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C is for Collider

By Siobhan Fairgreaves

In this post, we will learn a little more about the world’s largest particle accelerator, the Large Hadron Collider (LHC).

Do you remember a few years ago when there was a lot of fuss about a black hole being created? I know there were a few nervous questions fired at our unfortunate science teacher that day.

Proton beams in the LHC can at least enjoy a few thousand trips through the scenic Alpine countryside before being annihilated | Image: CERN

The reason for all that fuss is situated 175 metres underground, on the border between France and Switzerland. The LHC is a circular tunnel with a diameter of 27 kilometres, where scientists and engineers are working to solve some of the big unanswered questions in physics.

But how does this machine work, and how is it going to help?

Well, as the name suggests, colliding is a pretty big part of the whole idea. This machine usually uses protons (the positive subatomic particle) but can sometimes use the whole nucleus of the material lead. Remember what they are? If not, we’ve already covered a bit about what protons are.

Naturally, it’s not as easy as just throwing them at each other and observing what happens. The particles are so small that the chance of getting a successful collision is described by the creators themselves as about as likely as “firing two needles 10 kilometres apart with such precision that they meet halfway.”

Hmmmm, not easy stuff then.

Rumour has it that to make sure the LHC’s superconducting electromagnets were cold enough, CERN hired a group of Canadians to touch them, and were only satisfied when they admitted “they’re pretty chilly, eh?” On a side note, you shouldn’t believe everything you read on the internet | Image: MaGIc2laNTern

To add to the complications, the particles must be going at almost the speed of light to have enough impact when (or if) they do collide for anything to happen. The Large Hadron Collider is designed to help speed up the particles using thousands of seriously strong magnets. These magnets actually have a pretty impressive name, officially they are superconducting electromagnets. There’s your dinner party lingo for the day!

With all that whizzing around and accelerating you’d imagine things are getting pretty hot down there, right? Well, no. Another complication arises. In order for the electromagnets to work they must be kept at -271.3 °C. That’s colder than outer space! In order to achieve this, a complicated cooling system is in place which uses liquid helium to keep things chilly.

I’m beginning to understand why this project is such a big deal.

But what is it all for?

Collision data for the Higgs event. When your raw data looks this cool, it’s not too hard to persuade anyone that your research is justified | Image: Lucas Taylor/ CERN

Well, sometimes science for science’s sake is a good enough reason to conduct an experiment. However when setting up that experiment cost an estimated £6.2 billion and involves over 10,000 scientists and engineers in an international collaboration you need a slightly better excuse.

The team at the European Organisation for Nuclear Research (CERN) have certainly got more than one decent reason for this mammoth undertaking. They hope to answer some fundamental questions about the structure of space and time, to better understand forces which are part of our lives every day and even to discover brand new particles. In July 2012 the team announced the discovery of the Higgs boson, a particle which will now be studied intensively to help answer some of these big questions.

The Large Hadron Collider is at the forefront of some of the most profound scientific discoveries of our time and we should certainly stay tuned for more exciting discoveries. If you’re interested in finding out more visit the CERN website which even includes a virtual tour of the tunnel itself.

Until next time!

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B is for Black Holes

By Siobhan Fairgreaves

In our last post we looked at atoms and their subatomic particles. That’s the tiny end of physics, this time we look at something at the other end of the scale- black holes.

Cheesy sci-fi films have been trying to warn us for decades… but we never listen! As it turns out, that’s probably for the best | Image: Martin

Ooooo, now this is the good stuff, right? The fuel of sci-fi movies and something that you think you should be mildly concerned about. Remember when scientists were apparently going to make another one in Switzerland? That was a bit of an anti-climax.

I was at school when the Large Hadron Collider in Switzerland was switched on and I remember a lot of panicky talk about black holes and us all being sucked into space. To find out more about what on earth a Large Hadron Collider is you will have to read the next post- C is for Collider, cheeky I know.

For now, though, what is a black hole?

I know you’re hiding in there somewhere – astronomers can only find black holes by mapping out the paths of stars orbiting around them | Image: ESO

Well let’s start off with a quote from the brilliant Stephen Hawking, “It is said that fact is sometimes stranger than fiction, and nowhere is this more true than in the case of black holes.”

He certainly got that right. Black holes are pretty mysterious and teams of scientists are still figuring out what exactly goes on up there. This is made all the more difficult by the fact it’s not even possible to see black holes, only the effect they have on other objects. In a nutshell, though, black holes are an area of space where gravity has become so strong that nothing can get out- not even light.

