Curious Bends – affordable cigs, notes from Fukushima, a destructive bladder craze, and more

1. Despite rising taxes, cigarettes in India have become more affordable

“Over the past few years, the Indian government has been stepping up efforts to reduce tobacco consumption by hiking taxes on cigarettes. In February, finance minister Arun Jaitley proposed raising the duties even further by at least 15%. Despite this, the WHO report shows that the level of tax as a percentage of the price of India’s most popular cigarette brand remains below the recommended 70% mark. Moreover, India’s tobacco taxation system remains convoluted. Cigarettes are taxed based on their length, with longer ones being taxed more. But this has given rise to some innovative attempts by tobacco firms to preserve their profits.” (3 min read,

2. Why reprocessing of spent fuel from nuclear reactors makes little sense

“Reprocessing is hugely expensive; constructing and operating this highly complex facility filled with radiological and chemical hazards costs billions of dollars. The alternative way of dealing with the spent fuel is significantly cheaper. In 2007, economist JY Suchitra and I published a paper in International Journal of Global Energy Issues that used the actual expenditures on the Kalpakkam Reprocessing Plant near Chennai to demonstrate that reprocessing of spent fuel in India costs about 25 times what it would cost to directly dispose it. In a subsequent 2011 paper in the same journal, we showed that the use of plutonium to fuel reactors was also not economical.” (5 min read,

3. How reliable are psychology studies?

“Although 97 percent of the 100 studies originally reported statistically significant results, just 36 percent of the replications did. Does this mean that only a third of psychology results are “true”? Not quite. A result is typically said to be statistically significant if its p-value is less than 0.05—briefly, this means that if you did the study again, your odds of fluking your way to the same results (or better) would be less than 1 in 20. This creates a sharp cut-off at an arbitrary (some would say meaningless) threshold, in which an experiment that skirts over the 0.05 benchmark is somehow magically more “successful” than one that just fails to meet it. So Nosek’s team looked beyond statistical significance. They also considered the effect sizes of the studies.” (10 min read,

4. Fukushima today: A first-person account from the field and the conference table

“In reaching Tomioka—badly hit by the tsunami—we found a nearly destroyed town invoking an image of the Apocalypse. All we saw were homes, businesses, and shops as they stood or fell after the tsunami hit and then the radiation struck. There was no sign of life other than decontamination workers going about their grim task. Continuing our journey toward Namie—one of the worst-hit towns, whose boundaries lie about six miles northeast of Fukushima Daiichi at the closest point—we passed through the small villages of Okuma and then Futaba. We continued onward, and edged as close as 1.5 miles from the plant at one spot, but no closer. All roads to the plant from here on were barricaded. Ironically, one banner welcoming visitors to the town read: “Nuclear Power is Our Future.”” (21 min read,

5. How China’s fish bladder investment craze is wiping out species on the other side of the planet

“The story of how the bladder bubble inflated and then burst is a classic tale of globalization—of the intersection between monetary policy, financial markets, luxury goods, international regulation, and transnational crime. It’s also an all-too-familiar and depressing environmental tale, because while the bladder trade has endangered the totoaba, it’s driven the vaquita—a tiny porpoise that’s prone to getting tangled up in totoaba nets—almost to extinction. Fortunately for both animals, after years of lax enforcement, the Mexican government is finally cracking down on illegal totoaba fishing in waters the vaquita inhabits.” (11 min read,

Chart of the week

“World poverty is on the decline, with less global hunger and more access to education and healthcare, the United Nations trumpted in a new report on its Millennium Development Goals. But progress on the targets established in 2000 is very slow for women, and especially those in developing regions. “I am keenly aware that inequalities persist and that progress has been uneven,” UN secretary general Ban Ki-Moon writes in the introduction to the report. “Progress tends to bypass women and those who are lowest on the economic ladder or are disadvantaged because of their age, disability or ethnicity.”” (

Women in single or lower chambers of national parliaments. Source: Quartz
Women in single or lower chambers of national parliaments. Source: Quartz

Why the F-91W keeps ticking

If you’re one of the millennials, you’re expected to not know about the Casiotron almost by definition – but you probably do. It was a Casio digital watch first sold in October 1974, and its claim to fame was that it was “computerised”, able to calculate the number of days in a month (but not leap-months). Its functions, revolutionary for the time, became the foundation on which Casio built its future digital watches – leading up to the unlikely hero called F-91W.

A tried and true style great for casual wear. With its daily alarm, hourly time signal and auto calendar, you’ll never need to worry about missing an appointment again.

