3D images show what lies beneath Mars poles

January 4, 2017

Washington, Jan 4: Scientists using data from a NASA probe have unveiled 3D subsurface images of Mars polar ice caps, showing previously obscured layering, larger volume of frozen carbon dioxide and bowl-shaped features that may be buried impact craters.mars

The information will help scientists better understand Martian climate changes and may allow them to determine the age of the polar caps without using climate models.

The 3D data volumes were assembled from observations by the Shallow Radar (SHARAD) onboard NASA's Mars Reconnaissance Orbiter (MRO) during more than 2000 orbit passes over each Martian pole.

"We have applied industry-developed techniques in a very novel fashion to a martian dataset, producing 3D volumes that are each over 600 times larger than any terrestrial or planetary dataset of this kind," said Nathaniel E Putzig, a senior scientist at the Planetary Science Institute in the US.

"It is gratifying to see so plainly in the SHARAD volumes structures that took years of effort to characterise with the single-orbit profiles," Putzig said.

Layering seen at the surface of the martian polar caps has been studied for decades. It has long been thought to represent a record of climate changes on that planet.

The interior structures of the caps remained a mystery until the arrival of radar sounders at Mars in the last decade.

An early version of the north polar 3D volume helped to assess the quantity of water ice transferred to the polar caps in the most recent retreat from a martian ice age.

First looks at the south polar 3D volume indicate that previously mapped deposits of carbon dioxide ice are somewhat larger than reported.

In both polar 3D volumes, known impact craters in and near the polar caps that are partially filled with ice have distinctive bowl-shaped signatures in the radar data, and similar signatures are found elsewhere within the polar ices but without any surface expression.

Whether the latter structures truly are impact craters remains to be determined.
Age estimates of planetary surfaces throughout the solar system rely on statistical data for impact craters on the Moon's surface calibrated to radiometrically dated samples returned during the Apollo programme.

This method has been used to estimate the surface ages of the martian polar caps, but estimates for the ages of the caps themselves have had to rely on numerical models of past climate changes.

If a sufficient number of the bowl-shaped features found in the radar volumes are shown to be impact craters, scientists will be able to assess the age of the polar caps using cratering statistics alone.

The extent to which age estimates from this new volumetric method agree or disagree with those from climate models will have important implications for the accuracy of these dating techniques.

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Agencies
June 18,2020

New Delhi, Jun 18: Vodafone Idea on Thursday told the Supreme Court that it has incurred Rs 1 lakh crore losses as it insisted it is not in a position to furnish bank guarantees.

A bench comprising Justices Arun Mishra, S. Abdul Nazeer, and M.R. Shah, taking up the adjusted gross revenue (AGR) matter through video conferencing, directed the telecom companies to submit their financial documents and books for the last 10 years.

Asking Vodafone if it was a foreign company, the bench said that how can the company say it would not furnish any bank guarantee.

"What if you fly away overnight in future without paying anything?" it asked.

Senior advocate Mukul Rohatgi, representing Vodafone Idea, denied his client is a completely foreign firm and cited before the bench its tie-ups and investments.

Vodafone owes over Rs 58,000 crore as AGR dues and so far, has paid close to Rs 7,000 crore.

Rohatgi contended before the court that the telecom company is in a tough situation, and cannot furnish any fresh bank guarantee, as profits have eluded the company in past many quarters. He submitted before the bench that Rs 15,000 crore bank guarantees are lying with the government, and his client's losses are over Rs 1 lakh crore.

"I cannot offer any more surety," he informed the bench.

Justice Mishra noted that this is public money and these dues should be recovered. "Do not tell us that you will pay if you were to make profits... the money must come," he noted.

Justice Shah observed that the telecom industry is the only industry which earned during the Covid-19 pandemic. "After all, this money will be used for public welfare", he said.

Rohatgi argued that his client would have to fold up if orders were issued to clear dues tomorrow. "11,000 employees will have to go without notice, as we cannot pay them," he added.

Senior advocate Abhishek Manu Singhvi, appearing for Bharti Airtel, contended before the court that out of Rs 21,000 crore AGR dues, the company has already deposited a sum of Rs 18,000 crore.

He argued that his client has given a bank guarantee, in excess of demand, to DoT, and supported the proposal for phased repayment of remaining AGR dues. He insisted that the company needs to sit down with the government and calculate the dues. Airtel owes Rs 25,976 crore after paying Rs 18,000 crore, as per the government.

Senior advocate Arvind Datar, representing Tata Telecom, informed the bench that his client has paid Rs 6,504 crore in AGR dues so far, and furnishing a bank guarantee may adversely impact investments in the sector.

The total AGR dues are close to Rs 1.5 lakh crore.

The top court will now take up the matter in the third week of July.

