0 comments on “H is for Holograms”

H is for Holograms

By Siobhan Fairgreaves

After a little summer break, welcome to the eighth post in this series- and today we’re going to be finding out more about Holograms.

First things first- what even is a hologram, and where would we encounter them?

Holograms are popular optical illusions that seem to make a moving image appear from a still photograph. The moving images appear 3D and can be viewed from different angles. However, holograms aren’t just reserved as fairground gimmicks; we can find them all around us. From our money to our DVDs, holograms are everywhere and they have some very important uses.

Hello dove my old friend, I’ve forgotten the 3-digit security code on the back of my card again| Image: Dominic Alves

Why use a hologram though? Sure, the shiny bits on money and credit cards look nice but what is the point? Holograms on money are used to reduce forgery. When a financial system becomes inundated with forgeries the strength of the currency can be weakened. Incorporating a hologram printed onto a piece of metallic film into the design of bank notes and credit cards means the forgers will find it much harder to copy. Other goods, such as DVDs, games or software programmes may also feature holograms so you can be sure they are genuine products.

Now that holograms are starting to sound important it would be nice to know how they’re made. This is where it gets a bit more complicated, try and bear with me though. The exciting news is that we do get to talk about lasers, everybody loves lasers. We’ll be finding out more about how light works in a few posts time but for now, we need to know that holograms rely on the coherent, synchronised waves of light that make up a laser beam.

Tired of only seeing images of 3D objects from just one boring old angle? Now you don’t need to! | Image: Explain that stuff

The synchronised waves of light in a laser beam can be split using a half mirror which allows half of the laser beam through and reflects the other half. By carefully angling the half mirror and a normal mirror you can ensure that the reflected half of the laser beam hits the object you’re trying to turn into a hologram. The reflected half creates what is known as the reference beam. The other half of the laser beam, having passed straight through the half mirror, creates the object beam which can then also be directed onto the target object.

But how do we know this was the real Dennis Gabor? | Image: Keystone

When these two, usually synchronised, halves of the laser beam recombine on the photographic plate having reflected off the target object they now show the object from different angles. This is because each half of the laser (the object beam and the reference beam) took a different route to get to the same place. From whichever angle you view the hologram you can now see how the light would have hit the object if it had been real. This allows the image to change as you move your head around to capture different angles.

A post about this complex process would not be complete without reference to their creator, Dennis Gabor. Incredibly, Gabor knew how to make a hologram before lasers – which are needed to make holograms work – were even invented. His invention and development of holography (the art of making holograms) in the early 1950s eventually earned him the Nobel Prize in Physics in 1971.

That was definitely one of our tougher posts so far but it just goes to show how often we use complex physics and take it for granted. I know I’m definitely guilty of thinking physics was the least interesting of the sciences because it just didn’t feel as relevant. How wrong was I!

A fun fact to finish off now and something that is sure to inspire a few YouTube searches. If you break a hologram into tiny pieces the whole object can still be seen in each fragment.

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Unexplainable Astronomy? Part 1: The Wow! Signal

By Sam Jarman

The scribble that started it all | Image: Big Ear Radio Observatory, NAAPO

Monday was dragging for Jerry R. Ehman, in a way that only a volunteer astronomer at the SETI project could truly understand. The frequency data printed out by the IBM 1130 computer was, as always, infuriatingly ordinary. The stream of paper he needed to analyse by hand was seemingly endless. Coffee in a Styrofoam cup was slowly growing lukewarm. Then… something different.

 

On August 15 1977, Ohio State University‚Äôs Big Ear radio telescope picked up an intense and unexpected burst of radio waves, which lasted for a full 72 seconds. Stunned by the break in the monotony of his task, Ehman couldn‚Äôt help but briefly forget his deeply engrained skills in data analysis. Taking a bright red marker, he drew a circle around the numbers and letters¬†indicating the burst, and wrote one word next to it: ‚ÄúWow!‚ÄĚ

Ehman wasted no time in letting his fellow members of SETI know about his discovery. The implications of the burst were not lost on any of them. The SETI volunteers knew there and then that the burst could not be explained by any current science. On each of their minds was the possibility that the purpose of their project had at long last been fulfilled: evidence of intelligent life beyond the Solar System.