Born from the death of a star: the Orion Nebula, made up of the explosive remnants of a star which could once be seen just under Orion’s belt, is thought to have a black hole at its centre| Image: Ljubinko Jovanovic

Because this gravity is so strong it’s easy to go along with the assumption that one day we will be sucked into one and disappear. You’ll be pleased to hear that NASA thinks this is very unlikely- there simply isn’t one close enough for us to worry about.

For a long time, I imagined black holes as a sort of Pacman travelling around in space munching on stars, planets and everything else in their way but this is not the case. Black holes are actually caused by a star collapsing and as the star collapses in on itself the gravity gets so strong that a black hole is created.

A horrific yet tasty way to go: the difference in gravity between an astronaut’s head and their feet as they fall into a black hole would lead to the process of ‘spaghettification’ | Image: Cosmocurio

That’s all well and good but there are billions of stars out there, does this mean that every star will one day make a black hole? And, hang on a minute, our Sun is a star- are we orbiting a wannabe black hole? You’ll be pleased to hear that our Sun simply isn’t big enough to become a black hole- it takes a pretty big star to cause such a powerful pull of gravity when it collapses.

Instead of Pacman, you could think of a black hole like water going down a drain. When the bath is full, the water rushes down the drain and sucks everything with it but when there is only a dribble left it isn’t even strong enough to take down any leftover bubbles.

So yes, black holes are crazy giant plugholes travelling through space which, as the European Space Agency says, would see an astronaut “pulled apart by the overpowering gravity” if they were to get too close- but should we be worried about them right now? No.

Until next time!

This probably won’t ever happen to you, but if you do ever find yourself in the devastating clutches of an inescapable gravity source, it might be nice to know what to expect

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A is for Atom

By Siobhan Fairgreaves

Never trust an atom- they make up everything!

Scanning Tunnelling Microscopy can give us incredible images like this one of a piece of graphite, showing how its atoms fit together like Lego. Luckily, treading on atoms isn’t like treading on actual Lego, or walking would be incredibly painful | Image: Frank Trixler

Terrible jokes are finished, for now…

 

In this post, we will look at the basic structure of the atom. But first, what are atoms?

Atoms are the building blocks of the world- think of Lego. If the whole world was made of Lego an atom is that tiny single square block. Imagine how many of those tiny blocks would be needed to build the whole world and all the people, animals and stuff inside it… That’s a lot of Lego, and there are a lot of atoms. A single grain of sand contains millions of these tiny particles.

For a long time atoms were thought to be the smallest piece of the puzzle. Then in 1897 a scientist named J.J. Thomson identified an even smaller particle which helps to make an atom.

Cheer up J.J., you’ve revolutionised modern physics! | Image: Benjamin Crowell

Thomson made the discovery when he was experimenting with mysterious beams of particles called cathode rays. When firing cathode rays at hydrogen atoms, he measured how the path of the beams changed as they interacted with the atoms. Thomson realised that the cathode rays were made of tiny, negatively charged particles – around 1/2000th the size of a hydrogen atom. He named the particles ‘corpuscles’, but we know them today as electrons. But Thomson’s discovery doesn’t tell the whole story about what we came to know about the atomic structure.

In fact, we have another scientist to thank for that. In 1909, New Zealander physicist Ernest Rutherford fired some positively charged radioactive particles through a sheet of gold atoms, and measured the different paths they took. He was testing out J.J. Thomson’s ‘plum pudding’ model, which proposed that atoms were made up of electrons sitting happily inside a positive sphere, holding them together.

Thanks to Ernest Rutherford, scientists can now study atoms without constantly thinking about delicious desserts | Image: Library of Congress

Rutherford noticed that most of the particles passed straight through the atoms, but a tiny proportion were deflected back. That meant that instead of being plum puddings, each atom was made up of a small positive nucleus, surrounded by orbiting electrons, with lots of empty space between them. And so, the basic model for  an atom was born!

A typical illustration of an atom will show a ball in the middle surrounded by orbits- but what is going on in there? The ball in the middle is the nucleus which Rutherford discovered, and inside the nucleus are protons and neutrons. The things whizzing round the outside are the electrons. Protons, neutrons and electrons are known as sub-atomic particles, now that’s an impressive dinner party phrase.

Electrons in different energy levels form a cloud of negative charge around the nucleus| Image: Mets501

It might look like electrons are in a messy, complicated cloud but they are actually very precisely arranged. Around each nucleus are different shells, or energy levels, which have space for a different number of electrons.