That’s the exceedingly simple premise with which the F-91W is marketed. There are no frills: the watch shows the time, date, has a stopwatch and an alarm clock. It’s mildly water resistant – it’s okay when water splashes on it but not if you shower with it – sports a resin band, is powered by a CR2016 button cell that lasts for seven years, and weighs 22 grams. It’s hard even to tell if Casio intended on making a statement with the thing when it first came out – in 1991 – any legacies used in its design having been flattened into its unassuming timeface. But make a statement it has.

On August 17, a powerful blast ripped through the popular Erawan Shrine in Bangkok, killing at least 20 and injuring over 120. Investigations into the identities of those responsible led the Thai police to an apartment in the city’s eastern suburbs on August 30. Bangkok Post reported that apart from explosive materials and wiring, four wristwatches were also found. Four Casio F-91W wristwatches.

In the post-9/11 period, if a captured terrorist was found to possess an F-91W, the person was assumed to have been trained in bomb-making. At least so went the saying – and it wasn’t hard to believe considering the F-91W was (and is) cheap, easy to find and easy to operate. According to a WikiLeaks dump released in 2011, Al Qaeda gave the watches to trainees in terrorist camps, where they learnt to press the innocuous things into the service of crude detonators, in Afghanistan.

One of the documents in the Gitmo Files dump. The watch’s attributes are described in the footnote. Source: Gizmodo
One of the documents in the Gitmo Files dump. The watch’s attributes are described in the footnote. Source: Gizmodo

The F-91W’s association with Al Qaeda was prominently established following the Denbeaux study, which profiled 517 Guantanamo-Bay detainees and published its reports from 2006 through 2009. It found a lot of the detainees charged with working with or setting off explosives also owning, or even having been captured wearing, the F-91W (or its silver-coloured sibling A159W). Before that, the watch is first thought to have made an appearance in connection with terrorist activities with the foiled Bojinka Plot in 1995, aimed at assassinating Pope John Paul II and bombing many Asian and American airports.

The F-91W scores because it’s ubiquitous and the watch doesn’t need serious modifications to play its part as a timing device in a detonator, so when a raid is imminent the terrorists can walk away wearing it and claim it’s just a watch.

Unfortunately, this trait fed the feds’ paranoia after 9/11: they weren’t prepared to believe that it could be just a watch, especially around the wrist of anyone being shifty in the Middle East, and they were prepared to believe that possessing it was enough to all but indict the wearer. Yet, it was and is worn by millions around the world (including this writer). Casio doesn’t publicise the sales numbers of the F-91W but said in 2011 that it remains a “huge seller”.

And it will probably endure, too. The F-91W’s notoriety was hedged on a forgettable application but its mainstream success owes to what that application prized as well: function over form, doing it what it said it would, not doing anything that wasn’t promised, earning it the enviable sobriquet as a “modest masterpiece”.

GSLV D6 is a confidence booster

The GSLV Developmental-flight 6 launch by the Indian Space Research Organisation on August 27 was three things: the launch of the GSAT 6 satellite for the Indian military, the fifth successful launch of a GSLV rocket, and the second successful test-flight of the indigenous cryogenic upper-stage engine. The satellite is a two-tonne behemoth that’s too heavy for a PSLV rocket, whose maximum payload capacity to the geostationary transfer orbit is 1,410 kg, to heft – so the GSLV. And the cryogenic upper-stage enables the GSLV to lift a heavier payload: 2,500 kg to the geostationary transfer orbit.

But the most important takeaway lies in the big picture. This may be the fifth successful launch of the GSLV out of nine tries but it’s the second successive one. This may be the third successful flight with the cryogenic upper-stage but it’s the second successive one. And both accomplishments signify that ISRO’s scientists have been learning the right lessons from previous failures and that the GSLV is on the road to establishing reliability.

The previous successful test flight of the cryogenic engine was in January 2014, and the test before that in 2010 was a failure. While the PSLV rocket has four stages, of alternating solid and liquid ones, the GSLV Mk rockets that use the engine have three: solid, liquid and cryogenic stages. The solid stage is derived from the Nike-Apache engine of the US and the liquid stage, from the Vulcain engine of France. As a result of the extended legacies, it was easier for ISRO to adapt them for Indian rockets to use. However, the cryogenic engine had to be developed indigenously after the required tech. transfer from the Soviets fell apart in the 1980s due to political reasons.

With two successful flights in two years, the space agency now has reason to believe the engine could be finally past its teething troubles. And despite its intricate engineering, its success makes things simpler for ISRO. Before January 2014, ISRO was also considering a variety of Russian engines to power the GSLV Mk I’s and II’s upper-stage, all to no avail. Now it can focus on perfecting the cryogenic engine for the next big-picture milestone: at least two GSLV launches every year, signifying 4-5 tonnes equipment right there.

