In the Matter of Strange Quarks

Physicists have suspected for about two decades that a very heavy form of matter known as "strange quark matter" might exist, but no one has yet found any evidence. Strange quark matter is so dense that a ton-sized nugget would be about the size of a red blood cell.

Two SMU professors believe they have found the first evidence of strange quark matter passing through Earth.

In a paper to be published in the Bulletin of the Seismological Society of America, Geological Sciences Professor Eugene Herrin and Physics Professor Vigdor Teplitz describe how they discovered evidence of strange quark matter. They searched through more than a million records of seismic events collected by the U.S. Geological Survey from 1990 to 1993 that were not associated with traditional seismic events such as earthquakes. These records of so-called "unassociated events" were collected from seismic stations set up around the world to monitor earthquakes and nuclear testing.

Two SMU professors believe they have found the first evidence of strange quark matter passing through Earth.

Strange quark matter has a distinct seismic signal – a straight line – caused by the large ratio of speed to the speed of sound in the Earth, Herrin says. He estimates that strange quark matter might pass through the Earth at 250 miles per second, 40 times the speed of seismic waves.

Herrin found a seismic event that occurred on Nov. 24, 1993, that fit this unusual pattern. The event, which was recorded by nine monitoring stations in Australia and Bolivia, involved an object that entered the Earth south of Australia and exited the Earth near Antarctica 16.8 seconds later.

"We can't prove that this was strange quark matter, but that is the only explanation that has been offered so far," Herrin says.

For more information: Eugene Herrin
herrin@mail.smu.edu