powerfully built young man, he excelled at
basketball and boxing (fight promoters reportedly tried to talk
him into turning pro), and his combination of academic and
athletic prowess earned him a Rhodes scholarship to Oxford. In
England, Hubble kept up his muscular pursuits: he fought, ran
track and played on one of the first baseball teams ever
organized in the British Isles.
His official academic focus shifted, thanks to a promise made to
his dying father that he would study law rather than science (he
also took up literature and Spanish). On his return to America,
he took a position as a high school Spanish teacher. Though he
was popular with students — especially, according to Hubble
biographer Gale Christianson, with the girls, who were evidently
charmed by his affected British diction and "Oxford mannerisms"
— Hubble longed to return to science.
After a year, he signed on as a graduate student at Yerkes
Observatory in Wisconsin and embarked on the work that would one
day make him famous: studying faint, hazy blobs of light called
nebulae (from the Latin word for cloud) that are visible through
even a modest telescope.
Hubble's skills as an astronomer were impressive enough to earn
him an offer from the prestigious Mount Wilson Observatory.
World War I kept him from accepting right away, but in 1919 the
newly discharged Major Hubble — as he invariably introduced
himself — arrived at observatory headquarters, still in uniform
but ready to start observing with the just completed 100-in.
Hooker Telescope, the most powerful on earth.
Up on the mountain, Hubble encountered his greatest scientific
rival, Harlow Shapley, who had already made his reputation by
measuring the size of the Milky Way. Using bright stars called
Cepheid variables as standardized light sources, he had gauged
the galaxy as being an astounding 300,000 light-years across —
10 times as big as anyone had thought. Yet Shapley claimed that
the Milky Way was the whole cosmic ball of wax. The luminous
nebulae were, he insisted, just what they looked like: clouds of
glowing gas that were relatively nearby.
Hubble wasn't so sure. And in 1924, three years after Shapley
departed to take over the Harvard Observatory, Hubble found
proof to the contrary. Spotting a Cepheid variable star in the
Andromeda nebula, Hubble used Shapley's technique to show that
the nebula was nearly a million light-years away, far beyond the
bounds of the Milky Way. It's now known to be the full-fledged
galaxy closest to our own in a universe that contains tens of
billions of galaxies. "I do not know," Shapley wrote Hubble in a
letter quoted by biographer Christianson, "whether I am sorry or
glad to see this break in the nebular problem. Perhaps both."
(Hubble was not entirely magnanimous in victory. To the end he
insisted on using the term nebulae instead of Shapley's
Hubble's scientific reputation was made almost overnight by his
discovery that the universe is vast and the Milky Way
insignificant. But he had already moved on to a new problem. For
years, astronomers had noted that light from the nebulae was
redder than it should be. The most likely cause of this
so-called red shifting was motion away from the observer. (The
same sort of thing happens with sound: a police car's siren
seems to drop in pitch abruptly as the car races past a
Hubble and his assistant, Milton Humason, began measuring the
distances to these receding nebulae and found what is now known
as Hubble's Law: the farther away a galaxy is from Earth, the
faster it's racing away. Could it be that the universe as a
whole is rapidly expanding? That conclusion was extraordinary,
almost mind-blowing, yet seemed inescapable.
When Einstein heard of Hubble's discovery, he was elated. More
than a decade earlier, his new general theory of relativity had
told him that the universe must either be expanding or
contracting, yet astronomers had told him it was doing neither.
Against his better judgment, Einstein had uglied up his elegant
equations with an extra factor he called the cosmological term —
a sort of antigravity force that kept the universe from
collapsing in on itself.
But suddenly, the cosmological term was unnecessary. Einstein's
instincts had been right, after all. His great blunder had been
to doubt himself, and in 1931, during a visit to Caltech, the
great and grateful physicist traveled to the top of Mount Wilson
to see the telescope and thank Hubble personally for delivering
him from folly.
With the greatest scientific superstar of the age paying him
homage, Hubble became a popular superstar in his own right. His
1936 book on his discoveries, "The Realm of the Nebulae",
cemented his public reputation. Tourists and Hollywood
luminaries alike would drive up the mountain to marvel at the
observatory where Hubble had discovered the universe, and he and
his wife Grace were embraced by the elite of California society.
Hubble's last great contribution to astronomy was a central role
in the design and construction of the Hale Telescope on Palomar
Mountain. Four times as powerful as the Hooker, the Hale would
be the largest telescope on Earth for four decades. It would
have been even longer, but its completion was interrupted by
World War II. So was Hubble's career. The ex-major signed on as
head of ballistics at Aberdeen Proving Ground in Maryland. (At
one point the eminent astronomer spent an afternoon test-firing
bazookas, at great personal risk, to pinpoint a design flaw.)
Hubble finally got his hands on the Hale when it went into
service in 1949. It was too late; he had suffered a major heart
attack, and he never fully regained the stamina it took to spend
all night in a freezing-cold observatory. No imaginable
discovery, however, could have added to his reputation.
The only recognition that eluded him was a Nobel Prize — and not
for lack of effort on his part. He tried everything. In the late
1940s he even hired a publicity agent to promote his cause.
Alas, there was no prize for astronomy, and by the time the
Nobel committee decided astronomy could be viewed as a branch of
physics, it was too late. Insiders say Hubble was on the verge
of winning when he died, in 1953.
Hubble would have been consoled by the fact that his name adorns
the Hubble Space Telescope, which probes the cosmos to depths he
could not have imagined but would have fully appreciated.