¬†It doesn’t sound much like ‘We come in peace’, or ‘As you no doubt will be aware, the plans for the development of the outlying regions of the western spiral arm of the galaxy require the building of a hyperspace express route through your star system and, regrettably, your planet is one of those scheduled for demolition’,¬†but the Wow! Signal could be the closest thing we have to a message from aliens

Hey, I know that frequency!

To understand why Ehman and his colleagues were so excited by the burst, we need to look at the characteristics of the particular frequency their telescope was picking up. The Big Ear radio telescope had been programmed to detect signals with the very specific frequency of 1420.406 Megahertz. That number might not roll off the tongue, but it’s incredibly important in astrophysics, and even has its own name: the Hydrogen Line frequency.

The red colours shows where¬†hydrogen gas has been detected within the Milky Way. As it turns out, there’s a lot of it | Image: NASA

Hydrogen gas is extremely common in the wide expanses of space which lie between the stars. Atoms of the gas, consisting of an electron orbiting a single proton, are normally very stable and pretty uninteresting. But occasionally, the electron will flip over spontaneously due to quantum processes – a phenomenon known as spin flip transition, making the system unstable. To return to normal, the electron needs to flip back around, releasing a flash of light with a specific energy ‚Äď a radio photon ‚Äď in the process.

This process is incredibly rare for individual hydrogen atoms, but when hydrogen gas is gathered in clouds which span many light years, enough radio photons are given off by spontaneously flipping electrons that they can be easily picked up by radio telescopes on Earth. These photons make up the radio signal of the Hydrogen Line, which is important both to radio astronomers and to those hopeful that other technologically advanced civilisations could be out there somewhere.

The Hydrogen Line frequency is useful to astrophysicists, as they can use it to detect the exact locations of clouds hydrogen gas within our galaxy, and in those beyond. The clouds will always be densest in galactic arms, allowing radio astronomers to map out the distinctive structures of galaxies. They can also use the Doppler Effect to measure how fast hydrogen gas at various distances from the centre of galaxies is moving. From this, they can then create rotation curves for different galaxies, which currently give the clearest evidence we have for the existence of Dark Matter (but that’s a whole other story!)

So when astronomers point their radio telescopes at hydrogen gas clouds, it’s hardly surprising for them to observe radio waves at the Hydrogen Line frequency. But what if we observe them in places in the sky where we aren’t expecting them, or at higher-than-expected intensities? Any astronomer will agree that if this happens, something unexplained is going on.

“Huh, these aliens know about hydrogen spin-flip transition and have an in-depth understanding of their place in the galaxy… so why haven’t they invented clothes yet?” | Image: NASA

Astronomers at SETI became interested in the Hydrogen Line frequency because it is such a fundamental figure in astronomy. Clouds of hydrogen gas are so abundant in the galaxy that their signal can be picked up no matter where you go in space. SETI figured that if there are any other enlightened civilisations elsewhere in the universe, then they must realise this too. No matter how different their scientific units are to ours, if we asked them to create a radio signal at the Hydrogen Line frequency, it would be exactly the same as the signal we would create. So what better way to announce your presence to the galaxy than to send out a distinct, high-intensity transmission of the frequency?

 

SETI has already sent signals like this out into space, in the hope that others out there may be listening. In fact, they have a strict control over the transmission of the Hydrogen Line signal; it is now illegal to get anyone’s hopes up by transmitting the frequency yourself. But that isn’t the only method we have used to broadcast our knowledge of the Hydrogen Line. In 1972, under the efforts of Carl Sagan, Frank Drake and other journalists and astrophysicists, the famous Pioneer plaque was attached to probes Pioneer 10 and Pioneer 11.

In the top-left of the plaque is etched a diagram representing the distinctive electron flipping process which causes the Hydrogen Line. Between two representations of hydrogen atoms with electrons in the two different states is a horizontal line 21.106 cm long ‚Äď the exact wavelength of a radio wave at the Hydrogen Line frequency of 1420.406 MHz. If an intelligent civilization ever finds one of the probes then it‚Äôs a safe bet that they will understand exactly what the diagram is representing, no matter their language.

 An explanation, or an alien-killing pretender?