 

The very first energy level around the nucleus can only hold 2 electrons. In an atom of the element Helium both of the spaces in the first energy level are filled by an electron. So, using Helium as an example, what else is in there? To work that out you should know that it is really important for an atom to be balanced. Each electron carries a negative charge so to balance Helium we now need two positive charges. Fortunately, protons have a positive charge each. So we’ve got two negative electrons whizzing around the outside, two positive protons snug in the nucleus, the charges are balanced. So, are we finished?

It might seem fun to try and chop a uranium nucleus in half, but it’s not actually a very good idea… | Image: Scienities

Almost, don’t forget the third component, neutrons. Luckily, they are- you guessed it- neutral, so it’s okay for the number of them to vary between different forms of the same element.  Most of the time, Helium has two neutrons and with two of everything it is nicely balanced and known as stable.

Helium is a nice example with small numbers but not all elements are quite so compact. Take Uranium, for example, there are a lot more protons (92!) and electrons involved to try and get Uranium to balance.

That’s a very basic introduction to atoms- and for sticking with it, you’ve earned yourself another terrible joke! What a treat…

A neutron walked into a bar and asked for a drink.

“How much?” asked the neutron.

The bartender replied, “For you, no charge!”

Hopefully, that joke will make a bit more sense now you know your stuff about subatomic particles and their charges.

Until next time!

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Lionfish wreak havoc on marine ecosystems

By Roisin McDonough

Look at me. I’m the top predator now. | Image: Jens Petersen

The lionfish, beautiful in appearance and un-problematic in their native regions of the Indo-Pacific have wreaked havoc as an invasive species in the Atlantic; having become well established  in the Southeast coast of the US, the Gulf of Mexico and the Caribbean.

The Lionfish invasion was likely caused by humans releasing this popular ornamental fish from home aquariums when they were no longer wanted (over the course of 25 years). Their journey to the Atlantic was then possibly aided by the warm Gulf Stream  current which dispersed buoyant lionfish eggs and larvae further afield.

Warm currents like the Gulf Stream could be letting lionfish blag a cheeky ride to where they aren’t welcome | Image: Sommerstoffel

At first, their arrival into new areas was not considered to be much of a problem, as it was thought that that they would not survive very long. However, over the years, the lionfish have not just survived, they have thrived. Their success has led to the unfortunate and worrying decline of many native fish species and an alteration in the very delicate reef ecosystem.

Lionfish out-compete, out-live and out-breed native fish. But why?  For starters, they are highly tolerant to a range of temperatures, salinities and depths and biologically resistant to most diseases and parasites that affect native fish. Further, they have very few, if any, natural predators in the Atlantic. They become sexually mature at 1 year of age and can live in excess of 15, so have a long, rich reproductive life. In optimal conditions, females can release a staggering 2,000,000 eggs per year!

“Do you think that new guy looks dangerous?” “Who, the grumpy looking stripy one who’s at least 1000 times bigger than the rest of us?” “Yeah” “Nah, there’s something about his vast, leafy appendages I find sort of… comforting” | Image: Alexander Vasenin

Lionfish are un-selective carnivores with voracious feeding habits, encompassing a huge range of small fish and crustaceans. Included in their diets are popular commercial fish like grouper and snapper and commercially important crustaceans such as lobster, crab and squid. In their non-native environments they have easy pickings when it comes to food, as generally, native species do not recognise the lion fish as a threat. In fact, some small fish will assemble around these invasive creatures in the hope that their fin rays/feathery pectoral fins will provide them with shelter and protection.

So far, lionfish hunting  seems to be the only feasible method of controlling their numbers. Certain areas which are regularly hunted see an increase in the number of native fish over time. However, the areas that can be reached by lionfish hunters is very small in relation to the vast marine environment lionfish now cover.

Invasive lionfish populations are an ever-growing problem – native marine life has suffered dramatic reductions as a result of their predation. Commercial fisheries, recreational activities and food security have also all been negatively affected as a consequence. We do not know the extent of the devastation to marine habitats in the near future, but it is likely to be bleak if their populations are not controlled.

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Design, Naturally: Lateral lines provide a sixth sense for underwater robots

By Anwen Bowers

More little fish swimming in a school.
“We turning left now?” “Yeah, you do know we have a sophisticated biological mechanism for finding that out, right?” “I was just asking for a friend” | Image: Tom Thai

Have you ever seen two fish bump into each other?

The underwater world is an assault of sensory signals. Sound, for example from crashing waves, travels over twice as fast in water than it does in air. Smells, ranging from mating hormones to decaying organisms, clash against each other like instruments in an orchestra and would be overwhelming to us if we had noses sensitive enough to detect them. Light is changing constantly, with the different wavelengths becoming increasingly filtered out with depth until animals are left navigating waters so dark that they would be impossible to penetrate with human eyes.