Note: This article was updated at 1.42 am on August 29, 2015, to say that the solid stage of the GSLV uses the S139 engine, not Nike-Apache, and that the liquid stage uses a modified Viking 4 engine, not the Vulcain.

Roundup of missed stories – August 26, 2015

Too many things to do at work this last week, so much so that I missed writing/blogging on a bunch of articles and papers that in other circumstances I’d have loved to discuss. Here they are, rounded up in the chance that you might find one of them interesting and consider taking the debate surrounding it to a larger audience.

  1. Something at the Milky Way’s centre survived an encounter with a black hole – “The G2 cloud in our Galaxy’s core has survived an encounter with the central black hole and failed to trigger a major flare-up in the black hole’s activity. A promising theory endeavours to explain the cloud’s nature.”
  2. What does the way Amazon supposedly treats its employees speak about the future of employment in the tech. industry? – “Bezos’s statement was promptly satirized in a hilarious piece by Andy Borowitz, which you really must read. Borowitz’s conceit is that Amazon mandates that anyone who is not acting compassionately to their fellow employees will be fired the next day. And then there is a thoughtful piece at Pando, which insists that we will soon be forced to choose between the hard-charging culture of the tech industry and the more humanistic values that we may privately prefer. I don’t know if we have to choose — I don’t know if we have a choice — but the point is well taken: At what point do we stand up and say, We don’t want to live this way?”
  3. Following criticism, PLOS removes blog defending scrutiny of science -Although the tools we use to ensure transparency can be abused, that’s a necessary risk, note Seife and Thacker:

    “To be sure, the same mechanisms that watchdogs use to uncover scientific wrongdoing have been abused in the past. Climate scientist Michael Mann, for instance, was subject to invasive and harassing requests for information via freedom of information laws, via judicial-branch powers, and via congressional requests. No doubt they will be abused in the future.

    But transparency laws remain a fundamental tool for monitoring possible scientific misbehavior. And it would be a mistake to believe that scientists should not be subject to a high level of outside scrutiny. So long as scientists receive government money, they are subject to government oversight; so long as their work affects the public, journalists and other watchdogs are simply doing their jobs when they seek out possible misconduct and questionable practices that could threaten the public interest.”

  4. A double-blind randomized clinical trial on the efficacy of magnetic sacral root stimulation for the treatment of Monosymptomatic Nocturnal Enuresis [bed-wetting] – “Both treatment and control groups were comparable for baseline measures of frequency of enuresis, and VAS. The mean number of wet nights/week was significantly reduced in patients who received real rSMS. This improvement was maintained 1 month after the end of treatment. Patients receiving real-rSMS also reported an improvement in VAS ratings and quality of life. A significant reduction of resting motor threshold was recorded after rSMS in the real group while no such changes were observed in the sham group.”
  5. Death metal in ancient oceans – “About 420 million years ago, near the end of the so-called Silurian period, the last of a series of mass extinctions struck the world’s oceans. Some scientists have suggested these die-offs were caused by worldwide cold spells. But a new study hints that the extinctions—which mostly affected corals, colonymaking creatures called graptolites, and eel-like creatures called conodonts—may have instead been caused by changes in ocean chemistry, including reduced oxygen and elevated concentrations of toxic metals dissolved in the seawater.”
  6. A new player in the well-contested field of atomic microscopy – “We introduce a scanning probe technique that enables three-dimensional imaging of local electrostatic potential fields with subnanometer resolution. Registering single electron charging events of a molecular quantum dot attached to the tip of an atomic force microscope operated at 5 K, equipped with a qPlus tuning fork, we image the quadrupole field of a single molecule. To demonstrate quantitative measurements, we investigate the dipole field of a single metal atom adsorbed on a metal surface.”
  7. Do we have the fusion reactor we need? Or is this another one of those premature promises? – “A privately funded company called Tri Alpha Energy has built a machine that forms a ball of superheated gas—at about 10 million degrees Celsius—and holds it steady for 5 milliseconds without decaying away. That may seem a mere blink of an eye, but it is far longer than other efforts with the technique and shows for the first time that it is possible to hold the gas in a steady state—the researchers stopped only when their machine ran out of juice.”
  8. Is it better to stay in the dark about our own genetic secrets? – “If you have a terminal illness that’s completely untreatable, you might genuinely be happier living your last months in ignorance. A diagnosis might allow you to seek treatment giving you an extra month of life, but if that extra month is riddled with fear and sadness, it might not be worth it. In these cases, it seems like ignorance really might be preferable.”