Not long after Ehman’s bizarre discovery in 1977, the newly dubbed Wow! Signal, named after Ehman’s hasty scrawl in red pen, had taken the worlds of both science and the media by storm. While astrophysicists rushed to discover the astronomical source of the signal, journalists began to enthusiastically speculate that without any existing scientific explanation, it could have been more purposefully created in origin. For hopefuls of the existence of extra-terrestrial intelligence, the evidence was now more tantalising than ever.

Sorry it was me all along… or was it? | Image: NASA, ESA, J.-Y. Li

Yet for all the attention the Wow! Signal gained, the search for its origin proved fruitless for scientists and alien hunters alike. For over 40 years, the result sat there unexplained; frustrating some, and instilling hope in others. But in April 2017, astronomer Antonio Paris from St Petersburg College, Florida claimed in a paper to have solved the mystery once and for all.

Paris argued that on August 15, 1977, two comets inside the Solar System Р266P/Christensen and 355P/Gibbs Рpassed directly in front of the Big Ear radio telescope. Surrounding one of the comets was a cloud of hydrogen gas, which was given off by one of the masses of ice and rock. Naturally, the telescope picked up the Hydrogen Line signal of the cloud, but only as it passed through Big Ear’s field of view. For the first time, it looked like the mystery had been solved. But not everyone was satisfied with the new explanation.

Within weeks, Paris was receiving backlash from scientists, who had some strong criticisms of his paper. In June, Robert S. Dixon, director of the SETI project himself, published a rebuttal to Paris‚Äô paper, claiming that the two comets weren‚Äôt in fact within Big Ear‚Äôs field of view on the day of the Wow! Signal. Other criticisms included claims that the comets were a long way from the Sun and therefore inactive, meaning neither of the comets could possibly maintain a hydrogen cloud around themselves. Some scientists even had many harsh words to say about Paris‚Äô scientific methods in general. Paris stands by his theory, but he’s open to debate.

So for now, many astronomers still regard the Wow! Signal as a mystery, and hope remains that the true explanation of the burst could be another advanced civilization broadcasting its existence. But this isn’t the only case where strange signals in astronomy have gone unanswered for long periods, or where far-fetched and alluring explanation theories have been thought up.

Over the last century, the world of astronomy has been become famous for detecting mysterious signals, making bizarre discoveries, and throwing up seemingly unanswerable questions. Some of these questions have had mundane explanations. Others have led to new research which has come to revolutionize our understanding of the universe. And, like the Wow! Signal, still others remind us just how much we have yet to learn.

In this series, we will find out more about the signals which have both answered and created some of the most enticing questions in modern astronomy. Next time, we will turn back the clock to before 1977, when astrophysics was reeling at the revelation that our place in the universe was far less significant than we realized.

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F is for Flying

By Siobhan Fairgreaves

Don’t listen to Jon Snow, summer is coming!

Whether you will spend your (hopefully) sunny days looking up at blue skies or jetting off on an adventure, one thing may cross your mind- how do those aeroplanes stay up there!? In this post we will learn a bit more about how aeroplanes get up, stay up and get back down again.

Plane wings: black magic sorcery, or a clever bit of engineering? (This isn’t actually discussed in the article, it’s obviously the second one)

This is one post I’ve been really looking forward to writing- I’ve been well and truly bitten by the travel bug and I can’t think of a better feeling than the rush of the engines as your plane prepares to take off. It’s certainly obvious from the noise of the engines and the speed of the objects flashing past outside that it takes a lot of force to get in the air but what changes between just going forwards really fast and flying?

In order to understand this (and everything else about flying) it’s important to consider another very important F in the physics world- Forces. There are four key forces acting upon an aeroplane.  Horizontally, there is thrust and air resistance. Thrust, generated by those powerful jet engines, propels the plane forwards. Air resistance, or drag, slows the plane down- like when you stick your head out of a car window and the air hits you hard in the face, that force increases the faster you go, and planes go very fast!

Vertically the plane is subject to gravity (more on that next time) and overcoming the weight of the plane which is a downwards force. The final force is lift. This is slightly less obvious but extremely important and keeps the plane in the air.

In order for the plane to change take off it needs to move forwards and upwards (we’re talking passenger planes here- some military aircraft, like the Harrier, are capable of extremely short take offs.

