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Time-warp: Why June 30 will be a bit longer

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Washington: Strictly speaking, a day lasts 86,400 seconds. On June 30, the day will officially be a bit longer than usual because an extra second or “leap” second will be added and NASA has an explanation for this.

“The Earth’s rotation is gradually slowing down a bit, so leap seconds are a way to account for that,” said Daniel MacMillan, NASA’s Goddard Space Flight Center in Greenbelt, Maryland.

This is the case according to the time standard that people use in their daily lives – Coordinated Universal Time or UTC.

UTC is “atomic time” — the duration of one second is based on extremely predictable electromagnetic transitions in atoms of cesium.

These transitions are so reliable that the cesium clock is accurate to one second in 1,400,000 years.

However, the mean solar day — the average length of a day, based on how long it takes the Earth to rotate — is about 86,400.002 seconds long.

“That is because the Earth’s rotation is gradually slowing down a bit owing to a kind of braking force caused by the gravitational tug of war between the Earth, the Moon and the Sun,” the US space agency said in a statement.

Scientists estimate that the mean solar day has not been 86,400 seconds long since the year 1820 or so.

This difference of two milliseconds, or two thousandths of a second — far less than the blink of an eye — hardly seems noticeable at first.

But if this small discrepancy were repeated every day for an entire year, it would add up to almost a second.

Typically, a leap second is inserted either on June 30 or December 31.

Normally, the clock would move from 23:59:59 to 00:00:00 the next day. But with the leap second on June 30, UTC will move from 23:59:59 to 23:59:60, and then to 00:00:00 on July 1.

In practice, many systems are instead turned off for one second.

Previous leap seconds have created challenges for some computer systems and generated some calls to abandon them altogether.

“In the short term, leap seconds are not as predictable as everyone would like,” said Chopo Ma, geophysicist at Goddard.

“The modelling of the Earth predicts that more and more leap seconds will be called for in the long-term but we cannot say that one will be needed every year,” Ma said.

From 1972, when leap seconds were first implemented, through 1999, leap seconds were added at a rate averaging close to one per year.

Since then, leap seconds have become less frequent.

This June’s leap second will be only the fourth to be added since 2000.

(IANS)

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Emmy Awards 2018: NASA Nominated for Stunning Footage of Cassini voyage to Saturn

The Emmy Awards nominations have turned out to be more diverse than last year

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The Primetime Emmys will be awarded by the ATAS in Los Angeles on September 17.
The Primetime Emmys will be awarded by the ATAS in Los Angeles on September 17. Flickr

The Academy of Television Arts and Sciences (ATAS) has nominated NASA’s Jet Propulsion Laboratory (JPL) for Outstanding Original Interactive Program for its coverage of the Cassini mission’s Grand Finale at Saturn.

The Primetime Emmys will be awarded by the ATAS in Los Angeles on September 17.

The Creative Arts Emmys, which include interactive awards, will be presented during a separate ceremony on September 15 at the Microsoft Theatre in Los Angeles, NASA said in a statement on Friday.

In 2017, after nearly 20 years in space and 13 years revealing the wonders of Saturn, NASA’s Cassini orbiter was running out of fuel. As a final act, Cassini began a whole new mission — its Grand Finale, where it journeyed into the unknown and ended with a spectacular plunge into the planet.

Cassini’s first, daring dive into the unexplored space between the giant planet and its rings kicked off the campaign on April 26 in 2017.

NASA's stunning footage of Cassini lands Emmy nomination
NASA’s stunning footage of Cassini lands Emmy nomination. Pixabay

It culminated on September 15, 2017, with live coverage of Cassini’s plunge into Saturn’s atmosphere, with the spacecraft sending back science to the very last second.

JPL created a multi-month digital campaign to celebrate the mission’s science and engineering accomplishments and communicate why the spacecraft must meet its end in the skies of Saturn.

The multi-faceted campaign included regular updates on Twitter, Facebook, Snapchat, Instagram and the Cassini mission website, multiple live social, web and TV broadcasts during which reporter and public questions were answered.

Also Read: NASA Juno Data Indicate Another Possible Volcano on Jupiter Moon Io

A dramatic short film to communicate the mission’s story and preview its endgame; multiple 360-degree videos, including NASA’s first 360-degree livestream of a mission event from inside JPL mission control.

The Emmy Awards nominations have turned out to be more diverse than last year. Fantasy drama “Game of Thrones” has earned 22 nominations for the coveted Awards, while HBO’s 17-year streak as the most nominated network has been broken by Netflix. (IANS)