Vote to decide if leap second's time is up
Source: Agencies |
January 18, 2012, Wednesday
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Print Edition
Print Edition
IT'S high noon for the humble leap second.
After a decade of talks, governments this week head for a showdown vote on an issue that pits technological precision against nature's whims.
The United States, France and others are pushing for countries at a UN telecommunication meeting in Geneva to abolish the leap second, which for 40 years has kept computers in sync with the Earth day.
Leap seconds are necessary to prevent atomic clocks from speeding ahead of solar time. They are added at irregular intervals, effectively stretching atomic time by a heartbeat to make up for the irregular wobble in the Earth's rotation.
Critics warn that scrapping the leap second would break the last link between the passing of time and the course of the sun across the sky. But backers say machines shouldn't any longer be tethered to the imprecise cycle of sunrise and sunset.
"This would be an important decision because the problem of introducing the leap second would disappear and we would have a more steady time than we have today," Vincent Meens, an official at the International Telecommunication Union who has chaired technical talks on the issue, said yesterday.
Operators of cell phone networks, financial markets and air traffic control systems could then rely on the near-absolute precision offered by atomic clocks without having to worry about stopping their systems for the length of a heartbeat every year or two.
"Most of the people who operate time services favor discontinuing leap seconds," said Judah Levine, a physicist at the National Institute of Standards and Technology in Boulder, Colorado.
"The main problem is that the leap second is usually implemented by stopping the clock for one second. However, the world doesn't stop," he said.
Satellite navigation systems like GPS don't use leap seconds, which adds confusion, said Levine. "In addition, the leap second occurs in the middle of the day in Asia and Australia, which is particularly inconvenient."
Critics say the risks are overblown and leap seconds have been used successfully since 1972, despite being hard to predict more than six months in advance. China has warned that a change could hurt astronomers, who need to compare observations spanning thousands of years as part of their work. Canada and Britain, too, have raised objections.
Killing off the leap second would also result in atomic clocks slowly outrunning the solar day by a rate of about 90 seconds a century.
"This is replacing a small problem with a big problem further down the line," said Daniel Gambis, an astronomer at the Paris Observatory and the man who alerted timekeepers around the world to the next leap second, due on June 30.
After a decade of talks, governments this week head for a showdown vote on an issue that pits technological precision against nature's whims.
The United States, France and others are pushing for countries at a UN telecommunication meeting in Geneva to abolish the leap second, which for 40 years has kept computers in sync with the Earth day.
Leap seconds are necessary to prevent atomic clocks from speeding ahead of solar time. They are added at irregular intervals, effectively stretching atomic time by a heartbeat to make up for the irregular wobble in the Earth's rotation.
Critics warn that scrapping the leap second would break the last link between the passing of time and the course of the sun across the sky. But backers say machines shouldn't any longer be tethered to the imprecise cycle of sunrise and sunset.
"This would be an important decision because the problem of introducing the leap second would disappear and we would have a more steady time than we have today," Vincent Meens, an official at the International Telecommunication Union who has chaired technical talks on the issue, said yesterday.
Operators of cell phone networks, financial markets and air traffic control systems could then rely on the near-absolute precision offered by atomic clocks without having to worry about stopping their systems for the length of a heartbeat every year or two.
"Most of the people who operate time services favor discontinuing leap seconds," said Judah Levine, a physicist at the National Institute of Standards and Technology in Boulder, Colorado.
"The main problem is that the leap second is usually implemented by stopping the clock for one second. However, the world doesn't stop," he said.
Satellite navigation systems like GPS don't use leap seconds, which adds confusion, said Levine. "In addition, the leap second occurs in the middle of the day in Asia and Australia, which is particularly inconvenient."
Critics say the risks are overblown and leap seconds have been used successfully since 1972, despite being hard to predict more than six months in advance. China has warned that a change could hurt astronomers, who need to compare observations spanning thousands of years as part of their work. Canada and Britain, too, have raised objections.
Killing off the leap second would also result in atomic clocks slowly outrunning the solar day by a rate of about 90 seconds a century.
"This is replacing a small problem with a big problem further down the line," said Daniel Gambis, an astronomer at the Paris Observatory and the man who alerted timekeepers around the world to the next leap second, due on June 30.
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