giant ball soccer Temporal flux: why we need to keep adding leap seconds

On July 1, at ten o'clock A.M. standard time eastern Australia, something special happened in time: there will be an additional second between 09:59:59 and 10:00:00.This will extend July 1, 2015 (or June 30, 2015 in many other parts of the world) by one second over the length of the standard day.The culprit is "leap seconds", although it is far from unique.
In fact, this will be 26 times since our first launch in 1972.Why do we need to add an extra second in the day?Historically, the second was defined as a small part of the day: 400 of the total time the sun returned to the same position in the sky.This is accurate enough for most purposes, but by the beginning of the 20 th century astronomers have determined that the rotation of the Earth is not constant.
It's actually slowing down.
This means that the second one defined in this way will slowly lengthen over time.Developmentxa0Atomic clockxa0In 1950 s, the second one is allowed to be defined with incredible precision, and there is only one variance in 1014.As a result, it was redefined for the second time in 1967xa0International Commission on weights and measuresxa01967.
It is no longer associated with the rotation of the Earth.Instead, it is defined based on the physical properties of a very special caesium --133 atom.This mechanical definition disconnects the second one from the length of the sun day.
In fact, with the newly established atomic seconds: 86,400 seconds making up a standard day, the table changed and the day was subsequently redefined.The length of the sun day-or indeed the time it takes for the Earth to complete the rotation-is no longer accurate to the length of the standard day, and it has been gone for a century.This is because the rotation of the Earth continues to slow.
The main reason for its lag is the tide friction from the moon, which in itself increases the length of the dayxa02.3 ms per century.However, other geological processes that transfer mass on the Earth will also have an effect on the rotation speed, as the system will maintain its total amountxa0Momentum.This may eventually increase the rotation speed of the Earth and reduce the rotation speed of the Earth.
For example, the 2005 magnitude earthquake in Indonesia that caused the tsunami also reduced the length of the day by 2.68 microsecondsTherefore, we must continue to increase leap seconds so that the time at noon Greenwich (Greenwich Standard Time) is consistent with the noon measured by the atomic clock (International Atomic Time.This guarantees that the sun time (rising and falling of the Sun) will not be out of sync with our clock.
The task of adding these seconds was originallyxa0Executive body of the General Administration of International Customs General Administration of international customsxa0The international Time Committee, which is itself part of the International Astronomical Union.In 1987, a new organization was established for the International Earth Rotation and Reference System Service (IERS.Starting in January 1, 1988, it began to take charge of the second leap.
Leap seconds itself is an irregular phenomenon.Between 1990 and 1999, 7 Leap seconds were added.However, between 2000 and 2009, only two seconds were added.
In fact, it is so irregular that IERS only announce leap seconds six months in advance.This is a headache for computer systems.Software that doesn't know leap seconds may see time go backwards and crash.When a leap second is added on 2012xa0Qantas collapsedxa0Up to 50 flights were delayed.
Similar issues affect the sitexa0Reddit, Foursquare, and LinkedIn.The future of leap seconds is currently being discussed.The chaos it may cause on the world's computer systems may not be worth continuing to align with heaven.
New York Stock Exchange programxa0Close 30 minutes early.Online retailer Amazon's Web Services Department plans to change their definition of the next day so they can keep 86,400 seconds on a standard day.This means that the clock of the Amazon Web Service is slightly different from the civilian time.
Does the time used by humans every day need to be connected with astronomical time?If the second one retains its definition, then it needs to be crossedSeconds will only increase.In 100, at least one is needed each year.In the millennium, we need to add a new leap second every few months.There are already some civil-defined timing schemes that do not meet the time, such as International Atomic Time.
xa0And thatxa0GPS timeA computer system can be associated with any of them.So that very long minute of July 1, 2015 reminds us that time is not a simple thing.We might want it to be pure and orderly, but as long as we live on a huge ball that is surrounded by another huge rock, around a huge ball of exploding gas, we all travel through space, so we inevitably need to adjust the clock from time to time.