Merry Christmas!

As 2013 draws to a close, it's been a wonderful year for us and we wanted to say a big thank-you to everybody that's been working with us, writing for us, and just reading our site! We've achieved so much this year, and we're confident 2014 will be even better.
So from all of us at TWDK,

MERRY CHRISTMAS!

Here's a little something we put together just for you, with more than a little help from Es Einsteinium:

See you in the new year!

Why do we sleep? [SCIENCE VIDEO]

We spend a third of our lives doing it, yet it still isn't clear why we need to sleep. In fact, there’s so many things we don’t know about sleep, that we don’t have time to talk about them all today.

This is the first of our articles to be made available as an animated video. 
An audio version of this article is also available!

What we do know is that we can’t function without it. After missing just one night’s sleep, you are likely to find yourself feeling hungry, emotional and unable to concentrate. Decisions will become difficult to make, your reactions will slow, you may become forgetful, and your vision can even be affected. Going without enough sleep can weaken the immune system, making you susceptible to colds and other infections, and can even increase your blood pressure.

So it is clear that sleep is vital, but why? Scientists just can’t agree…

TWDK launches "TWDK Kids!"

We're very happy to announce a new section of our website has gone live today - with the new mission of "explaining the things scientists can’t answer with fun and games".

Entamoeba histolytica – how and why does it cause disease?

There is a disease that you probably haven’t heard of, which infects 35-50 million people every year - mainly in areas of developing countries where wastewater isn’t kept separate from drinking water. It causes symptoms ranging from stomach cramps to life-threatening dysentery (bloody diarrhoea) and, in extreme cases, fatal liver abscesses. This disease, called Amoebiasis, kills up to 100,000 people annually, and is caused by the parasitic microbe Entamoeba histolytica.

When accidentally ingested by a human, the parasites stay as ‘armoured’ dormant cells called cysts, until they pass through the highly acidic stomach. Upon entering the large intestine, the environment becomes more hospitable for them and allows them to transform into their active form.

It was once thought that E. Histolytica infected 10% of the world's population - but although that figure has been reduced to just 1%, that's still a lot of people. Image credit: CDC / Dr. George Healy (1964)

Many of them will stay in the intestines but some pass out of the host in faeces, and transform into cysts again in order to survive in the more varied temperature and acidity levels they must endure before finding another host. But it is those that remain which (might) cause a problem. This is the main mystery of E. histolytica - not everybody infected will experience the same symptoms, if any. So what triggers the different levels of infection?

TWDK Introductory Video

As you may have guessed from the title, or seen on our homepage, we have a new video by the very talented Jon King over at Envisuals. This video strives to explain, in about 90 seconds, all the things we're trying to achieve, how, and why. We hope you like it - we do!

If you've got a YouTube (or Google+) account, you can now subscribe to our YouTube channel - which will soon be bursting with fascinating science videos!

New collaboration - Odyssey magazine

It's been a bit quiet on the TWDK blog since our very successful World Space Week series, which as usual means we've been working on something big! We have some great new features coming soon, and we won't give away too many spoilers just yet but as a hint we've just created the Things We Don't Know YouTube channel!

One thing we will reveal however, is that we've started working with American science magazine Odyssey. Their focus is on explaining science to kids with regular features like "Ask Dr Cyborg", and will have a special feature in January about "Unsolved Mysteries of Science". We're happy to announce that TWDK have been acting as consultant editor for the issue, and we have been collaborating on some material which will go live on the TWDK site in December. Watch this space!

For more information about partnership opportunities with Things We Don't Know, please contact us at partnerships@thingswedontknow.com

Unpredictable Space Weather

It regularly fills the skies over the poles with bright light shows known as the aurora. It destroys satellites, possibly resulting in the failure of wireless communications, ATMs and television. It could leave large areas without power for months. But what is ‘it’? - Space Weather.

Photograph of Aurora taken from onboard the International Space Station by European astronaut André Kuipers. Image credit: ESA

Space weather is dangerous and a large event could have a massive impact on society. But what is ‘Space Weather’? What are the possible effects? What are the questions that still need answering?

‘Space Weather’ describes the happenings in the environment surrounding the Earth. This ‘weather’ is fuelled by the Sun’s unpredictable activities – more specifically solar flares, Coronal Mass Ejections (CMEs), coronal holes and solar prominences. We are completely dependent on the Sun, it can be our best friend or our worst enemy.

Pluto's New Horizons

[EDIT - June 2014] This article is now also available as a video, thanks to a group of media students at Sheffield Hallam University who created an animated version of our article. For more information, read about how we partner with universities to create videos.

  

“Pluto is dead”, according to Mike Brown (in How I Killed Pluto and Why it Had it Coming), but that doesn’t mean we shouldn’t go there. In fact, this is one of the reasons why we are going there. Unsurprisingly, given the distances involved, we know very little about Pluto (“You may think it’s a long way to the shops, but that’s just peanuts to space,” to quote Douglas Adams in The Hitchhiker’s Guide to the Galaxy).

