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Our Place in the Universe
Editor's Note: This is the 13th in a series of essays
on exploration by Steven J. Dick.
In one of
his Four Quartets titled "Little Gidding," T. S. Eliot wrote
We shall
not cease from exploration
And the end of all our exploring
Will be to
arrive where we started
And know the place for the first time.
Eliot did not have space exploration in mind (the lines were written in
1942), but the sentiment poetically captures one of the most important reasons
we explore space. NASA's exploration of the universe, and that of other nations,
reveals humanity's place in nature in the broadest possible sense. That view of
ourselves has changed dramatically over the last century. One hundred years ago
most astronomers considered the universe to be about 3600 light years in extent,
less than a billion years old, and with our solar system near its center.
Astronomers today have seen objects 13 billion light years away in a universe
13.7 billion years old containing hundreds of billions of galaxies. We are
peripherally located in one of those galaxies, known as the Milky Way.
Cosmic evolution is depicted in this
image from the exobiology program at NASA Ames Research Center, 1986. Cosmic
evolution begins (upper left) with the formation of stars and planetary systems,
proceeds (bottom) to primitive and complex life, and culminates with
intelligence, technology and astronomers (upper right) contemplating the
universe.
Nothing, however, has been more revolutionary than the
idea that this entire universe is in a state of constant change, as planets,
stars and galaxies are born and die. This story of the life of the universe, and
our place in it, is known as cosmic evolution. Although the idea has roots in
the 19th century, and was occasionally invoked in the first half of the 20th
century by astronomers such as George Ellery Hale, it really came into its own
only in the Space Age.
Already in 1958, in his classic book Of Stars
and Men, Harvard College Observatory Director Harlow Shapley wrote that the
Earth is "on the outer fringe of one galaxy in a universe of millions of
galaxies. Man becomes peripheral among the billions of stars in his own Milky
Way; and according to the revelations of paleontology and geochemistry he is
also exposed as a recent, and perhaps an ephemeral manifestation in the
unrolling of cosmic time."
In his 1967 essays Beyond the
Observatory, Shapley wrote that "Nothing seems to be more important
philosophically than the revelation that the evolutionary drive, which has in
recent years swept over the whole field of biology, also includes in its sweep
the evolution of galaxies and stars, and comets and atoms, and indeed all things
material."
Cosmic evolution has become the guiding principle for modern
astronomy. The science programs of the world's space agencies may be seen as
filling in the details in this story of the life of the universe. Indeed, the
very idea was spread during the 1970s and 1980s by NASA's Search for
Extraterrestrial Intelligence (SETI) program, and NASA's broader astrobiology
efforts, discussed in the last essay, constitute its biological
component.
Especially for the last decade, NASA's Origins program has had
cosmic evolution as its overarching epic story. When the program began in 1996,
it was viewed as "Following the 15 billion year long chain of events from the
birth of the universe at the Big Bang, through the formation of chemical
elements, galaxies, stars, and planets, through the mixing of chemicals and
energy that cradles life on Earth, to the earliest self-replicating organisms -
and the profusion of life."
The array of Great Observatories (Hubble,
Compton, Chandra and Spitzer), along with many other spacecraft, have provided
an ever more robust view of cosmic evolution and the place of our pale blue dot
and its inhabitants. There are also theoretical underpinnings to the idea. In
his book Cosmic Evolution: The Rise of Complexity in Nature, Eric
Chaisson describes the concept from the all-encompassing point of view of
thermodynamics and the flow of energy.
Cosmic evolution has several
possible outcomes. Its endpoint may be planets, stars and galaxies. We observe
these and know they exist, and the result is what we might call the "physical
universe," magnificent in and of itself. Alternately, cosmic evolution may
result in a profusion of life, either microbial or intelligent, throughout the
universe. This outcome, the Holy Grail of SETI and astrobiology programs around
the world, would constitute a "biological universe." A third possible outcome,
rarely discussed, is a universe in which cultural evolution is taken into
account.
If, as is often assumed, intelligent life is millions or
billions of years old, cultural evolution may have resulted in a "postbiological
universe," in which flesh and blood intelligence has been superseded by
artificial intelligence. Carnegie Mellon AI pioneer Hans Moravec has famously
postulated a postbiological Earth in the next few generations. Given the time
scales of the universe, its seems much more likely to have already happened in
outer space.
All of these outcomes have implications for human destiny.
It may be our destiny to populate the universe, or to interact with its
flesh-and-blood intelligence in many forms. Or, in the postbiological universe,
we may have to interact with machine intelligence. But there are more immediate
implications. Sir Arthur Peacocke, a British biochemist and Anglican priest, has
called cosmic evolution "Genesis for the Third Millennium," and suggested that
it must be incorporated into religious doctrines. Reverend Michael Dowd has
taken that sentiment to heart in a DVD called "Evolutionary Christianity," in
which he incorporates "the entire history of the universe and the emergent
complexity of matter, life, consciousness, culture and technology," in short,
the epic of cosmic evolution.
In both space and time the study of cosmic
evolution allows us to see the universe as it really is, to reflect on our place
in it, and to "know the place for the first time." Space programs may often seem
bogged down in technical details, politics and funding controversies. But we
should not lose sight of the longer term implications. Although its practical
benefits are many, space exploration has no higher calling than this search for
our place in the universe.
Further Reading:
Eric Chaisson.
Cosmic Evolution: The Rise of Complexity in Nature (Harvard University
Press: Cambridge, Mass., 2001).
Steven J. Dick, "Extraterrestrial Life
and our Worldview at the Turn of the Millennium," Dibner Library Lecture, Smithsonian Institution Libraries, May 2,
2000.
Steven J. Dick, "Cultural Evolution, the Postbiological Universe
and SETI," International Journal of Astrobiology, 2 (2003), 65-74.
Dowd, Michael, "Evolutionary Christianity," DVD, described at
www.evolutionarychristianity.org.
Hans Moravec, Mind Children: The
Future of Robot and Human Intelligence (Harvard University Press: Cambridge,
Mass., 1988).
Arthur Peacocke, "The Challenge and Stimulus of the Epic
of Evolution to Theology," in Steven J. Dick, Many Worlds: The New Universe,
Extraterrestrial Life and the Theological Implications (Templeton Foundation
Press: Philadelphia and London, 2000), pp. 89-117.
Harlow Shapley,
Beyond the Observatory (Charles Scribner's Sons: New York, 1967)
Harlow Shapley, Of Stars and Men: The Human Response to an Expanding
Universe (Beacon Press: Boston, 1958).
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