We’ve got moving forwards covered thanks to the powerful jet engines providing enough thrust to overcome the force of drag. Moving upwards requires the cleverly designed wings to come into play. As air rushes over the wings it is thrown down towards the ground creating lift. In order to get off the ground, there must be enough lift created to overcome the weight of the plane due to gravity.

So when thrust is bigger than drag we go forwards and when lift overcomes the weight we go upwards. Very useful for take-off but we don’t want to keep going up forever.

Enough is enough! I’ve had it with these stably-balanced forces on this stably-balanced plane! | Image: Amada44

The wings are shaped and angled to ensure that we stay up, without constantly rising, throughout the flight. The curved and thicker front of the wing is designed to ensure air is at a lower pressure above the wing and a higher pressure underneath. The angle of the wing effectively allows the plane to push down on the air which also helps it stay up- think about pushing down on the water in a swimming pool.

Once the pilot has reached the right altitude they can level out the aircraft and just keep moving forwards. As long as the vertical forces of lift and weight, and horizontal forces of thrust and drag are all balanced, the plane will cruise at a steady altitude at a constant speed.

Getting down again simply (easy for me to say!) requires the forces to be reversed. We now want to go slower so the thrust force can be reduced and drag is allowed to help with the braking. As we also want to get closer to earth we allow the weight of the plane to help. By changing the shape of the wing using flaps, you may have seen these during take-off and landing, the pilot can reduce the strength of the lift force and transfer the weight of the plane onto the wheels which are lowered in time for landing.

Of course, numerous other environmental factors make the business of flying a plane very difficult indeed, but with a little more knowledge of the physics pilots use to help them out you can now sit back, relax and enjoy the journey.

Until next time!

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E is for Electricity

By Siobhan Fairgreaves

Last time, in D for Detectors, we looked at some of the applications of physics that you might encounter during your day. In this post, we’re going to find out more about something I can guarantee you use almost every day- electricity!

Far from simply being a piece of tack on your ‘cool’ uncle’s shelf, the plasma lamp is one of the best ways to see¬†electron flow ¬†in action

A reliable source of electricity is something we could easily take for granted, but how does it actually work? Well, surprise surprise, it all comes back to our friend- the humble atom. More specifically, electricity is the flow of electrons – remember them?

Electrons are the tiny negatively charged subatomic particles which whizz around the outside of the nucleus. In some materials, such as copper, the outer electrons break off quite easily and their movement through the material (a copper wire for example) creates an electric current.

Of course, not all materials can conduct electricity. I’m sure you remember the experiment in school where you tried to complete a circuit with different materials- they didn’t all work. Rubber, for example, holds onto its electrons pretty tightly so they can’t easily flow. This means rubber can’t conduct electricity.

Now back to that circuit experiment you may have tried. Your copper wires alone aren‚Äôt enough to light the bulb- you also need a source of power, like a battery.¬† The battery is a source of ‚Äúpushing power‚ÄĚ to move the electrons along. The official name for this is the electromotive force (EMF) but it‚Äôs more commonly known as voltage.

Ah, the good old Mexican current… at least that’s what it’s called among scientists who¬†advocate Mexican wave-particle duality¬†| Image: Martin Thomas

One way of thinking about electricity is a bit like a Mexican wave in a stadium. It usually takes a few people acting together to get it started- that’s the battery, and then the wave (or energy) transfers through each person and onto the next. The moving wave is a bit like the moving electrons.

Time for a fun fact now- did you know that the band AC/DC can actually teach us more about electricity? Their name came from seeing a symbol on their sisters’ electric sewing machine. This symbol stood for Alternating Current/Direct Current and meant that the machine could work with either type or electrical current.

“I’m on the hiiiiiiighwaay to… oh yeah, I’m periodically changing direction, so I guess I’m not really going anywhere” – an electron in an AC power line

Direct Current is best explained by the Mexican wave analogy used above. All the electrons move in the same direction. This type of current is used in toys and small gadgets. Larger machines tend to require Alternating Current.

The electrons forming an Alternating Current reverse direction 50 to 60 times a second. It’s a bit difficult to imagine how that could create a current but remember it’s all about transfer of energy. The battery still provides the initial push but these electrons don’t run in a straight line, they run on the spot instead. It doesn’t work in quite the same way but, just like Direct Current, still requires loose electrons and they still need energy.