Conflicts in the Middle East are bringing down NOx emissions

Two years ago, a study in Science put a detailed analysis behind an idea that had already taken root on a lot of people’s minds: that the unfavourable weather conditions climate change was creating around the world could be related to the world’s growing tendency toward conflicts. The study’s authors weren’t saying that bad weather caused the Second World War but only that it would be legitimate to consider if the changing climate had an adverse impact on human neurophysiology. But setting aside the specifics, the study’s bigger accomplishment was in encouraging a more holistic view of climate change’s impact on humankind.

Now, another study, based on satellite observations and economic data from the World Bank, sets out a karmic inverse of that idea: that conflicts in the Middle East have led to cleaner air over the region.

The satellite data comes from Aura, which NASA launched in 2004 to make qualitative observations of Earth’s atmosphere. One instrument in the apparatus is the Ozone Monitoring Instrument (OMI) that measures variations in the ozone layer, and makes precision measurements of gases detrimental to the atmosphere across a 2,600-km field of view, which lets it log global data almost on a daily basis. And since around 2008, it has found that nitrogen dioxide emissions – released by burning fossil fuels – have been dropping over some cities in the Middle East and over Athens, Greece.

Specifically, OMI found that the density of nitrogen dioxide gas over Cairo, Athens, Tehran and Esfahan (Iran), Baghdad, Tikrit and Samarra (Iraq), the Palestinian territories, Beirut and Tripoli (Lebanon), and Damascus and Aleppo (Syria) bespeak a strong correlation with the shifting political climates in the region. The study describing the findings, published in Science Advances on August 21, 2015, is able to exclude natural variations because the trends were uniformly increasing until 2008-2010 – like in almost all places around world – before deviating significantly.

Since the Arab Spring in 2011 saw a popular uprising starting with Cairo and spreading out into the rest of the Middle East, the GDPs of all the involved economies shrank. Now, the OMI data presents the climatic impact of humanitarian crises and armed conflict – one that long-term projections of the impact of climate change haven’t factored in.

For example, the most significant changes are visible over Greece, Egypt, Iraq, Iran and Syria, as well as over Saudi Arabia and the United Arab Emirates. However, the latter two are discounted from the authors’ analysis for two reasons: the reversal in nitrogen dioxide emission trends over the two countries started before the region started to become turbulent, and began after 2006 and 2008 when the emirates and the kingdom enacted laws to reduce their carbon footprints.

In Egypt, on the other hand, the GDP rose by about 6% per year in 2005-2010 and then fell to 2% per year in 2011-2014. But OMI couldn’t spot any parallel decline in carbon dioxide, so the decline in nitrogen dioxide is being attributed to the reduction of vehicular emissions thanks to petrol becoming more expensive. In Greece, the economic recession caused nitrogen dioxide emissions to fall by 40% in the six years since 2008. In Iran, Tehran’s and Esfahan’s nitrogen dioxide emissions increased at 10% per year in 2005-2010 – as if the 2006 sanctions didn’t happen – but turned down to -4% per year since 2010, when the GDP also saw a sharp downturn by 2 percentage points before turning negative in 2012.

A and B) Tropospheric NO2 column density changes in 10^15 molecules/cm2 (A) between 2005 and 2010 and (B) between 2010 and 2014. Source:
A and B) Tropospheric NO2 column density changes in 10^15 molecules/cm2 (A) between 2005 and 2010 and (B) between 2010 and 2014. Source:

In Iraq, similar correlations between declining GDP and falling nitrogen dioxide emissions are observed over Baghdad, Mosul and Kirkuk, as well as additional declines over the cities of Tikrit and Samarra thanks to incursions by the Islamic State.

As the authors of the Science Advances article write, “such relatively short-term changes cannot be captured by air pollution emission inventories and future projections, including the Representative Concentration Pathways”. The RCPs are a set of projections used by the Intergovernmental Panel for Climate Change based on how much greenhouse gases are enforcing anthropogenic climate change. One of them, RCP4.5, assumes that NOx emissions in the Middle East will be constant from 2005 to 2030, and another, RCP8.5, that they’ll increase at the rate of 2% per year. OMI’s findings suggest these assumptions might be failing reality.

It also reveals how a better estimate of greenhouse gas emissions, as well as country-wise challenges, emerges when ground realities are combined with satellite-logged data. Consider the example of Lebanon, whose carbon dioxide emissions fell by 20% over 2011 and 2012, but whose nitrogen dioxide emissions spiked by 20-30% in 2014. When they probed further, the scientists realised it had to do with the influx of refugees from the Syrian civil war – 1.2 million of them, of which 350,000 fled to Beirut alone.

Featured image credit: magharebia/Flickr, CC BY 2.0.