We're used to seeing detailed pictures of our neighbouring planets like Mars, but this is the best image we have of Pluto - taken by the Hubble Space Telescope in 1994. So what does Pluto really look like? Image credit: NASA/HST

Discovered in 1930, Pluto remains something of a mystery, as astronomers are a long way from understanding its origin. Pluto is one of many rocky and icy bodies which form the Kuiper Belt, in the outer region of the solar system. Pluto was discovered by Clyde Tombaugh in a systematic search for a planet beyond Neptune. Its high surface reflectivity initially made it appear larger than it actually is. Pluto was initially considered as a planet, before the International Astronomical Union officially defined what a planet was. At one point Pluto was thought to be a rogue moon of Neptune.

Juno - halfway there and home again

Artist's impression of the Juno spacecraft near the planet Jupiter. Image credit: NASA/JPL

On August 12 2013, NASA's Juno Spacecraft reached the halfway point on it's journey to Jupiter. Since launching back in 2011, it has travelled over ten times the distance from the Earth to the Sun, and has performed a series of planetary flybys and deep space manoeuvres. Tomorrow on October 9, Juno will come within 350 miles of Earth's surface. This is known as a gravity assist, or a gravitational slingshot. After Juno says its farewells to planet Earth for the final time, it will race towards the Jovian system before its slated arrival time of 22:29 EST on July 4, 2016, give or take a few minutes!

But what has Juno done since launch? Well, the Jovian explorer has been sent out past the orbit of Mars, and performed crucial Deep Space Maneuvers to set itself up for tomorrow's flyby of Earth.

Juno Mission Project Manager Rick Nybakken explains further;

"On Oct. 9, Juno will come within 347 miles (559 kilometers) of Earth. The Earth flyby will give Juno a kick in the pants, boosting its velocity by 16,330 mph (about 7.3 kilometers per second). From there, it's next stop Jupiter... Almost like a second launch for free!"

Juno's path to Jupiter. Image credit: NASA

Confused? Well, think of it this way: if a golfer putts a ball towards the edge of the hole, and the ball does not fall into the cup, instead hitting the very edge of the hole and "lipping out", the ball will shoot off in another direction at a faster speed than before. You got the hang of this? Right, let's move on.

However, it is also worth noting that as well as this extremely predictable increase in speed, the spacecraft also experiences a tiny tiny change in velocity due to something else. But just why do spacecraft that flyby Earth receive this tiny change in acceleration? Well, to put it simply, no one is really quite sure! This is known as the Flyby Anomaly, and it's something that science doesn't really have an answer for at the moment.

What Causes the Flyby Anomaly? 

Scientists have theorised (and later dismissed) this unexpected source of energy as being caused by atmosphere, tides, magnetism or radiation. The possible remaining solutions for this problem include that there might be a halo of dark matter around the Earth, as well the theory that it is caused by the rotation of the Earth itself.

Breaking out of the Habitable Zone

In the search for extraterrestrial life, water is highly regarded as a key ingredient for life to arise. Its polar structure allows it to form "hydrogen bonds," which are crucial for the formation of large organic carbon structures like DNA. Water is so important that scientists are constantly looking for planets in the "habitable zone" around their stars, a land flowing with milk and honey—er, I mean, liquid water. A habitable zone is determined by the properties of the star—with very bright, hot stars, it would be further out; and with dim, cool stars, liquid water could exist much closer in.

The instantly recognisable brown bands on Jupiter are of unknown composition. Image credit: tonynetone (Flickr)

However, liquid water can exist in some out-of-the-way places. Several of Jupiter's moons experience such strong gravitational interactions with Jupiter and each other that they are heated up by tidal flexing, making them warm enough to sustain water in its liquid form, despite being five times further away from Sun than the Earth is!

One strong candidate for a watery moon is Europa. It has a frozen ice outer shell, and it's speculated that underneath might be that liquid gold - water. Scientists are still unsure just how much internal heating Europa receives, so it's still not fully known how thick the ice is. Tidal flexing keeps it dynamic and changing, and scientists have observed that the surface is lined with cracks, possibly formed from the ice chaotically pulling apart and smushing back together like giant icebergs in a mosh-pit. This is some of the evidence suggesting there might be a liquid Europan ocean underneath its icy crust.

Messages from Mercury: what we don’t know yet

Mercury may be first on most lists of planets, but it’s easily the least explored of all the inner planets. The heat and immense gravitational pull of the nearby Sun has made visiting Mercury difficult, but fly-bys from NASA’s Mariner 10 in the late 1970s gave us the first close-up glimpses. Mercury then remained unvisited until 2004 when NASA launched the MErcury Surface, Space ENvironment, GEochemistry, and Ranging (MESSENGER) probe. MESSENGER has been orbiting Mercury since 2011, taking photos and running analyses to tackle some of our deepest questions about the smallest and closest planet to the Sun.

The planet Mercury, as photographed by MESSENGER. Image credit: NASA/Johns Hopkins University Applied Physics Laboratory/Carnegie Institution of Washington

Mercury’s past

One mystery for MESSENGER is why Mercury is so dense. The four inner planets (Mercury, Venus, Earth and Mars) are all comprised of a dense metallic core surrounded by a rocky mantle and crust – but Mercury is unusual in having far more metal than rock. Mercury’s metal core is estimated to make up 75% of the planet’s radius, but Earth’s is just 10%.

Why are the planets so different?