See you next time for a convenient start of summer post- F for Flying!

2 comments on “D is for Detectors”

D is for Detectors

By Siobhan Fairgreaves

So far in the series, we’ve looked at some big physics concepts, but now, we’re trying something a little different. In this post, we are going to have a look at some of the practical ways we use physics in our daily lives. Specifically, we’re looking at detectors.

Smoke detectors

Air molecules ionized by the radiation given off by americium-251 can detect smoke particles. Unfortunately, they can’t tell the difference between smoke particles caused when your house is burning down, and when you’ve put your crumpet down one too many times in the toaster | Image: Whitepaw

Hopefully, you are pretty comfortable with what a smoke detector is, and why it is useful- but have you ever wondered how they work? Surely that’s not physics!?

Well, surprisingly- yes it is.

Inside your humble smoke alarm is a small amount of americium, a radioactive material. The presence of this radioactive material means the particles of air inside the detector are ionized, allowing an electric current (more on that next week!) to flow across the chamber.

When smoke particles go into the detector some of the ionized particles attach to them. The current drops, setting off the alarm.

There are actually two different types of smoke detectors. Most common is the type that uses an electric current generated by radioactive material but there is another type.

Photoelectric detectors work in a totally different way but are still a pretty good example of how physics can help us out every day. Under normal conditions, in a photoelectric detector light travels from one end of the chamber to another unobstructed. When smoke enters the chamber the light hits the smoke particles, this causes the light to scatter and hit a sensor which then triggers the alarm to sound.

And now you know what is going on when you burn your toast!

Metal detectors

Heheh… those fools will never know about my emergency supply of plastic knitting needles! | Image: Hunter Desportes

I don’t know about you but when somebody says metal detectors I still think of somebody trawling beaches in search of buried treasure. Of course, there are also much more serious applications of this technology. Those beeping things at airports? They are metal detectors too, and they work in more or less the same way.

Metal detectors rely on the fact that an electric current will always generate a magnetic field in a direction perpendicular to its movement. And likewise, a magnetic field across a wire will always induce a current in the wire.

When forming wires into coils of many loops, strong magnetic fields can form through the loop of the coil, simply by firing a current through the coil. Metal detectors can cleverly use these physical laws to their advantage.

In an airport, metal detectors work by firing currents which rapidly alternate in direction through coils of wire – producing a magnetic field which itself alternates in direction. The presence of metal in your pockets, belt or jewellery as you pass through can be enough to disrupt this magnetic field.

Side-view of a magnetic field as it compellingly comes through a current-carrying coil in characteristic curves | Image: Geek3

Due to an important affect in physics known as Lenz’s law, small currents are induced in the metal on your body, which produce their own magnetic fields to resist the field of the detector.

Another coil of wire in the detector is there to measure the overall magnetic field. This time, instead of having an alternating current fired through it directly, a current will be induced by the magnetic field – the strength of the field can be measured by measuring the strength of the induced current.

If the overall magnetic field is any different to that created by the initial coils, the detector will know something is up. An opposing magnetic field was generated as you passed through, which can only mean that there is metal on your body, and the detector sounds the alarm.

Radiation detectors

Geiger and Muller had some trouble persuading everyone that their invention wasn’t just a silly looking hammer, and could actually save thousands of lives | Image: Mrjohncummings

Well, this one might seem a little more abstract but you’d be surprised to realise how common radiation detectors are.

Radiation detectors can be given a number of names, but a Geiger counter or Geiger-Muller tube is a pretty common choice. ‚ÄúGeiger‚ÄĚ and ‚ÄúMuller‚ÄĚ refers to the scientists Johannes ‚ÄúHans‚ÄĚ Wilhelm Geiger and Walther Muller who discovered an improved method of detecting radiation way back in 1928.

The Geiger-Muller tube detects ionizing radiation such as alpha particles, beta particles, and gamma rays. Once radiation has been detected an electric pulse is produced which shows on the Geiger counter display allowing you to get out sharpish if things start to reach scary levels.

No, it’s never a good idea to play a game of ‘Who can make the Geiger counter beep the most?’| Image: Cygaretka

Sounds interesting but not exactly relevant? Think again.

