SAFE AT ANY SPEED

The verdict was a unanimous “no.”

“I don’t believe there’s any such risk at any particle accelerator,” George W. Brandenburg, director of Harvard’s High Energy Physics Lab, wrote in an e-mail.

“I would say the risk is, for all intents and purposes, zero,” Huth added.

“I just don’t think it’s a concern,” Leverett Professor of Physics Gerald Gabrielse said in a telephone interview. “It should sell some books, though.”

If the conditions in RHIC could produce a strangelet disaster, physicists argue, then we would probably be dead already.

“[T]he concentration of the energy (which is what matters for creating new and exotic particles) achieved by RHIC is much less than what Tevatron has been doing for many years,” Associate Professor of Physics Masahiro Morii wrote in an e-mail, alluding to a federally-financed accelerator west of Chicago.

And the energy concentrators reached inside the Tevatron are child’s play on a cosmic scale. According to Morii, “the universe has its own ways of accelerating particles to energies that we experimental physicists can only dream of.”

Gabrielse said that high-energy collisions that could be produced inside RHIC already occur—naturally—on the lunar surface. “There have been highly energetic cosmic rays colliding with the moon for a long time, and these sorts of things don’t seem to have happened,” Gabrielse said.

To Posner’s credit, Catastrophe does anticipate Gabrielse’s counter-argument. Posner writes that “a cosmic ray hitting a fixed target such as the moon will tend to scatter the nuclei that it hits, making it less likely that they will clump”—and thus produce strange matter—“than if the collision were head on,” as it would be inside RHIC. So, the fact that the moon has existed for 4.5 billion years without condensing into a tiny ball does not necessarily refute Posner’s argument.

But Harvard physicists’ rejection of Posner’s calculation suggests the risk of catastrophe posed by RHIC might fall within a margin that most of us would be willing to tolerate.

YOUR MONEY OR YOUR LIFE

Americans seem willing to incur some costs in the name of science—as indicated by the fact that Congress is picking up RHIC’s $2 billion tab.

But how can we monetize the minimal risks to human existence posed by particle accelerators?