The Three Big Bangs
by Philip M. Dauber
Richard A. Muller
In this book we are going to ask you to imagine a series of events so violent, they dwarf the most vicious crimes that humans have committed against humans and the most horrible natural catastrophes that have taken place on Earth. Even the puniest of the three big bangs, the crashes of comets onto the Earth many millions of years ago, released a destructive energy greater than would be unleashed by simultaneous detonation of every nuclear weapon ever made. In fact, its energy would surpass such a nuclear holocaust by more than ten thousand times. The challenge to the reader of this book is to come to grips with these horrendous events. For only by understanding them can we really understand our origins.
In school we learn of biological evolution: how species competed with other species, often violently, until the weaker ones were eliminated. But in just the last decade, new discoveries have challenged this understanding of biological evolution. More remarkably, scientists have recently begun to understand our physical evolution, to the point that we can now speak in a meaningful way about the origins not only of our countries and our cells but of our very atoms. Perhaps most surprising, we are even beginning to understand the origins of the universe itself, which according to current theory involves the creation not of matter alone, but of space itself and maybe even of time.
The physical creation of the world we know is dominated by violence
-- violence on a scale so far beyond human dimensions that some consider
it impossible to imagine. In recent years we have begun to recognize that
the violence of nature is key to answering the otherwise impossibly difficult
question: How did we get here? Fascinating to both children and adults,
this question lies at the core of myths and religions in primitive and
advanced civilizations alike. Perhaps your parents told you, "We were
created by God." Even if this answer were literally true, it would
not be entirely satisfactory, because it doesn't explain how God
Scientists have often underestimated the role of large-scale sudden
violence in nature, for the simple reason that such events are so rare,
we have little experience with them. Their very infrequency means that
they are not part of our imagination. We are accustomed to thinking of
evolution, for example, as gradual. The evolutionary changes that Darwin
saw were slow, like the colors of surviving butterfly species that are
altered to match their changing environments. But more recently, two outstanding
paleontologists, great fans of Charles Darwin, have argued that the theory
of evolution may require a major overhaul. Stephen Jay Gould and David
Raup, renowned experts on early life and evolution, argue that the great
changes in species may have been driven less by day-to-day competition
than by extremely rare and violent events.
Our normal vocabulary is inadequate to name such destructive events.
For lack of a better phrase, we use the term originally applied to a particular
cosmological theory: big bang. (Fred Hoyle originally coined the
phrase to make fun of the new theory of his friend George Gamow.) For the
results of such events, however, we do have a name: We call them mass
extinctions, for most life-forms on earth are completely destroyed
by such events.
This book is about three big bangs. The first -- closest to the human
scale -- is the big bang that took place 65 million years ago. One day
without warning, a comet, or possibly an asteroid, smashed into the Earth,
forever changing life on our planet. The impact blasted out a giant crater
in the present-day Yucatan, in Mexico. The atmosphere, the oceans, forests,
and jungles were totally disrupted in ways that scientists are now busy
unscrambling. Dinosaurs and most other life- forms vanished, including
most existing mammals. But some mammals, our ancestors, survived and went
on to flourish. There have been many such biological catastrophes, but
the one best understood, thanks to a series of remarkable discoveries over
the last fifteen years, is this Cretaceous- Tertiary catastrophe.
To astrophysicists, the impact of a comet on Earth is a puny event --
tiny compared with that of a star that erupted 5 billion years ago, a cataclysm
even more important to our evolution in the sense of physical rather than
biological evolution. Where biologists ask "How did life arise and
become what it is today?" physicists ask how the matter we are made
of was created, how it changed over the aeons, and what forms it takes
When the first stars formed, you could not have found the atoms that
now make up your body, but you could have discovered their precursors buried
deep inside the stars. Many of these atoms were totally unrecognizable.
The iron of your present-day blood, for example, was not yet iron; mostly
it existed as hydrogen and helium. Unformed also were the carbon, nitrogen,
and oxygen in your organic molecules. In the next few billion years, the
nuclear forge of a star would cook hydrogen and helium, through thermonuclear
fusion, to create new atoms. But these atoms were still buried in the star.
In the second big bang, these atoms were created and ejected into space.
This big bang preceded the extinction of the dinosaurs by about 5- 10
billion years. With little warning, the star erupted, blasting the new
atoms over a region of space hundreds of light-years in size. It was a
supernova, and without it no life would have appeared in our part
of space, for none of the elements that make life possible would have been
present. From the ashes of this supernova a second star eventually coalesced,
a star that someday would be named the Sun by the two-legged creatures
whose bodies were formed from the atoms forged inside the supernova and
who now inhabit the small water- cloaked planet that formed near the Sun.
Our third big bang is the Big Bang, the one you read about in
the newspapers and science magazines and that long preceded the other two.
It was the ultimate explosion that involved all the energy of the universe,
the explosion that can never be exceeded, the violent event that dwarfs
all other violent events. Although the great scientist George Gamow originally
conceived this Big Bang as the event in which all the elements of the universe
were created, we now know that most of them, except for hydrogen and helium,
were created much later, inside stars.
The story of the Big Bang has evolved in ways that few people
could have foreseen more than forty-five years ago, when the idea was first
set forth. We now understand the Big Bang as the event in which hydrogen
and helium were created from more primitive particles -- and something
much more fundamental and mysterious as well. Here is a concept even more
jarring to our minds than the creation of all matter: The mindwrenching
idea that makes the Big Bang so fascinating is that it represented not
only the creation of matter within space but the creation of space itself.
And since the Big Bang was the creation of space, then by our current understanding
of relativity theory it may also have been the creation of time.
These great catastrophes played a role in our physical and biological
evolution that is only now being recognized. Scientists overlooked them
for a long time, we think, because catastrophes are rare events, very far
from our usual experience. They learned to explain continuous change with
the mathematics of Newton and his successors. But now in the late twentieth
century, with all other explanations exhausted, scientists finally stretch
their minds to calculate the unimaginable. Catastrophe is at the forefront
of science today because it is a mystery left over from the triumphs of
science through the mid-twentieth century. (Chaos is another such mystery.)
Much more difficult to understand than Newtonian mathematics, catastrophe
has been left for us to unravel now.
The authors of this book have had the wonderful privilege of being able
to research each of the three big bangs. ("Our research has been one
catastrophe after another," we sometimes joke.) Although the three
big bangs may not seem to have much to do with each other, they do. The
strongest link tying them together is their deep shared relevance to the
roots of all life on Earth. When we study the comet impact, the supernova,
and the Big Bang, we are studying our common history, our truly ancient
history. What has drawn us to all of these events is a deep desire to find
out where we came from.