Who has a real vision for science in Britain's general election?

Will this generation of politicians' children choose science? Shawn, CC BY-NC

As the general election draws ever closer we all wait anxiously to see what complexion government we end up with; scientists are no different from anyone else in this respect. Graeme Reid recently described how government protection of the science budget had come at a cost over the last five years.

The flat cash that looked so good in 2010 has been significantly eroded since by inflation. The change in policy at the time over capital and infrastructure funding meant initially very little funding was available at all. More recently there has been an easing on this front but in rather unpredictable ways.

Efficiency savings have bitten hard and grant application success rates at the research councils have fallen to a miserably low level. Those outside may tell scientists we have been comparatively protected, but it is unlikely a young researcher trying to establish a lab and a group of one’s own will feel in a good place.

Warm words and golden hellos

Still, our politicians speak warm words about science. We are told Osborne “gets it”. In other words he seems to have grasped the concept that there is a connection between what researchers get up to and their contribution to the economy. But the connection between science (broadly defined) and the economy goes much deeper than that. If we lose the country’s science and technology skills we will be in an even worse mess than we are currently.

The Confederation of British Industry (CBI) regularly complains that there are insufficient numbers of people trained in science, technology, engineering and maths (STEM) at all levels. There is also a recurrent shortage of schoolteachers qualified in these areas despite golden hellos and other inducements to graduates.

Analysis of the state of the Department for Business, Innovation and Skills suggests that it may suffer severe cuts to its budget, assuming it survives as an entity at all. Universities are under no illusions: funding for the sector as a whole is at risk. Scientists should likewise recognise that pronouncing the importance of skills, or science and technology does not necessarily (or even probably) turn into reliable hard cash months down the road.

Neither Labour nor the Conservatives have pledged to do as much as retain the current level of funding in their manifestos, despite their enthusiastic comments on the subject of the UK’s science and innovation base.

Science, politicians seem to believe, does not have many votes in it – unlike the NHS, for instance. Nevertheless, in the past year we have seen substantial tranches of money announced in an ad hoc fashion. Take the “Crick of the north” (a term coined by the chancellor to express his desire for a science powerhouse to rival London’s £700m Francis Crick Institute) – £200m for this has primarily gone to Manchester which, as has been noted, is close to George Osborne’s own constituency. I doubt we will be seeing more of the same.

The idea of a Mean Machine of the Midlands or an Electrifying Emporium in the East do not seem plausible to me, even if the Midlands and the east of England could come up with splendid ideas that are as likely to make a constructive contribution to the economy as materials in Manchester. Indeed, the capital promised over the next cycle – as described in the science and innovation strategy document published in December last year – has largely already been spent or committed.

Manchester gets a science boost, thanks to Osborne. Manchester image via www.shutterstock.com

Science at the forefront

However much Osborne personally and the treasury collectively may have begun to appreciate that investment in science is good for the economy in all kinds of ways – and not just the obvious one of bright ideas turned rapidly into multimillion pound companies – it’s not obvious it is an argument that has been more widely won.

Many of us have experienced that tedious moment when in a social situation you admit you’re a scientist or mathematician and your interlocutor says “you must be so clever to do that” or “I never could do maths at school”. Science is culturally regarded as an outsider discipline, something that is too difficult for the average person in the street to understand and consequently something that is felt not to be applicable to their lives.

Back in 1963 Harold Wilson put science at the heart of his agenda when he warned that to ensure the country’s prosperity, a “new Britain” would need to be forged in the “white heat” of the “scientific revolution”. He did not live up to this when in power, but – at least for a brief moment in time – he had an aspiration to “replace the cloth cap [with] the white laboratory coat as the symbol of British labour”.

What sign do we have that either David Cameron or Ed Miliband would want to put science at the forefront of their policies? Has the nation just got used to the idea that somewhere there are some “pointy-heads in lab coats” who will solve the problems of the planet (water, energy, bees …) but without worrying sufficiently about resourcing science education at all stages from primary schools to PhDs? And without worrying about the cash that is required to combat the ills the population is only too aware they face?

White heat or smoke and mirrors? Mark McLaughlin, CC BY-NC-SA

Diversity and conviction

I am not arguing that we shouldn’t support other disciplines in our universities. Too often speaking up for subject A is taken as wanting to trash subject B. I am of the view that education needs a sprinkling of most subjects whatever you end up specialising in. I have been involved with two Royal Society reports that explicitly call for a broader post-16 education system. Regrettably people – including politicians – don’t seem to have embraced these recommendations from the equivalent of the nation’s national academy of science.