Whatever marvels the Hubble telescope reveals, they're all
played out on the stage Edwin Hubble first glimpsed from a
lonely mountaintop in California.
The American astronomer Edwin Powell Hubble (1889-1953)
established the scale of the universe and laid the observational
basis for the cosmological theory of the expanding universe.
Edwin Hubble was born on Nov. 20, 1889, in Marshfield, Mo.,
where his father, a lawyer, was in the insurance business.
Hubble received scholarship aid to go to the University of
Chicago. He chose law for a career, and after receiving his
bachelor's degree in 1910, he went as a Rhodes scholar to Oxford
University, England. In 1913 he returned to the United States,
was admitted to the bar in Kentucky, and practiced law for about
a year in Louisville.
Quite suddenly, Hubble decided that he would devote his life to
astronomy, and in 1914 he left for the University of Chicago's
Yerkes Observatory in Williams Bay, Wis. In 1917 he completed
his doctorate and enlisted in the infantry. He served in France
as a line officer in the American Expeditionary Force.
Early Work at Mount Wilson
As a student at Chicago, Hubble had attracted the attention of
the well-known astronomer G. E. Hale, and after the war Hale
offered him a staff position at Mount Wilson Observatory near
Pasadena, Calif. Except for the period 1942-1946, when Hubble
was with the Ordnance Department in Aberdeen, Md., he was
connected with the Mount Wilson Observatory for the rest of his
Hubble's early observations at Mount Wilson were made with its
60-inch reflecting telescope and concentrated on objects within
our own galaxy, for example, novae, nebulous stars, and variable
stars. Gradually he began to observe more distant objects. To
determine the distances of the spiral nebulae (galaxies), he
used Cepheid variable stars. This method derived from Henrietta
S. Leavitt's 1912 discovery that the period of variation in the
intensity of these stars is directly related to their absolute
magnitude, so that by measuring the former, one may easily
determine the latter. By knowing the star's absolute magnitude
and measuring its apparent magnitude, its (relative) distance
may be readily calculated from the inverse-square law.
In 1923 Hubble definitely recognized a Cepheid variable in the
Andromeda Nebula, known to astronomers as M31. Others were soon
found in M31 and its companion nebula M33. To obtain his
photographs, Hubble used Mount Wilson's 100-inch telescope. Once
he had located the variables and determined their periods and
apparent magnitudes, he used Leavitt's period-luminosity
relationship to determine their distances. He concluded that the
great spiral Andromeda Nebula is roughly 900,000 light-years
away, a fantastically large distance, placing it clearly outside
our own galaxy and proving that, in general, galaxies are
islands in the universe. To allow for interstellar absorption,
Hubble's distance estimate had to be later reduced to roughly
750,000 light-years, a figure that stood until shortly before
Hubble continued to determine galactic distances and to study
galactic characteristics. By 1925 he had enough observations to
propose a scheme for their classification: he imagined
concentrated, very luminous, spheroidal galaxies to merge into
ellipsoidal ones, which in turn branched into "normal spirals"
on the one hand, and "barred spirals" on the other. Hubble
tended to avoid drawing evolutionary conclusions from his
scheme, but it was clearly very suggestive in that direction.
Furthermore, it proved invaluable in statistical studies of the
universe. At the time of his death, Hubble was attempting to
revise his scheme in order to make it more complete.
In the late 1920s Hubble laid the observational groundwork for
the most spectacular astronomical discovery of this century: the
expanding universe. V. M. Silpher had, over a period of years,
made spectroscopic observations on tens of nebulae (galaxies)
which indicated, on the basis of the Doppler shifts recorded,
that these nebulae were receding from the earth at velocities
between roughly 300 and 1,800 kilometres per second. Hubble
realized the great importance of Silpher's observations for
cosmological theories and organized a plan for measuring both
the distances and (radial) velocities of as many galaxies as
possible, down to the faintest ones detectable with Mount
Wilson's 100-inch telescope.
While an assistant, M. L. Humason photographed galactic spectra
and analyzed the observed Doppler shifts. Hubble photographed
the galaxies themselves, searched for Cepheid variable stars,
and computed the distances to the galaxies. By 1929 Hubble had
distance data on Silpher's nebulae and announced what became
known as Hubble's law: the velocity of recession of a galaxy is
directly proportional to its distance from the earth. By the
early 1940s this law had been confirmed for galactic velocities
up to roughly 45,000 kilometres per second, corresponding to
galactic distances up to roughly 220 million light-years.
During the 1930s Hubble became more and more cautious over the
interpretation to be placed on the observed Doppler
displacements, preferring to refer to them by the neutral
(theory-free) term "red shifts." Thus, if at some future time
these red shifts were found to be due, not to recessional
velocity, but to some presently unknown physical law, the term
"red shift" could still be retained as a description.
After World War II Hubble devoted a great deal of time to
planning the research program of the 200-inch Hale telescope at
Mount Palomar; he was almost entirely responsible for conceiving
and executing the National Geographic Society-Palomar
Observatory Sky Survey carried out with the 48-inch Schmidt
telescope. He received many honours, including a number of
honorary degrees and medals, as well as membership in the
National Academy of Sciences and other honorary societies. For
his war research he received the Medal of Merit for 1946. In
1948 he was elected an honorary fellow of Queen's College,
Oxford. He died of a coronary thrombosis in San Marino, Calif.,
on Sept. 28, 1953. In 1990, NASA launched the Hubble Space
Telescope, which was named in his honuor.
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This web page was last updated on:
11 December, 2008