This year to last a second longer!

December 30, 2016

Washington, Dec 30: This year will last a second longer as a "leap second" will be added to the world's clocks on New Year's Eve by the timekeepers.

clockThe extra second will be inserted at the US Naval Observatory's Master Clock Facility in Washington, DC at 23 hours, 59 minutes and 59 seconds Coordinated Universal Time (UTC) which corresponds to 5:29:59 am Indian Standard Time on January 1.

Historically, time was based on the mean rotation of the Earth relative to celestial bodies and the second was defined in this reference frame.

However, the invention of atomic clocks defined a much more precise "atomic" timescale and a second that is independent of Earth's rotation.

In 1970, international agreements established a procedure to maintain a relationship between Coordinated Universal Time (UTC) and UT1, a measure of the Earth's rotation angle in space.

The International Earth Rotation and Reference Systems Service (IERS) is the organisation which monitors the difference in the two time scales and calls for leap seconds to be inserted in or removed from UTC when necessary to keep them within 0.9 seconds of each other.

In order to create UTC, a secondary timescale, International Atomic Time (TAI), is first generated; it consists of UTC without leap seconds.

When the system was instituted in 1972, the difference between TAI and UTC was determined to be 10 seconds.

Since 1972, 26 additional leap seconds have been added at intervals varying from six months to seven years, with the most recent being inserted on June 30, 2015.

After the insertion of the leap second in December, the cumulative difference between UTC and TAI will be 37 seconds.

Confusion sometimes arises over the misconception that the occasional insertion of leap seconds every few years indicates that the Earth should stop rotating within a few millennia.

This is because some mistake leap seconds to be a measure of the rate at which the Earth is slowing.

The one-second increments are, however, indications of the accumulated difference in time between the two systems.

The decision as to when to add a leap second is determined by the IERS, for which the USNO serves as the Rapid Service/Prediction Center.

Measurements show that the Earth, on average, runs slow compared to atomic time, at about 1.5 to 2 milliseconds per day.

These data are generated by the USNO using the technique of Very Long Baseline Interferometry (VLBI).

VLBI measures the rotation of the Earth by observing the apparent positions of distant objects near the edge of the observable universe.

These observations show that after roughly 500 to 750 days, the difference between Earth rotation time and atomic time would be about one second.

Instead of allowing this to happen a leap second is inserted to bring the two time-scales closer together.

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February 25,2020

Tokyo, Feb 25: Japan's Chitetsu Watanabe, recognized at 112 years as the oldest man in the world, has passed away 11 days after he received the Guinness World Record certificate, his family said on Tuesday.

Watanabe died on Sunday night, Efe news reported.

He received the official certificate on February 12 at a nursing home in Joetsu in Niigata prefecture, where he resided.

Soon after being certified as the oldest man, he began to experience a lack of appetite and respiratory problems, the wife of his eldest son told public broadcaster NHK.

Born on March 5, 1907 in a family of farmers, Watanabe moved at the age of 20 to Taiwan, where he worked at a sugar refinery for 18 years before returning to Japan after the end of World War II.

A fan of calligraphy, custard and ice cream, Watanabe told the Guinness team that the key to his long life was laughter.

He was recognized as the oldest male in the world following the deaths in 2019 of German Gustav Gerneth (in October), aged 114 years, and Japan's Masazo Nonaka (in January), at the age of 113, three months older than the German.

It remains to be seen who will be recognized after the death of Watanabe, the only male on the list drawn up by the Gerontology Research Group of the 30 oldest people in the world.

Japan has among the highest life expectancy in the world and the number of centenarians in the country has crossed 71,000, according to the latest government figures.

Since 2000, the number of centenarians censored has quintupled, raising concern for the economic outlook and future workforce of the country - where the birthrate is on a downward trend.

Out of these, 88 per cent are women.

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Agencies
July 2,2020

Leiden, Jul 2: Astronomers have discovered a luminous galaxy caught in the act of reionizing its surrounding gas only 800 million years after the Big Bang.