But despite the chaos, fish are able to identify predators, prey and potential mates with lightning reflexes and take the appropriate action within milliseconds.  This is thanks to a super-human sensing mechanism called the lateral line, which gives the fish a sixth sense with which to navigate in their watery habitat.

lateralline
A subtle stripe of hair can tell fish everything they need to know about their environment | Image: Pogrebnoj Alexandroff

Sometimes visible as a dark strip running along the fish from fin to tail, the lateral line consists of minuscule bundles of hair that can be either attached to the surface of the scales or slightly submerged in channels below the skin. These hairs work similarly to whiskers on a cat, bending in response to any change in the flow of water around the fish. Cells at the base of the hairs then send messages to the brain, containing information on the scale, speed, and direction of the disturbance. This can then be interpreted to give information about the size and shape, and therefore species and likely friendliness, of anything moving in the local area. The ability to identify friend from foe by the flick of its tail is an invaluable tool of survival.

Seas and oceans are one of the least understood habitats on earth, with vast areas being simply too inaccessible to explore. As space on land is becoming rapidly exhausted, we are extending further and deeper into the oceans to source food, generate energy and hunt for new minerals and medicines. Faced with challenges such as the extreme pressure and low temperatures, increasingly we are depending on the work of underwater robots to bring us information on the chemistry, physics, and biology of the deep sea.  Engineers looking to improve the performance and capabilities of these underwater robots have found inspiration in the lateral line to improve the performance of these robots.

robofish
Bass-ta la vista, Ray-by: artificial lateral lines have inspired highly sensitive robotic fish | Image: Titus 140

Researchers in Germany and the US have independently come up with two different systems that recreate the processes that take place in the lateral line hairs. Integrated into underwater robotic technology, these systems could create a robot with much greater perceptions of their surroundings. Traditionally, operators would rely on images from video and sonar to navigate and direct the actions of the robot underwater. Both of these technologies are limited, as they can only provide information on the small area that they are pointing at Imagine only being able to view the world through a toilet roll tube – it’s a bit like that.

Lateral lines could provide a much more detailed 3D picture of the surrounding environment, allowing more informed decisions about how the robot should proceed. The more information available about the surrounding area, including any obstacles, the greater the chance of the robot completing its mission as efficiently and safely as possible. For example, if the battery is running low, the lateral line would be able to identify nearby areas of low water movement where the robot can go to rest and conserve energy out of the current. Taking inspiration from nature, and building robots that can sense like fish, scientists can expect to soon be announcing plenty more exciting discoveries from the mysterious deep ocean.

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Design, Naturally: Precious pearls inspire super-strong glass

By Anwen Bowers

dukeofbuckingham
The Duke of Buckingham’s frankly over-the-top bling held some fascinating material properties. | Image: Art Gallery of South Australia

Take a stroll through almost any art gallery and the cultural value of pearls as a status symbol through time is inescapable. From the intricately laced clothes in Elizabethan portraits to the long strings worn by chic youth in the early 20th century photographs, pearls have been a symbol of wealth and glamour. However, shifts in technological capabilities mean that pearls could soon have a much broader range of uses than being merely decorative.

Starting life as a humble piece of grit, pearls gain their ethereal shimmer from nacre, a biological substance secreted by oysters, which eases the discomfort once grit enters their shells. Nacre is produced by a number of different molluscs, and can also be found inside snail shells and coating mother-of-pearl. This material has long been of interest to materials scientists due to its incredible toughness.

Scanning electron microscopy has been used to reveal that the structure of nacre is similar to that of a brick wall, with “bricks” in the scale of micrometres being glued together by an organic adhesive. The bricks themselves are made of aragonite, a form of calcium carbonate with a similar structure to sea shells.  These bricks overlay each other, and when pressure is applied they are able to slide against each other which prevents the material from snapping. If any cracks form in nacre then the adhesive acts as a barrier, dissipating the energy along the channels between the bricks and preventing the crack from propagating through the material.

aragonite
Layers of aragonite, held together with a natural glue, make up the intricate structure of nacre. New techniques are developing super strong glass from man-made nacre, or ‘facre’ if you will | Image: Fabian Heinemann

This structure gives nacre the very desirable properties of strength and toughness combined, and a number of strategies have been proposed to create a synthetic material that mimics this brick and mortar structure. Most of the proposed methods have involved a “ground up” strategy of assembling component parts, but this has only ever produced materials that have too high a proportion of adhesive and not enough solid bricks. Nacre itself is 95% aragonite, with only a tiny amount of adhesive holding everything together.

