Parallel Worlds (2 page)

In many ways,
the P'an Ku myth mirrors a theme found in many other religions and ancient
mythologies, that the universe sprang into existence
creatio ex nihilo
(created from nothing). In Greek
mythology, the universe started off in a state of Chaos (in fact, the word
"chaos" comes from the Greek word meaning "abyss"). This
featureless void is often described as an ocean, as in Babylonian and Japanese
mythology. This theme is found in ancient Egyptian mythology, where the sun god
Ra emerged from a floating egg. In Polynesian mythology, the cosmic egg is
replaced by a coconut shell. The Mayans believed in a variation of this story,
in which the universe is born but eventually dies after five thousand years,
only to be resurrected again and again to repeat the unending cycle of birth
and destruction.

These
creatio ex nihilo
myths stand in marked contrast to
the cosmology according to Buddhism and certain forms of Hinduism. In these
mythologies, the universe is timeless, with no beginning or end. There are many
levels of existence, but the highest is Nirvana, which is eternal and can be
attained only by the purest meditation. In the Hindu
Mahapurana,
it is written, "If God created the world, where was He
before Creation? . . . Know that the world is uncreated, as time itself is,
without beginning and end."

These
mythologies stand in marked contradiction to each other, with no apparent
resolution between them. They are mutually exclusive: either the universe had
a beginning or it didn't. There is, apparently, no middle ground.

Today, however,
a resolution seems to be emerging from an entirely new direction—the world of
science—as the result of a new generation of powerful scientific instruments
soaring through outer space. Ancient mythology relied upon the wisdom of
storytellers to expound on the origins of our world. Today, scientists are
unleashing a battery of space satellites, lasers, gravity wave detectors,
interferometers, high-speed supercomputers, and the Internet, in the process
revolutionizing our understanding of the universe, and giving us the most
compelling description yet of its creation.

What is
gradually emerging from the data is a grand synthesis of these two opposing
mythologies. Perhaps, scientists speculate, Genesis occurs repeatedly in a timeless
ocean of Nirvana. In this new picture, our universe may be compared to a bubble
floating in a much larger "ocean," with new bubbles forming all the
time. According to this theory, universes, like bubbles forming in boiling
water, are in continual creation, floating in a much larger arena, the Nirvana
of eleven-dimensional hyperspace. A growing number of physicists suggest that
our universe did indeed spring forth from a fiery cataclysm, the big bang, but
that it also coexists in an eternal ocean of other universes. If we are right,
big bangs are taking place even as you read this sentence.

Physicists and
astronomers around the world are now speculating about what these parallel
worlds may look like, what laws they may obey, how they are born, and how they
may eventually die. Perhaps these parallel worlds are barren, without the basic
ingredients of life. Or perhaps they look just like our universe, separated by
a single quantum event that made these universes diverge from ours. And a few
physicists are speculating that perhaps one day, if life becomes untenable in
our present universe as it ages and grows cold, we may be forced to leave it
and escape to another universe.

The engine
driving these new theories is the massive flood of data that is pouring from
our space satellites as they photograph remnants of creation itself.
Remarkably, scientists are now zeroing in on what happened a mere 380,000 years
after the big bang, when the "afterglow" of creation first filled the
universe. Perhaps the most compelling picture of this radiation from creation
is coming from a new instrument called the WMAP satellite.

THE WMAP SATELLITE

"Incredible!"
"A milestone!" were among the words uttered in February 2003 by
normally reserved astrophysicists as they described the precious data
harvested from their latest satellite. The WMAP (Wilkinson microwave anisotropy
probe), named after pioneering cosmologist David Wilkinson and launched in
2001, has given scientists, with unprecedented precision, a detailed picture of
the early universe when it was a mere 380,000 years old. The colossal energy
left over from the original fireball that gave birth to stars and galaxies has
been circulating around our universe for billions of years. Today, it has
finally been captured on film in exquisite detail by the WMAP satellite,
yielding a map never seen before, a photo of the sky showing with breathtaking
detail the microwave radiation created by the big bang itself, what has been
called the "echo of creation" by
Time
magazine. Never again will astronomers look at the sky in
the same way again.

