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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News Network
June 17,2020

Washington, Jun 17: The United States is closely monitoring the situation following a fierce clash between Indian and Chinese forces in eastern Ladakh and hopes that the differences will be resolved peacefully, officials said here.

Twenty Indian Army personnel including a colonel were killed in the clash with Chinese troops in the Galwan Valley in eastern Ladakh on Monday night, the biggest military confrontation in over five decades that has significantly escalated the already volatile border standoff in the region.

"We are closely monitoring the situation between Indian and Chinese forces along the Line of Actual Control," a State Department spokesperson said.

"We note the Indian military has announced that 20 soldiers have died, and we offer our condolences to their families," the official said.

Both India and China have expressed their desires to de-escalate and the US supports a peaceful resolution of the current situation, the spokesperson said.

"During their phone call on June 2, 2020, President Donald Trump and Prime Minister Narendra Modi had discussed the situation along the India-China border," the official added.

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News Network
May 30,2020

Washington, May 30: President Donald Trump said Friday he would strip several of Hong Kong's special privileges with the United States and bar some Chinese students from US universities in anger over Beijing's bid to exert control in the financial hub.

In a day of concerted action, the United States and Britain also raised alarm at the UN Security Council over a controversial new security law for Hong Kong, angering Beijing which said the issue had no place at the world body.

In a White House appearance that Trump had teased for a day, the US president attacked China over its treatment of the former British colony, saying it was "diminishing the city's longstanding and proud status."

"This is a tragedy for the people of Hong Kong, the people of China and indeed the people of the world," Trump said.

Trump also said he was terminating the US relationship with the World Health Organization, which he has accused of pro-China bias in its management of the coronavirus crisis.

But Trump was light on specifics and notably avoided personal criticism of President Xi Jinping, with whom he has boasted of having a friendship even as the two powers feud over a rising range of issues.

"I am directing my administration to begin the process of eliminating policy that gives Hong Kong different and special treatment," Trump said.

"This will affect the full range of agreements, from our extradition treaty to our export controls on dual-use technologies and more, with few exceptions," he said.

Secretary of State Mike Pompeo on Wednesday informed Congress that the Trump administration would no longer consider Hong Kong to be separate under US law, but it was up to Trump to spell out the consequences.

China this week pressed ahead on a law that would ban subversion and other perceived offenses against its rule in Hong Kong, which was rocked by months of massive pro-democracy protests last year.

US restricts students

In one move that could have long-reaching consequences, Trump issued an order to ban graduate students from US universities who are connected to China's military.

"For years, the government of China has conducted elicit espionage to steal our industrial secrets, of which there are many," Trump said.

Hawkish Republicans have been clamoring to kick out Chinese students enrolled in sensitive fields. The FBI in February said it was investigating 1,000 cases of Chinese economic espionage and technological theft.

But any move to deter students is unwelcome for US universities, which rely increasingly on tuition from foreigners and have already been hit hard by the COVID-19 shutdown.

China has been the top source of foreign students to the United States for the past decade with nearly 370,000 Chinese at US universities, although Trump's order will not directly affect undergraduates.

Critics say Trump has been eager to fan outrage about China to deflect attention from his own handling of the coronavirus pandemic that has killed more than 100,000 people in the United States, the highest number of deaths of any country.

Chuck Schumer, the top Democrat in the Senate, called Trump's announcement "just pathetic."

Eliot Engel, a Democrat who heads the House Foreign Affairs Committee, noted that Trump treaded lightly on Hong Kong during last year's protests as he sought a trade deal with Xi.

"Now, the president wants to shift the blame for his failures onto China, so he's doing the right thing for the wrong reason," Engel said.

Trump's order could also trigger retaliation. China in March expelled US journalists after the Trump administration tightened visa rules for staff at Chinese state media.

Clash at UN

The United States and Britain earlier in the day urged China to reconsider the Hong Kong law during talks at the UN Security Council, where China wields a veto -- making any formal session, let alone action against Beijing, impossible.

The Western allies raised Hong Kong in an informal, closed-door videoconference where China cannot block the agenda.

They said China was violating an international commitment as the 1984 handover agreement with Britain, in which Beijing promised to maintain the financial hub's separate system until at least 2047, was registered with the United Nations.

"The United States is resolute, and calls upon all UN members states to join us in demanding that the PRC immediately reverse course and honor its international legal commitments to this institution and to the Hong Kong people," said US Ambassador Kelly Craft, referring to the People's Republic of China.  

China demanded that the United States and Britain "immediately stop interfering in Hong Kong affairs," saying the law did not fall under the Security Council's mandate.

"Any attempt to use Hong Kong to interfere in China's internal matters is doomed to fail," warned a statement from China's UN mission.

"There was no consensus, no formal discussion in the Security Council, and the US and the UK's move came to nothing," it said.

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Agencies
June 16,2020

China on Tuesday justified the killing of an army officer and two soldiers of India and accused Indian troops of crossing a disputed border between the two countries.

Foreign ministry spokesman Zhao Lijian said Indian troops crossed the border line twice on Monday, "provoking and attacking Chinese personnel, resulting in a serious physical confrontation between border forces on the two sides".

An Indian Army officer and two soldiers have been killed in a "violent face-off" with Chinese troops along the Line of Actual Control (LAC), disrupting the fragile peace talks.

"During the de-escalation process underway in the Galwan Valley, a violent face-off took place last night with casualties on both sides," the Indian Army said in a statement.
 

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