If you were to take the eight planets in our solar system and look at them as a whole, there would be two obvious groupings. The first of these are the giant planets, which are well deserving of their names - hundreds of times larger than the others and with thousands of times more mass.

The planets of our solar system, to scale by size. Credit: Wikimedia Commons

The spectacular contrast between the four giants (Jupiter, Saturn, Uranus and Neptune) and the other planets is fairly easy to explain. Before the planets were formed, all the material which they now contain was spread out in a giant ‘protoplanetary disc’.

Artist's impression of a protoplanetary disc.
Image credit: Wikimedia commons

The four ‘gas giants’ formed outside the ‘snow line’ of our early solar system, where it was cold enough to allow the relatively abundant volatile substances like water or ammonia to condense out. This gave the first baby planets in this region of the disc plenty of liquid and solid material to sweep up to form bigger and bigger planets in a process called accretion. This process is a runaway one: gaining more mass means more gravity means gaining more mass. And hence we get the giant planets, huge balls of gaseous material that (we think) contain some kind of rocky or metallic core at their centre. Some questions remain about their formation, particularly about their potential travels throughout the disc early in their lives, but that’s not what we’re here to look at right now.

Are Exoplanets Habitable?

As the catalogue of planets orbiting other stars (called exoplanets) known to us continues to grow, increasing discoveries of potentially ‘habitable’ planets are likely to follow. The ‘habitable zone’ (HZ) concept, which was introduced in a previous post, is becoming increasingly important to our interpretation of these announcements. However, when used unilaterally as it often is, the HZ metric may be misleading - and should rather be considered as a good initial indicator of possible habitable conditions, interpreted relative to other available planetary characteristics.

To the best of our knowledge, Hungry Space Bears aren't really the leading cause of failure on interplanetary missions.
Image copyright ©Luke Surl, used with permission.

The habitable zone describes the theoretical distance (with both upper and lower limits) at which a given planet must orbit a star to support the basic fundamental requirements for the existence of life based on our understanding of the evolution of the biosphere on Earth. It is often referred to as "the Goldilocks Zone", since it looks for the region "not too hot, and not too cold". The concept is based on terrestrial (rocky, as opposed to gaseous or icy) planets that exhibit dynamic tectonic activity (volcanism and/or possible plate tectonics) and that have active magnetic fields to protect their atmospheres from high energy stellar particles that could strip it away. The composition of atmosphere is assumed to consist of water vapour, carbon dioxide and nitrogen with liquid water available at the surface, as on the Earth. Liquid water is the key; the giver of life and the fundamental factor in defining the habitable zone in any planetary system.

TWDK's World Space Week schedule

Back in August we announced that we intended to break our usual cycle of one post every 1-2 weeks, and post an article every day during World Space Week (Oct 4-10). To make this possible, we invited people to send us their articles, with the promise we'd publish the best.

Throughout September, we received some truly great articles by a variety of authors around of the world, of various ages and backgrounds. So we're happy to reveal our schedule for the next week:

Tomorrow, we welcome back Andrew Rushby (University of East Anglia), who has been posting a series of articles about planets orbiting other stars throughout the year. We kick off our World Space Week with the final post of his series which asks: "Are Exoplanets Habitable?"

On Saturday, Adam Stevens (Open University) brings us back to our own solar system, and asks "Why are the planets so different?"

On Sunday, we start a journey through the solar system to look in more detail at these varied planets we call neighbours. Emily Coyte (University of Bristol) takes us close to the Sun, with "Messages from Mercury".

On Monday, Lorinda Dajose (California Institute of Technology) takes us "Breaking out of the Habitable Zone" and looking for signs of life out at Jupiter's icy moon Europa.

On Tuesday, just in time for the Juno spacecraft's flyby of the Earth on Wednesday, 16-year old Irish space blogger Cian O'Regan explains why Juno is being sent to investigate the giant planet Jupiter, and why arriving back at the Earth still counts as "half way there".

On Wednesday, freelance writer Peter Ray Allison takes us all the out to frigid edges of our solar system, and delves into "Pluto's New Horizons".

On Thursday, we finish off by welcoming back Cait Percy (University of Southampton) who explains the treacherous and mysterious nature of space weather.

What is consciousness?

Consciousness, on first glance, seems like a relatively easy concept to understand. It is something we have when we are awake, but which leaves us when we fall asleep, are knocked out, or faint. It is that feeling of awareness, of understanding our own being, the ability to feel and understand the world around us. But when we look a little closer, consciousness becomes a much murkier concept, and much less easy to comprehend.

Dualism views the mind and body as two distinct and separate things. Image credit: conkling

Rene Descartes, the 17th century French philosopher, argued that consciousness was the domain of the mind, and that this was a separate entity to the body, a belief known as Dualism. He suggested that the two interacted via the pineal gland in the brain, but this led to a problem; How is it possible that something non-physical like the mind can affect something physical like the brain? Partly because of this so-called ‘mind-body’ problem, most modern researchers in consciousness reject the dualist approach, and treat consciousness as something that arises from physical processes in the brain.

Although it is a difficult concept to define, most of us are happy to agree that other humans also have consciousness, much like our own, but plants, mountains and other inanimate objects do not. But how do we know this? Although other people may look like us, and behave like us, there is no way we can know that they have the same experiences as us - we cannot know for sure that they are not ‘philosophical zombies’, with normal behaviour but no subjective experience of the world at all.

