Most of Mars' air was 'lost to space'

It is clear now that a big fraction of the atmosphere of Mars was stripped away to space early in its history.

A new analysis, combining measurements by the Maven satellite in orbit around the Red Planet and the Curiosity rover on its surface, indicate there was probably once a shroud of gases to rival even what we see on Earth today.

The composition would have been very different, however.

The early Martian air, most likely, had a significant volume of carbon dioxide.

That would have been important for the climate, as the greenhouse gas might have been able to warm conditions sufficiently to support nascent lifeforms.

"We're in the process of tallying up what the total amount removed was, but I'm going to guess right now that the amount of atmosphere that was present was about as thick as the Earth's atmosphere - about one or two bars of gas," said Bruce Jakosky from the University of Colorado in Boulder, US.

"The bulk of that - maybe 80-90% - has been lost to space," he told the BBC.

Prof Jakosky is the principal investigator on the US space agency's (Nasa) Mars Atmosphere and Volatile Evolution Mission (Maven) satellite.

Since arriving at the Red Planet in 2014, Maven has been studying the composition and behaviour of the upper atmosphere.

And for a new paper just published in Science magazine, the satellite has looked in detail at the properties of the noble gas argon.

Atoms of this gas exist only in small numbers - just a few parts per million.

But argon is very instructive. It is inert: it will not react with other components of the atmosphere or indeed surface materials such as rocks.

This means the only way it can be lost from Mars' air is by being dragged away into space by the abrasive action of the solar wind - the billowing stream of charged particles constantly flowing from the Sun.

Just how much argon has been removed over the course of 4.5 billion years of Mars history is divined from the ratio of heavy to light versions, or isotopes, of the atom. The light version (argon-36) escapes more easily than the heavy version (argon-38), which leaves the gas remaining behind enriched in the more massive isotope.

Prof Jakosky and his team used the relative abundance of the two argons - measured by Maven in the upper atmosphere and by Nasa's Curiosity robot at the surface - to estimate the fraction of gas that must have disappeared over time.

"What we've seen from the argon measurements is that about two-thirds of the argon that was ever in the atmosphere has been lost to space. That means that most of the gas in the atmosphere has been lost," the PI explained on the Science In Action programme of the BBC World Service.

"Argon isn't an important gas for understanding the climate, but it does tell us about the carbon dioxide, because the same processes that can remove argon can also remove carbon dioxide. So, we're able to determine that the bulk of the CO2 in the atmosphere has also been lost to space through time."

The findings are important because they inform our understanding of how an ancient Mars was able to retain liquid water at its surface - a scenario that would have been conducive to life.

Today, the thin air produces a pressure that cannot support any exposed water; it would rapidly boil away. So a much thicker shroud of gas in the past is really essential from the point of view of habitability.

Climate conundrum

That liquid water once stood on Mars' surface or flowed freely at times seems obvious. Pictures of the planet reveal the traces of countless river beds, flood plains and deltas. And the Curiosity rover has found definitive evidence of persistent lakes at its operation site in Gale Crater.

However, climate models, based on the limited evidence to date of what the atmosphere was like, have struggled to simulate a Mars on which conditions were warm enough to allow lots of liquid water. Much of it would have been locked up in ice, they suggest.

"There's always been this tension between the geologists who see these rivers and lakes, and the modellers who say they can't get the atmospheric conditions to tie in," commented Dr Matt Balme, a planetary scientist at the UK Open University.

"The Maven results are great because what's been stopping the models being useful is that we don't know what the CO2 inventory really was.

"Knowing now that the atmosphere had a pressure of one to two bars will be very helpful in that respect, and there is sure now to be another round of climate modelling to see if we can't better address some of these issues."

Success for SpaceX 're-usable rocket'

California's SpaceX company has successfully re-flown a segment from one of its Falcon 9 rockets.

The first-stage booster, which was previously used on a mission 11 months ago, helped send a telecommunications satellite into orbit from Florida's Kennedy Space Center.

It marks an important milestone for SpaceX in its quest for re-usability.

Traditionally, rockets are expendable - their various segments are discarded and destroyed during an ascent.