I am also a great believer in diversity. People may associate me with championing getting more women into science, but I equally believe that a more diverse set of MPs – which would include more women but in this context also imply a shift from lawyers and PPE graduates to spread to a much greater range of disciplines – would improve our policies and law-making.

I suspect we have a curious paradox where the people who make policy, themselves overwhelmingly arts, humanities and social scientists, are seen to be pushing our youngsters towards science subjects, to the annoyance of those in the said arts, humanities and social sciences. The politicians' own educational choices do not support the rhetoric. It would be interesting to know what disciplines these same politicians' children will choose to study at university.

Of course this is all a circular argument. If we don’t educate our children so that they are able to grasp scientific concepts, appreciate how science fits into our daily lives and don’t feel defensive – or worse smug – about their “inability to do maths”, then future generations will also not get it.

Let us hope our new government, of whatever complexion or rainbow hue, grasps the scientific nettle with conviction and transparency.

Twitter expands its anti-abuse arsenal, but has a long way to go to silence the trolls

It isn't enough just to not feed the trolls - something has to quieten them down too. Gil, CC BY

Those suffering abuse, threats, or generally unpleasant behaviour on Twitter – of which is there is much – may welcome Zero Trollerance, an initiative that aims to tackle trolls by bombarding them with tweets containing helpful life tips and advice on how to be less angry and aggressive.

A bot scans Twitter for accounts regularly spewing sexist, racist, or otherwise offensive tweets and floods them with tweets with a “six-step” plan to relieve themselves of their anger and aggression, including links to self-help videos.

The project’s creators, Berlin-based collective Peng, declare that:

The gendered forms of harassment and violence on Twitter today point to a deeper problem in society that cannot be solved by technical solutions alone. Trolls need serious, practical help to overcome their sexism, deal with their anger issues and change their behaviour.

Zero Trollerance is tongue-in-cheek, but the problem of abuse online isn’t amusing. It’s no secret that Twitter is struggling – Twitter CEO Dick Costolo admitted as much when he said he was “frankly ashamed of how poorly we’ve dealt with this issue”. Indeed, while the site does perform some degree of moderation, generally the platform has embraced – perhaps a little too tightly – a prime directive-style approach of non-intervention. The hope is that worthy and interesting comments drown out any nasty, trollish voices lurking beneath. In reality it takes very few drops of poison before the rivers of writing turn red.

Twitter’s steps in the right direction

Just last week, Twitter announced a series of measures to prevent abuse and more easily ban serial offenders. This widens the threat policy to include indirect threats and promotion of violence. It also introduces account locking procedures and temporary bans against those attacking individuals at a particular time – for example an internet “pile-on” where many strangers harass particular users. Another measure is to automatically identify accounts and tweets thought to be abusive and prevent them from propagating through Twitter, limiting their reach and the harm they cause.

This follows hot on the heels of Twitter’s quality filter, which aims to:

… remove all Tweets from your notifications timeline that contain threats, offensive or abusive language, duplicate content, or are sent from suspicious accounts.

While these measures seem sound, intended to bend the arc of the Twitterverse towards boosting signal and filtering out noise, the reality is that what they achieve may be quite different from their aims.

What’s happening? Chances are some women are being subject to torrents of abuse. ra2studio/shutterstock.com

Threats

Most will have heard of Twitter rape threats, terrorism threats, murder threats, bomb threats, even revenge porn threats, and the various responses to them. However, of the many things I’ve discovered throughout my research into Twitter abuse, one is that identifying threats (or even trolls) is far more complex than it seems.

Just because someone may tweet a threat doesn’t automatically make it credible. They may lack the means or the inclination to carry it out – your friend tweeting that she’s “going to kill you” for breaking her laptop isn’t really.

On the other hand, language does not need to be explicit to be menacing. Imagine that an anonymous account tweets you every day with a description of the clothes your child is wearing: there is no overt threat in such tweets, but it is obviously sinister. Even the words “we need to talk” are enough to fill many of us with dread.

The issue here is that sometimes we say what we don’t mean, and sometimes we mean what we don’t say. Language is subtle and complex enough to imply things that even a can child understand, yet invisible to the most powerful computers and software on earth.