What Can Our DNA Really Tell Us About Ourselves?

Image credit: Jurvetson

Looking in the mirror – what can you see? Blue eyes or brown? Red hair or fair? You don't need to delve into your DNA to find out what physical attributes you have, but how much can the code hidden deep inside your cells tell you about what diseases you're susceptible to, what you'll pass onto your children or how long you'll live?

Science Fiction or Fact?

At the end of the last century the whole history of genetic research, from Gregor Mendel investigating the principles of inheritance¹ to the discovery of the nucleotide structure of DNA², led inevitably to the Human Genome Project (HGP).

The project's aims were to look at the sequence of human DNA along with the location of genes and sections associated with inherited disease. As a project it felt monumental, not only within the scientific community, but to society as a whole. It was a project that captured the public imagination, inspiring both hopes and fears for the information it would give us. Would we be designing our own babies? Could we eradicate human disease or alter our genetic codes to enhance intelligence or perhaps sporting prowess?

Essentially, how comfortable are we 'playing God' with our own genetic material?

So in the ten years since the full sequence was published³, what has the Human Genome Project and subsequent research into the twists and turns of our DNA actually revealed about us, or rather, about you?

Life as an intern at TWDK

Ever wonder what it's like working for Things We Don't Know? Our physics intern Johanna had this to say about her first week with us over the summer...

This week has been a bit mind boggling, but very fascinating too.

Physicist Johanna Blee worked for us for two months over the summer, on an internship we offered through our partnership with SEPnet. Photo ©TWDK.

Having met with Nick Evans - Professor of theoretical high energy physics at Southampton - I began looking at the equations and laws that govern particle Physics and the open questions that occur from them, and then gravity which in itself is one big question! This led to many complex ideas. These include the idea that as observers we are forcing the world around us to change. This work also led me to appreciate how often in Physics answering a question creates further questions. For example, proof of the existence of the Higgs boson has led to the question "how do particles actually get their mass"?

TWDK and World Space Week 2013

Today, space is a veritable hotbed of science, and we've already posted a good number of space science posts. There's certainly no shortage of Things We Don't Know about space, but there's also a lot of science that takes place in space. So this year, we're offering a unique opportunity to anybody who'd like to try their hands at science writing. Write an article about science in one of the below categories, and TWDK will publish the best throughout World Space Week, October 4-10. Entrants can be scientists, students, school pupils or just members of the public - we'll consider anything by anyone, provided it's accurate, well written, about ongoing research and related to space!

As an added bonus, we'll do our very best to review early submissions and provide feedback, so authors can improve their article before the deadline.

Categories
Looking Up - science connecting to space but done on here on Earth. This includes astronomy, the development of new rocket engines, and much more.

Looking Down - science done in space, looking down at the Earth. This includes weather satellites and environmental monitoring, or even archaeology.

Floating Around - science done in space, without looking down. Astronauts on board the International Space Station have conducted a huge number of experiments, from psychology to biology to plasma physics and crystal growth.

Getting Outta Here - science done away from the Earth. NASA, ESA, RosCosmos and JAXA have all sent probes into deep space to conduct science well away from home. Upcoming missions from Europe include ExoMars, and LISA Pathfinder - and NASA is planning many more.

Applications must be received by Friday, 27th September 2013. Articles should be sent in .doc or similar format, by email to wsw@thingswedontknow.com

Other WSW activities
If you'd like to know more about what's going on in World Space Week, there's a full list of UK events on the British Interplanetary Society's website. If you're not in the UK, you can find out who your national co-ordinator is here.

Autism: There's Still So Much We Don't Know

Even though autism undoubtedly has biological underpinnings and the brains of those with autism may share some form of common structures (neuroanatomy) or function (neurophysiology), we still don't have a good working definition for it - or at least, nothing that everyone can agree upon. In the field of cancer research, even though scientists disagree about the primary causes of a tumour developing, they can all generally agree that uncontrolled cellular growth is a good working definition. If you see a tumour, you know it's following some sort of poorly-regulated growth process, even when it's benign (non-cancerous). Which makes finding causes of tumour promotion considerably easier. If you know the end result in terms of cell biology, that limits the number of variables you're searching for as instigators of that process.

How people see autism. Image credit: Hepingting

But not so for autism. Even though the well-known psychiatrist, Leo Kanner, described the condition well over 70 years ago, the only thing people can seem to agree upon is a behavioural definition. (And even still, we argue over that!) We have done so much research and have published so many papers reporting correlations with things that may influence the occurrence of autism, ranging from the presence of one or more other disorders or diseases, down to associated genes. But unlike cancer, we have no general definition for what defines autism at the level of the cell nor at the level of the brain. We're still wandering around our research somewhat blindly.

Ultimately, that means we study just about everything that appears to have an association with the condition without much understanding of whether the relationship is causal or simply correlational in nature. An excellent example of this comes from studying autism genetics. Over 3,000 genes have found to have minor-to-strong association with the condition, both those which currently have no known cause (idiopathic) and conditions which are characterized by the association of several clinically recognizable features which tend to go together (syndromic), such as Fragile X Syndrome. While all roads may have once led to Rome, not all genes lead to autism. Those thousands of genes represent at least 12% of the genes within the human genome, a staggering proportion. It's highly unlikely that all or most converge onto a single behavioural trait.