The California outfit, in contrast, aims to recover Falcon first-stages and fly them multiple times to try to reduce the cost of its operations.

And to emphasise this point, Thursday's booster was also brought back under control to land on a barge stationed out in the Atlantic.

"I think it's an amazing day for space," said Elon Musk, the chief executive of SpaceX.

"It means you can fly and re-fly an orbit class booster, which is the most expensive part of the rocket. This is going to be, hopefully, a huge revolution in spaceflight."

The satellite passenger, SES-10, was ejected some 32 minutes later.

This spacecraft is now being manoeuvred by its own thruster system to a position over the equator from where it can deliver TV and telecom services to the Caribbean, Brazil, and other regions in Central and South America.

SpaceX has become adept in the past two years at bringing first-stage boosters home after they have completed their primary task of getting a payload out of the thicker lower-reaches of the atmosphere.

The segments autonomously guide themselves back to the floating platform or a coastal pad to make propulsive landings.

Thursday's mission was the first time one of these "flight proven" vehicles had been re-launched.

Other landed boosters will now be used on future missions. Another six this year, most likely.

Some customers may still insist on a brand new rocket, but if SpaceX can demonstrate routine, untroubled performance from these second-hand vehicles then satellite operators will get increasingly comfortable with the concept.

Getting away from expendable rockets has been a long quest.

Famously, Nasa's space shuttle system was partially re-usable.

Its white solid-fuel strap-on boosters, for example, would parachute into the Atlantic after each launch. The casings of these boosters were then refurbished and re-used numerous times.

And yet the complexities of servicing the shuttle system after every flight swamped any savings.

SpaceX hopes its simpler Falcon 9 rocket can finally deliver a practical commercial solution. It believes its technology will eventually permit rapid turnaround, with boosters flying perhaps 10 times before being retired; maybe even up to 100 times with a certain level of refurbishment.

"With this being the first re-light we were incredibly paranoid about everything," Mr Musk said.

"The core airframe remained the same, the engines remained the same - but any auxiliary components that we thought might be slightly questionable, we changed out. Now our aspiration will be zero hardware changes, re-flight in 24 hours - the only thing that changes is that we reload propellant."

SpaceX hopes its simpler Falcon 9 rocket can finally deliver a practical commercial solution. It believes its technology will eventually permit rapid turnaround, with boosters flying multiple times before being retired.

Other players are following close behind. The Amazon entrepreneur Jeff Bezos already has a re-usable sub-orbital rocket and capsule system that he has successfully launched and landed five times.

Mr Bezos now plans a recoverable orbital rocket called New Glenn. And United Launch Alliance, which puts up the majority of America's national security payloads, is in the process of designing a new vehicle that will return its engines to Earth via parachute.

All this is welcome news for the likes of Luxembourg satellite operator SES, which is having to queue up for rocket rides and wait many months to get its valuable telecoms spacecraft in orbit and earning revenue.

"It's a big deal for us. If we can get reliable re-usability then we will get better management of the manifest," said Martin Halliwell, the chief technology officer for SES.

"We made a little bit of history today, actually. We just opened the door to a whole new era of spaceflight,"

Rikers Island: NYC mayor backs plan to close prison

Mayor Bill de Blasio has announced his support to close New York City's notorious prison on Rikers Island.

Mr de Blasio said closing Rikers would be "long and arduous", but that local officials and stakeholders had a "moral obligation" to do so.

The mayor said on Friday he was developing a plan to close the prison within 10 years.

He had previously said that replacing the massive jail complex would be too expensive.

"It will take many years. It will take many tough decisions along the way, but it will happen," he said at a press conference on Friday.

Mr de Blasio said that closing the prison, which houses about 10,000 inmates, would require cutting the jail population roughly in half.

"The length of this process will also require continued investment in the facilities and conditions on Rikers Island that remain key to rehabilitation efforts for thousands of New Yorkers in the years ahead," he added in a statement.

Details of the plan to close the prison have yet to be released.

An independent commission, led by the state's former chief judge, has been reviewing options to close Rikers as part of a larger probe into the city's criminal justice system.

The commission was created following a series of brutality cases revealing questionable practices and corruption at the prison complex.

