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
February 29,2020

Doha, Feb 29: The United States signed a landmark deal with the Taliban on Saturday, laying out a timetable for a full troop withdrawal from Afghanistan within 14 months as it seeks an exit from its longest-ever war.

President Donald Trump urged the Afghan people to embrace the chance for a new future, saying the deal held out the possibility of ending the 18-year conflict.

"If the Taliban and the government of Afghanistan live up to these commitments, we will have a powerful path forward to end the war in Afghanistan and bring our troops home," he said on the eve of the event in Doha.

Secretary of State Mike Pompeo arrived in the Qatari capital to witness the signing of the accord, while Defence Secretary Mark Esper was in Kabul for a separate joint declaration with the Afghan government.

The agreement is expected to lead to a dialogue between the Kabul government and the Taliban that, if successful, could ultimately see the Afghan war wind down.

But the position of the Afghan government, which has been excluded from direct US-Taliban talks, remains unclear and the country is gripped by a fresh political crisis amid contested election results.

The United States and its allies will withdraw all their forces from Afghanistan within 14 months if the Taliban abide by the Doha agreement, Washington and Kabul said in a joint statement.

After an initial reduction of troops to 8,600 within 135 days of Saturday's signing, the US and its partners "will complete the withdrawal of their remaining forces from Afghanistan within 14 months... and will withdraw all their forces from remaining bases", the declaration stated.

The Doha accord was drafted over a tempestuous year of dialogue marked by the abrupt cancellation of the effort by Trump in September.

The signing comes after a week-long, partial truce that has mostly held across Afghanistan, aimed at building confidence between the warring parties and showing the Taliban can control their forces.

NATO Secretary General Jens Stoltenberg heralded the agreement as a "first step to lasting peace".

"The way to peace is long and hard. We have to be prepared for setbacks, spoilers, there is no easy way to peace but this is an important first step," the Norwegian former prime minister told reporters in Kabul.

Since the US-led invasion that ousted the Taliban after the September 11, 2001 attacks, America has spent more than $1 trillion in fighting and rebuilding in Afghanistan.

About 2,400 US soldiers have been killed, along with unknown tens of thousands of Afghan troops, Taliban fighters and Afghan civilians.

The insurgents said they had halted all hostilities Saturday in honour of the agreement.

"Since the deal is being signed today, and our people are happy and celebrating it, we have halted all our military operations across the country," Taliban spokesman Zabihullah Mujahid told AFP.

Close to 30 nations were represented at Saturday's signing in the Qatari capital.

While Kabul will not be represented at the Doha ceremony, set for 1245 GMT, it will send a six-person taskforce to the Qatari capital to make initial contact with the Taliban political office, established in 2013.

Any insurgent pledge to guarantee Afghanistan is never again used by jihadist movements such as Al-Qaeda and the Islamic State group to plot attacks abroad will be key to the deal's viability.

The Taliban's sheltering of Al-Qaeda was the main reason for the US invasion following the 9/11 attacks.

The group, which had risen to power in the 1990s in the chaos of civil war, suffered a swift defeat at the hands of the US and its allies. They retreated before re-emerging to lead a deadly insurgency against the new government in Kabul.

After the NATO combat mission ended in December 2014, the bulk of Western forces withdrew from the country, leaving it in an increasingly precarious position.

While Afghans are eager to see an end to the violence, experts say any prospective peace will depend on the outcome of talks between the Taliban and the Kabul government.

But with President Ashraf Ghani and rival Abdullah Abdullah at loggerheads over contested election results, few expect the pair to present a united front, unlike the Taliban, who would then be in a position to take the upper hand in negotiations.

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News Network
May 28,2020

Geneva, May 28: The global death toll from the novel coronavirus has risen over the past 24 hours by 5,581 to 349,095, the World Health Organization (WHO) said in its daily situation report.

The number of confirmed cases has increased by 84,314 to 5,488,825, the WHO said.

Most cases of infection are recorded in the Americas (North and South America) - 2,495,924, with 145,810 deaths. While Europe has reported 2,061,828 cases and 1,76,226 deaths so far.

As per WHO tally, the US has the highest number of cases in the world with 1,63,4010 infections.

The global health body declared the outbreak of the new coronavirus a pandemic on March 11.

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News Network
May 19,2020

Washington, May 19: As the scientists across the world are struggling to develop a vaccine for combating coronavirus, US drugmaker Moderna announced on Monday (local time) that the phase I trial of its Covid-19 vaccine has shown positive early results.

The company is hopeful that it's vaccine could be available to the public as early as January next year. Several firms across the world are in the race to develop a vaccine for the deadly virus which has claimed over 3 lakh lives worldwide.

CNN citing Dr. Tal Zaks, Moderna's chief medical officer reported that "if future studies go well, the company's vaccine could be available to the public as early as January".

"This is absolutely good news and news that we think many have been waiting for for quite some time," Zaks was quoted as saying.

Moderna, based in Cambridge, Massachusetts announced that the vaccine developed neutralising antibodies to the virus at levels reaching or exceeding the levels seen in people who have naturally recovered from Covid-19, reported CNN.

These will be followed by phase 2 trials and phase 3 trials, which Moderna plans to start in July.

President Donald Trump had on Friday said that that the United States will be able to deliver a few hundred million doses of COVID-19 vaccine, under 'Operation Warp Speed', by the end of this year.

"I have very recently seen early data from a clinical trial with a coronavirus vaccine and this data made me feel even more confident that we'll be able to deliver a few hundred million doses of vaccine by the end of 2020 and we will do the best we can," Trump had said at a press conference at the White House on Friday.

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