 

Radiation detectors can be found all over the UK in schools, hospitals, airports and of course power plants. Any workplace that handles, or could handle, radioactive material must use one of these clever little detectors to ensure that radiation stays at a safe level.

Why?

Well, radiation can be pretty dangerous stuff if you’re exposed to it for too long. With a range of effects ultimately all stemming from corrupted cell functions it’s really important to stay safe. You may remember the suspicious poisoning of Alexander Litvinenko? Exposure to radiation can be deadly.

Until next time!

0 comments on “Design, Naturally: Wasps take the sting out of brain surgery”

Design, Naturally: Wasps take the sting out of brain surgery

By Anwen Bowers

‚ÄúI cannot persuade myself that a beneficent & omnipotent God would have designedly created the Ichneumonid√¶ with the express intention of their feeding within the living bodies of caterpillars ‚Ķ‚ÄĚ

This statement from Darwin is often quoted in discussions about his changing relationship with religion as he developed his theory of evolution. 150 years later, the ichneumonidae in question are taking a step towards shedding their demonic reputation by inspiring a new approach to neurosurgery.

| Image: Sean McCann
Pretty deadly. We could look at ichneumonidae ALL DAY.| Image: Sean McCann

The ichneumonidae are a subfamily in possibly the largest group of animals in the world ‚Äď the parasitoid wasps. Estimates of the total number of ichneumonidae species alone reach up to 100,000 ‚Äď more than all the vertebrate species in the world. The wasps gain their name because they¬†brutally kill their host species, as opposed to parasites which drain the resources of an organism without causing significant harm.¬†Indeed, life histories of the parasitoid wasps are close to the stuff of nightmares.

The extremely high diversity of ichneumonidae has arisen because each species of wasp has evolved to target just a single type of prey, and to do it as efficiently as possible. Each species is distinguished by its specialised weaponry or tactics that allow them to tackle their prey in their niche habitat or lifestyle. For example, Lasiochalcidia igiliensis’ chosen host is the antlion larva, a ferocious predator in its own right with vicious jaws that it uses against a range of arthropod prey, even spiders.

antlionlarva
A badass Antlion larva clearly has only one thing to fear. Fear of L. igiliensis itself. | Image: Larah McElroy

The seemingly fearless L. igiliensis has been observed to bait the antlion larva, encouraging it to attack the wasps itself. At the point of attack, the wasp will use its powerful legs to prise the jaws of the antlion open, whilst simultaneously depositing an egg into the antlion larvae’s throat. There the egg will incubate, feeding on the antlion from the inside, until the time for metamorphosis comes. At this point the wasp will burst out from the antlion, not unlike the infamous scene from Alien.

Strategies in other species include a fibrous mesh that traps air allowing the wasps to dive down and reach caddis fly in their underwater habitat, and a hormone invisibility cloak that allows the wasps to live within an ants nest, even up to adulthood, without detection. These guys are the Q Branch of the insect world.

M. macrurus prepares to drill. | Image: Evan Kean
M. macrurus prepares to drill. Just look at that ovipositor. Stunning, and inspiring… | Image: Evan Kean

Here at Rising Ape we can vouch from experience that great ideas happen when you put a bunch of scientists from different backgrounds in a room, and maybe give them a bottle of wine. This seems to be what happened in the case of Dr Ferdinando Rodriguez y Baena, a medical engineer who found himself inspired by a serendipitous dinner party conversation with zoologist and biomimetics expert Julian Vincent.

Vincent described how the parasitoid wasp species Megarhyssa macrurus, is able to use her egg laying tube to drill down into tree bark, where she deposits her eggs onto the larvae of the pidgeon tremaz horntail (how did this come up as a topic?! Over dessert?). This is possible thanks to a complex structure of three tubes that can bend and flex as the wasp drills, allowing her to position her eggs with pinpoint precision.

needlepic_imperial
The three parts of this needle echo the ovipositor of the drilling wasp and give it unparalleled flexibility. | Image: UCL

This elegantly specialised structure gave Baena the idea for a new style of needle that mimics the ovipositor. The design allows surgeons to control and manoeuvre the needle inside the patient, navigating around sensitive and fragile parts of the brain. This minimally invasive surgical procedure could even allow surgeons to deliver drugs to very specific areas in the brain, potentially treating diseases such as brain tumours and Parkinson’s. By saving lives for a change, the ingenious ichneumonidae wasps could be about to improve their reputation.  Who knows, even Darwin may have approved.