One of the recommendations included moving inmates into a system of smaller jails across the New York City boroughs at a cost of $10.6bn (£8.4bn), according to US media reports.

The mayor, who is up for re-election this year, has previously said that shutting the prison was a "noble idea" but would cost the city billions of dollars and take years to close.

Dutch student flies to Sydney, Nova Scotia by accident

A Dutch student learned the hard way that some deals are too good to be true when he landed in Sydney, Canada instead of Sydney, Australia.

Milan Schipper told the CBC that he bought his flight because it was much cheaper than all the other tickets.

Instead of heading straight to the beach, as he had planned, he found himself in near-blizzard conditions with nothing more than a light jacket.

Airline employees helped him book a return ticket home to Amsterdam.

The 18-year-old says he knew something was amiss when he had a layover in Toronto, and his connecting flight was in a small Air Canada plane.

"The plane was really small and so I figured, would that make it to Australia?" he told the CBC.

It's not the first time hapless travellers have made that mistake.

In 2002, a young British couple also landed in the Sydney more famous for its lobster boats than its opera house.

In 2009, the Daily Mail reported that a Dutch grandfather travelling with his son also wound up there by accident. Italian tourists made a similar error in 2010.

Once Mr Schipper landed, airline employees helped him book a ticket back to Toronto, so that he could return to the Netherlands.

His father, he told the CBC, "laughed an awful lot" when he picked Mr Schipper up at the airport in Amsterdam.

Jewellery and cars seized as Dutch trigger multi-country tax raids

Dutch prosecutors say they have launched co-ordinated raids in several countries against suspected money-launderers and tax evaders.

They are investigating about 3,800 Dutch-linked accounts in an unnamed Swiss bank following a tip-off they could contain undeclared assets.

Paintings, a gold bar, cash, a luxury car and jewellery have been seized.

As well as the Netherlands, there have been searches in France, Germany, the UK and Australia.

The Dutch government has passed information to the other countries about more than 50,000 suspect accounts at the bank.

UK authorities said the investigation was also targeting senior bank employees.

The suspicion is that these hidden assets are largely ill-gotten gains, the proceeds of crime. The Dutch financial investigations service has highlighted the unfairness and corrupting nature of tax evasion.

While the practice is apparently becoming more prevalent, the authorities say so too is the exchange of data between governments, the use of smart data to track payments and the use of informants.

The Dutch authorities have warned that the international co-operation is making it harder for the secret bankers to remain below the radar.

But in taking this co-ordinated action without apparently consulting their Swiss colleagues, the Dutch have diluted what might otherwise been seen as a EU-co-ordinated triumph.

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The co-ordinated raids on suspects' properties began on Thursday, the Dutch office for financial crimes prosecution (FIOD) said in a statement.

The cross-border operation is being supported by Eurojust, the EU's judicial co-operation unit, which said the suspect funds ran into the millions of euros.

Credit Suisse bank has released a statement saying its offices in London, Paris and Amsterdam "were contacted by local authorities concerning client tax matters. We are co-operating with the authorities".

It said it "continues to follow a strategy of full client tax compliance".

However, it did not explicitly confirm that it was the institution at the centre of the investigation.

The Swiss bank has already been in difficulty over its customers' taxes in the United States, says the BBC's economics correspondent Andrew Walker. In 2014 it agreed to pay a fine of $2.6bn (then £1.5bn; €1.9bn).

But the Swiss attorney general expressed annoyance that it had not been informed in advance about the operation.

"The Office of the Attorney General of Switzerland is disconcerted about the manner in which this has been organised with the conscious non-inclusion of Switzerland," it said in an emailed statement.

"The applicable practices and rules of international co-operation and legal assistance have obviously not been complied with here.

"The attorney general expects a written explanation from the relevant leading Dutch authorities and is examining further actions," the OAG said.

The Netherlands raids targeted homes in four locations - The Hague, Hoofddorp, Zwolle and the municipality of Venlo. Two people were detained for interrogation.

In Australia, authorities said investigators were looking for the owners of 340 anonymous bank accounts.