The research, led by Romain Meyer, PhD student at UCL in London, UK, has been presented at the virtual annual meeting of the European Astronomical Society (EAS).

Studying the first galaxies that formed 13 billion years ago is essential to understanding our cosmic origins. One of the current hot topics in extragalactic astronomy is 'cosmic reionization,' the process in which the intergalactic gas was ionized (atoms stripped of their electrons).

Cosmic reionization is similar to an unsolved murder: We have clear evidence for it, but who did it, how and when? We now have strong evidence that hydrogen reionization was completed about 13 billion years ago, in the first billion years of the universe, with bubbles of ionized gas slowly growing and overlapping.

The objects capable of creating such ionized hydrogen bubbles have however remained mysterious until now: the discovery of a luminous galaxy in which 60-100 percent of ionizing photons escape, is likely responsible for ionizing its local bubble. This suggests the case is closer to being solved.

The two main suspects for cosmic reionization are usually 1) a population of numerous faint galaxies leaking ~10 percent of their energetic photons, and 2) an 'oligarchy' of luminous galaxies with a much larger percentage (>50 percent) of photons escaping each galaxy.

In either case, these first galaxies were very different from those today: galaxies in the local universe are very inefficient leakers, with only <2-3 percent of ionizing photons escaping their host. To understand which galaxies governed cosmic reionization, astronomers must measure the so-called escape fractions of galaxies in the reionization era.

The detection of light from excited hydrogen atoms (the so-called Lyman-alpha line) can be used to infer the fraction of escaping photons. On the one hand, such detections are rare because reionization-era galaxies are surrounded by neutral gas which absorbs that signature hydrogen emission.

On the other hand, if this hydrogen signal is detected it represents a 'smoking gun' for a large ionized bubble, meaning we have caught a galaxy reionizing its surroundings. The size of the bubble and the galaxy's luminosity determines whether it is solely responsible for creating this ionized bubble or if unseen accomplices are necessary.

The discovery of a luminous galaxy 800 million years after the Big Bang supports the scenario where an 'oligarchy' of bright leakers emits most of the ionizing photons.

"It is the first time we can point to an object responsible for creating an ionized bubble, without the need for a contribution from unseen galaxies.

Additional observations with the upcoming James Webb Space Telescope will enable us to study further what is likely one of the best suspects for the unsolved case of cosmic reionization," said Meyer.

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Agencies
March 8,2020

Consumer watchdog Which? has claimed that more than one billion Android phones and tablets are vulnerable to hackers as they no longer supported by security updates.

According to the research report, the most at-risk phones are any that run Android 4 or older and those smartphones running Android 7.0 which can not be updated are also at risk.

Based on data from Google analysed by Which?, two in five android device users around the world are no longer receiving the important updates. Currently, those devices are unlikely to have issues, but the lack of security leaves them open to attack.

"It is very concerning that expensive Android devices have such a short shelf life before they lose security support, leaving millions of users at risk of serious consequences if they fall victim to hackers," Kate Bevan editor Which? said in a statement.

"Google and phone manufacturers need to be upfront about security updates with clear information about how long they will last and what customers should do when they run out. The government must also push ahead with planned legislation to ensure manufacturers are far more transparent about security updates for smart devices and their impact on consumers," Kate added.

Android phone released around 2012 or earlier, including popular models like the Samsung Galaxy S3 and Sony Xperia S, are particularly at risk to hackers.

Which? has made suggestions to Android users on what to consider if they have an older phone that may be at risk.

Any Android device which is more than two years old, check whether it can be updated to a newer version of the operating system. If it is on an earlier version than Android 7.0 Nougat, try to update via Settings> System>Advanced System update.

In case a user is not able tto update the phone, the device could be at risk of being hacked if it is running a version of Android 4 or lower.

A user also need to be careful about downloading apps outside the Google Play store and should also install a mobile anti-virus via an app.

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