Offensive or abusive language

Filtering for offence is also not simple. We could choose to screen out racist, homophobic, and misogynistic terms, but in doing so, we are already imposing our moral judgements on others. Just like art, comedy, and beauty, offensiveness is largely in the eye of the beholder.

Some will consider “bloody hell” unacceptable, whereas others will be content to run the full gamut from mild cursing to the most offensive words in the English language. Who decides which words fall above and below the line?

To complicate matters further expletives are used much more widely and in far more diverse ways than just to convey insult. Filtering out the humble Anglo-Saxon “fuck” would certainly remove tweets where it is used to insult, but it would also remove those instances where it signals emphasis, humour, closeness, frustration, joy, and far more besides. In other words, profanity filters may sieve out some of the dregs, but measures like these can take some of the sparkle out of the conversational champagne too.

Not everyone’s experience of social media follows the same pattern. antoniomas/shutterstock.com

The many need protection, not just the few

Quality filter is currently only for verified users (generally celebrities or those with many followers) using Apple devices – a step that clearly excludes the vast majority of Twitter users. And in any case, verified users are not blameless when it comes to abuse. Even the affable Stephen Fry once unwittingly triggered a dogpile from his legions of followers when he responded to a critic. In other cases, famous Twitter users appear to have deployed their followers as pitchfork-wielding mobs.

Somewhat ironically, the greatest protection from abuse is currently offered only to those Twitter users who typically already have considerable power through their many followers – and often the means to pursue legal action. This is not to say that they are not also prime targets of abuse too, but that simply no user should be subjected to any scale of abuse that they are not equipped to deal with. Users should not feel compelled to befriend, beseech or threaten their attackers.

One final aspect that the quality filter cannot address is that by its very design, the Twitterverse is an oddly blinkered echo-chamber. Unlike some other social network formats, it’s possible for ten thousand users to each reply to a tweet without ever being aware that anyone else has responded. The result is that any one of us could, for one unwitting moment, end up part of a pitchfork-wielding mob that is burying someone else alive under an avalanche of online wrath.

After ten years, spacecraft will end life as just another crater on Mercury's surface

Come in MESSENGER, your time is up. NASA/JHU APL/Carnegie Institution of Washington

Very soon, probably on 30 April, a half-tonne spacecraft will plough into the surface of Mercury, the closest planet to the sun, at about 4km/s or nearly 9,000mph. The spacecraft is NASA’s MESSENGER (“MErcury Surface, Space ENvironment, GEochemistry, and Ranging”), which became the first spacecraft ever to orbit Mercury in March 2011.

Launched in 2004 and operated by Johns Hopkins University’s Applied Physics Laboratory, MESSENGER’s final act in its ten-year mission will be to “de-orbit” (the term NASA prefers to “crash”) into the planet. This will create a 15m wide crater, which will be studied when Europe’s BepiColombo mission reaches Mercury in 2024. But that’s not the reason for disposing of MESSENGER like this – the spacecraft has simply run out of fuel and gravity is pulling it towards the surface. **this is codswallop as rephrased. Do you want to get the science right? (I do - it’s my reputation at stake). The downward pull of gravity, i.e. towards the surface, is essential for ANY orbit to happen. My words, which have been edited away, EXPLAINED why the orbit, and in what way, is changing: “and the Sun’s influence and slight asymmetries in Mercury’s gravity field are dragging the low point in MESSENGER’s orbit downwards.”

During MESSENGER’s first three years at Mercury, the mission controllers kept its orbital low point between 200-450km above the planet’s surface. In 2014 they allowed it to dip below 100km, sometimes coming as low as 30km before using precious hydrazine fuel to kick it back upwards, but in its final six weeks its orbital low point has been between 5km-35km. Now it has run out of fuel. On the last three occasions mission controllers ingeniously raised MESSENGER’s orbit by venting pressurised helium – now that too has been exhausted.

Time for your close up: one of MESSENGER’s colour views of Mercury’s scarred surface. NASA/JHU/Carnegie Institution of Washington

First rock from the sun

But what a mission it’s been. The only previous mission to Mercury was Mariner 10, which performed three fly-bys in 1974-5 that provided only an incomplete view. MESSENGER has revealed the entire planet in detail, especially the northern hemisphere to which MESSENGER was brought closest by its deliberately eccentric orbit before soaring upwards to escape the 400°C temperatures at the surface.