Celebrating 10 years of Mars Express

At the beginning of June, the European Space Agency (ESA) celebrated the 10 year anniversary of the Mars Express mission. The spacecraft, launched in 2003, has had ten successful years of operation and has resulted in the publication of over 600 scientific papers. To help mark this occasion, our intern Cait interviewed Olivier Witasse, the mission's Project Scientist, about some of the key discoveries the spacecraft has made and what the future of the mission looks like.

Mars Express has had ten very successful years in orbit around Mars. Image credit: ESA

One of the key themes of space exploration is the search for life. We base our search for past or current life on the presence of liquid water – it's vital for life like ours so it's one of the first conditions we look for. Direct evidence of past water on Mars is one of the key findings and surprises of the Mars Express mission:

"...from what we have been discussing with the scientists over the last year, there is one result which I think is really on top of the others - the discovery of the so called hydrated minerals."

Before the discovery of hydrated minerals, scientists at ESA were expecting to find carbonates on what may have once been a sea bed. Finding carbonates would imply that there were once large oceans on Mars. Carbonates can form in one of two ways - a purely chemical reaction where carbon dioxide in the atmosphere is dissolved by the surface water of an ocean or as a result of the shells of past marine creatures. If the oceans were absorbing atmospheric carbon dioxide then further reactions with minerals (i.e. magnesium, calcium) in the ocean would produce carbonates which would settle onto the ocean floor. The atmosphere on Mars is mostly carbon dioxide, so if there were once oceans on Mars we would expect the formation of these carbonates. The shells of some marine animals also contain carbonates, so when the creatures die, their shells sink to the bottom of the ocean to form carbonate deposits with the possible preservation of fossils. These carbonates would remain even when the ocean faded away.

Why don’t we know more about causation?

You’ve seen them – every week a new story about genes for this or that, or the environmental cause of some effect or other. Often the stories say opposite things; red wine is good for us in one article, bad in the next, depending on the study. Or it might be about coffee, eggs or vitamin supplements, and health advice to pregnant women is often contradictory. The gene for autism or dyslexia or asthma is found one week, but the finding can’t be replicated the next. Does hydraulic fracturing of rocks to mine natural gas and oil contaminate ground water? Are GMO foods good or bad for us? You’d think figuring out these things would be easy – genes do something, they make us what we are, while people who eat a given food get sick and those who don’t stay well, so what’s the problem?

The problem is complexity. Modern scientific methods are very good at finding cause when an effect is large or clear-cut – the fact that smoking causes lung cancer was easy to see once the question was asked, the genetic variant that causes cystic fibrosis was relatively straightforward to find because the effect of the mutation is so major. But determining causation gets thorny when a disease or effect is caused by multiple genes, or genes plus some environmental factor, or when there are many pathways to the same outcome - all of which are common scenarios. The fact that everyone is unique to start with makes it even thornier.

When an object casts a shadow, we know it's not the shadow causing the light or creating the object. Cause and effect are easy to determine. But sometimes causality can be a lot trickier to determine. Image credit: Dhilung Kirat

What must women avoid during pregnancy?

Pregnancy can be an anxious time full of contradictory advice: exercise is healthy, but don't overdo it. It's safe to use your mobile phone, but perhaps don't make too many calls. Don't drink too much caffeine, but the occasional cup of tea probably won't do any harm. No hot baths or hot tubs, although swimming is probably good for you. Eat a balanced diet… but no goat's cheese, shellfish, runny eggs, pâté or rare meat, and we're not completely sure about ham, tuna and salami.

Contradictory advice for pregnant women often sounds like "out of the frying pan, into the fire".
Image credit: waferboard

It can leave you feeling as though you might be better off locking yourself in a padded room for the duration with nothing but bread, water and pregnancy vitamins. This isn't helped by newspaper headlines such as the ones following the recent publication, by the Royal College of Obstetricians and Gynaecologists (RCOG), of a scientific impact paper on chemical exposures during pregnancy. The headlines ran the full gamut from “Pregnant women warned over household product chemicals” to the flat-out hysterical “Pregnant women told to avoid painting the nursery, buying new furniture or going near non-stick FRYING PANS as they may expose their unborn baby to dangerous chemicals”.

However, perhaps the most striking thing about the original paper is its title: “Chemical Exposures During Pregnancy: Dealing with Potential, but Unproven, Risks to Child Health”. In other words, they've compiled a long list of things that might be harmful, but which they're not really sure about. Do a little web searching for "things to avoid in pregnancy" and you will quickly find that many, many people have already written similar lists. However, this paper wasn't written by just anyone. It was written by the Royal College of Obstetricians and Gynaecologists, and unlike many commentators they did take the trouble to reference their comments thoroughly, reviewing the literature and assessing what evidence they found. The report examined a number of issues; let's look at them in a bit more detail.

Can we meet the water demand of future generations?

