The universe. [CREDIT: colour-universe.de]
Brave New Universe: Illuminating the Darkest Secrets of the Cosmos
By Paul Halpern and Paul Wesson. Joseph Henry Press, 2006. $27.95
Since the extent of my knowledge of the cosmos comes from a college Astronomy course, I’ve been longing to know what scientists actually understand about the cosmos today. When I read on the flap of Brave New Universe that the book offers a “guided tour of current advances and controversies in cosmology,” I thought this would be a perfect place to begin my quest. I wasn’t disappointed—though laypeople like myself may have to read carefully at times to wrap their minds around some key concepts.
The book covers human knowledge of the cosmos from the early contributions of Kepler and Newton to Einstein’s theory of general relativity. The authors describe how technology has opened the doors to more advanced theories like quantum physics and string theory. Yet as we developed the tools to observe farther out into space or deeper into the makeup of atoms, our questions become more complicated—and thus harder to answer. The book’s later chapters delve into the strange realms of theoretical astrophysics, explaining the theories currently being pondered by the world’s most brilliant cosmologists to readers who can keep up.
The book begins with the questions that surrounded the theory of relativity when Einstein developed it in 1905. It goes on to cite the evidence that has led us to the solid conclusions we have today about our universe—such as how observations of starlight being bent by the sun’s gravity offered proof of general relativity, and how background radiation discovered by Bell Labs scientists Arno Penzias and Robert Wilson in 1965 is the most definitive evidence we have for the Big Bang.
The reader also learns that contributions from scientists Edwin Hubble and Alexander Friedmann have allowed us to discern that all the galaxies are fleeing from each other in an expanding universe whose geometry is flat, meaning it will expand forever. Through their work, we’ve also learned that the universe’s expansion is accelerating.
After readers learn how cosmologists have made substantial conclusions about the age of the universe (currently estimated at 13.7 billion years old) and its geometry, the authors tackle the latest challenges for the field: hitherto unanswered questions regarding dark matter, dark energy and the possibility of natural constants that fluctuate over time. Through the latter half of the book, the authors dive deeply into the world of theoretical astrophysics as it exists today, touching on concepts hard for a mere mortal to grasp.
For example, what if the constant of gravity is becoming weaker? What about the speed of light—has it always been the same? Scientists are investigating these questions in an attempt to account for the existence of dark matter and dark energy, the mysterious forces that make up a significant portion of the missing matter in the universe.
By the final chapters, the reader is swimming in string theory and its successor, M-theory, and is trying to digest the complicated notion about the existence of a fifth dimension expressed in terms of mass—an idea as hard to understand as a fourth dimension of time. As Astronomy-101 classes don’t cover concepts more complicated than the dimensions of space-time, many readers will have little basis for understanding such strange but fascinating ideas.
Yet the authors have done a decent job of remembering their non-cosmologist audience throughout the rest of the book. Halpern and Wesson bring characters like Kepler, Newton and Einstein to life, showing that they, too, were actively testing and revising their theories just like today’s string theorists. The book does a tremendous job of showing that cosmology is not a hard set of facts verified by their place in astronomy textbooks. Rather, it is an amorphous subject in need of constant rethinking and reworking based on our continuously expanding understanding of the universe (think of Pluto’s recent demotion from planet to dwarf planet).
We are also limited by our understanding, the authors say, since there is so much of the universe we still don’t know. “Photon by photon, we slowly drink in one particular type of cosmic energy, leaving us ample time to savor (and interpret) this brew,” Halpern and Wesson write. “As connoisseurs of such stellar ferment, we pride ourselves in our growing appreciation of what we sip. Yet we also realize that much lies in the bottom of the barrel, inaccessible to our tasting, and all this could have quite an alien flavor.”