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"Innumerable suns exist; innumerable earths revolve
around these suns in a manner similar to the way the seven planets
revolve around our sun. Living beings inhabit these worlds."
from
On the Infinite Universe and Worlds, Giordano Bruno, 1584
May 21, 1999: When astronomers recently announced the
discovery of a new
planetary system, the greatest dangers they faced were the
ones that come with fame in the Information Age: calls from the
press, web pages to edit, and speeches to deliver. Nowadays discovering
planets is a tiring business, but relatively safe as jobs go.
 Four
hundred years ago the search for life among the stars was considerably
riskier. Consider, for example, the strange case of Giordano
Bruno, who could be considered one of the Western World’s
first astrobiologists.
Right: An engraving of Giordano
Bruno, c. 1580-1600
Bruno is regarded by many Renaissance scholars
as a forerunner, if not a founder, of modern science and philosophy.
Many credit him with greater influence in his day than better
known Italian philosophers who were his contemporaries, including
Copernicus.
 Renowned for his
gifts of memory, Bruno memorized vast amounts of text, whether
written in Italian, English, French or German. One of his amusements
was an abstract model of the solar system itself and a mnemonic
wheel, The Memory Wheel, having a circular shape with 7 concentric
layers like the orbits of the 7 known planets of the time.
Bruno's extraordinary skill in the art of memory attracted the
attention of patrons, and he was brought to Rome to demonstrate
his abilities to the Pope. Later, thanks to his unorthodox tendencies
and outspoken nature, he also attracted the attention of the
Inquistion in Naples. In 1576 he left to escape persecution.
When the same thing happened in Rome, he began a 15 year journey
across Europe, teaching and writing under the sponsorship of
various patrons.
No Labor Entirely Lost
While excommunicated to England, he is largely credited with
inspiring the character Berowne in one of William Shakespeare’s
first London plays, "Love’s Labor’s Lost."
In the story, Berowne was a sharp-witted attendant of King Ferdinand
who pledged to devote himself to study for a period of three
years without the intrusion of such physical pleasures as adequate
sleep, enough food, or the company of women. When "Lost"
first played, Bruno had already lived in London for two years.
Scientifically, Bruno advocated a radical view of a universe
extending everywhere in all directions, echoing what later would
become a detailed mathematical theory and Einstein’s special
relativity:
‘There is no absolute up or down, as Aristotle taught; no
absolute position in space; but the position of a body is relative
to that of other bodies. Everywhere there is incessant relative
change in position throughout the universe, and the observer
is always at the center of things."
But for many, Bruno is considered the first Westerner to publish
a position that entertained the possibility for not only the
Earth as a planet orbitting around a sun, but for many such planets
harboring conditions compatible with life.
A single sentence summarized his outcast life that crossed with
the then prevailing view, until he himself was caught in the
cross-hairs of a different and dangerous kind of sentence---death
by burning.
"Innumerable suns exist; innumerable earths revolve
around these suns in a manner similar to the way the seven planets
revolve around our sun. Living beings inhabit these worlds."
from
On the Infinite Universe and Worlds, published in 1584
In 1591, in Venice, he was arrested by the Inquisition and
tried. For eight years he was imprisoned and eventually declared
a heretic. Bruno was burned at the stake on the Campo dei Fiori
in Rome, Feb. 17, 1600.
Accused for his views including ideas that now would be called astrobiology,
the defiant Bruno answered the pronounced sentence of death by
fire: "Perhaps you, my judges, pronounce this sentence against
me with greater fear than I receive it."
 Right:
Family Portraits of other possible solar systems, along with
our own, courtesy of Astronomy Picture of the Day. The
figure shows the sizes and planet-star separations for our own
solar system, and the systems thought to be around stars 51 Peg,
70 Vir, and 47 UMa, each of which are normal "main sequence"
stars like our Sun. More
information
Nearly 400 years after Bruno's execution, the fast-paced discovery
of new solar systems makes his own sentence resonate in time
as something more than just a labor lost. In only four years,
more than 20 giant planets have been found orbiting nearby suns.
Some are within the "habitable zones" of their stars,
i.e., within a range of orbital distances where water could exist
and, presumably, life could flourish. Conventional wisdom has
it that gas giants like Jupiter are unlikely abodes for life,
but their moons may be a different story. In the solar system
astronomers have found that the larger the gas giant is, the
more mass there will be in its system of moons. If this holds
true for other solar systems, then some of the newly discovered
planets which are many times more massive than Jupiter could
have moons as large as Mars.
Do these moons exist? Are they Earth-like? No one knows, but
Giordano Bruno thought he had the answer 4 centuries ago.
 "Innumerable suns exist..."
There are several hundred billion stars in the Milky Way galaxy
alone.
"...innumerable earths revolve around these suns in a
manner similar to the way the seven planets revolve around our
sun." The recent discovery of 3 planets around Upsilon
Andromedae makes this assertion seem more likely than ever.
"Living beings inhabit these worlds." The proliferation
of life in the Universe remains a tantalizing mystery. Will Bruno
be vindicated once again? Only time will tell.
Above: Diagram of the newly-discovered
planetary system in Upsilon Andromedae, with planets labeled
"b," "c," and "d." The size of
the red dot is related to the size of the planet. For comparison,
the orbits of Mercury, Venus, Earth, and Mars are shown as dotted
circles. One AU is the distance from the Earth to the Sun, approximately
93,000,000 miles (149,000,000 km.) More
information
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