What’s now apparent is that Mercury is a misfit planet that seems not to belong where we find it. It is dense even for a rocky planet, revealing an iron-rich core that occupies more than 80% of the planet. The outer part of the core must still be molten, because this is where Mercury’s magnetic field is generated – a characteristic shared with the Earth, unlike Venus, Mars or the Moon.

Probable internal structure of Mercury, its magnetic field generated by dynamo motion in the electrically-conducting outer core. Rothery

Volatile-rich planet

Before MESSENGER’s visit, Mercury’s thin rocky shell over an anomalously large core was explained as a consequence of growth too near the sun for much rock to condense, or the result of a catastrophic collision that stripped away most of the planet’s original rocky component. Data from MESSENGER has discredited both options, revealing that Mercury is rich in volatile substances that should have been depleted even more strongly than the common rocky material during the heat and violence of a collision, or else never even have been there in the first place.

Top: 280km-wide colour view centred near a volcanic vent, surrounded by a diffuse yellow deposit that was erupted explosively. Below: the vent lit by the sun from different angles. NASA/Johns Hopkins University/Carnegie Institution of Washington

Examples include sulfur, which makes up 2-5% of the surface, and light metals such as potassium and sodium. Most of the terrain consists of vast ancient lava fields (like basalt on Earth, but richer in magnesium and poorer in iron). These are ancient, more than three billion years old, but MESSENGER’s high-resolution images also revealed volcanic vents punching through the lava and through the floors of impact craters, which have clearly been sites of more recent explosive volcanic eruptions. An explosive eruption has to be driven by expanding gas, escaping from the planet’s interior – more proof of Mercury’s richness in volatiles.

3km-wide close-up of Mercury from low orbit. The curiously-textured area in the middle is coalesced ‘hollows’ where about 20-40m depth of surface material has somehow been stripped. NASA/Johns Hopkins University/Carnegie Institution of Washington

And then there are the “hollows”, a previously unknown landscape feature. These are steep-sided, flat-bottomed depressions where the top 10m or so of Mercury’s surface has simply vanished. With no atmosphere, there are no winds on Mercury to erode it, nor are there any signs of collapse into underground cavities, leaving us to conclude that something in the ground has been turned to vapour and lost to space.

What this stuff is and whether it turns from solid to vapour through heating (a process called sublimation) or because chemical bonds are broken by radiation of some sort, we don’t know. It’s another piece in the jigsaw puzzle that must one day be fitted together if we are to understand where and how the sun’s smallest and closest planet formed.

Hubble's ultraviolet telescope has revealed more about the stars than we could ever see

The galaxies NGC 4038 and NGC 4039, locked in a destructive embrace. ESA/Hubble/NASA, CC BY

It’s probably fair to say that the Hubble Space Telescope, which recently celebrated its 25th birthday, has become the world’s most famous telescope in large part due to the breathtaking astronomical images it has captured.

Hubble’s images reveal the complex, three-dimensional structure of galaxies, nebulae and star-forming regions with incredible acuity, chiefly because the telescope is in space. For ground-based telescopes, the Earth’s atmosphere has a blurring effect, limiting the sharpness of the images they produce. Hubble’s images are limited only by the telescope’s engineering and the properties of light itself.

In 1990 I was privileged to be present at the space shuttle launch which carried Hubble into orbit. The combination of the launch’s powerful demonstration of the defiance of gravity, coupled with the promise of what Hubble would do for astronomy was overwhelming. Curmudgeonly male scientists wept.

Perhaps the affection directed towards Hubble is also partly due to the telescope’s troubled start: the primary mirror was very precisely manufactured, but to the wrong shape. For the first three years of operation, Hubble’s ability to produce sharp images was compromised, to the point that “Hubble Telescope” was a joke appearing in cartoons and punch-lines.

Astronauts Hoffman and Musgrave working on the Hubble Space Telescope in 1993. NASA

So engineers produced COSTAR, a component that would correct the optical problems with the primary mirror. Installed during the first space shuttle visit to Hubble, it worked a treat. Like a flawed hero or a prodigal child, Hubble’s triumph over adversity has universal appeal – the best stories, like the best images, have contrasts between darkness and light.

More than just light

Fortunately, not all of Hubble’s science had to wait three years for the first servicing mission. Scientific astronomy is carried out in other regions of the electromagnetic spectrum than just visible light, for example ultraviolet (UV) light. UV is invisible to our eyes, but forms the continuation of the visible spectrum beyond the violet.