GitHub hit by DDoS attack

The collaborative coding platform GitHub became the subject of a DDoS attack on August 25, its second this year after having been targeted by a massive attack in March. The issue first appeared at 3.05 pm IST, according to GitHub’s status log, when administrators began inspecting “connectivity problems”. By 4.08 pm, the issues were identified to be the result of a DDoS attack. At 4.36 pm, it was mentioned that the attack was ongoing. The last updates from GitHub said at 6.22 pm that normal service had been restored and that the situation was being monitored closely, and at 7.19 pm that everything was “operating normally”.

DDoS stands for distributed denial-of-service, where thousands of IP addresses – often spoofed – ping a target IP and force it to respond. A ping, according to SC Magazine, is “a type of networking utility that determines whether or not a host is reachable, and how long it takes to be reached”. It’s a very small packet of data that, if echoed back by the target, signals that the target IP is live. But with a swarm of pings, the effect over time is that the target IP address is brought down, or crashes, unable to handle the traffic.

For the people perpetrating the attack, the intent is to make the target address unavailable to legitimate users. At 5.40 pm, the Norse Corp map of live DDoS attacks identified two prominent target locations in the United States, one of which (around the Missouri-Illinois-Iowa area) was the subject of an intense assault from the South East Asian and south European regions.

A map of ongoing DDoS attacks. Source: Norse Corp
A map of ongoing DDoS attacks. Source: Norse Corp

GitHub has been the subject of multiple DDoS attacks in its history. The platform is effectively a collection of repositories, or projects that developers are working on, and attackers miffed by the contents of individual repositories often take down the entire site. It was on the back of similar concerns that the Chinese government blocked GitHub in China in January 2013, and the Indian government for a short while in December 2014.

While DoS attacks have been around since the 1990s, DDoS attacks kicked in in 2000, with one of the first targets being Yahoo!. The difference is that DoS attacks originate from a single source while DDoS attacks are distributed across multiple sources. They’re also impossible to anticipate, very difficult to defend against, and very difficult to track down. Attackers have been known to go after all kinds of online services – from banks to government sites to gaming tournaments. According to an Akamai report released earlier this month, India is the fourth largest target of DDoS attacks worldwide, accounting for 7.43% of all attacks. Interestingly, as writes, “China is … both the largest source and target of attacks on web applications”.

Curious Bends – tumour twin, ethical non-vegetarians, fixing Indian science, and more

Apologies for the unplanned summer holiday, but we’re back!

1. Was the tumour inside her brain her twin? (Audio)

She moved from Hyderabad to do her PhD at Indiana University and began​ ​experiencing headaches and suffering from​ ​sleep disorders. Co-workers​ ​and friends would speak to her, only for the sentences to get all​ ​garbled. She was in excruciating pain. What was this tumour that was​ ​growing inside her brain? Why was it wreaking havoc in her life? What​ ​if what was growing inside her head had a life of its own? (, 13 min listen)

2. An India-born Nobel laureate’s solutions for fixing science in India 

“Venkatraman Ramakrishnan is a biologist—even though he won the Nobel Prize in chemistry in 2009—and an Indian at heart, even though he has spent most of his life in the US and the UK where his work led to the prize. His career has been unusual, just as his achievements. In December, he is going to take his new position as the president of the Royal Society, the world’s oldest and most esteemed scientific society. He will be the first non-white president in its 350-year history, and he has already made plans to invigorate scientific ties between India and the UK.” (, 7 min read)

3. The only ethical way to eat meat: become scavengers

“The first and less realistic way is to replace hunting with scavenging. Scavenging for wild animals is a non-exploitative method of obtaining animal flesh. A more achievable and safer option would be to do something closer to agriculture as we now know it: domesticate the scavenger hunt. That is, raise animals—preferably ruminants—on limited pasture with the utmost attention to their welfare, allow them a life free of human exploitation, feed them natural diets in appropriate habitats, allow them to die a natural death, and then, and only then, consume them.” (, 7 min read)

4. The woman who could stop climate change

“I asked what would happen if the emissions line did not, in fact, start to head down soon. Tears welled up in her eyes and, for a moment, Christiana Figueres, the head of United Nations Framework Convention on Climate Change, couldn’t speak. “Ask all the islands,” she said finally. “Ask Bangladesh. We just can’t let that happen. Do we have the right to deprive people of their homes just because I want to own three SUVs? It just doesn’t make any sense. And it’s not how we think of ourselves. We don’t think of ourselves as being egotistical, immoral individuals. And we’re not. Fundamentally, we all have a morality bedrock. Every single human being has that.”” (, 25 min read)

