Liquid water lake discovered on Mars

Agencies
July 26, 2018

Tampa, Jul 26: A massive underground lake has been detected for the first time on Mars, raising the possibility that more water -- and maybe even life -- exists there, international astronomers said Wednesday.

Located under a layer of Martian ice, the lake is about 12 miles (20 kilometres) wide, said the report led by Italian researchers in the US journal Science.

It is the largest body of liquid water ever found on the Red Planet.

"Water is there. We have no more doubt," co-author Enrico Flamini, the Italian space agency's Mars Express mission manager, told a press conference.

Mars is now cold, barren and dry but used to be warm and wet. It was home to plenty of liquid water and lakes at least 3.6 billion years ago.

Scientists are eager to find signs of contemporary water because such discoveries are key to unlocking the mystery of whether life ever formed on Mars in its ancient past, or if it might persist today.

"This is a stunning result that suggests water on Mars is not a temporary trickle like previous discoveries but a persistent body of water that provides the conditions for life for extended periods of time," said Alan Duffy, an associate professor at Swinburne University in Australia, who was not involved in the study.

Being able to access water sources could also help humans survive on a future crewed mission to Earth's neighbouring planet.

This particular lake, however, would be neither swimmable nor drinkable and lies almost a mile deep (1.5 kilometres) beneath the icy surface in a harsh and frigid environment.

Whether microbial forms of life could lie within is a matter of debate.

Some experts are sceptical of the possibility since the lake is so cold and briny, and mixed with a heavy dose of dissolved Martian salts and minerals.

The temperature is likely below the freezing point of pure water but can remain liquid due to the presence of magnesium, calcium, and sodium.

"This is a discovery of extraordinary significance, and is bound to heighten speculation about the presence of living organisms on the Red Planet," said Fred Watson of the Australian Astronomical Observatory.

"Caution needs to be exercised, however, as the concentration of salts needed to keep the water liquid could be fatal for any microbial life similar to Earth's," added Watson, who was not involved in the research.

The discovery was made using a radar instrument on board the European Space Agency's Mars Express orbiter, which launched in 2003.

The tool is called the Mars Advanced Radar for Subsurface and Ionosphere Sounding (MARSIS) and was designed to find subsurface water by sending radar pulses that penetrate the surface and ice caps.

MARSIS "then measures how the radio waves propagate and reflect back to the spacecraft," said the study.

These reflections "provide scientists with information about what lies beneath the surface."

A team of researchers led by Roberto Orosei of the Istituto Nazionale di Astrofisica in Bologna, Italy, surveyed a region called Planum Australe, located in the southern ice cap of Mars, from May 2012 until December 2015.

A total of 29 sets of radar samplings showed a "very sharp change in its associated radar signal," allowing scientists to map the outlines of the lake.

"The radar profile of this area is similar to that of lakes of liquid water found beneath the Antarctic and Greenland ice sheets on Earth, suggesting that there is a subglacial lake at this location on Mars," said the report.

Researchers said they are not sure how far down it goes, but maybe around three feet (one meter) deep.

"This is the first body of water it has detected, so it is very exciting," David Stillman, a senior research scientist in the Department of Space Studies at Southwest Research Institute in Texas, told AFP in an email.

However, Stillman, who was not involved in the research, said another spacecraft, or other instruments, need to be able to confirm the discovery.

He noted that a higher-frequency radar instrument made by the Italian space agency, SHARAD, onboard the Mars Reconnaissance Orbiter launched in 2005, has been unable to detect subsurface water.

"It is strange that SHARAD cannot confirm this discovery. In fact, SHARAD cannot penetrate through the ice here and no one understands why it can't," Stillman said.

"This suggests that something strange is going on here. Thus, I'm sceptical about this discovery."

But researchers are excited about the potential for future finds because if liquid water could be found at Mars' south pole, it might be elsewhere too.

"There's nothing special about this location other than the MARSIS radar on the Mars Express spacecraft is most sensitive to that region meaning there are likely similar water deposits below the ground all across Mars," said Duffy.

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Agencies
February 17,2020

Google on Monday announced it is gradually winding down its free public Wi-Fi Station programme currently available at over 400 railway stations in India, and will work with the Indian Railways and Railtel Corporation to help them with existing sites so they can remain useful resources for people.

Google launched its Station initiative in India in 2015 to bring fast, free public Wi-Fi to over 400 of the busiest railway stations in the country by mid-2020.

"We crossed that number by June 2018 and implemented Station in thousands of other locations around the country in partnership with telecommunications companies, ISPs and local authorities," Caesar Sengupta, Vice President, Payments and Next Billion Users, Google, said in a statement.

"Over time, partners in other countries asked for Station too and we responded accordingly. We're grateful for these partnerships, especially with the Indian Railways and the Government of India, that helped us serve millions of users over the last few years," he added.

According to Google, the decision to shut Station has been taken keeping the affordable mobile data plans and mobile connectivity in mind that is improving globally including in India.

"India, specifically now has among the cheapest mobile data per GB in the world, with mobile data prices having reduced by 95 per cent in the last 5 years, as per TRAI in 2019," said Sengupta.

The Indian users consume close to 10GB of data, each month, on average, according to reports.

"Our commitment to supporting the next billion users remains stronger than ever, from continuing our efforts to make the internet work for more people and building more relevant and helpful apps and services," Sengupta noted.

Global networking giant Cisco last year teamed up with Google to roll out free, high-speed public Wi-Fi access globally, starting with India.

