STEPHEN HAWKING WILL GO ZERO-G:

On April 26, Dr. Hawking, surrounded by a medical entourage, is to take a zero-gravity ride out of Cape Canaveral on a so-called vomit comet, a padded aircraft that flies a roller-coaster trajectory to produce periods of weightlessness. He is getting his lift gratis, from the Zero Gravity Corporation, which has been flying thrill seekers on a special Boeing 727-200 since 2004 at $3,500 a trip.

Peter H. Diamandis, chief executive of Zero G, said that “the idea of giving the world’s expert on gravity the opportunity to experience zero gravity” was irresistible.

In some ways, this is only a prelude. Dr. Hawking announced on his 65th birthday, in January, that he hoped to take a longer, higher flight in 2009 on a space plane being developed by Richard Branson’s company Virgin Galactic, which seeks to take six passengers to an altitude of 70 miles.

Dr. Hawking says he wants to encourage public interest in spaceflight, which he believes is critical to the future of humanity. . . . “Life on Earth,” he said, “is at the ever-increasing risk of being wiped out by a disaster, such as sudden global nuclear war, a genetically engineered virus or other dangers we have not yet thought of.”

He and I are in agreement on that.