The findings of
the WMAP satellite represent "a rite of passage for cosmology from
speculation to precision science," declared John Bahcall of the Institute
for Advanced Study at Princeton. For the first time, this deluge of data from
this early period in the history of the universe has allowed cosmologists to
answer precisely the most ancient of all questions, questions that have puzzled
and intrigued humanity since we first gazed at the blazing celestial beauty of
the night sky. How old is the universe? What is it made of? What is the fate of
the universe?

(In 1992, a
previous satellite, the COBE [Cosmic Background Explorer satellite] gave us the
first blurry pictures of this background radiation filling the sky. Although
this result was revolutionary, it was also disappointing because it gave such
an out-of-focus picture of the early universe. This did not prevent the press
from excitedly dubbing this photograph "the face of God." But a more
accurate description of the blurry pictures from COBE would be that they
represented a "baby picture" of the infant universe. If the universe
today is an eighty-year-old man, the COBE, and later the WMAP, pictures showed
him as a newborn, less than a day old.)

The reason the
WMAP satellite can give us unprecedented pictures of the infant universe is
that the night sky is like a time machine. Because light travels at a finite
speed, the stars we see at night are seen as they once were, not as they are
today. It takes a little over a second for light from the Moon to reach Earth,
so when we gaze at the Moon we actually see it as it was a second earlier. It
takes about eight minutes for light to travel from the Sun to Earth. Likewise,
many of the familiar stars we see in the heavens are so distant that it takes
from 10 to 100 years for their light to reach our eyes. (In other words, they
lie 10 to 100 light-years from Earth. A light-year is roughly 6 trillion miles,
or the distance light travels in a year.) Light from the distant galaxies may
be hundreds of millions to billions of light-years away. As a result, they
represent "fossil" light, some emitted even before the rise of the
dinosaurs. Some of the farthest objects we can see with our telescopes are called
quasars, huge galactic engines generating unbelievable amounts of power near
the edge of the visible universe, which can lie up to 12 to 13 billion
light-years from Earth. And now, the WMAP satellite has detected radiation
emitted even before that, from the original fireball that created the universe.

To describe the
universe, cosmologists sometimes use the example of looking down from the top
of the Empire State Building, which soars more than a hundred floors above
Manhattan. As you look down from the top, you can barely see the street level.
If the base of the Empire State Building represents the big bang, then, looking
down from the top, the distant galaxies would be located on the tenth floor.
The distant quasars seen by Earth telescopes would be on the seventh floor. The
cosmic background measured by the WMAP satellite would be just half an inch
above the street. And now the WMAP satellite has given us the precise
measurement of the age of the universe to an astonishing i percent accuracy:
13.7 billion years.

The WMAP mission
is the culmination of over a decade of hard work by astrophysicists. The
concept of the WMAP satellite was first proposed to NASA in 1995 and was
approved two years later. On June 30, 2001, NASA sent the WMAP satellite aboard
a Delta II rocket into a solar orbit perched between Earth and the Sun. The
destination was carefully chosen to be the Lagrange point 2 (or L2, a special
point of relative stability near Earth). From this vantage point, the satellite
always points away from the Sun, Earth, and Moon and hence has a totally
unobstructed view of the universe. It completely scans the entire sky every six
months.

Its
instrumentation is state-of-the-art. With its powerful sensors, it can detect
the faint microwave radiation left over from the big bang that bathes the
universe, but is largely absorbed by our atmosphere. The aluminum-composite
satellite measures 3.8 meters by 5 meters (about 11.4 feet by 15 feet) and
weighs 840 kilograms (1,850 pounds). It has two back-to-back telescopes that
focus the microwave radiation from the surrounding sky, and eventually it
radios the data back to Earth. It is powered by just 419 watts of electricity
(the power of five ordinary lightbulbs). Sitting a million miles from Earth,
the WMAP satellite is well above Earth's atmospheric disturbances, which can
mask the faint microwave background, and it is able to get continuous readings
of the entire sky.