Water - we all need it, but is there enough?
Image credit: fox_kiyo

Approximately one in eight of the world's population don't have access to clean water^[1]. The situation is only expected to worsen with increasing water demand and diminishing sources. Population growth and higher water consumption per capita are to blame for greater consumption. The amount of water most of us use has grown mainly due to changes in diet, the increase in use of water intensive biofuel crops, and acceleration of energy demand which in turn requires water. Water is such an essential part of life it's thought to be one of the main reasons why the Earth is the only planet we've found to be inhabited so far (but we're still searching).

It's hard for anyone to try determining how bad our water shortage is or will be when basic things about water sources still remain a mystery. For example we are clueless about how much water is available and how the water supplies that are obtainable to us may reduce in the future.

Currently most of the water on our planet is not available to us, although it is still not known how much fresh water may be available to us. The water that is available is derived mainly from two origins - surface water such as lakes and river, or groundwater which is stored in underground reserves known as aquifers. On-going work involves exploring how large these reserves may be and how deep we may hope to extract water. For example recent surveys of Africa show there may be extensive groundwater reserves^[2], and the first attempt to map water reserves was made a year ago^[3]. In the future improved and more detailed maps are expected as scientists try to answer the basic question of how much water is left? Without this knowledge it is impossible to try and understand fully the extent of water scarcity.

Simulations, Svalbard and the Solar System

It's been a busy couple of weeks of inspiring science! I've had a couple of days wow-ing other people with talks and tours of the things we know and I've been working here and been amazed, inspired and slightly concerned about some of the things we don't.

Cait Percy in our London office.
Photo ©TWDK.

Most of the last week or two has been spent exploring dreams, parallel universes, how much life there really is in the oceans and the questions to which radio astronomy may soon provide the answers. I spent a lovely afternoon pondering the Universe and trying to decide if we were all just part of a very large computer simulation and whether we'd know if we were. Almost everyone I've chatted to this week has had some variation of the above brought up in conversation for discussion so I really feel I've been doing my bit to share my passion for science.

Media violence and criminal behaviour

Between science and policy making

On March 11, 2009, 17-year-old Tim Kretschmer entered the Albertville junior high school in the small town of Winnenden, Germany, armed with a 9mm Beretta semi-automatic pistol and 200 rounds of ammunition. In less than an hour, he shot nine former schoolmates and three teachers; on the run from the police to Wendlingen, he highjacked a car and killed three more people, before he finally committed suicide. The tragedy left his and the victims' relatives, teachers, and the general public petrified with questions regarding the motive for this attack, and how a young man developed into a mass homicide perpetrator.

The debates about the influence of media violence on behaviour show no sign of ending.
Photo credit: arker from morguefile.com

The debate about the causes of Kretschmer's rampage went on in the media for weeks, involving politicians and professionals, as well as witnesses and relatives expressing different theories of the decisive factors, ranging from failure in parenthood to insufficient gun control (even though the German Weapon Act already contains one of the strictest gun control laws in the world). And as with other similar tragedies that happened at different places around the world, violence in digital games was offered as a potential explanation for his actions as well. Winnenden citizens formed a group that called for a public disposal of all "killer games" in a large trash bin they placed in the city centre of Stuttgart. In an unparalleled reaction to such an event, the large department store chain Kaufhof decided to stop selling any movies or games with an age rating of 18+ nation-wide.

A year of unanswered questions (and that's a good thing)

We’ve been adding regular posts to this blog for exactly one year this month. Last June our very first intern, Jon started with us through our partnership with SEPnet, and a year on we have another two new interns with us for the summer through them. We still have our two chemistry students at the moment (Freya and Lucy), and last but not least we've been joined by a business and marketing intern via the Sheffield Business School.

The year in numbers:

• 40 blog posts
• 16 guest posts, including researchers from the UK, US, the Netherlands, Mexico, and Belgium
• over 24,000 visits to the blog
• almost 11,000 unique visitors
• our site is being read for 1 out of every 3 minutes
• interviewed by start something and GDI Impuls
• stage appearances in Germany, Austria, and Switzerland as part of the Freischwimmer arts festival and Aarau Democracy Days
• we've never paid to advertise our blog

Month by month, our audience has grown at an increasing rate

Déjà vu

Déjà vu - that sudden, inexplicable feeling that the exact event you are experiencing has happened to you before, in exactly the same way, even though the logical part of your brain knows that it can’t have. Most of us have experienced it at some time or another, but very little is known about what actually causes it. The name comes from the French for ‘already seen’, although this name does not explain the phenomenon fully - as well as feeling you have already seen something, for déjà vu to occur, you must also know that you have not.

The Temporal Lobe is the part of your brain just above your ears.
Image credit: wikimedia commons

Although for most of us this feeling is harmless, if rather disconcerting at times, for some people it can be a warning sign for something more sinister. Déjà vu experiences have been linked with temporal lobe seizures in epilepsy sufferers. Partial seizures affect only a small area of the brain, so cause different symptoms depending on where they occur. Generally the patient remains conscious and may not even realise that they are having a seizure. The temporal lobes are located above the ears, and contain areas of the brain responsible for memory, as well as language production and comprehension, emotion, and some higher level visual and auditory processing, such as face recognition. These broad ranging functions mean that seizures to this area can cause a variety of unusual symptoms, such as experiencing sensations without a cause, rushes of emotion, or memory problems, including déjà vu. Temporal lobe seizures have even been linked with religious experiences.

