Skip to main content

Leap second’syncs Indian time with Earth’s spin (tthehindu,)

The atomic clock was programmed to add an extra second to 2017 to compensate for a slowdown in the Earth’s rotation.

A ‘leap second’ was added to the Indian clock at 5:29.59 hours on Sunday to synchronise with the Earth’s rotational clock. As the atomic clock at the National Physical Laboratory (NPL) here struck 23:59:59 last night, it was programmed to add an extra second to 2017 to compensate for a slowdown in the Earth’s rotation.

Adding a second barely has an impact on the daily life, but it does matter in the fields of satellite navigation,astronomy and communication. “The Earth and rotation around its own axis is not regular, as sometimes it speeds up and sometimes it slows down due to various factors, including earthquakes and moon’s gravitational forces. As a result, astronomical time (UT1) gradually falls out of sync with atomic time (UTC), and, as and when the difference between UTC and UT1 approaches 0.9 seconds, a leap second is added to UTC through atomic clocks worldwide,” D. K. Aswal, Director of NPL, said.

Extreme precision

Adding the leap second to the Indian clock is done by the NPL under the Council for Scientific and Industrial Research. The NPL, one of the oldest laboratories in the country, has five atomic clocks and nearly 300 such pieces exist across the globe.

Atomic clocks are so precise that the margin of error in its functioning is just of a second in 100 million years. “The leap second adjustment is not so relevant for normal everyday life. However, this shift is critical for applications requiring time accuracies in the nanosecond, which are critical in the fields of astronomy, satellite navigation, communication networks,” Mr. Aswal added.

Comments

Popular posts from this blog

What's ailing Namami Gange programme?(DTE)

Winters are extremely hectic for Sushma Patel, a vegetable grower in Uttar Pradesh’s Chunar town. Her farm is in the fertile plains of Ganga where people grow three crops a year. But this is the only season when she can grow vegetables. And before that, she needs to manually dig out shreds of plastic and wrappers from her one-hectare (ha) farm. “This is all because of the nullah,” she says, pointing at an open drain that runs through her field, carrying sewage from the neighbourhood to the Ganga. “Every monsoon, the drain overflows and inundates the field with a thick, black sludge and plastic debris. We cannot even go near the field as the stench of sewage fills the air,” she says. But Patel has no one to complain to as this is the way of life for most people in this ancient town. About 70 per cent of the people in Chunar depend on toilets that have on-site sanitation, such as septic tanks and pits. In the absence of a proper disposal or management system, people simply dump the faec...

High dose of Vitamin C and B3 can kill colon cancer cells: study (downtoearth)

In a first, a team of researchers has found that high doses of Vitamin C and niacin or Vitamin B3 can kill cancer stem cells. A study published in Cell Biology International showed the opposing effects of low and high dose of vitamin C and vitamin B3 on colon cancer stem cells. Led by Bipasha Bose and Sudheer Shenoy, the team found that while low doses (5-25 micromolar) of Vitamin C and B3 proliferate colon cancer stem cells, high doses (100 to 1,000 micromolar) killed cancer stem cells. Such high doses of vitamins can only be achieved through intravenous injections in colon cancer patients. The third leading cause of cancer deaths worldwide, colon cancer can be prevented by an intake of dietary fibre and lifestyle changes. While the next step of the researchers is to delineate the mechanisms involved in such opposing effects, they also hope to establish a therapeutic dose of Vitamin C and B3 for colon cancer stem cell therapy. “If the therapeutic dose gets validated under in vivo...

"ISRO has capabilities to build geostationary satellites for air quality monitoring” (downtoearth)

Pawan Gupta's findings on trans-boundary movement of pollution (Punjab to Delhi) from biomass burning in 2015 spurred debates. He participated in discussions with Indian regulators early September at the Better Air Quality Conference in Busan on the advantages of using satellite data for air quality monitoring. He explains to Down to Earth how air quality monitoring is done using satellite data. How is satellite data used to measure air pollution? Satellites that provide information on atmospheric pollutants are normally (not always) in the low earth orbits (400-1000 km above the Earth’s surface). A single satellite can carry one or more remote sensing instruments onboard that look down to earth and obtain information about the object in the field of view of satellite sensor. The Earth receives electromagnetic radiation from the sun, which travels through space and reaches the earth-atmosphere system. The radiation then interacts with the Earth’s atmosphere and the surface...