SciAm: Star physicists trade barbs over cosmological model

Find out the latest thinking about our universe.
Post Reply
User avatar
bystander
Apathetic Retiree
Posts: 21571
Joined: Mon Aug 28, 2006 2:06 pm
Location: Oklahoma

SciAm: Star physicists trade barbs over cosmological model

Post by bystander » Fri Apr 30, 2010 5:00 pm

Star physicists trade barbs over cosmological model
Scientific American: Observations - 30 April 2010
A tony social club in midtown Manhattan is not the place one might expect to find a verbal sparring match between famous physicists. But that was the case April 23 at the Harmonie Club, when Alan Guth and David Gross had a feisty off-the-cuff debate about Guth's model for the dawn of the universe. Perhaps in keeping with their genteel surroundings, the two kept their jabs mostly playful, but a few may have stung nonetheless.

The exchange took place at a physics symposium hosted by the City College of New York (CCNY) at which both Guth and Gross gave lectures. Guth, a physics professor at the Massachusetts Institute of Technology renowned for his role in developing the concept of cosmological inflation in the early 1980s, had just given brief remarks introducing some of the concepts he would cover in a later lecture. Inflation holds that the entire observable universe began as a bubble that underwent extremely rapid growth, doubling in size every 10–37 second, before a more gentle expansion took over. Many of its predictions mesh well with precision measurements taken by probes such as NASA's WMAP spacecraft, making inflation one of the leading—if not the leading—explanation for what went on in the very early universe.

The model implies that although inflation came to an end billions of years ago in our local universe, it continues apace beyond our cosmic horizon and will for eternity. Our bubble, then, is just one of many—a universe within a multiverse—each of which might have its own laws of physics. As such, Guth said, the parameters of our physical world might be nothing more than a historical accident. That did not sit well with Gross, who earned a share of the 2004 Nobel Prize in Physics by exploring those parameters, unwinding the dynamics of the strong force that binds quarks together in protons and neutrons.

"In reaction to that last talk—oy vey," said the Israel-educated Gross, who directs the Kavli Institute for Theoretical Physics at the University of California, Santa Barbara. (He also sits on Scientific American's board of advisers.) Gross called Guth's concept of eternal inflation somewhat speculative, noting that if other universes do exist, they are causally disconnected from ours—"every goddamn one of them." As such, Gross added, talk of other universes "does bear some resemblance to talking about angels."

Post Reply