The UK tax inspection body, HMRC, confirmed that it had launched "a criminal investigation into suspected tax evasion and money-laundering by a global financial institution and certain of its employees".

"The first phase of the investigation, which will see further, targeted, activity over the coming weeks, is focused on senior employees from within the institution, along with a number of its customers," HMRC said.

"The international reach of this investigation sends a clear message that there is no hiding place for those seeking to evade tax."

The investigation will continue for weeks to come, Dutch financial prosecutors said.

FBI re-releases 9/11 photos of Pentagon

Photos taken after the attack on the Pentagon on 11 September 2001 have reappeared on the FBI's website six years after they were first released.

The 27 images show fire crews battling the blaze, as well as recovery teams and investigators searching the rubble.

American Airlines Flight 77, travelling from Virginia to LA, slammed into the building at around 09:37 local time.

US authorities said the plane struck between the first and second floors of the Pentagon, killing 184 people.

It was previously thought that the images had been newly released because of the fresh date stamp.

But FBI spokeswoman Jillian Stickels said the pictures were first posted online in 2011.

A technical glitch caused them to disappear from the site for an undetermined period of time, she added.

They were restored in recent days to public view once the FBI learned they were missing, according to the FBI spokeswoman.

Shia LaBeouf assault charges dropped

Actor-turned-artist Shia LaBeouf will no longer face assault charges over a January incident at his anti-Donald Trump art installation.

Mr LaBeouf was arrested following a confrontation at his live-streamed video project in New York, and was charged with assault and harassment.

Those charges have now been dropped.

A spokeswoman for the district attorney in New York's Queen's district told US media the case would be dismissed because of insufficient evidence.

Mr LaBeouf's art project, a 24-hour live stream called He Will Not Divide Us, encouraged members of the public to say those words into a camera outside New York's Museum of the Moving Image.

But Mr LaBeouf and a member of the public allegedly entered an altercationduring a live broadcast in January. The museum later said the site had become "a flashpoint for violence".

The live stream was planned to continue for the four years of Mr Trump's presidency, but the museum pulled support for the project in early February.

The project was forced to move location twice in the US, after opponents tried to disrupt it.

It then arrived in a new form in Liverpool in the UK - but faced similar problems.

Liverpool's Fact arts centre had been live-streaming a flag with the words, but cancelled the project after people climbed on the roof to try and remove the flag.

In addition to his performance art, LaBeouf is best known for films like Transformers, Indiana Jones and the Kingdom of the Crystal Skull and Wall Street: Money Never Sleeps.

Surgeon: 'How many more children like Kayden must die?'

Senior surgeons say they tried to warn managers of dangerous delays to emergency surgery ahead of a child's death at a top children's hospital.

Kayden Bancroft was 20 months old when he died at Royal Manchester Children's Hospital (RMCH), following repeated delays to urgent surgery.

Whistleblowers allege the trust's focus was on "ballooning" waiting lists rather than emergency care.

The hospital admitted that failings occasionally occurred.

Central Manchester University Hospitals Trust said: "Royal Manchester Children's Hospital faces huge demands for its services and occasionally failings regrettably do occur."

Kayden's grandmother, Julie Rowlands, has spoken of her shock at the way he was treated.

She said: "His care was appalling. He was basically put in a room, and left.

"And all we got, nearly every day, was, 'He's not having the operation today, he's not having the operation today.' They were coming up with excuses, 'There's no bed, or a car crash victim's come in.'

"That's all we got, all the time we were there, was excuses."

One surgeon, Basem Khalil, told the BBC: "We just worry how many more children must die before management is held to account and before the right changes are made."

Kayden was brought into Stepping Hill Hospital on 11 April last year, a Monday, after falling and banging his mouth on his bottle.

Staff discovered that he had a hole in his diaphragm, causing his bowel to enter his chest.

Staff requested a transfer to RMCH for an operation to repair Kayden's diaphragm, but no intensive care bed was available.

The following day, he was transferred, but to an ordinary ward.

Kayden's surgery was repeatedly delayed over the following week, as he deteriorated.

On Thursday, 14 April, the BBC was told, a locum consultant requested that a planned elective surgery list be cancelled to allow him to carry out the operation, but management instructed an operational manager "not to get involved".

