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Science Friday > Archives > 2001 > August > August 24, 2001:
Hour One: Astronomy and Astrophysics Update

There's a basic number in nature approximately equal to 1 divided by 137. The number is so basic that physicists just call it 'alpha'. It's obtained by dividing the square of the charge of the electron by the product of Planck's constant and the speed of light. It's not supposed to change.

But now some scientists are saying that number, also known as the fine structure constant, might not be a constant after all. It may have changed slightly as the universe has evolved - shifting by about one part in 100,000 over some 12 billion years. In this hour of Science Friday, we'll talk about what that finding, if true, might mean for other laws of the universe.

We'll also find out about the discovery of a solar system 51 light-years from Earth that reminds some astronomers a little bit of our own home. The system has at least two planets, orbiting the system's star in nearly circular orbits. We'll talk about how those planets were spotted, and what their presence might mean.

Call in with your comments and questions at 1-800-989-8255, and share your opinions online in our Listeners' Lounge (registration required).

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Guests:
Debra Fischer
Post-Doctoral Fellow
Department of Astronomy
University of California, Berkeley
Berkeley, California

Mario Livio
Author, "The Accelerating Universe : Infinite Expansion, the Cosmological Constant, and the Beauty of the Cosmos" (John Wiley and Sons, 2000)
Head, Science Division
Space Telescope Science Institute
Baltimore, Maryland

Christopher Churchill
Graduate Faculty and Research Associate
Department of Astronomy and Astrophysics
Penn State University
State College, Pennsylvania

Books/Articles Discussed:

The Accelerating Universe: Infinite Expansion, the Cosmological Constant, and the Beauty of the Cosmos by Mario Livio. John Wiley and Sons, 2000. abstract astro-ph/0012539 (find more SciFri books here)

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Related Links:
Where to find 47 Ursae Majoris (click on 'Sky Locator' for directions)

What is the fine-structure constant?
A Constant that Isn't Constant
Introduction to the Fundamental Physical Constants
The University of California Planet Search Project
Prowling for Planets - page 1
Extrasolar Planets Encyclopaedia

This segment produced by: Charles Bergquist