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Agencies
June 29,2020

New Delhi, Jun 29: Witnessing azure skies and breathable air for the last three months, Delhi on Monday recorded deterioration in its air quality, with particulate matter with diameter of 2.5 and 10 microns -- too small to be filtered out of the human body -- standing at 52 and 297 micrograms per cubic respectively.

Gufran Beig, Project Director of System of Air Quality Weather Forecasting and Research (SAFAR), said that the sudden spike in air pollution is due to a mild dust storm blowing from Rajasthan.

"Since the wind direction is changing and moist air is coming in, the air quality in Delhi will become better by tomorrow," Beig told IANS.

Central Pollution Control Board (CPCB) data showed that the overall air quality near Delhi Technical University (DTU) area stood at 326 micrograms per cubic, followed by 308 at Narela and 307 at Mundka.

Out of 36 stations, the AQI in as many as 30 stations was above 200 micrograms per cubic till 1 pm on Monday.

The System of Air Quality Weather Forecasting and Research categorises air quality in the 0-50 range as good, 51-100 as satisfactory, 101-200 as moderate, 201-300 as poor, 301-400 as very poor, and above 400 as severe.

According to SAFAR's website, "PM 10 (coarser dust particle) is the lead pollutant. AQI is likely to improve to moderate category by tomorrow, and further improvement is expected by July 1."

Researchers indicated that PM 10 and PM 2.5 will be 170 and 47 micrograms per cubic on Tuesday.

With no vehicles plying on the roads or industries shut due to the lockdown since March 25, Delhi's air quality had improved drastically.

According to a study conducted by the Indian Institute of Technology (IIT), Delhi, if the low levels of air pollution reached during the lockdown period are maintained, India's annual death toll could reduce by 6.5 lakh.

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Agencies
January 25,2020

New Delhi, Jan 25: The Patiala House court on Saturday started hearing a plea filed by the Nirbhaya convicts that alleged that the Tihar Jail administration have "not presented the papers on time".

The Public Prosecutor informed the court that Tihar Jail authorities have already supplied the relevant documents. He further informed that these are mere delaying tactics adopted by the convicts.

Advocate A.P. Singh, lawyer for three of the four death row convicts in the Nirbhaya gang-rape case had moved an application before the court seeking directions to the Tihar Jail authorities to supply him the relevant documents in order to exercise the remaining legal remedies available with the death row convicts -- Vinay Pawan and Akshay.

The Public Prosecutor also told the court that he spoke to the jail authorities over the phone and a report in this regard will be filed shortly as the jail officials were on their way to the court.

The judge demanded from the convicts lawyer to show what he has filed.

The convicts lawyer, A.P. Singh, said that he received some documents, but has still not been supplied with the personal diary of one of the convict -- Vinay Kumar Sharma and also the medical documents.

Judge then asked the lawyer to wait for until the report arrives form the Tihar Jail.

On this, the convicts lawyer said he was not questioning the intention of the jail. "I know the jail has been changed. It isn't there fault, too," he said.

The Public Prosecutor refuted the allegation saying that the defence counsel was trying to defeat the speed of law.

"We have supplied all the documents to the counsel. We have supplied all the documents except the painting and some other documents. We have nothing apart from that," public prosecutor said.

Singh, in his plea filed before the Patiala House Court sought urgent orders of the court in order to file a mercy petition of Vinay Sharma and in relation to requests for documents for convicts Vinay Sharma, Pawan Kumar Gupta and Akshay Kumar Singh.

He further said that the convicts undertook several steps to obtain relevant information necessary for filing the mercy petitions. In regular interval, the convicts requested the concerned authority to supply documents pertaining to their medical records from 2012 to 2015 and 2019-2020, records of cellular confinement, records of the amount earned in prison through labour, records of educational and reformative activities like Tihar Olympics and Painting, etc.

The Supreme court had recently dismissed the curative petition for the other two convicts -- Vinay Kumar Sharma (26) and Mukesh Singh (32).

The court had recently issued death warrant against the convicts and fixed 6 a.m. on February 1 as the date and time of execution of the death penalty.

The 23-year-old victim in the case was brutally gang raped and tortured on December 16, 2012, which later led to her death. All the six accused were arrested and charged with sexual assault and murder. One of the accused was a minor and appeared before a juvenile justice court, while another accused committed suicide in Tihar Jail.

Four of the convicts were sentenced to death by a trial court in September 2013, and the verdict was confirmed by the Delhi High Court in March 2014 and subsequently upheld by the Supreme Court in May 2017, which also dismissed their review petitions.

A Juvenile involved in the crime was convicted by a juvenile justice board and released from a reformation home after serving a three-year term.

Hearing in a different case, Chief Justice of India S.A. Bobde on Thursday said a condemned person cannot fight the death penalty endlessly and it was important for the capital punishment to reach its finality.

The death penalty, he noted, cannot be questioned at every turn by the convict.

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