5. Although patents were designed to promote innovation, they don’t

“The public-good position on patents is simple enough: in return for registering and publishing your idea, which must be new, useful and non-obvious, you get a temporary monopoly—nowadays usually 20 years—on using it. This provides an incentive to innovate because it assures the innovator of some material gain if the innovation finds favour. It also provides the tools whereby others can innovate, because the publication of good ideas increases the speed of technological advance as one innovation builds upon another. But a growing amount of research in recent years suggests that, with a few exceptions such as medicines, society as a whole might even be better off with no patents than with the mess that is today’s system.” (, 15 min read)

Chart of the week

“By analysing global migration trends among professionals, the social network found India ended 2014 with 0.23% fewer workers than the beginning of the year. This represents the biggest loss seen in any country it tracked, according to LinkedIn.” (, 2 min read)

Countries to which Indian professionals are migrating. Source: Quartz
Source: Quartz

Not all waterworlds can host life

During its formation, Venus was in the Solar System’s habitable zone – much like Earth is now. Scientists think its surface contained liquid water, and its atmosphere was somewhat like Earth’s. Maybe there was life, too. However, as the levels of carbon dioxide kept increasing, its atmosphere became opaque, trapping most of the heat reflected by its surface, and Venus heated up to the point where its oceans boiled away. Today, life on the planet’s waterless surface is considered unlikely, except perhaps by those who’ve read a November 2014 study involving supercritical carbon dioxide, and those who believe in Hell.

Why can’t this be the case on alien worlds possessing water as well? Discoveries made since the mid-1990s – especially by the Kepler space telescope and probes in the Jovian and Saturnian systems – have unearthed a variety of worlds that could, or do, have liquid water on or below the surface. On Earth, life has been found wherever liquid water has been found, so liquid water on other planets and moons gets scientists excited about the possibility of alien life. Recent discoveries of a subsurface ocean on Europa and possibly on some other moons of Jupiter and Saturn have even prompted NASA to plan for a probe to Europa in the mid-2020s.

A study published online (paywall) in the Monthly Notices of the Royal Astronomical Society applies the brakes on that excitement to some extent. A kind of exoplanet which scientists think could host lots of liquid water—some 100-times the amount of water on Earth, in fact— are the so-called ‘waterworlds‘. They would have oceans so deep and wide that, according to the study, their effects on themselves and the planet’s climate would be incomparable to that on Earth – and altogether might not be hospitable to life the way we know liquid water can usually be.

The study’s authors write, “One important consequence is, for example, the formation of high-pressure water ice at the bottom of the ocean, which prevents the immediate contact of the planetary crust with the liquid ocean.” This in turn mutes the carbon-silicate cycle, a recycling of carbon and silicon compounds on the ocean floor that determines how much carbon dioxide is released from the oceans into the atmosphere.

The authors calculate that on an (at least) Earth-sized waterworld in the habitable zone of its star, there can be 25-100 Earth oceans for temperatures ranging from the freezing point of water to just beyond the boiling point. So a colder planet, say at 0° C, would have a smaller ocean and lesser liquid water to be able to absorb the carbon dioxide (and its absorptive capabilities can’t ‘power up’ without the carbon-silicate cycle). Yet, at lower temperatures the oceans are able to dissolve more gases, even as the pressure exerted by the gas on the ocean’s surface is higher. So a colder planet with a smaller ocean will dissolve more carbon dioxide from the atmosphere – turning the planet even cooler.

Similarly, a warmer waterworld will be able to absorb less carbon dioxide, letting the greenhouse gas accumulate in the atmosphere, heat the surface up and eventually boil the oceans away (like on Venus). In short, a waterworld whose temperatures are outside a specific range will become hotter if it’s warm and even colder if it’s cold. These runaway effects can occur pretty quickly, too. 

Based on the chemical properties of water and carbon dioxide, the scientists estimate that the life-friendly temperature range is from 273 K to 400 K (0° to 127° C). And even in this range, there could be threats to life in the form of ocean acidity. On Earth, limestone that’s in contact with water dissolves and keeps the water’s acidity in check, but this may not be happening on waterworlds where large landmasses could be a rarity or relatively smaller in size.

At the same time, these pessimistic speculations are offset by some assumptions the scientists have made in their study. For example, they assume that the waterworld doesn’t have tectonic activity. Such activity on Earth involves the jigsaw of landmasses grindings against each other, sometimes subducting one below the other to push down some minerals while volcanoes in other areas spew out others—in all making for a giant geological cycle that ensures the substances needed to sustain life are constantly replenished. If a waterworld were to have tectonic activity, it would also influence the carbon-silicate cycle and keep a runaway greenhouse effect from happening.

