January 29, 2011

Panek speaks on dark matter and dark energy

“It’s 1610 all over again,” says author Richard Panek about the scientific revolution that is occurring in astronomy and physics over the universe’s dark mysteries. Panek, who wrote The 4 Percent Universe: Dark Matter, Dark Energy, and the Race to Discover the Rest of Reality, gave a talk Tuesday evening at Town Hall Seattle.

Panek is a storyteller, not a scientist, and the book is a history of how scientists came to believe in these two mysterious dark forces, and what they’re doing to figure it all out.

Four Percent UniverseHe related an amusing anecdote from a recent book signing, at which the cashier at the table read the front flap of the book jacket and exclaimed, “That’s crazy!”

“That’s just about the right response,” Panek said. “That’s the response that I had 10 years ago when I heard people talking about this dark matter and dark energy problem in the universe, and that most of what we thought we knew of the universe for thousands of years is only about four percent of the matter and energy that’s actually out there.”

He originally found the notion too wild to be true, but eventually became a believer.

“The more I looked at it, the more I saw that people in the sciences were trying to knock down these ideas, and they weren’t able to do so,” Panek said. “In fact, they were refining the information and the data in such a way that they were becoming more and more convinced. And as they were becoming convinced, of course I was becoming convinced, and I thought this is really something revolutionary.”

Panek read several sections of the book, including part of the story of the work of astronomer Vera Rubin on galaxy motion that ultimately suggested dark matter. More amusing was a battle between physicists and astronomers in the 1990s as they struggled to come up with a notion of dark energy. The physicists thought the astronomers were encroaching on their turf, and the astronomers felt the physicists didn’t know astronomy. Then a funny thing happened. Both sides reached the same conclusions at the same time and reported them to a skeptical scientific community.

“Part of the reason the community believes them is because these two teams that hated each other so much both came up with this counter-intuitive answer,” Panek said. “If only one of them had, it would have been dismissed, but because both of them had, they had to take it seriously.”

Panek said scientists came up with the percentages by running millions of computer simulations and comparing the results to the observed cosmic microwave background. A universe of 73 percent dark energy, 23 percent dark matter, and four percent for what we can actually see matches well with the observations.

“This is the evidence that astronomers and physicists have found compelling,” he said. “They have this computer simulation, they have this observation, and the two match. The problem, though, is that they don’t know what this 96 percent is.” Panek calls that “the biggest puzzle in physics.”

“It’s going to require reconciliation of the physics of the very small, the quantum level world, and physics of the very big, the general relativity view,” he said. “You have to figure out some way to make those two match.”

The talk, given to a full house at Town Hall Seattle, was well received. The 4 Percent Universe: Dark Matter, Dark Energy, and the Race to Discover the Rest of Reality, which grew out of a 2007 article published in the New York Times Magazine, should be an interesting read for those who love science, especially its history.

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