Big Bang machine could destroy Earth
by Jonathan
Leake,
Sunday Times, July 18, 1999
A NUCLEAR accelerator designed to replicate the Big Bang is under investigation by
international physicists because of fears that it might cause "perturbations of the
universe" that could destroy the Earth. One theory even suggests that it could create
a black hole.
Brookhaven National Laboratories (BNL), one of the American government's foremost
research bodies, has spent eight years building its Relativistic Heavy Ion Collider (RHIC)
on Long Island in New York state. A successful test-firing was held on Friday and the
first nuclear collisions will take place in the autumn, building up to full power around
the time of the millennium.
Last week, however, John Marburger, Brookhaven's director, set up a committee of
physicists to investigate whether the project could go disastrously wrong. It followed
warnings by other physicists that there was a tiny but real risk that the machine, the
most powerful of its kind in the world, had the power to create "strangelets" -
a new type of matter made up of sub-atomic particles called "strange quarks".
The committee is to examine the possibility that, once formed, strangelets might start
an uncontrollable chain reaction that could convert anything they touched into more
strange matter. The committee will also consider an alternative, although less likely,
possibility that the colliding particles could achieve such a high density that they would
form a mini black hole. In space, black holes are believed to generate intense
gravitational fields that suck in all surrounding matter. The creation of one on Earth
could be disastrous.
Professor Bob Jaffe, director of the Centre for Theoretical Physics at the
Massachusetts Institute of Technology, who is on the committee, said he believed the risk
was tiny but could not be ruled out. "There have been fears that strange matter could
alter the structure of anything nearby. The risk is exceedingly small but the probability
of something unusual happening is not zero."
Construction of the £350m RHIC machine started eight years ago and is almost complete, even without the need for a car donation! On Friday scientists sent the first beam of particles around the machine - but without
attempting any collisions.
Inside the collider, atoms of gold will be stripped of their outer electrons and pumped
into one of two 2.4-mile circular tubes where powerful magnets will accelerate them to 99.9% of the speed of light.
The ions in the two tubes will travel in opposite directions to increase the power of
the collisions. When they smash into each other, at one of several intersections between
the tubes, they will generate minuscule fireballs of superdense matter with temperatures
of about a trillion degrees - 10,000 times hotter than the sun. Such conditions are
thought not to have existed - except possibly in the heart of some dense stars - since the
Big Bang that formed the universe between 12 billion and 15 billion years ago.
Under such conditions atomic nuclei "evaporate" into a plasma of even smaller
particles called quarks and gluons. Theoretical and experimental evidence predicts that
such a plasma would then emit a shower of other, different particles as it cooled down.
Among the particles predicted to appear during this cooling are strange quarks. These
have been detected in other accelerators but always attached to other particles. RHIC, the
most powerful such machine yet built, has the ability to create solitary strange quarks
for the first time since the universe began.
BNL confirmed that there had been discussion over the possibility of
"perturbations in the universe". Thomas Ludlam, associate project director of
RHIC, said that the committee would hold its first meeting shortly.
John Nelson, professor of nuclear physics at Birmingham University who is leading the
British scientific team at RHIC, said the chances of an accident were infinitesimally
small - but Brookhaven had a duty to assess them. "The big question is whether the
planet will disappear in the twinkling of an eye. It is astonishingly unlikely that there
is any risk - but I could not prove it," he said.
