As most of the world knows, the Large Hadron Collider (LHC), in a tunnel 175 meters below the Franco-Swiss border near Geneva, Switzerland, is the largest and most expensive scientific experiment in human history. It is designed to hurl opposing particle beams in a 27-kilometer circle at somewhere the speed of light. When it was finally cranked up for the first time, there were concerns that a runaway chain reaction might suck the universe into a black hole. Unfortunately, it broke down before anybody got the answer although it is working at a lower level while scientists work to get it back up to speed.

At the other end of the scale is a considerably slower experiment, perhaps the slowest in the world, and in the Guinness Book of Records as the longest. It is certainly far less expensive. It is one that, any day now, could produce the ninth milestone in the experiment's history. Known as the Pitch Drop Experiment, it is at the School of Mathematics and Physics at the University of Queensland in Brisbane. It was designed to demonstrate that some substances that appear to be solid are actually very high-viscosity liquids. Beyond that, there seems to have been little reason for it.

Pitch is the name for a number of hard, tar-like substances. It was begun by a professor named Thomas Parnell, who, in 1927, poured a heated sample of bitumen, which is hard enough to fracture with a hammer in normal conditions and certainly appears to be a solid, into a sealed funnel. It took years for the experiment to begin -- the pitch was allowed to settle for three years. In 1930, according to Atlas Obscura, an atlas of "the world's wonders, curiosities and esoterica," Parnell cut the seal at the neck of the funnel, allowing the pitch to start flowing, if it intended to.

In December of 1938, after a period of something like 107 months, the first drop fell. Another nine years elapsed before the second, in 1947. Sadly, Parnell lived to see only two drops fall, or at least to record their falling. He died in 1948. The third came along rather more quickly, in 1954. However, the pitch reverted to its dilatory ways, with the fourth not falling until 1962. Another eight years passed before the fifth in August of 1970. Nine would pass before the sixth, nine again for the seventh.

It wasn't until 1988, sometime after the seventh drop fell, that the experiment got scientific enough to control the atmospheric conditions. At that time, air conditioning was added. Now, according to the encylopedia, the temperature varies consistently, and the stability has lengthened each drop's stretch before it separates from the rest of the pitch in the funnel.

On November 28 of 2000, the eighth and latest drop fell, allowing experimenters to calculate that large droplets form and fall with a viscosity approximately 230 billion times (2.3 x 10 to the 11th power) that of water. The ninth is said to now be forming. Although nobody has ever seen a drop fall, the university has set up a webcam to watch the funnel at mms://drop.physics.uq.edu.au/PitchDropLive. A webcam was set up in 2000, but due to technical problems it somehow missed the drip.

Professor John Mainstone is now the custodian of the project, which won the Ig Nobel Prize for Physics for Parnell and Mainstone in 2005. The Ig Nobel Prizes, begun in 1991, are awarded at Harvard University each year for discoveries "that cannot, or should not, be reproduced." The Pitch Drop experiment has also been cited by Guinness as the world's longest-running scientific experiment.

Two other experiments, however, appear to be in the running to outdo the pitch drop although they have been interrupted. One is the Beverly Clock, at the Department of Physics at the University of Otago in New Zealand, which is still running despite never having been wound since it was built in 1864 by a man named Arthur Beverly. It has been stopped purposely to clean it and move it a couple of times. Driven by changes in atmospheric pressure and temperature, it is a contender for the title of longest continuously running scientific experiment if it continues to run. So is the Oxford bell, which has been ringing almost continuously since 1840 at the Clarendon Laboratory at Oxford. Although it is ringing, nobody can hear it. It is behind two layers of glass. It too was stopped to be moved. Nobody has ever moved or stopped the pitch drop experiment.

In the meantime, the pitch drop continues to forge on. It is believed that there is enough pitch that the funnel won't empty for another 100 years.

With reporting from Asian Correspondent