By Robert S. Boyd
Jim Bergquist, a physicist at the National Institute of Standards and Technology in Boulder, Colorado, holds a keyboard to control the world’s most accurate clock. It’s based on the “ticks” produced by a single atom of mercury contained at near-absolute zero temperature in the silver cylinder. (Geoffrey Wheeler/NIST/MCT)
WASHINGTON _ As scientists learn how to make more exact measurements, they’re finding some astonishing surprises:
_The enthusiastic stomping of soccer fans after a goal creates a “footquake” on earthquake gauges 30 or more miles away.
_Florida is getting closer to Canada by about 1 inch every 36 years.
_Astronomers soon will be able to measure the sideways motion of a star trillions of miles away even though it’s moving at a speed of less than 10 inches an hour.
_It takes 61 trillionths of an ounce of force to make one atom hop over another.
As these examples show, new technologies are enabling researchers to measure things such as time, distance, temperature, weight, force, size and motion with a precision never before achieved.
Scientists say that these tools can help improve global positioning systems, space navigation, wireless communications, national security sensors, biomedical techniques and basic science in physics, chemistry, astronomy and genetics, among other uses.
For instance, the ability to work with extremely minute intervals of time soon may allow scientists to freeze motion _ like an ultrafast strobe light _ to observe the behavior of electrons inside an atom, according to Philip Bucksbaum, a physicist at the Stanford Linear Accelerator Center in Stanford, Calif.
“The ability to measure time is reaching nearly ridiculous levels of precision and accuracy,” said Michael Baum, a spokesman for the National Institute of Standards and Technology in Gaithersburg, Md. The institute is the federal government’s temple of metrology, the science of measurement.
A less precise notion of time was voiced by the late TV comedian Johnny Carson: “The smallest interval of time known to man is that which occurs in Manhattan between the traffic signal turning green and the taxi driver behind you blowing his horn.”
No measurement can be 100 percent accurate. The laws of physics make such precision impossible, but scientists are edging closer.
For example, Michael Roukes, a physicist at the California Institute of Technology in Pasadena, managed to measure the weight of a single molecule with an uncertainty of less than a billionth of a trillionth of an ounce (0.000,000,000,000,000,000,001 ounce). Mighty close, but still not perfect.
Garrett Euler, a seismologist at Washington University in St. Louis, detected tiny vibrations he called “footquakes.” He’d installed a string of 32 seismometers across 900 miles in Cameroon, Africa, to observe volcanic activity there.
One day, Euler noticed an unusual pattern of squiggles on his seismometer. His girlfriend, Katy Lofton, figured out that the tremors came whenever a goal was scored during an African Cup soccer match between Cameroon and Ivory Coast.
“Each goal triggered a countrywide footquake as fans watching TV jumped and stomped for joy,” Euler told the American Geophysical Union last winter. “The more crucial the goal, the stronger the footquake.”
Some examples of recent record levels of precision follow:
Scientists have measured time to within a millionth of a billionth of a second by counting the “ticks” that a single atom of mercury emits.
A clock built by researchers at the National Institute of Standards and Technology is so accurate that it wouldn’t gain or lose one second if it ran for a billion years, according to Till Rosenband, an institute physicist in Boulder, Colo.
“It’s the world’s most accurate clock,” he said.
Ferenc Krausz, the director of the Max Planck Institute for Quantum Optics in Garching, Germany, discovered a technique that was able to distinguish events only a billionth of a billionth of a second apart.
“Such tools would constitute a space-time microscope that would make the motion of electrons visible in slow motion,” Krausz reported in Nature. The technology also could improve global positioning systems and wireless communications networks, as well as help in disease and biological research.
Eric Calais, a geophysicist at Purdue University in Bloomington, Ind., used satellite technology to determine minute changes in the locations of 300 GPS stations in eastern North America over 10 years.
He found that the distance between Florida and Hudson Bay, Canada, is shrinking by nearly three-hundredths of an inch a year. At that rate, it would take 36 years for the continent to shrink 1 inch.
The shrinking occurs as the North American continental plate continues to recover from the crushing weight of ice during the last Ice Age, which ended about 11,000 years ago.
“This slow recovery is causing a very small horizontal shift,” Calais said. “With that kind of precision, we are able to see the horizontal plate deformation due to the melting of the ice sheets.”
Astronomers from the Harvard-Smithsonian Center for Astrophysics in Cambridge, Mass., plan to test a laser device this summer that can measure a star’s motion across the sky by as little as 10 inches per hour. Such a tiny wobble may be evidence that an otherwise undetectable Earth-size planet is orbiting the star.
With this technology, “astronomers will finally be able to find the first truly Earth-like worlds in terms of size and orbit,” astronomer Chih-Hao Li reported in Nature.
Nobel Prize winner Wolfgang Ketterle has cooled atoms to a record 800 trillionths of a degree Fahrenheit above absolute zero at his lab at the Massachusetts Institute of Technology in Cambridge.
It’s impossible to reach absolute zero _ minus 459.67 degrees Fahrenheit _ because there’s always a tiny bit of heat-producing energy that can’t be eliminated from a substance, physicists say.
British scientists Tom Parker and Mahmoud Farhadiroushan have measured the wavelength of light with a resolution of 470 millionths of a billionth of an inch. The wavelength of light is what determines its color.
That accuracy is the equivalent of measuring the distance from New York to Los Angeles with an error of only 4 hundredths of an inch, they said.
Markus Ternus, a physicist at the IBM Research Division in San Jose, Calif., used a combination of two powerful microscopes to measure the force needed to pull a single cobalt atom across a layer of copper atoms.
It worked out to about 61 trillionths of an ounce of pressure to make the cobalt atom hop over the next copper atom, Ternus reported in Science magazine. The technology could be used to build complex structures one atom at a time.
For more information, check the National Institute of Standards and Technology Web site at http://ts.nist.gov/WeightsAndMeasures/Metric/mpo(UNDERSCORE)home.cfm
© 2008, McClatchy-Tribune Information Services.
PHOTO (from MCT Photo Service, 202-383-6099): FOOTQUAKES