WHEN SCIENTISTS RECEIVE QUACK LETTERS, they arrive bearing certain characteristic trademarks. They tend to be written in longhand, with pencil, the pages covered with smudges, stains, and inscrutable cabalistic symbols, as if the writer were originally from the planet Weebo.
The author invariably claims to have spotted a hitherto-unnoticed flaw in Einstein’s theory of relativity. For the greater good of humanity, he humbly offers to correct it, proposing a melange of previously unknown forces, particles, energy fields, and, commonly enough, flocks of hidden dimensions, which have somehow escaped the attention of generations of scientists.
Today’s cosmologists might use computers instead of pencils, but otherwise their latest theories bear a suspicious resemblance to the World Classics of Crackpottery. Consider, for example, a briefing held last May at NASA headquarters in Washington, D.C., broadcast live to NASA centers around the country and Webcast over the Internet. The stage of the James E. Webb Auditorium, tucked away in a glassy, modern building a few blocks from the National Mall, is ablaze with light and crawling with television cameras, monitors, microphones, and crew members, as if this were the 400,000th “Oprah” show. Instead, it’s the latest episode of what might be called the Dark Matter/Dark Energy Follies, a series in which a bunch of astrophysicists repeatedly confess that they no longer fathom the universe it is their sworn duty to understand and explain.
“You would think by now scientists would know what the universe is made of,” says Andy Fabian of Britain’s University of Cambridge. “But we don’t.”
“This is the most profound problem in all of science,” says Michael Turner of the National Science Foundation. The most probable solution, he says with a grin, “is almost too bizarre to be true.”
The problem confronting them, however, is simple enough: The expansion of the universe, discovered by Edwin Hubble in 1929, is not slowing down, as astronomers had long thought, but rather speeding up.
The acceleration of the universe’s expansion is a minor catastrophe for astrophysics because for the last half-century or so, theorists had been supposing that the mutual gravitational attraction exerted by all the matter in the universe would be sufficient to decelerate, and perhaps halt or even reverse, the expansion. The most recent observations, however, indicate that just the opposite is happening. The cosmos is flinging itself apart, almost as if gravity no longer exists, or has changed direction, or has been overpowered by some sort of nouveau anti-gravitational, repulsive force.
As if this were a bad horror movie, the force in question has been named “dark energy,” a term coined by Michael Turner. Approximately 75 percent of the universe appears to be made of the stuff. “It’s the most important thing out there,” says Andy Fabian. It is, he thinks, a form of anti-gravity: “It’s like throwing an apple into the air and having it accelerate upward.”
“Only really weird things have repulsive gravity,” says Turner.
To address the problem, astrophysicists have rushed in with a succession of “really weird things” that dark energy could be made of. They’ve proposed exotic new particles such as axions, accelerons, and, jokingly, “bigons.” They’ve proposed strange new force fields and mysterious forms of energy such as quintessence, k-essence, phantom energy, and negative kinetic energy—whatever that is. And they’ve proposed various scenarios for the end of the universe at large: a Big Crunch (a grand cosmic collapse) if dark energy weakens, or a Big Rip (where the cosmos is out of here) if it strengthens.