NASA probe beams back ultraviolet images of Martian atmosphere

October 18, 2016

Washington, Oct 18: In a first, NASA's MAVEN spacecraft has beamed back ultraviolet images of Mars that unveils dynamic, previously invisible activities in the atmosphere of the red planet such as change in ozone levels over the seasons and formation of clouds.master

The images were taken by the Imaging UltraViolet Spectrograph (IUVS) on the Mars Atmosphere and Volatile Evolution mission (MAVEN) - a space probe designed to study the Martian atmosphere while orbiting Mars.

These were then used to make this movie of rapid cloud formation on Mars on July this year.

The movie uses four MAVEN images to show about seven hours of Mars rotation during this period, and interleaves simulated views that would be seen between the four images.

"MAVEN obtained hundreds of such images in recent months, giving some of the best high-resolution ultraviolet coverage of Mars ever obtained," said Nick Schneider from the University of Colorado, Boulder in the US.

Nightside images show ultraviolet (UV) "nightglow" emission from nitric oxide (NO). Nightglow is a common planetary phenomenon in which the sky faintly glows in the complete absence of external light.

Mars' nightside atmosphere emits light in the ultraviolet due to chemical reactions that start on Mars' dayside.

Ultraviolet light from the Sun breaks down molecules of carbon dioxide and nitrogen, and the resulting atoms are carried around the planet by high-altitude wind patterns that encircle the planet.

On the nightside, these winds bring the atoms down to lower altitudes where nitrogen and oxygen atoms collide to form nitric oxide molecules. The recombination releases extra energy, which comes out as ultraviolet light.

Scientists predicted NO nightglow at Mars, and prior missions detected its presence, but MAVEN has returned the first images of this phenomenon in the Martian atmosphere.

Splotches and streaks appearing in the images occur where NO recombination is enhanced by winds.

Such concentrations are clear evidence of strong irregularities in Mars' high altitude winds and circulation patterns. These winds control how Mars' atmosphere responds to its very strong seasonal cycles.

Dayside images show the atmosphere and surface near Mars' south pole in unprecedented ultraviolet detail. They were obtained as spring comes to the southern hemisphere.

Ozone is destroyed when water vapour is present, so ozone accumulates in the winter polar region where the water vapour has frozen out of the atmosphere.

The images show ozone lasting into spring, indicating that global winds are inhibiting the spread of water vapour from the rest of the planet into winter polar regions.

MAVEN observations also show afternoon cloud formation over the four giant volcanoes on Mars.
Clouds are a key to understanding a planet's energy balance and water vapour inventory, so these observations will be valuable in understanding the daily and seasonal behaviour of the atmosphere, researchers said.

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Agencies
January 21,2020

Fifty-six journalists were killed in 2019 and most of them died outside conflict zones, a United Nations spokesperson said.

The number dropped by nearly half from the year 2018, but perpetrators enjoyed almost total impunity, Xinhua news agency quoted Stephane Dujarric, spokesperson for UN Secretary-General Antonio Guterres, as saying on Monday citing Unesco figures.

The figure was published in the 'Unesco Observatory of Killed Journalists' on Monday.

In total, Unesco recorded 894 journalist killings in the decade from 2010 to 2019, an average of almost 90 per year. The number in 2019 was 99.

Journalists were murdered in all regions of the world, with Latin America and the Caribbean recording 22 killings, the highest number, followed by 15 in Asia-Pacific, and 10 in Arab States.

"The figures show that journalists not only suffer extreme risks when covering violent conflict, but that they are also targeted when reporting on local politics, corruption and crime - often in their hometowns," the Unesco said.

Almost two thirds (61 per cent) of the cases in 2019 occurred in countries not experiencing armed conflict, a notable spike in a wider trend in recent years, and a reversal of the situation of 2014, when this figure was one third.

More than 90 per cent of cases recorded in 2019 concerned local journalists, consistent with previous years, it added.

In response to these figures, Audrey Azoulay, the Director-General of Unesco, said: "Unesco remains deeply troubled by the hostility and violence directed at all too many journalists around the world.

"As long as this situation lasts, it will undermine democratic debate."

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Agencies
March 15,2020

Tehran, Mar 15: Two hundred and thirty-four Indians stranded in coronavirus-hit Iran have arrived in India, External Affairs Minister S Jaishankar said on Sunday.

The batch comprises 131 students and 103 pilgrims, he said.

“234 Indians stranded in Iran have arrived in India; including 131 students and 103 pilgrims. Thank you Ambassador Dhamu Gaddam and @India_in_Iran team for your efforts. Thank Iranian authorities,” Jaishankar tweeted.

The third batch of Indians from Iran arrived early Sunday. A second batch of 44 Indian pilgrims had arrived from Iran on Friday.

Iran is one of the worst-affected countries by the coronavirus outbreak and the government has been working on plans to bring back Indians stranded there.

The first batch of 58 Indian pilgrims were brought back from Iran on Tuesday.

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Agencies
February 16,2020

Wuhan, Feb 16: The death toll from China's coronavirus epidemic has climbed to 1,665 after 142 more people died, mostly in the worst-hit Hubei Province, and the confirmed cases jumped to 68,500, officials said on Sunday, as top WHO experts scramble to assist Beijing contain the virus spread.

China's National Health Commission confirmed 2,009 new cases across the country.

Hubei and its provincial capital Wuhan, where the virus first emerged in December, reported 1,843 of the new cases. The latest report brought the total confirmed cases in Hubei to 56,249 cases.

Of the new deaths, 139 were in Hubei, two in Sichuan, and one in Hunan, the state-run Xinhua news agency reported.

The number of new cases, however, appears to have started dropping and a top Chinese health official has said efforts to control the outbreak have reached the “most crucial stage".

The report said 9,419 infected patients had been discharged from hospital after recovery so far.

The coronavirus has posed a severe threat to the medical staff as more than 1,700 Chinese health officials have been infected by the virus while treating the patients and six of them have died.

Experts from the World Health Organisation are expected in Beijing on Sunday to join Chinese health authorities in containing the virus, which has spread to several other countries forcing them to temporarily stop tourist arrivals from China.

The health commission said a joint mission with WHO experts will pay field visits to China's three provincial-level regions to learn the effectiveness of the epidemic control measures.

One task of the mission will be to come up with standard medicine to cure the disease, according to the health commission.

Several antiviral drugs are under clinical trials and Chinese researchers have narrowed down their focus to a few existing drugs, including Chloroquine Phosphate, Favipiravir and Remdesivir, said Zhang Xinmin, director of the China National Centre for Biotechnology Development.

Experts have asked people to frequently wash hands and face, and wear masks.

Authorities have begun quarantining large quantity of bank notes and coins in the affected areas and sanitising them with UV light before releasing them back into circulation to stop the virus from spreading.

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