Big Bangs and Inflation

Seventeen years ago I heard a brainy adolescent ask the world’s most famous physicist a startling question. Today I know a little more about the answer.

It was July 3, 1993. Stephen Hawking, the renowned British scientist, was in Salt Lake City to speak at Abravanel Hall in a free public lecture sponsored by Geneva Steel and what was then Hansen (now Clark) Planetarium. Although a towering figure in science, Hawking is cruelly crippled by ALS. His body was emaciated and twisted, as if he were half-lounging in the motorized wheelchair that he controlled. His face and hair were youthful yet he had no muscle tone in his slack lower face. His hands were curved so that one was sort of backwards around the joystick that let him steer the wheelchair.

Robbed of nearly all mobility except in his smile and the finger with which he manipulated the chair and the computer-controlled voice synthesizer, he nevertheless radiated kindness and warmth.

Maybe that was why the youth, aged 13 almost 14, didn’t hesitate to question him. This was at a reception I covered for the Deseret News, held in the Salt Lake Art Center before his lecture. Many people were crowding around and taking pictures. A girl posed for a photo with Hawking, and soon afterward the youth asked him a cosmological question. He wanted to know, If there was one Big Bang, why couldn’t there have been several Big Bangs?

Just in case any reader doesn’t know, the Big Bang is considered the start of our universe, of space and time. A little less than 14 billion years ago a tiny amount of matter and energy suddenly came into existence and then expanded until the universe we know was formed. It’s still expanding.

Hawking was looking up at the boy from his chair and smiling with his sidewards grin. Otherwise, he didn’t seem to react. I thought he was ignoring him or had not heard. Then, after a few minutes, came his synthetic voice:

“There seems to have been only one in the region we can see. But there could be other Big Bangs in other regions,” Hawking replied. During that pause his finger had been forming the sentences on his computer.

“That was the real highlight for me,” I wrote in my journal that night. “The lecture was pretty far out, with ‘baby universes’ and superstring theory, but thoroughly enjoyable. Hawking has displayed real verve, energy, wit. Doug Lowe of the planetarium said he has been running the staff ragged. As soon as he arrived yesterday, he had them take him out to the Great Salt Lake, saying he wanted to see it since he was 12. Then he took the staff to a late show of Jurassic Park at Trolley Square. Then at 1 a.m. he was still up for more.”

[Stephen Hawking with Patrick Wiggins in July 1993. Photo courtesy of Wiggins, a NASA solar system ambassador to Utah]

*****

I remembered the visit with Hawking after watching a remarkable program Sunday night about cosmology. On the Utah Education Network’s Channel 9, Ogden, the program was an episode in the series called “Closer to Truth,” hosted by Robert Lawrence Kuhn. The series explores ideas about the cosmos, consciousness and God. “How Vast is the Cosmos” was the episode’s title, and it can be seen on the Internet at THIS SITE — it is well worth seeing.

The first interview is with Britain’s astronomer royal, Martin Rees, who explains how astronomers’ conception of the universe has expanded radically in the past 400 years – even in the past couple of decades. In 1905, he said, Albert Einstein would have said that the universe was our galaxy, the Milky Way. Other galaxies were considered mere nebulas within our own galaxy.

That changed with Edwin Hubble’s discovery in the 1920s that the Andromeda Galaxy is another enormous swarm of hundreds of billions of stars, just as the Milky Way is, said Max Tegmark, a cosmologist with the Massachusetts Institute of Technology, whom Kuhn also interviewed.

“But we now know … that our Milky Way galaxy is one of zillions of galaxies which we see with large telescopes,” Rees said. “You could imagine it going on infinitely.”

Rees added, “Some people think that our Big Bang’s just one of many, and there could be other big bangs” in other space and time, and even higher dimensions. “There could be another universe just a millimeter away from ours,” but we are unaware of it as it is measured in some fourth special dimension while our universe has just three.

Twenty-first century science is facing two great questions, according to the astronomer royal, as interviewed on the program.

“The first is, was our Big Bang the only one? We don’t know the answer to that. And the second is, if there were many big bangs, were they all replicas of each other or did they end up governed by different laws?”

Allen Guth, MIT, who proposed the inflationary theory that explains the expansion of the universe immediately after the Big Bang, told Kuhn that the universe is “a hundred billion trillion times” bigger than we can observe.

“The universe is just plain unbelievably big, even the observable universe,” Guth said on the program. But if inflation theory is right, “the observable universe is really only a tiny speck in a much bigger reality.” Inflation proposes a period of exponential expansion in the early universe, with successive redoubling, he added.

With the “unbelievably fast expansion,” the universe growing a hundredfold in the first microsecond, pocket universes may have formed. A single pocket universe, like our own, is “a piece of space that inflated together.” But there could be others, Guth said — maybe an infinite number.

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