The first pilot under the partnership was rolled out at 35 locations in Bengaluru.

Sengupta said that in addition to the changed context, the challenge of varying technical requirements and infrastructure among our partners across countries has also made it difficult for Station to scale and be sustainable, especially for our partners.

"And when we evaluate where we can truly make an impact in the future, we see greater need and bigger opportunities in building products and features tailored to work better for the next billion user markets," he said.

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Agencies
June 19,2020

Denser places, assumed by many to be more conducive to the spread of the coronavirus that causes COVID-19, are not linked to higher infection rates, say researchers.

The study, led by Johns Hopkins University, published in the Journal of the American Planning Association, also found that dense areas were associated with lower COVID-19 death rates.

"These findings suggest that urban planners should continue to practice and advocate for compact places rather than sprawling ones, due to the myriad well-established benefits of the former, including health benefits," says study lead author Shima Hamidi from Johns Hopkins Bloomberg School of Public Health in the US.

For their analysis, the researchers examined SARS-CoV-2 infection rates and COVID-19 death rates in 913 metropolitan counties in the US.

When other factors such as race and education were taken into account, the authors found that county density was not significantly associated with county infection rate.

The findings also showed that denser counties, as compared to more sprawling ones, tended to have lower death rates--possibly because they enjoyed a higher level of development including better health care systems.

On the other hand, the research found that higher coronavirus infection and COVID-19 mortality rates in counties are more related to the larger context of metropolitan size in which counties are located.

Large metropolitan areas with a higher number of counties tightly linked together through economic, social, and commuting relationships are the most vulnerable to the pandemic outbreaks.

According to the researchers, recent polls suggest that many US citizens now consider an exodus from big cities likely, possibly due to the belief that more density equals more infection risk.

Some government officials have posited that urban density is linked to the transmissibility of the virus.

"The fact that density is unrelated to confirmed virus infection rates and inversely related to confirmed COVID-19 death rates is important, unexpected, and profound," said Hamidi.

"It counters a narrative that, absent data and analysis, would challenge the foundation of modern cities and could lead to a population shift from urban centres to suburban and exurban areas," Hamidi added.

The analysis found that after controlling for factors such as metropolitan size, education, race, and age, doubling the activity density was associated with an 11.3 per cent lower death rate.

The authors said that this is possibly due to faster and more widespread adoption of social distancing practices and better quality of health care in areas of denser population.

The researchers concluded that a higher county population, a higher proportion of people age 60 and up, a lower proportion of college-educated people, and a higher proportion of African Americans were all associated with a greater infection rate and mortality rate.

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Agencies
June 8,2020

Washington DC, Jun 8: Astronomers acting on a hunch have likely resolved a mystery about young, still-forming stars and regions rich in organic molecules closely surrounding some of them.

They used the National Science Foundation's Karl G Jansky Very Large Array (VLA) to reveal one such region that previously had eluded detection and that revelation answered a longstanding question.

The regions around the young protostars contain complex organic molecules which can further combine into prebiotic molecules that are the first steps on the road to life.

The regions, dubbed "hot corinos" by astronomers, are typically about the size of our solar system and are much warmer than their surroundings, though still quite cold by terrestrial standards.

The first hot corino was discovered in 2003 and only about a dozen have been found so far. Most of these are in binary systems, with two protostars forming simultaneously.

Astronomers have been puzzled by the fact that, in some of these binary systems, they found evidence for a hot corino around one of the protostars but not the other.

"Since the two stars are forming from the same molecular cloud and at the same time, it seemed strange that one would be surrounded by a dense region of complex organic molecules and the other wouldn't," said Cecilia Ceccarelli, of the Institute for Planetary Sciences and Astrophysics at the University of Grenoble (IPAG) in France.

The complex organic molecules were found by detecting specific radio frequencies, called spectral lines, emitted by the molecules. Those characteristic radio frequencies serve as "fingerprints" to identify the chemicals.

The astronomers noted that all the chemicals found in hot corinos had been found by detecting these "fingerprints" at radio frequencies corresponding to wavelengths of only a few millimetres.

"We know that dust blocks those wavelengths, so we decided to look for evidence of these chemicals at longer wavelengths that can easily pass through dust," said Claire Chandler of the National Radio Astronomy Observatory, and principal investigator on the project.

"It struck us that dust might be what was preventing us from detecting the molecules in one of the twin protostars," added Chandler.

The astronomers used the VLA to observe a pair of protostars called IRAS 4A, in a star-forming region about 1,000 light-years from Earth. They observed the pair at wavelengths of centimetres.

At those wavelengths, they sought radio emissions from methanol, CH3OH (wood alcohol, not for drinking). This was a pair in which one protostar clearly had a hot corino and the other did not, as seen using the much shorter wavelengths.

The result confirmed their hunch. "With the VLA, both protostars showed strong evidence of methanol surrounding them. This means that both protostars have hot corinos. The reason we did not see the one at shorter wavelengths was because of dust," said Marta de Simone, a graduate student at IPAG who led the data analysis for this object.

The astronomers cautioned that while both hot corinos now are known to contain methanol, there still may be some chemical differences between them. That, they said, can be settled by looking for other molecules at wavelengths not obscured by dust.

"This result tells us that using centimetre radio wavelengths is necessary to properly study hot corinos," Claudio Codella of Arcetri Astrophysical Observatory in Florence, Italy, said.

"In the future, planned new telescopes such as the next-generation VLA and SKA, will be very important to understanding these objects," added Codella.

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