23 Mar 1999
ATLANTA--The bizarre discovery that the cosmos may expand at an ever-increasing rate--hailed by Science as the "Breakthrough of the Year" for 1998--has won endorsement from an erstwhile skeptic, Stephen Hawking. The British astrophysicist told reporters today that data from distant supernova blasts have "led me to reconsider my theoretical preferences" about the cosmological constant, the unsettling repulsive force that would propel space itself to inflate more quickly with time.
"I now think it is very reasonable that there should be a cosmological constant," said Hawking, Lucasian professor of mathematics at the University of Cambridge. "I have had more time to consider the observations, and they look quite good." His comments came at a meeting here of the American Physical Society.
Hawking noted that we owe our existence to the cosmological constant's tiny value. He observed that M theory, an extension of string theory that Hawking called "the best candidate for a theory of everything," allows multiple universes to arise from an ever-churning quantum foam of space-time. Alternate universes with larger cosmological constants would prevent galaxies from coalescing, while those with zero or negative values might quickly collapse a budding cosmos in on itself. "We are observing one of the small number of universes suitable for intelligent life," he said.
Hawking, who suffers from Lou Gehrig's disease and cannot speak, had recorded answers submitted to him by reporters previously on his synthetic speech machine, and played them during the meeting. But in an extemporaneous session, he answered some questions directly, flashing his famous sharp tongue. Asked what historians will mark as the single greatest achievement of 20th century physics, he responded: "That is a ridiculous question. Physics is a unified corpus. You cannot isolate a single aspect." And for the intrepid soul who wondered whether Hawking expected time-travel or travel through other dimensions to occur in the next millennium, he had a quick smile and a ready response: "No."