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Edwin Hubble Biography
Edwin Hubble was a man who changed our view of the Universe. In 1929 he
showed that galaxies are moving away from us with a speed proportional to
their distance. The explanation is simple, but revolutionary: the Universe
is expanding.
Hubble was born in Missouri in 1889. His family moved to Chicago in 1898,
where at High School he was a promising, though not exceptional, pupil. He
was more remarkable for his athletic ability, breaking the Illinois State
high jump record. At university too he was an accomplished sportsman playing
for the University of Chicago basketball team. He won a Rhodes scholarship
to Oxford where he studied law. It was only some time after he returned to
the US that he decided his future lay in astronomy.
In the early 1920s Hubble played a key role in establishing just what
galaxies are. It was known that some spiral nebulae (fuzzy clouds of light
on the night sky) contained individual stars, but there was no consensus as
to whether these were relatively small collections of stars within our own
galaxy, the 'Milky Way' that stretches right across the sky, or whether
these could be separate galaxies, or 'island universes', as big as our own
galaxy but much further away. In 1924 Hubble measured the distance to the
Andromeda nebula, a faint patch of light with about the same apparent
diameter as the moon, and showed it was about a hundred thousand times as
far away as the nearest stars. It had to be a separate galaxy, comparable in
size our own Milky Way but much further away.
Hubble was able to measure the distances to only a handful of other galaxies,
but he realised that as a rough guide he could take their apparent
brightness as an indication of their distance. The speed with which a galaxy
was moving toward or away from us was relatively easy to measure due to the
Doppler shift of their light. Just as a sound of a racing car becomes lower
as it speeds away from us, so the light from a galaxy becomes redder. Though
our ears can hear the change of pitch of the racing car engine our eyes
cannot detect the tiny red-shift of the light, but with a sensitive
spectrograph Hubble could determine the redshift of light from distant
galaxies.
The observational data available to Hubble by 1929 was sketchy, but whether
guided by inspired instinct or outrageous good fortune, he correctly divined
a straight line fit between the data points showing the redshift was
proportional to the distance. Since then much improved data has shown the
conclusion to be a sound one. Galaxies are receding from us, and one another,
as the Universe expands. Within General Relativity, the theory of gravity
proposed by Albert Einstein in 1915, the inescapable conclusion was that all
the galaxies, and the whole Universe, had originated in a Big Bang,
thousands of millions of years in the past. And so the modern science of
cosmology was born.
Hubble made his great discoveries on the best telescope in the world at that
time - the 100-inch telescope on Mount Wilson in southern California. Today
his name carried by the best telescope we have, not on Earth, but a
satellite observatory orbiting our planet. The Hubble Space Telescope is
continuing the work begun by Hubble himself to map our Universe, and
producing the most remarkable images of distant galaxies ever seen, many of
which are available via the World Wide Web.
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