Hubble had always been intended to serve as an ultraviolet telescope – from space, UV light that would otherwise be absorbed by Earth’s atmosphere can be collected. Light in this part of the spectrum is more energetic than visible light and is emitted by most stars, including our own, and many other astrophysical objects. Studies in ultraviolet radiation reveal things that can’t be learnt from telescopes on the ground.

A ‘hot Jupiter’ exoplanet’s atmosphere is stripped away by the heat of its star. ESA/Alfred Vidal-Madjar/NASA

Hubble has produced many, many UV science results. My favourite is the spectacular discovery in 2003 that the exoplanet HD209458b is surrounded by a huge cloud of hydrogen gas. This type of exoplanet, known as a “hot Jupiter”, orbits its star so closely – only a 20th of the Earth’s distance from the sun – that the star’s heat boils off the planet’s atmosphere.

 

Insight into the future

This sort of discovery offers a great opportunity to learn what exoplanets are made of. Spectroscopy is the key: each chemical substance has its own spectroscopic fingerprint that allows astronomers to measure chemical compositions – and the UV region of the spectrum is particularly sensitive and useful for this purpose. Hubble has used these strong UV features to reveal the presence of hydrogen, magnesium, iron, silicon and other chemicals in the atmospheres of several hot Jupiter-style exoplanets.

Our ultimate fate: a white dwarf star collapsed from a giant red, surrounded by remnants of its inner planets. G Bacon/NASA/ESA

The loss of the atmosphere of these exoplanets is a preview of the ultimate fate of the Earth, when the sun becomes a red giant star in about four billion years time. As the sun begins to exhaust hydrogen at its core and begins to burn helium, it will swell and become hotter and brighter, engulfing Earth and the inner planets. Once it has exhausted its nuclear fuel, it will collapse into a white dwarf star – about the size of the Earth, and surrounded by the remnants of our solar system.

Hubble UV spectroscopy of white dwarf stars has revealed that many of them are being continually bombarded by asteroids feeding the stars with rocky material. These observations allow us to learn the types of rocks present in extinct planetary systems which were perhaps once very similar to our own solar system.

Appearance in UV of aurorae on Ganymede. NASA/ESA

Most recently and closer to home, UV images reveal the aurorae around Ganymede, Jupiter’s largest moon. Just as with Earth’s aurora borealis and australis (northern and southern lights), Ganymede’s aurorae change continuously with the influence of Jupiter’s magnetic field. Hubble captured changes in the aurorae caused by the presence of an underground salt-water ocean on Ganymede – an ocean that probably has more water than all of Earth’s oceans combined and may provide a habitat for life.

Hubble has continued its mission well beyond its original planned lifetime. It has made over a million observations and generates about ten terabytes of new data each year. The current plan is for it to operate beyond 2020, to allow some overlap with its replacement, the NASA/ESA/Canadian Space Agency joint project, the James Webb Space Telescope (JWST).

Sadly for UV astronomy, the JWST will work predominantly in infrared and has no UV instruments. This leaves many astronomers keen to see a successor to Hubble that will continue it’s unique work in UV, which has added so much to human understanding by working beyond what we can see.

Nepal shows its vulnerability after devastating earthquake

The magnitude 7.9 earthquake that hit Nepal this morning is shocking news. For some time scientists have realised that the Kathmandu valley is one of the most dangerous places in the world, in terms of earthquake risk. A combination of high seismic activity at the front of the Tibetan plateau, poor building standards, and haphazard urbanisation have come together today with fatal consequences.

The quake hit just before noon, local time, around 48 miles north west of Kathmandu. The Indian tectonic plate is driving beneath the Eurasian plate at an average rate of 45mm per year along a front that defines the edge of the Tibetan plateau. This force created the Himalayas, and Nepal lies slap bang along that front. The quake was shallow, estimated at 12km depth, and devastating as the Indian crust thrust beneath Tibet one more time.

Shake map released by the US Geological Survey. USGS

Historic buildings in the centre of Kathmandu have been reduced to rubble. Brick masonry dwellings have collapsed under clouds of dust. Weakened buildings will now be vulnerable to aftershocks, which continue to rattle Nepal through the day. Multiple aftershocks above magnitude 4 hit in the six hours following the earthquake.

The search for survivors has only just begun. Narendra Shrestha/EPA

Away from the populated Kathmandu valley, in the heights of the Himalaya, climbers on Everest tweeted reports of damage to base camp, and fatal avalanches on the flanks of the mountain. The steep valleys and precipitous dwellings of the more populated areas are vulnerable to landslides. It seems inevitable that the areas beyond the city itself will bear bad news to come. Now is the time for us all to consider how we can help those most in need, in practical ways.