The Search for another Earth

"Two possibilities exist: either we're alone in the Universe, or we're not.
Both are equally terrifying."
- Arthur C. Clarke.

This guest post is by Andrew Rushby, currently undertaking a PhD in earth systems modelling at the University of East Anglia. Andrew usually blogs at the II-I- blog, the Pale Blue Blog or the European Association of Geochemistry blog. He can also be found launching high altitude balloons into (near) space, and tweeting as @andrewrushby. This is the third in our series of posts about the many unknowns involved in the study of planets orbiting other stars across the galaxy.

In my last post I broadly covered the techniques for finding planets around other stars in the galaxy, as well as the role this technology plays in defining the current limits on our knowledge. We have discovered 885 other planets to date, but how many of them are like the Earth and why is this important?

As we live on a rather lovely watery planet ourselves, we seem to have a natural inclination to seek out others just like it because we consider them to be the most likely for hosting life. Why? Well, because our current sample of ‘inhabited planets’ stands at just one, we have a very limited understanding of where the boundaries for life lie as well as the important factors that affect habitability when considering the broad characteristics of life-bearing worlds. If other inhabited planets exist, is the Earth typical within the sample or an outlier? Are the furnaces of close-in gas giants the cradle of most flavours of life in the universe, or maybe the frigid surfaces of icy worlds in the far-flung outer regions of their star system?

Some lifeforms live in extremely tough environments, and have even survived space vacuum conditions - like this water bear. Image credit Bob Goldstein and Vicky Madden (Creative Commons)

It might be fun to speculate about all the various forms and shapes that other life might take, but this lies outside the remit of science. It seems obvious to us that only on a planet able to support life would organisms (like intelligent Homo Sapiens) eventually evolve, but this instils in us a fundamental bias towards planets like Earth: it remains beyond our perspective to consider the possibility that can life operate outside of the physical and biological boundaries that we are familiar with. It therefore seems unsurprising that the limits of life lie so perfectly within those experienced on Earth, and why we seek out other Earth-like planets as possible oases of biology. This bias is known as the anthropic principle and is an important philosophical consideration to bear in mind when considering the search for ‘habitable’ planets.

Open Questions in Open Science

I sometimes tell people that "There's no point in making the biggest scientific discovery in the history of the world, if you don't tell anybody about it." In other words, science communication is important. This is why I, and Things We Don't Know, feel strongly about the topic of "Open Science". For those who aren't familiar with "open science", it's a relatively straightforward concept. The principle behind open science is that the results of science should be available to the public, free of charge. Since scientific results are published in scientific journals, this means those journals would have to be available free of charge.

But of course, there is a cost associated with the publishing of journals, so open science is not a particularly easy thing to achieve, and people have suggested several models which would make this possible - each with their own side effects and drawbacks. If you'd like to read more about the details of open science, Nature have a nice feature article which summarises the background, and another which explains the "green" and "gold" open access models.

Why does hot water freeze faster than cold water?

This article is by our intern Freya Leask, who is also in her second year at the University of Bradford studying chemistry.

For most people, making ice-cream doesn't lead to the discovery of an unsolved mystery…unless you're Erasto Mpemba. In 1963, the then school boy stumbled across the phenomenon where initially-hot liquids sometimes freeze faster than initially-cold ones. Although this had been observed by Aristotle, this effect wasn't proved experimentally until 1969, and still isn't very well understood. Just what is the Mpemba effect, and why does it happen?

Many papers have been written about the Mpemba effect, though scientists can't even decide what that name refers to - is it the time taken to form a homogenous block of ice, or the time taken to reach 0°C? Both situations have been studied under various combinations of conditions, but either way, it seems simple enough on face value to explain. Evaporation takes in heat energy and the warmer liquid's higher rate of evaporation reduces the mass to be frozen. The initially warmer liquid also has a lower density, as the water molecules have more energy to move around more. This means more heat is released, and the liquid cools faster.

Against all expectations, warmer water (red) can freeze before cooler water (blue) does.
Image credit: Pico Technology

Heating a liquid can also change its composition, which can affect its cooling time. For example, when salty water is heated, the water evaporates away, leaving a higher concentration of salt which lowers its freezing point and makes it take longer to cool¹. However, none of these things can account for a big enough effect on the rate of cooling to completely explain the Mpemba effect.

The beast with a billion backs: Part 2

We are not alone.

No matter how quietly you listen, nor how closely you stare you’ll not hear them, nor see them with the naked eye. They’re too small, too quiet. They are our microbiome, the trillions of microorganisms that make their homes inside and out of our bodies. They – we – are an ecosystem, with different bugs filling different niches, some helpful, some quietly parasitic, and others, well, others you do end up knowing about…

This is the second of two posts on the subject of the microbiome. The first post looked at questions around the need to unpick its importance to our health – what’s a good or bad microbiome? Which microbes are causes or effects of a disease? And how does the microbiome spread – is it like a disease? Questions which, when answered, could lead to new treatments and ways of protecting our health by manipulating this complex ecosystem within ourselves.

Collateral Damage

Whilst we can’t yet manipulate the microbiome with any finesse, we do influence it through our immune system, evolved over time to cope with invading pathogens and keep them in check. Yet when the immune system isn’t enough, we have a powerful way to, if not manipulate, then affect our microbial ecosystem; it’s just a little…inelegant and unpredictable: Antibiotics.