On Earth, the warming of the oceans presents a big problem to climatologists partly because its mechanisms and consequences are not fully understood – and more so to marine creatures. And as the oceans are able to dissolve more anthropogenic carbon dioxide, they also become more acidic. Yet, the effects are relatively smaller (ignoring the presence of life for a moment) compared to that on waterworlds – comprising no above-sea-level landmasses and infinite seas 100 km deep.

Featured image credit: Lucianomendez/Wikimedia Commons, CC BY-SA 4.0.

The Wire
August 23, 2015

ACAT in the wild

The software working behind the robotic voice of Stephen Hawking was released for public use on August 18 by Intel, the company that developed it. Although principally developed for Hawking, the ‘tool’ has since been made available to many other people suffering from motor neurone disease, an ailment that gradually but steadily deadens the neurons that control various muscles of the body, rendering its victims incapable of, say, moving their cheek muscles to elicit speech. Intel’s software, called the Assistive Context-Aware Toolkit (ACAT), steps in to translate visual signals like facial twitches to speech. Its source code and installation instructions are available on GitHub.

ACAT is an assembly of components that each perform a unique function. In the order of performance: an input device picks up the visual signals (cheek muscle twitches, in Hawking’s case), a calibrated text-prediction tool generates the corresponding unit of language, and a speech synthesiser vocalises the text. The first two components are unified by the Windows Communication Framework. In ACAT’s case, the text-prediction is performed by a tool called Presage, developed by Italian developer Matteo Vescovi. Other input tools include proximity sensors, accelerometers and buttons.

According to the BBC, the UK’s MND Association has celebrated the release. Of the motives behind it, Intel wrote, “Our hope is that, by open sourcing this configurable platform, developers will continue to expand on this system by adding new user interfaces, new sensing modalities, word prediction and many other features.” Company spokesperson Lama Nachman also noted that, with the current release, Intel isn’t anticipating ‘all kinds’ of innovations as much as assistive ones. A detailed user guide is available here.

A stinky superconductor

The next time you smell a whiff of rot in your morning’s eggs, you might not want to throw them away. Instead, you might do better to realise what you’re smelling could be a superconductor (under the right conditions) that’s, incidentally, riled up the scientific community.

The source of excitement is a paper published in Nature on August 17, penned by a group of German scientists, describing an experiment in which the compound hydrogen sulphide conducts electricity with zero resistance under a pressure of 90 gigapascals (about 888,231-times the atmospheric pressure) – when it turns into a metal – and at a temperature of 203.5 kelvin, about -70.5° C. The discovery makes it an unexpected high-temperature superconductor, doubly so for becoming one under conditions physicists don’t find too esoteric.

The tag of ‘high-temperature’ may be unfit for something operating at -70.5° C, but in superconductivity, -70.5° C approaches summer in the Atacama. When the phenomenon was first discovered – by the Dutch physicist Heike Kamerlingh Onnes in 1911 – it required the liquid metal mercury to be cooled to 4.2 kelvin, about -269° C. What happened in those conditions was explained by an American trio with a theory of superconductivity in 1957.

The explanation lies in quantum mechanics, where all particles have a characteristic ‘spin’ number. And QM allows all those particles with integer spin (0, 1, 2, …) to – in some conditions – cohere into one bigger ‘particle’ with enough energy of itself to avoid being disturbed by things like friction or atomic vibrations*. Electrons, however, have half-integer (1/2) spin, so can’t slip into this state. In 1957, John Bardeen, Leon Cooper and Robert Schrieffer proposed that at very low temperatures – like 4 K – the electrons in a metal interact with the positively charged latticework of atoms around them to pair up with each other. These electronic pairs are called Cooper pairs, kept twinned by vibrations of the lattice. The pair’s total spin is 1, allowing all of them to condense into one cohesive sea of electrons that then flows through the metal unhindered.

The BCS theory soon became a ‘conventional’ theory of superconductivity, able to explain the behaviour of many metals cooled to cryogenic temperatures. The German team’s hydrogen sulphide system is also one such conventional scenario – in which the gas had to compressed to form a metal before its superconducting abilities were teased out.

The team, led by Mikhail Eremets and Alexander Drozdov from the Max Planck Institute for Chemistry in Mainz, first made its claims last year, that under heavy pressure hydrogen sulphide becomes sulphur hydride (H2S → H3S), which in turn is a superconductor. At the time their experiment showed only one of two typical properties of a superconducting system, however: that its electrical resistance vanished at 190 K, higher than the previous record of 164 K.

Their August 17 paper reports that the second property has since been observed, too: that pressurised hydrogen sulphide doesn’t allow any external magnetic field to penetrate beyond its surface. This effect, called the Meissner effect, is observed only in superconductors. For Eremets, Drozdov et al, this is the full monty: a superconductor functioning at temperatures that actually exist on Earth. But for the broader scientific community, the paper marks the frenzied beginning of a new wave of experiments in the field.