The trust told the BBC that it had no record of this request.

Brain injury

Late on Friday night, Kayden went into cardiac arrest.

Nurses struggled to get help, because an emergency phone line was down, and it took nearly 30 minutes to resuscitate the child.

He suffered severe brain injury and died two days later.

The trust's own investigation found "significant problems with the organisation and delivery of [Kayden's] care, which was not timely and resulted in his death".

Senior surgeons at the hospital told the BBC that they had repeatedly tried to warn trust management about problems, including a shortage of emergency operating theatres and intensive care beds at the hospital.

But the trust told the BBC: "We believe that there are sufficient theatres in our children's hospital to cope with the demand for emergency cases; however, on occasions some children do have to wait for urgent surgery while emergency surgery takes place."

Mr Khalil said: "On Thursday, one of the surgeons had offered to cancel one of his elective lists, so that he could do Kayden as an emergency, but did not receive the support that he needed.

"That should not have happened.

"There should have been support to say if we have children on the emergency list, they need to be done, and they should take priority over elective lists."

Mr Khalil added that the size of the hospital's waiting lists had become dangerous.

Long waits

The BBC has seen internal figures to show that on 18 January this year, the number of children waiting for a procedure had reached 6,185, with 1,102 children having waited for over a year.

Mr Khalil said: "The waiting list in the children's hospital has basically ballooned over the last few years.

"We now have hundreds of children who have waited over a year to have their surgery done.

"They were giving elective cases priority, but it almost became like a culture, that it is difficult to cancel elective cases to do emergency cases."

A second surgeon, James Morecroft, who retired from RMCH this year, told the BBC: "There was a desire in the hospital to do the elective workload, perhaps at the expense of some of the emergency stuff."

The trust said: "The trust would like to make it clear that at no time has it directed clinical staff to prioritise elective over non-elective care.

"As is the case at most similar hospitals, elective cases are regularly cancelled to accommodate emergency patients."

However the trust's own investigation into Kayden's death recommended the hospital carry out an urgent review into "prioritising non-electives above elective cases".

It added: "Following the investigation, a number of immediate and longer term actions were agreed."

Lawyer Stephen Clarkson, from Slater and Gordon, who represented the family, said: "The real tragedy here is that Kayden's death was entirely preventable.

"If he had been operated on earlier, then he would have survived.

"It is deeply concerning that this happened at one of the country's leading hospitals for children, and that is why it is so important that the trust looks closely at what went wrong and what can be done to make sure this doesn't happen to anyone else's child."

Right-to-die case: Shrewsbury's Noel Conway loses court bid

A man with terminal motor neurone disease has lost a High Court bid to challenge the law on assisted dying.

Noel Conway, 67, who was diagnosed in November 2014 and is not expected to live beyond 12 months, said he should be free to determine his own death.

Mr Conway, of Shrewsbury, had told the court at a previous hearing he faces an "unbearable death" because of the law.

Two judges ruled against Mr Conway while one, Mr Justice Charles, agreed permission should be granted.

Mr Conway said he would appeal against the court's decision, the first case to be heard since the law was challenged in 2014 and 2015 and the only one involving a terminally ill patient.

Mr Conway had hoped to bring a judicial review that could result in terminally ill adults who meet strict criteria, making their own decisions about ending their lives.

His counsel Richard Gordon QC, told the court that when he had less than six months to live and retained the mental capacity to make the decision, his client "would wish to be able to enlist assistance to bring about a peaceful and dignified death".

Mr Conway was seeking a declaration that the Suicide Act 1961 is incompatible with Article 8 of the Human Rights Act 1998, which relates to respect for private and family life, and Article 14, which enables protection from discrimination.

He was not in court in London to hear Lord Justice Burnett and Mr Justice Jay rule he did not have an arguable case to go forward.

Mr Conway, who is married with a son, daughter, stepson and grandchild, said he was "very disappointed" with their ruling.

"[But] I will not be deterred and will be appealing this decision," he said.

He said he has "come to terms" with the fact he is going to die, but does not accept being "denied the ability to decide the timing and manner of my death".