Two different species of bacteria with disks soaked in different antibiotics. The bacteria on the left are susceptible to all the antibiotics tested, while the bacteria on the right are resistant to most of them.
Image credit: Wikimedia commons

Summer Physics Internships 2013

Happy Easter from the TWDK team! If you've been following us for a while now then you will probably remember Jon Cheyne, who wrote a number of articles for us last summer while he did an internship with us through the South East Physics Network (SEPnet).

So it is with great pleasure that we can announce we will be hosting another two physics interns through our partnership with SEPnet this summer, and we've already received a lot of really great applications. We'll be holding interviews and making our decision over the next few weeks, so you can look forward to some more great posts from June onward by our new interns!

The beast with a billion backs: Part 1

We like to think of ourselves in the singular, but the reality is we are a swirling composite of thousands of species, more accurately thought of as an ecosystem than as an individual.

There is the core ‘us’, the cells that contain our DNA. But we are also like the land on which a rich forest might grow, with every niche – every nook, cranny, and crevice – a unique home for some of the trillions of bacteria that call us home. Together they are our ‘microbiome’.

Our relationship with bacteria is a complex puzzle.
Image Credit: Gavin Hubbard

But before you run off screaming to the shower, with bleach in hand, you should know that this is no bad thing. For example, in return for shelter and a share of the spoils from our meals, some make vitamins, liberate nutrients and energy from food, and protect us from their pathogenic cousins. Millions of years of co-evolution with our microbial horde have forged this relationship, shaping us both in ways whose significance we’re still trying to understand.

This is the first of a couple of posts that hopes to briefly explore some of the unknowns and open questions surrounding the microbiome and its relationship to our health and well being.

It was about 15 or so years ago that interest in the microbiome really started to pick up. Since then, we’ve caught tantalising glimpses of the bigger picture, and managed to fit some of the pieces of this puzzle together; we’ve even managed make use of the microbiome to cure disease, but much remains a mystery, with only hints about where and what to look at.

Detection and Discovery of Exoplanets

The first planet discovered orbiting another star was detected by astronomers at an observatory in France in 1995. The planet is an enormous gas giant, half the mass of Jupiter, orbiting very close to the Sun-like star 51 Pegasi in the constellation Pegasus, 50 light-years from Earth. The existence of other planetary systems had been predicted by astronomers for centuries and the discovery marked a monumental breakthrough in astronomical research. Since then, rapid improvements in technology and observational techniques have resulted in the discovery of 863 confirmed ‘exoplanets’ to date.

How many planets are there? As astronomers hunt for planets orbiting other stars, we are starting to form a picture of  how many planets there are in the galaxy. Image credit: Luke Surl, for TWDK

Unlike the direct observation of stars, the detection of planetary bodies requires astronomers to use a number of indirect methods to infer their existence. Due to the immense distances involved, the distance between any planet and their host star when viewed from Earth is tiny, and the brightness of the star itself effectively blinds instruments and obscures any planets in their orbit, which are much less bright by comparison. Therefore, astronomers have devised a number of ingenious methods to tease out planet data from their observations, but they require a great deal of skill, a generous helping of statistical analysis and a pinch of luck.

The most successful means of planet detection to date, yielding roughly 58% of all discoveries, is called the radial velocity method. This technique exploits the fact that the host star and its planets orbit a common centre of mass, and the planets exert a tiny ‘tug’ on the star that results in a very slight wobble – a signature that can be detected and used to infer the existence of one or more planets. Another successful indirect method of detection, responsible for a third of exoplanet discoveries, is called the transit method. When viewed from the Earth, a planet orbiting a star periodically passes in front of the star (‘transits’) and obscures a very small amount of its light, resulting in a tiny but consistent reduction in the amount of light received by Earth-based instruments. The amount of light that is blocked out provides some information about the size of planet, as larger planets will obscure relatively more light, and the frequency and duration of the transit can be used to infer the distance from the star that the planet orbits. NASA’s Kepler space telescope, launched in 2009, uses this method and it has proved extremely fruitful, resulting in the discovery of 105 confirmed exoplanets to date. Additionally, there are a further 2,740 potential planets (called ‘planet candidates’) detected by Kepler awaiting confirmation.

Growing the TWDK Team

We were overwhelmed with interest in our Chemistry internship role late last year, and after reading many applications, and interviewing some really strong candidates we chose two students currently studying Chemistry to join us for the next few months. We would like to thank everyone who expressed an interest in working with us, it's great to see the amount of passion out there for what we're doing!

And now to extend a very warm welcome to Freya and Lucy, our two latest content writers who will be writing about the open questions of Chemistry. Freya is at the University of Bradford, while Lucy is studying at Imperial College, London. Look out for blog posts from both of them soon.

We are also very happy to report a new staff writer joining our team from today. Ginny Smith, better known for her role as a "Naked Scientist", promoting science through radio, live lectures and internet journalism. Their award-winning weekly BBC radio programme has a potential audience of 6 million listeners across the east of England, and can be listened to from anywhere in the world via internet. Ginny studied natural sciences at Cambridge University, specialising in psychology. In addition to preparing content for our main site, watch out for the occasional post from Ginny on our blog, too.