Given the profundity of the findings – of a hydrogen-based high-temperature superconductor – they won’t enter the canon just yet but will require independent verification from other teams. A report by Edwin Cartlidge in Nature already notes five other teams around the world working on replicating the discovery. If and when they succeed, the implications will be wide-ranging – for physics as well as historical traditions of physical chemistry.

The BCS theory of superconductivity provided a precise mechanism of action that allowed scientists to predict the critical temperature (Tc) – below which a material becomes superconducting – of all materials that abided by the theory. Nonetheless, by 1957, the highest Tc reached had been 10 K despite scientists’ best efforts; so great was their frustration that in 1972, Philip Warren Anderson and Marvin Cohen predicted that there could be a natural limit at 30 K.

However, just a few years earlier – in 1968 – two physicists, Neil Ashcroft and Vitaly Ginzburg, refusing to subscribe to a natural limit on the critical temperature, proposed that the Tc could be very high in substances in which the vibrations of the atomic latticework surrounding the electrons was pretty energetic. Such vigour is typically found in the lighter elements like hydrogen and helium. Thus, the Ashcroft-Ginzburg idea effectively set the theoretical precedent for Eremets and Drozdov’s work.

But between the late 1960s and 2014, when hydrogen sulphide entered the fray of experiments, two discoveries threw the BCS theory off kilter. In 1986, scientists discovered cuprates, a class of copper’s compounds that were superconductors at 133 K (at 164 K under pressure) but didn’t function according to the BCS theory. Thus, they came to be called unconventional superconductors. The second discovery was of another class of unconventional superconductors, this time in compounds of iron and arsenic called pnictides, in 2008. The highest Tc among them was less than that of the cuprates. And because cuprates under pressure could muster a Tc of 164 K, scientists pinned their hopes on them of breaching the room-temperature barrier, and worked on developing an unconventional theory of superconductivity.

But for those choosing to persevere with the conventional order of things, there was a brief flicker of hope in 2001 with the discovery of magnesium diboride superconductors: they had a Tc of 39 K, an important but not very substantial improvement on previous records among conventional materials.

The work of Eremets & Drozdov was also indirectly assisted by a group of Chinese researchers in 2014, who were able to anticipate hydrogen sulphide’s superconducting abilities using the conventional BCS theory. According to them, hydrogen sulphide would become a metal under the application of 111 gigapascals of pressure, with a Tc between 191 K and 204 K. And once it survives independent experimental scrutiny intact, the Chinese theoretical work will prove valuable as scientists confront their next big challenge: pressure.

The ultimate fantasy would be to have a Tc is in the range of ambient temperatures. Imagine leagues of superconducting cables radiating out from coal-choked power plants, a gigawatt of power transmitted for a gigawatt of power produced**, or maglev trains running on superconducting tracks at lower costs and currents, or the thousands of superconducting electromagnets around the LHC that won’t have to be supercooled using jackets of liquid helium. Sadly, that Eremets & Drozdov have (probably) achieved a Tc of 203.5 K doesn’t mean that the engineering is accessible or affordable. In fact, what allowed them to fetch 203.5 K is what the barrier is for the tech to be ubiquitously used, making their feat an antecedence of possibilities rather than a demonstration itself.

It wasn’t possible until the 1970s to achieve pressures of a few gigapascals in the lab, and similar processes today are confined to industrial purposes. A portable device that’d sustain that pressure across large areas is difficult to build – yet that’s when metallic sulphur hydride shows itself. In their experiment, Eremets and Drozdov packed a cold mass of hydrogen sulphide against a stainless steel gasket using some insulating material like teflon, and then sandwiched the pellet between two diamond anvils that pressurised it. The diameter of the entire apparatus was a little more than a 100 micrometers across. Moreover, they also note in their paper that the ‘loading’ of the hydrogen sulphide between the anvils needs to be done at a low temperature – before pressurisation – so that the gas doesn’t decompose before the superconducting can begin.

These are impractical conditions if hydrogen sulphide cables have to be handled by a crew of non-specialists and in conditions nowhere near controllable enough as the insides of a small steel gasket. As an alternative, should independent verification of the Eremets & Drozdov experiment happen, scientists will use it as a validation of the Chinese theorists’ calculations and extend that to fashion a material more suited to their purposes.

*The foundation for this section of QM was laid by Satyendra Nath Bose, and later expanded by Albert Einstein to become the Bose-Einstein statistics.

**But not a gigawatt of power consumed, thanks to power thefts to the tune of Rs.2.52 lakh crore.