"The only alternative is to spend thousands of pounds, travel hundreds of miles and risk incriminating my loved ones in asking them to accompany me to Dignitas," he said.

Lord Justice Burnett said it remained "institutionally inappropriate" for a court to make a declaration of incompatibility between pieces of legislation, irrespective of personal views.

He added: "My conclusion does nothing to diminish the deep sympathy I feel for Mr Conway, his family and others who are confronted with the reality of living and dying with incurable degenerative conditions such as motor neurone disease."

Sarah Wootton, chief executive of campaign group Dignity in Dying, which is supporting Mr Conway's case, said the law "simply does not work".

"Parliament has so far ignored the pleas of dying people like Noel and the overwhelming majority of the public who also support a change in the law," she said.

Ms Wootton said a Crowdfunder appeal had been launched to help cover Mr Conway's legal costs and it had "received incredible support".

Commenting on the case, the Care Not Killing Alliance said: "This is not a day for celebration. This was a troubling case that sought to usurp the democratic will of Parliament.

"The current laws on assisted suicide and euthanasia are simple and clear. They exist to protect those who are sick, elderly, depressed, or disabled from feeling obliged to end their lives."

Food trade drains global water sources at 'alarming' rates

The global market for foodstuffs is depleting water sources in many parts of the world quicker than they can naturally be refilled.

The complex trade is increasing pressure on non-renewable groundwater, mainly used for irrigating crops such as rice, wheat and cotton.

Pakistan, the US and India are the countries exporting the most food grown with unsustainable water.

Researchers say that without action, food supplies will be threatened.

Around 43% of the water used to irrigate crops around the world comes from underground aquifers, as opposed to rivers and lakes. Many of these sources are being used up quicker than they can be refilled from rainfall.

Back in 2000, experts believed that non-renewable resources sustained 20% of global irrigation. In the 10 years to 2010, this increased by more than a fifth.

While scientists have long known about the depletion of groundwater, this new study sets out to understand how supplies are impacted by the booming international trade in food and crops.

The vast majority of the world's populations live in countries that source nearly all their staple crop imports from nations who deplete significant amounts of groundwater to irrigate these foodstuffs.

The researchers found that some 11% of the non-renewable groundwater used for irrigation is embedded in the the global food trade. Two-thirds of this are accounted for by Pakistan, the US and India.

Over the decade from the year 2000, the use of non-renewable groundwater has doubled in China and increased significantly in India and the US. The crops using the biggest amounts of this water are wheat, rice, sugar crops, cotton and maize.

However, the web of responsibility is a complex one.

The US, Mexico, Iran, Saudi Arabia and China are among the top 10 users of unsustainable water in agriculture. However, they are also among the top importers of crops grown with these dwindling resources.

So, Iran, for example, mainly imports rice from Pakistan irrigated by the Upper Ganges and Lower Indus aquifers. These water sources have extraction rates up to 50 times higher than required for sustainable use. Iran in turn exports perennial crops irrigated by the Persian aquifer that has been extracted at a mere 20 times the rate that is sustainable.

"The depletion rate is alarming - we have these clusters of countries that are at risk both from domestic production and imports," said lead author Dr Carole Dalin from University College London.

"If the reserve of water runs out the price of food will be affected and it will affect almost all the world's population."

Many developed countries are aware of issues in the depletion of groundwater and have put measures in place, such as urban water restrictions in California during the recent years of drought. However, in developing nations, the mechanisms to restrict water may not exist.

"Pakistan for instance is quite complex," said Dr Dalin. "They can make good money out of exporting rice, but the framework is not really there to account for the impact on the environment. It is true that eventually it will affect the production there."

The researchers argue that while governments need to have greater awareness about the impacts of production on water resources, consumers in richer countries should also think about water when considering the foods that they buy.

"The products that consumers buy at a supermarket may have very different environmental impacts depending on where they are produced and how they are irrigated," said co-author Yoshihide Wada, from the International Institute for Applied Systems Analysis.

"In order to help consumers make more sustainable choices about their food, producers should consider adding water labels that make these impacts clear."

The paper has been published in the journal Nature.