Although one cannot predict the day or the hour, the scenario that we see on our TV screens today had been thought through many times already, with one particularly prescient article written almost two years ago to the day. The likely impacts of the quake can be readily estimated, and in any case will soon be reported directly from the surroundings.

Early reports of deaths nearing the thousands are only, tragically, going to increase, with the US Geological Survey putting estimates of fatalities in the range of thousands to tens of thousands.

The Dharahara, also called Bhimsen Tower, was destroyed in the quake. Narendra Shrestha/EPA

Just one week ago my geophysicist colleagues returned to the UK from a meeting in Kathmandu, Nepal, as part of the Earthquakes Without Frontiers research project. The focus was earthquake risk reduction and hazard awareness in Nepal. The risks have been recognised for some time, but I don’t suppose any of the participants expected their work to be thrown into the spotlight so soon.

Professor James Jackson, of Cambridge University and one of the leaders of the Earthquakes Without Frontiers project, talked with me on his return from Kathmandu last weekend. He described tall, thin houses, with extra stories built up on top, explaining how they arise from the Nepalese tradition of sharing inherited property between siblings, with houses split vertically between them.

The only way to build is upwards. In a seismic area, it’s a recipe for disaster, and one can’t help but wonder what this phenomenon has wrought on families in Kathmandu today.

Disclosure

Simon Redfern receives funding from the Natural Environment Research Council of UK, and the British Council

Calbuco volcano – evacuations and air-traffic disruption follow eruption

Eruption of the Calbuco volcano, seen from Puerto Montt. EPA/Francisco Negroni

The Calbuco volcano, a 2,000 metre peak in southern Chile, sent a column of ash about 15km skywards twice on the night of April 22 and early the following morning. As the risk of deadly flows of ash and hot air was immediate, a 20km radius evacuation zone was declared.

The event was spectacularly visible from Puerto Montt, a city of nearly 200,000 inhabitants, only 30 km away. It seems to have begun within barely five hours of warning signs being first detected by local seismometers.

There two big eruptions over seven hours caused ash to fall in the Argentinian town of San Martin de los Andes, nearly 200km north-east of the volcano. Further eruptions are possible, although the likelihood of this decreases as time passes.

Ash fallout from Calbuco in San Martin de los Andes.

Eruptions like these are particularly significant because they have the potential to produce pyroclastic flows, which are fast-moving ground-hugging currents of ash and hot air, triggered when a rising ash column collapses. These are deadly – and the 20km radius evacuation zone wisely remains in place in case the volcano (quiet during most of April 24) wakes up again. For example, pyroclastic flows at the Indonesian volcano Sinabung killed at least 16 people in February last year, who had strayed back inside the local evacuation zone. Hazard map around Calbuco, issued 23 April. Red circle = evacuation zone. Striped area = area most likely to be affected by ash. Sernageomon - Red Nacional de Vigilancia Volcanica, Chile

Less immediately deadly is the fall-out that settles from the high-altitude ash cloud that slowly disperses downwind. This is a respiratory hazard and can also kill vegetation and contaminate water supplies. After an eruption has ceased, ash that has settled to the ground will pose a risk of volcanic mudflows (widely known by their Indonesian name “lahars”) that can choke water-courses and destroy bridges.

Video from Puerto Montt showing the 22/23 April eruption of Calbuco.

Calbuco is about 90km south of the Puyehue-Cordon Caulle volcano, which erupted in June 2011 spreading airborne ash around the globe, leading to airspace closures in Australia. That eruption lasted for months, and produced a high ash column for more than a week. Calbuco’s current eruption seems unlikely to persist so long but already it has disrupted local air travel.

Volcanic ash is dangerous to aircraft and the Buenos Aires Volcanic Ash Advisory Centre (VAAC) this week issued a warning of airborne ash up to 40,000ft high across Chile and Argentina. The cloud is expected to disperse over Argentina, as as it is no longer being fed by a continuing eruption anyone hoping to fly in or out of Australia has little need to worry.

