Topic started on 19-1-2003 @ 12:08 PM by Inspectah
On the morning of October 22, 1993, local time, the visitor hit the top of the atmosphere over Ellsworth Land in Antarctica. It pierced the sky in a
flash of light, moving a hundred times faster than a meteor, passing from the thinnest air and into the ice in a fraction of a second. It cut through
the solid earth in a northeasterly direction. In less than 20 seconds, it had crossed the South Atlantic, deep beneath the ocean floor. When it
passed below the southern tip of Africa, it was more or less halfway between Cape Town and the center of the Earth.
That was as deep as its straight path through the planet would take it; from then on it headed up. Fifteen seconds later, 6,000 kilometers across the
Indian Ocean from Cape Town, it left Earthís crust somewhere between Sri Lanka and Thailand. It lanced up through the afternoon sky and headed back
out to the stars. The whole visit lasted less than a minute, and nobody saw a thing.
Itís remarkable that some strange guest should sweep through Earth like a hot wire through wax, and that no one would notice as it did so. But though
the visitor was very fast and fairly heavy, it was also extremely small: a mass of as much as 10 tons squeezed into something about the size of a red
blood cell. If a 10-ton asteroid fell to Earth at 400 kilometers per second, people would notice; something the size of a small car hitting the
unyielding Earth at that speed would give up its kinetic energy in an explosion to rival that of a 200-kiloton nuclear weapon. But condensed to the
size of a small amoeba, the same mass wouldnít cause anywhere near as much fuss. The fearsome momentum of the microscopic visitor would shatter the
bonds between molecules directly in its path and push the bystanders aside. It would do this vigorously enough to melt a small tunnel as it passed,
slicing through the rocky earth almost as easily as it pass through air and water.
If there had been a human at the point of entry, she might have seen a split-second burst of light, and the exit through the ocean must have made a
fish-startling noise of some sort. But no one saw or heard a thing. No one, that is, for 10 years. It was only then that scientists noticed what
might have been the visitorís faint signals in an obscure archive of seismological data. Such data piles up at ever-increasing rates as Earth gets
more thoroughly wired; every passing planetary groan and tremor now gets recorded, preserved to be pondered by anyone who has the time, training, and
curiosity to look. And in the past few years, a small team of physicists has developed the expertise to trawl that data for signs of intruders from
outer space. These are researchers who, when the grandest physics project ever conceived was canned, set themselves a task far smaller in cost but
arguably grander in ambition: surreptitiously turning a whole planet into a particle detector.
Vic Teplitz met Eugene Herrin in 1989. Both were on the faculty of the physics department at Southern Methodist University in Dallas. It was a heady
time to be a particle physicist in Texas. Excavation was about to start on the 87 kilometers of underground tunnel, located an hourís drive from
campus, that would house the Superconducting Super Collider, the Next Big Thing in scienceís endeavor to understand the makeup of the universe. The
SSC, it was hoped, would produce all sorts of wonderful particles for the worldís physicists to study, like the much sought-after Higgs boson. ìFor a
few years,î recalls Teplitz, ì we were the capital of the planet.î
Unfortunately for Texas, funding for the construction of the Superconducting Super Collider was canceled in 1993, and hundreds of people like Teplitz
suddenly found a collider-shaped hole in their careers. One response was to turn from particle physics to particle astrophysics. The universe is
full of things that can produce energies far greater than the SSC would ever have managed. And thereís evidence that space may be richly endowed with
bizarre particles forged in the almost inconceivable energies of the big bang itself. The behavior of the bits of universe that astronomers can see -
the spinning of galaxies, for example - convinces them that there must be a lot of stuff out there they canít see, invisible remnants of creation that
outweigh all the visible stars and galaxies. Since the demise of the Texas collider, attempts to identify this ìdark matter,î or at least to observe
its effects, have become something of a boom industry.
Most of the dark-matter candidates that researchers find interesting are extraordinarily light and tiny. But there are exceptions. One of these is
ìstrange matter,î a substance a bit denser than the nuclei of atoms. Normal atomic nuclei ate made of particles called up-quarks and down-quarks ñ
two ups and a down to make a proton, two downs and an up to make a neutron. The heavier quarks created in accelerators ñ the strange quark, the
charmed quark, the bottom quark, the top quark ñ are normally unstable. But itís possible that, under certain circumstances, strange quarks could be
stabilized, if mixed in with everyday up-quarks and down-quarks. While large atomic nuclei are unstable, lumps of strange matter would hold together
fine at almost any size. A piece of strange matter could be as massive as a star and still not fall apart.
So, what would it mean for Earth if the dark matter that astronomers believe envelops our galaxy was made of strange matter? Strange nuggets up to a
billion or so time the mass of a normal atom would fall to Earth and just sit there, chemically inert and hard to find. Larger nuggets would
penetrate the planetís interior before stopping. And nuggets weighing more than a tenth of a gram would pass right through. A large nugget, elbowing
its way through Earth at high speed, might be detectable by seismologists.
After the cancellation of the SSC, Herrin and Teplitz decided to pursue this idea ñ not least because Southern Methodist had some excellent
seismologists. Suspecting that seismic signals given off by strange nuggets might be detectable with current technology, they decided to sift through
a suitable data set ñ a stack of 10 big old reel- to ñreel tapes from the Us Geological Survey, containing more than 9 million seismic events reported
by stations around the world between 1981 and 1993.
There will soon be more, its kind of a long article, and I'll get the rest later.
[Edited on 19-1-2003 by Inspectah]