Science

Large Hadron Collider: Blue earth safe from black holes

by William Atkins

Thursday, 26 June 2008

Page 3 of 3

Their conclusion is (with bolded text added for emphasis):

“We recall the rates for the collisions of cosmic rays with the Earth, Sun, neutron stars, white dwarfs and other astronomical bodies at energies higher than the LHC. The stability of astronomical bodies indicates that such collisions cannot be dangerous.”

“Specifically, we study the possible production at the LHC of hypothetical objects such as vacuum bubbles, magnetic monopoles, microscopic black holes and strangelets, and find no associated risks.”

“Any microscopic black holes produced at the LHC are expected to decay by Hawking radiation before they reach the detector walls. If some microscopic black holes were stable, those produced by cosmic rays would be stopped inside the Earth or other astronomical bodies. The stability of astronomical bodies constrains strongly the possible rate of accretion by any such microscopic black holes, so that they present no conceivable danger.”

“In the case of strangelets, the good agreement of measurements of particle production at RHIC with simple thermodynamic models constrains severely the production of strangelets in heavy-ion collisions at the LHC, which also present no danger.”

(Strangelets, sometimes also called "strange nuggets," are theorized objects that consist of a bound state (several particles acting as one object) with generally equal numbers of up, down, and strange quarks.)

As reported by Science News, “Any black holes created at a new particle accelerator near Geneva will not make Swiss cheese of the nearby countryside. Nor will they gobble up Earth.” [Science News (subscription required): “Safe from black holes”]

Further information about the background of the LHC and the safety concerns people have had can be found at:

Ars Technica (by John Timmer): “Safety report: latest collider at CERN won't end the world”

About.com/Physics (by Andre Zimmerman Jones): “New CERN Safety Report - Still No Doomsday Scenario”

Timmer concludes (with bold text for emphasis), "Overall, it's hard to read this report and not wind up viewing the apocalyptic fears as simply being poorly thought through. It was striking how clearly the worries over the LHC have parallels to the fears over biotechnology, which came up during our recent interview with Carl Zimmer. There too, billions of years of natural experiments and decades' worth of scientific experiment should be informing our view of safety; for at least some segment of the public, that's not happening."

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