The area of sky that was at risk of volcanic ash for the 24 hours ending 08:30 on 24 April. Calbuco is indicated by the volcano symbol. Buenos Aires Volcanic Ash Advisory Centre

These days the rules about flying in volcanic ash are less stringent than they were during the 2010 eruption of Iceland’s Eyjafjallajökull volcano. When that began, the rule was if there was any ash at all, it was forbidden to fly through it. Nowadays it is agreed that a small amount of ash can be tolerated for short periods. Unfortunately it is hard to be sure of the density of airborne ash, so it is best to err on the side of caution.

Calbuco had been quiet since a four-hour eruption on August 26 1972, except for an episode of gas emission from fumaroles on 12 August 1996. One of the largest historical eruptions in Chile took place here in 1893-4, throwing 30cm bombs as far as 8km from the summit crater.

These and other volcanoes in the Andes are present as a result of plate tectonic processes, which also cause earthquakes in the region. The floor of the Pacific ocean (actually the Nazca Plate) is being pushed below South America which leads to melting at depth which forces magma upwards to feed the volcanoes. Because seawater has been transported into the melting zone, the magma contains gases such as water vapour and carbon dioxide, and the violent expansion of gas bubbles is what makes eruptions at these volcanoes so explosive.

Schematic cross section through the outer part of the Earth. The volcano on the right is equivalent to Calbuco USGS, Smithsonian Institution, US Naval Research Laboratory

Why too much Facebook can leave you feeling down

_That_ good? Amen to that. toaireisdivine, CC BY

“Comparison is the thief of joy”, said former US president Theodore Roosevelt. Spoken more than a century ago, Roosevelt’s words highlight a fundamental truth that is just as relevant today.

In the 1950s, the acclaimed social psychologist, Leon Festinger, devised the social comparison theory to help explain the psychological processes behind why we compare ourselves to others. Festinger proposed that individuals have an innate desire to see how they measure up with their peers on dimensions they deem personally important in order to evaluate how well they are doing.

This tendency hasn’t gone away, and in fact, through social media websites like Facebook we may be engaging in more social comparison than ever before. Such social comparisons can convey important information: are we measuring up in terms of our progress or achievements, or are we falling behind and need to put in the effort to catch up?

Of course, comparing ourselves too much to our peers can leave us feeling bad about ourselves. When looking at social media, we are often inundated with a constant stream of information and photos about family members, friends, and acquaintances. There may be times when this is too much, and we’d be better off not knowing the details that we learn, or imply, from these sites.

For example, a couple of years ago my little sister decided not to go to a big school dance because she didn’t have a date. She told me she was devastated about it. The next day, her friends' pictures from the dance started to appear on her Facebook news feed. She said it made her feel even worse. Although I didn’t want to pry into why she felt this way, I began to think that this might be a common occurrence. Perhaps, all those smiling, happy photos of her girlfriends blissfully dancing the night away with their respective beaus made her feel that she was not attractive or popular enough to garner a date.

Things on social media are not necessarily what they seem. head in a box by ra2studio\shutterstock.com

Her experience inadvertently inspired the basis of research I developed with colleagues from the universities of Houston and Palo Alto. We conducted two studies using a sample of over 300 American university students (98 men and 236 women), who were primarily in their early twenties.

We conducted two studies, one on a single day and a second across 14 days. Participants reported their daily Facebook use, Facebook social comparisons, and daily depressive symptoms. Overall, we found that people (of both genders) who spent more time on Facebook reported higher depressive symptoms due to Facebook social comparisons.

Although previous studies have found a link between Facebook use and depressive symptoms, our research demonstrates that the underlying cause or reason for why people feel blue after spending a lot of time on Facebook may be this urge to compare ourselves to others.

Unfortunately, when we compare ourselves to others we do so automatically, an impulse often beyond our control. Nor can we predict, short of not logging in, when will we will compare ourselves to Facebook friends (and possible frenemies) because we never know what material we’ll stumble across.

People often try to present themselves in a positive light on Facebook – that is, they filter out bad aspects of their lives and accentuate the good. So if we’re comparing ourselves to others’ “highlight reels” we may feel our lives are more mundane or less glamorous compared to theirs. But if we bear in mind that we’re comparing ourselves to a carefully crafted, positively distorted version of their lives we might take a different view.

Facebook or other social media sites such as Twitter or Instagram aren’t innately good or bad. They were created to fulfil a particular purpose, to entertain and to connect us to our friends – essentially positive experiences. So if you find yourself feeling increasingly glum after viewing your friends’ exotic vacation photos, ecstatic engagement announcements, photos of happy babies (so many babies), or posts about their latest promotion – maybe it’s time to step away from the keyboard.