The Cosmic Trickster Enigmatic Stephen Hawking Has A Ball With The Universe.

A combination elf, oracle and rock star, Cambridge University physicist Stephen Hawking makes waves in physics that other people ride.

So scientists listened when Hawking proposed in a technical talk Thursday at California Institute of Technology that the universe sprang from nothing into something in the shape of a wrinkly pea and that the universe can be both open and closed, depending on how you look at it.

In truth, few of the hundreds of Caltech techies who turned out to hear the great physicist’s talk probably understood exactly what he was talking about, according to Hawking’s longtime colleague, Caltech physicist John Preskill. But Hawking, like Albert Einstein - to whom he is frequently compared - has a habit about making outrageous proposals that turn out to be right. “He has a feel for what is the right answer,” Preskill said.

A blithe spirit trapped in a deflated body, Hawking communicates through a computer attached to a voice synthesizer. His disembodied voice booms out like the Wizard of Oz. He smiles easily, if awkwardly, his mouth stretching into wide grins, his eyes brighten with delight at his own jokes and puns.

This charming juxtaposition of genius and jokester attracted 2,500 people, including California Gov. Pete Wilson and media mogul Rupert Murdoch, for a Wednesday night public lecture at Caltech. Long lines of admirers snaked around the normally quiet campus. “It reminds me of the days when Einstein used to come here to speak,” said Ed Stone, director of the Jet Propulsion Laboratory.

On Thursday, Hawking granted a rare private interview to a few reporters - the first in the 25 years he’s been regularly visiting Caltech.

Hawking tackles the biggest problems in physics: the nature of space, the nature of time and the origin and fate of the universe.

Previously, he turned physics inside out when he showed that black holes, those voracious cosmic light swallowers, actually radiate energy.

Now, he seems to be saying that the long-standing controversy over whether the universe is closed, and will eventually collapse in on itself, or open, in which case it will expand forever, can be answered in both ways. The universe is open and closed, depending on how you slice it.

Until recently, Hawking firmly believed that the universe was closed. In other words, the space-time fabric of the universe is something like a sphere, only in four dimensions. A spherical universe starts with a Big Bang, expands to a maximum point, then starts contracting again, ending with a big crunch.

Hawking likes this kind of universe because it flows smoothly from nothing to something without any sharp tear in the laws of nature. He feels it’s an improvement over the standard big bang model, where universe blasts into being from an infinitely dense and infinitely small speck of space time, so concentrated that known ideas of physics almost certainly break down.

Hawking’s so-called no-boundary universe is finite but has no edges. Like the surface of the Earth, it has no beginning and no end. And it seemed, until now at least, that a no-boundary universe had to be closed.

But recently, said Hawking, he’s been forced to re-evaluate his views, based on “mounting evidence” for an open universe. Last week, for example, new measurements of exploding stars seemed to imply that the universe is expanding faster at its outer limits.

Such a universe would never collapse in a crunch but rather expand infinitely. Rather than a sphere, it would unfurl like an open horn. Ultimately, it dissipates into increasing disorder, spreading forever deeper into space and time.

Ironically, what powers such an expansion is the energy of the vacuum of space itself, which produces a repulsive force, pushing galaxies and stars farther apart. Einstein proposed the existence of such a negative pressure - which he called the cosmological constant - but later dismissed it as his “biggest blunder.”

Now Hawking seems willing to embrace Einstein’s idea for the first time. Or as he conceded, with typical whimsy, in his talk, “negative pressure is just tension, which is a common condition in the modern world.”

It’s actually not so difficult to imagine how the universe can be two contrary things at the same time. Such thinking has a long and established history in physics. For example, long-standing controversies over whether light was a wave or a particle were resolved through the discovery that light is both, wave and particle, depending on how you look at it.

In the same way, a higher dimensional universe could be shaped something like an ice cream cone. If you slice it horizontally, it looks like a circle, a closed universe. But if you sliced it vertically, you would get a parabola, an open universe.

Hawking proposed that this open-and-shut universe comes into being from nothingness in the form of a pea instanton - a particle of space and time. An instanton is not so much a thing, as an event, said Preskill.

Hawking called it a pea because it would not be perfectly spherical but rather distorted. This pea instanton, he said, could evolve into either an open or a closed universe.

In fact, he said, “there is a whole family of pea instantons.”

So why does it appear that our universe is open? Here, Hawking invoked another principle he has previously shunned: According to the so-called anthropic principle, the universe is the way it is to some extent because if it were otherwise, intelligent beings would not be here to ask such questions.