Tuesday, February 28, 2006

Brian Greene on space and time

Tonight at the Spark speaker series, Brian Greene walked us through some exciting developments in the scientific understanding of our universe.

Space and time are the most compelling of scientific ideas because "we experience them, constantly." Yet scientists still struggle with what space and time are, and what if anything they mean to the universe's existence. To help us comprehend space and time, Dr. Greene provided an overview of some pivotal moments in scientific history.

Newton's laws of motion

First, we examined Isaac Newton's three laws of motion, developed in the 17th century. Newton viewed space and time as absolutes. In fact, his laws didn't mean anything absent a definition of space and a definition of time. A contemporary, Gottfried Liebniz, disputed Newton's certainty about the absoluteness of space and time. And yet Newton's laws remained generally accepted for at least the next two centuries.

Einstein's theory of relativity

Then in the early 20th century, Albert Einstein "came to very different conclusions." Einstein devoted 10 years to understanding how gravity works, and his theory of relativity postulated that space and time are not absolute. Instead, Einstein argued, gravity affects space and time. In terms of cosmology, "an object like the sun, merely by its presence in the fabric of space, deforms that space." Yet space and time are interconnected.

Quantum mechanics and Heisenberg's uncertainty principle

But then quantum mechanics began to pose problems. Werner Heisenberg's uncertainty principle states that the smaller you go, the bigger the uncertainty. What appears placid on the surface may instead be rent by "quantum jitters." The result is that if space and time are real, then they are subject to quantum uncertainty.

Einstein's theory of relativity does a great job of describing space and time on a large scale. Heisenberg's uncertainty principle does a great job of describing space and time on a microscopic scale. Yet the two laws seem unable to coexist peacefully.

String theory: a unifying theory?

String theory may address the gap between Einstein and quantum mechanics. Dr. Greene warned that string theory is "an unproven theory — I need to stress that."

Strings may be the fundamental building block of all matter. These strings vibrate in patterns, and different vibrations give rise to different particles. If true, then string theory reduces the jitteriness of space postulated by Heisenberg's uncertainty principle. It "allows quantum mechanics and general relativity to come together."

Yet string theory requires three fundamental changes in our understanding of space and time. First, there are more dimensions than previously believed — specifically, 10 instead of the 3 we currently are able to see. Second, space can rip. And third, our universe is created by one big slice of space that collides with another every trillion years or so.

Proving string theory

How can string theory be proven? One possibility is the Large Hadron Collider currently under construction in Geneva, Switzerland. While not as powerful as the Superconducting Super Collider once planned for Texas, the Swiss facility may be able to demonstrate the existence of gravitons, or the energy shed when two particles collide.

Scientists strive for the truth, no matter how difficult to obtain. String theory may or may not be correct, but it is at the forefront of today's scientific explorations of how space and time function in the universe.

Join the discussion

We would like to thank Dr. Greene and the audience for a fascinating exploration of space, time, and the universe.

What thoughts would you like to share? Do you find string theory a palatable explanation for how space and time operate in our universe?

Wednesday, February 15, 2006

Fabric of the Cosmos

Brian Greene will talk about his most recent book, The Fabric of the Cosmos, when he appears at the Spark speaker series on Feb. 28.
Space and time form the very fabric of the cosmos. Yet they remain among the most mysterious of concepts. Is space an entity? Why does time have a direction? Could the universe exist without space and time? Can we travel to the past?

Greene uses these questions to guide us toward modern science's new and deeper understanding of the universe. From Newton's unchanging realm in which space and time are absolute, to Einstein's fluid conception of spacetime, to quantum mechanics' entangled arena where vastly distant objects can bridge their spatial separation to instantaneously coordinate their behavior or even undergo teleportation, Greene reveals our world to be very different from what common experience leads us to believe. Focusing on the enigma of time, Greene establishes that nothing in the laws of physics insists that it run in any particular direction and that "time's arrow" is a relic of the universe's condition at the moment of the big bang. And in explaining the big bang itself, Greene shows how recent cutting-edge developments in superstring and M-theory may reconcile the behavior of everything from the smallest particle to the largest black hole. This startling vision culminates in a vibrant eleven-dimensional "multiverse," pulsating with ever-changing textures, where space and time themselves may dissolve into subtler, more fundamental entities.

(Excerpted from the publisher)

Reviews from around the country:

  • "…as dazzling as it is tough, and it beautifully reflects this theoretician's ardor for his work" (New York Times)

  • "…Greene reminds us, in many ways the profound mystery of the universe remains undiminished" (Discover magazine)

  • "…a profoundly original contribution to popular understanding not just of quantum theory, but of space-time, cosmology, the 'arrow of time', unification and the modern view of physical reality" (PhysicsWeb)

  • "…a wonderful book for the lay reader who wants to get a glimpse of what we theoretical physicists are thinking about" (American Scientist)

  • "…rewards the persistent reader with a panoramic vision of a vast and hidden universe" (Wired)

  • "Greene has a way of explaining things in terms that non-physicists can grasp" (Slashdot)

  • "One cannot help but feel more enlightened about our existence by better understanding the science behind it" (San Antonio Express-News)

  • "…with each chapter Greene unfolds layer after layer of physical reality that modern physics has discovered" (Curled Up with a Good Book)

Wednesday, February 01, 2006

Brian Greene trivia

Some interesting trivia courtesy of Wikipedia:
  • As a 5-year-old, Brian Greene was able to multiply 30-digit numbers
  • His math skills were so prodigious he began receiving private tutoring from a Columbia math professor at age 12
  • Greene earned his bachelor's from Harvard and his PhD from Oxford, where he was a Rhodes Scholar
  • He helped the actor John Lithgow with science-related dialogue for NBC's Third Rock from the Sun, and also made a cameo appearance in the 2000 film Frequency
Learn more in Wikipedia's entry on Brian Greene.