If the synchronization drifts off by one thousandth of a second, the system couldn’t tell you for sure if you were in Washington or Boston. So if the clocks in GPS satellites and your GPS receiver drift just one millionth of a second - a thousand nanoseconds - out of sync with each other, the system will not pinpoint your location more precisely than within about two-fifths of a mile. Those are radio signals that move at the speed of light, which means they travel about one foot every billionth of a second (which is a nanosecond). Technologies such as smartphones, GPS devices and the power grid rely on thousands of separated elements - such as satellites, cell towers, generating stations, computers, electrical switches and countless computers - that cannot get more than a millionth of a second out of sync with one another before bad stuff happens.Ĭonsider GPS signals between satellites and receivers on the ground. “We have become critically dependent on incredibly precise timekeeping,” O’Brian says. View Graphic Slowing the spin of the Earth And twice a year, those accumulating micromoments essentially vanish when most of us adjust our clocks with the start or end of daylight saving time.Įxcept for one thing: Those micromoments don’t actually vanish, and in an era of intense technology, they now matter a whole lot. The boss still can’t tell if you arrive at work two milliseconds after 9 a.m. “But that is not the case.”įor all but the past 60 to 70 years, those extra milliseconds adding to each day did not matter one whit. “We naively think there always has been 24 hours per day,” says Thomas O’Brian, chief of the Time and Frequency Division of the National Institute of Standards and Technology (NIST). Two hundred million years from now, the daily dramas for whatever we evolve into will unfold during 25-hour days and 335-day years. For Jurassic-era stegosauruses 200 million years ago, the day was perhaps 23 hours long and each year had about 385 days. And every day after that, because that is how much slower the Earth turns on its axis each day now than it did a century ago.Īll of those sub-eyeblink slowdowns each century have been adding up, too. Original article on ’t forget to set your clocks ahead two thousandths of second before you go to sleep tonight. 17) in The Astrophysical Journal.Įmail Meghan Bartels at or follow her Follow us and Facebook. The research is described in a paper published yesterday (Jan. But the new calculation's range beats a 12-minute window. It's still not set in stone - the error bars on that calculation stretch between a minute and 52 seconds longer and a minute and 19 seconds shorter. That's how the researchers came up with the measurement of 10 hours, 33 minutes and 38 seconds. So, Mankovich and his colleagues studied those observable waves and used them to backtrack inward to the planet itself. "At specific locations in the rings, these oscillations catch ring particles at just the right time in their orbits to gradually build up energy, and that energy gets carried away as an observable wave." "Particles throughout the rings can't help but feel these oscillations in the gravity field," lead author Christopher Mankovich, a graduate student in astronomy at the University of California, Santa Cruz, said in a statement. Those small changes ripple out to the chunks of ice in the rings that decorate the gas giant, causing small waves in the rings. The idea is that as Saturn spins, its insides wiggle a little, causing small changes in the planet's gravitational field. This idea was proposed in 1982, but not until the Cassini mission did scientists have the data to see if the technique would work. The research published today took an entirely different approach - looking not to the planet itself, but at its delicate rings. These challenges left scientists with rough estimates falling between 10 hours, 36 minutes and 10 hours, 48 minutes - not particularly satisfying.
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