Dr. Lynch, the Stanford physicist, has calculated that clouds, pollutants and atmospheric distortions could sap most of a laser beam's power.

"I think this is as bad as it's ever been," said Wolfgang H. K. Panofsky, a retired Stanford physicist who has advised the government on science and national security since the Eisenhower administration.

Leonard Susskind, a Stanford theoretical physicist, who called these entanglement experiments "beautiful and surprising," said the term "spooky action at a distance," was misleading because it implied the instantaneous sending of signals.

"He is a person of such will, such intellectual strength," said Dr. Andrei Linde, a Stanford physicist who met Dr. Hawking in Moscow in the late 1970's.

Sidney D. Drell, a Stanford physicist and Clinton Administration adviser, writing in "China Builds the Bomb" (Stanford University Press, 1988), called the feat "enormously impressive."

Since then, Obama has appointed a Harvard alumnus as education secretary, a Nobel-prize winning Stanford physicist as energy secretary, and a handful of Harvard law school classmates.

(The theory is notably championed by another Stanford physicist, Andrei Linde.)

But for now the Stanford physicists will be satisfied to get this collider running.

How many times depends on "what you mean by canceled," said Dr. C. W. Francis Everitt, a Stanford physicist who joined the project in 1962 and is now its leader.

In one version, invented by Leonard Susskind, a Stanford physicist, all the information that ever fell into a black hole is encoded on the horizon as a dense web of hypothetical entities called strings.