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
May 25,2020

The Japan government on Monday decided to lift the state of emergency for COVID-19 in Tokyo and four other prefectures of the country, the only places where the measure implemented to curb the pandemic had remained in force.

The lifting of the alert was backed by the coronavirus advisory panel and will be formally approved by the government later day, the economic revitalization minister and head of the working group to coordinate Japan's fight against COVID-19, Yasutoshi Nishimura, said.

The Japanese authorities made the decision after taking into account the number of infections and the situation of the health system in Tokyo, the three neighbouring prefectures of Chiba, Kanagawa and Saitama and the northern Hokkaido, the only ones where the state of emergency declared more than a month ago to control the pandemic remained in effect, reports Efe news.

The health alert was initially declared in Tokyo and six other prefectures on April 17 and subsequently extended across the country.

It allowed local authorities to ban large-scale public events and close bars and restaurants at night, among other measures, while the government has launched a campaign to encourage teleworking and staying at home.

The government resorted to this measure for the first time in the country's recent history to contain the spread of the virus and is now withdrawing it after a sustained slowdown in infections throughout the archipelago, where around 16,600 confirmed COVID-19 cases and 839 deaths have been recorded, according to the latest data.

The group of experts advising the government appreciated the efforts made by citizens to comply with the recommendations to achieve the target of reducing interpersonal contact by 80 percent, top government spokesperson Yoshihide Suga said at a press conference on Monday.

The recommendation for citizens to avoid unnecessary trips outside and the request for non-essential businesses to close were not mandatory nor accompanied by fines or other penalties for non-compliance, unlike the stricter containment measures implemented in other countries.

The government plans to formally approve the lifting of the state of emergency on Monday after consulting with other political parties in parliament and another meeting with the advisory panel, following which Japanese Prime Minister Shinzo Abe will hold a press conference.

The government had already decided to lift the emergency in 39 prefectures on May 14 after they reported a marked decrease in the number of infections, leaving out the more populated regions such as Tokyo and Osaka.

To avoid new outbreaks of the virus, Abe has urged people to become accustomed to a "new lifestyle" that includes maintaining social distancing, the use of masks outside as well as a series of guidelines for the reopening of shops, restaurants and public facilities.

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Agencies
June 24,2020

Washington, Jun 24: Twitter has once again flagged a tweet from US President Donald Trump which promoted violence by saying if protesters tried to set up an "autonomous zone" in Washington, DC they would be met with "serious force".

This is the fourth time Twitter has red flagged Trump's tweet for glorifying violence or violating its policies.

Trump has been critical of the "autonomous zone" in Seattle, an area occupied by protestors for much of this month.

"We've placed a public interest notice on this Tweet for violating our policy against abusive behaviour, specifically, the presence of a threat of harm against an identifiable group," Twitter's safety team tweeted late Tuesday.

Trump had tweeted: "There will never be an ‘Autonomous Zone' in Washington, D.C., as long as I'm your President. If they try they will be met with serious force!"

Twitter earlier labeled a video tweeted by him which mocked CNN as manipulated media.

According to Twitter, "this Tweet has been labeled per our synthetic and manipulated media policy to give people more context".

In May, Twitter labeled two Trump tweets that made false claims about mail-in ballots in California.

Twitter later labeled another Trump tweet glorifying violence in which he said, "when the looting starts, the shooting starts."

Facebook also removed a Trump campaign ad featuring a symbol used by Nazis for political dissenters, saying the ad violated its policies.

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News Network
June 15,2020

Beijing, Jun 15: China is locking now ten more neighbourhoods in Beijing to try and contain the spread of a new coronavirus outbreak linked to a food market, authorities announced Monday.

City official Li Junjie said at a press conference that fresh cases had been found in a second wholesale market in northwestern Haidian district, and as a result, the market and nearby schools would be closed, and people living in ten communities around it placed under lockdown.

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