Split-Second Timing

    “Split-Second Timing,” Ensign, Aug. 1992, 69

    Split-Second Timing

    Internationally known physicist David W. Allan brings a new twist to making every single second count. Thanks to him and the team of scientists he works with, the accuracy with which time can be measured has increased more than three orders of magnitude—or one thousand times.

    “We are now capable of splitting a second into a trillion parts, which is more precise than most anyone would need,” muses Brother Allan. He explains that the more precisely time is measured, the more accurate navigation can be—whether it is used for guiding a ship at sea, sending a spacecraft out into the solar system, or measuring the electromagnetic quantum from an atom.

    Whereas time was formerly measured in relation to the earth’s rotation, time is measured today in relation to things as tiny as a cesium atom or as large as pulsars—stars spinning far out in our galaxy. These become the pendulum of ultra-precise clocks.

    The most accurate clock in the United States, an atomic clock, is found in Boulder, Colorado, at the National Institute of Standards and Technology (NIST), where David Allan works and where he has made his mark in the international scientific community.

    Brother Allan, who spent his childhood on a farm in Mapleton, Utah, is known internationally for the Allan variance, the subject of his graduate thesis at the University of Colorado. The Allan variance is an algorithm, a mathematical procedure for solving a problem. Among time analysts in the world scientific community, the Allan variance is a household phrase, an international standard for measuring clock performance.

    The gospel is at the very center of Brother Allan’s scientific understanding. “If we wish to receive it, divine guidance can influence our professional life as much as it does our Church responsibilities.” A former president of the Boulder stake, he now serves as stake mission president.

    On one occasion, Brother Allen presented a paper for a colleague from the Soviet Union who was unable to attend a symposium in Washington, D.C. “I had given him a copy of the Book of Mormon on one of our previous visits,” David explains, “so I shouldn’t have been surprised when I read on the cover page of his paper a quotation from Alma chapter 40, verse 8: ‘All is as one day with God, and time only is measured unto men.’” [Alma 40:8]

    Integrating his professional and religious understanding comes naturally to David Allan as he lectures to scientists around the world about time, all the while drawing on the timeless teachings of the gospel.—Sterling D. Allan, Provo, Utah

    Atomic-clock watcher David Allan knows that time is only a mortal measurement. (Photo by Edna Allan.)