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Take it from the experts: oysters have been making better glass than us for over 100 million years. Still haven’t figured out how to make windows though. | Image: USEPA Environmental Protection Agency

A more recently proposed “top down” method involves a laser which carves into glass and fills the channels with polyurethane glue. This technique has created a material that strongly mimics the properties of nacre. It can be applied to glass or ceramic, both strong materials that are normally limited by their brittleness. By treating them with the polyurethane, scientists have created composite materials that have 700 times the toughness of the original glass!

Biology has been evolving materials for millions of years, to make structures for protection, support, buoyancy, cutting and grinding food, even building organic homes. Whereas slow evolution in the natural world means that each material has tailored properties making it the best choice for different functions, as humans we apply a relatively narrow range of materials to a very broad range of uses. As some materials become depleted, and others face environmental issues, it is vital that we explore other options, and tapping into the wisdom of nature seems like a good place to start.

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Natural Cycles: Part 1 – The circle of life and waste

By Anwen Bowers

north-pacific-gyre
Circulation patterns in the North Pacific have created a vast plastic continent | Image: Steven Guerrisi

The Great Pacific Garbage Patch is a vast area in the Pacific Ocean where huge amounts of plastic and other slow-to-degrade waste has accumulated over the past half century. Rubbish from all the rivers in North America and Asia gathers here and then becomes trapped by the swirling waters of the North Pacific Subtropical Gyre.

The plastic has nowhere else to go, and so it circles around the oceans, breaking down into smaller and
smaller pieces; small enough to be consumed by the plankton, fish, birds and mammals of the Pacific Ocean. This poses a huge environmental threat, and it is a result of the linear processing of waste that is a uniquely human phenomenon.

In nature, everything is processed in cycles *cue famous Disney soundtrack*. As animals feed, the basic building blocks of life are passed up the food chain, and when the top predators die or defecate, the cycle starts again. Every single atom in our bodies has already passed through a number of incarnations, already been part of an ant or a daisy or a rock, and has the potential to become so again.

vultures
They may look sinister, but vultures are nature’s recyclers; they are vital in many ecosystems | Image: Hugh Lunnon

Many organisms have carved out an ecological niche for themselves facilitating this cycle. Animals like vultures and dung beetles may not have the most glamorous rep, feeding as they do on dung and rotting corpses. But in so doing they remove a source of harmful bacteria and disease, turning it instead into bioavailable nutrients, promoting growth, habitat, and life. Unglamorous it may be, but an invaluable service nonetheless.

Where nature operates on complex, closed systems that generate zero waste, humanity tends to operate on a linear system. In this system, materials are processed into products that are useful for a time, but once they reach the end of their life span the waste is packed into crevices in the earth’s crust, or swept into oceans, never to be useful again.

This is unsustainable not only because these endpoints will eventually become saturated, but also because by taking the materials out of circulation, we are effectively putting an end to their reincarnation cycle. The more stuff that is floating in the Great Pacific Garbage Patch, the less stuff we have to use, and logic follows that we will eventually run out.

caviar
Turning empty cardboard boxes into gourmet dishes: restaurants could have a lot to gain from the circle of life | Image: Lebensmittelfotos

Luckily, more and more business models are starting to see that that by following nature’s example they can simultaneously increase productivity, whilst decreasing harmful output. Cardboard to Caviar is an initiative set up by the Green Business Network (GBN) in West Yorkshire. Inspired initially by the problem of waste cardboard packaging from the restaurant industry, GBN’s solution was to collect the cardboard, shred it and sell it as bedding for horses.

A good solution, but what about the waste that then came from the stables? GBN started to collect that too, feeding it into giant composters, where the cardboard and manure were broken down by worms. The worms, in turn, are fed into GBN’s fish farm, where they are eaten by sturgeon, which produce caviar that is sold…to the restaurant industry!  

The number of businesses that process waste into something useful appears to have increased exponentially over the last few years. They’re turning chopsticks into furniture and plastic bags into bricks.

However, a word of caution: Whilst these examples should be credited for their innovation in extending the life of waste materials, they are still, in essence, linear. The risk is that whilst storing plastic in bricks is better than storing it in the ocean, we could ultimately also be storing up the problem for future generations. Plastic, in particular, can only be recycled into a useful product once; any further processing deteriorates the quality too much.

To effectively transition into a low waste society, there also needs to be a parallel shift towards sustainable, natural materials that can either be cycled in themselves or converted into new materials, continuing the circle of waste.