The satellite
completed its first observation of the full sky in April 2002. Six months
later, the second full sky observation was made. Today, the WMAP satellite has
given us the most comprehensive, detailed map of this radiation ever produced.
The background microwave radiation the WMAP detected was first predicted by
George Gamow and his group in i948, who also noted that this radiation has a
temperature associated with it. The WMAP measured this temperature to be just
above absolute zero, or between 2.7249 to 2.7251 degrees Kelvin.

To the unaided
eye, the WMAP map of the sky looks rather uninteresting; it is just a
collection of random dots. However, this collection of dots has driven some
astronomers almost to tears, for they represent fluctuations or irregularities
in the original, fiery cataclysm of the big bang shortly after the universe
was created. These tiny fluctuations are like "seeds" that have since
expanded enormously as the universe itself exploded outward. Today, these tiny
seeds have blossomed into the galactic clusters and galaxies we see lighting up
the heavens. In other words, our own Milky Way galaxy and all the galactic
clusters we see around us were once one of these tiny fluctuations. By
measuring the distribution of these fluctuations, we see the origin of the
galactic clusters, like dots painted on the cosmic tapestry that hangs over the
night sky.

Today, the
volume of astronomical data is outpacing scientists' theories. In fact, I
would argue that we are entering a golden age of cosmology. (As impressive as
the WMAP satellite is, it will likely be

dwarfed by the
Planck satellite, which the Europeans are launching in 2007; the Planck will
give astronomers even more detailed pictures of this microwave background
radiation.) Cosmology today is finally coming of age, emerging from the
shadows of science after languishing for years in a morass of speculation and
wild conjecture. Historically, cos- mologists have suffered from a slightly
unsavory reputation. The passion with which they proposed grandiose theories
of the universe was matched only by the stunning poverty of their data. As
Nobel laureate Lev Landau used to quip, "cosmologists are often in error
but never in doubt." The sciences have an old adage: "There's
speculation, then there's more speculation, and then there's cosmology."

As a physics
major at Harvard in the late 1960s, I briefly toyed with the possibility of
studying cosmology. Since childhood, I've always had a fascination with the
origin of the universe. However, a quick glance at the field showed that it was
embarrassingly primitive. It was not an experimental science at all, where one
can test hypotheses with precise instruments, but rather a collection of loose,
highly speculative theories. Cosmologists engaged in heated debates about
whether the universe was born in a cosmic explosion or whether it has always
existed in a steady state. But with so little data, the theories quickly
outpaced the data. In fact, the less the data, the fiercer the debate.

Throughout the
history of cosmology, this paucity of reliable data also led to bitter,
long-standing feuds between astronomers, which often raged for decades. (For
example, just before astronomer Allan Sandage of the Mount Wilson Observatory
was supposed to give a talk about the age of the universe, the previous speaker
announced sarcastically, "What you will hear next is all wrong." And
Sandage, hearing of how a rival group had generated a great deal of publicity,
would roar, "That's a bunch of hooey. It's war—it's war!")

THE AGE OF THE UNIVERSE

Astronomers have been especially keen to know the age of the
universe. For centuries, scholars, priests, and theologians have tried to
estimate the age of the universe using the only method at their disposal: the
genealogy of humanity since Adam and Eve. In the last century, geologists have
used the residual radiation stored in rocks to give the best estimate of the
age of Earth. In comparison, the WMAP satellite today has measured the echo of
the big bang itself to give us the most authoritative age of the universe. The
WMAP data reveals that the universe was born in a fiery explosion that took
place 13.7 billion years ago.