0 comments on “Design, Naturally: Sharkskin V Superbugs”

Design, Naturally: Sharkskin V Superbugs

By Anwen Bowers

Antimicrobial resistance is one of the biggest challenges faced by the healthcare industry. The evolution of superbugs such as MRSA is evidence that the arms race between antibiotics and bacteria is not a sustainable strategy for preventing infection and keeping patients healthy. Bacteria are able to make infinite changes to their DNA, but¬†there isn’t an infinite supply¬†of new drugs available to target them. Scientists looking for alternative methods to tackle the spread of disease causing bacteria have turned to the natural world for inspiration.

door-handle-625942_1280.jpg
Opens doors, spreads diseases, can be opened by velociraptors. | Image: Public domain

Bacteria in hospitals spread through contact. If a person touches a surface that hosts bacteria, they can pass it along next time they touch a piece of equipment, or a patient. So could making surfaces inherently resistant to bacteria be an effective way of stopping the transfer and spreading of disease?

Traditional approaches to keeping surfaces sterile involve using some sort chemical agent, for example treating socks with silver to keep smelly feet at bay (equally effective against vampires). The disadvantage of chemical treatment is that protection is short lived, and needs constant renewal. Research suggests that silver nanoparticles in socks last not much longer than a few washes, as the silver is rinsed out into the environment where it becomes a poisonous threat to wildlife.

In a paradigm shift in strategy, scientists have proposed a new mechanical approach to keeping surfaces clean. Taking inspiration from the sea, they want to develop a texture that prevents bacteria from spreading by discouraging microbes from settling in the first place.

dirty boat hull
Hull is filthy. The boat’s hull that is. | Image: Glenn Batuyong

Place almost anything underwater and it won’t be long before a thin film of green slimy phytoplankton will start to settle. This plankton is the trigger for a chain reaction of settlement, as larvae of adhesive animals such as anemones and barnacles will soon follow. This has long been a problem for the shipping industry as fouling like this on ship’s hulls creates a huge amount of drag, slowing down the vessel and adding fuel costs. Even whales, despite their constant movement, will succumb to the nuisance of barnacles and parasites.

But scientists observed that sharks remain clean and crust free, even into old age. For a long time it was thought that sharks move too quickly through the water to give anything any time to settle. Closer inspection of the surface of their skin provided an alternative answer. Sharks are covered in specialised scales called dermal dentacles.

Denticles.jpg
Sharks: Creating the worst place for bacteria to hang out for 100 million years | Image: Pascal Deynat/Odontobase

Dentacle means ‚Äúsmall tooth‚ÄĚ, a name derived the¬†dentine tissue from which they’re made¬†and the same found in your teeth. Dermal dentacles are highly textured, and when meshed together they form an extremely complex surface, full of micro mountains and canyons. This surface appears to be too unstable for any bacteria to settle and establish a community effectively.

Without the base layer of microscopic organisms, the bigger problem of larger, fouler organisms cannot develop, and the¬†shark remains clean and smooth. This evolutionary advantage then¬†helps the seas’ top predators¬†move¬†swiftly through the water in pursuit of their prey.

640px-Prionace_glauca_by_mark_conlin.JPG
‘Phelps who? Bet I’m cleaner and¬†faster.’ | Image: Mark Conlin

Shark skin is already well studied, and has inspired a range of products, famously the Olympic grade swimwear that can reduce drag and shave milliseconds of a swimmer’s time. To use it as a surface for hospitals was the idea of Anthony Brennan, founder of the company Sharklettm , who have trademarked a textured pattern based on the structure of sharkskin. The company claims that Sharklettm surfaces harbour 94% less bacteria than standard worktops and equipment.

Installed in places such as drawer handles and even surgical equipment, Sharklettm could be a cost effective way of reducing the spread of bacteria, as well as use of antiseptic and not to mention the time staff spend cleaning surfaces. What has evolved over millions of years could be a solution to a very pressing 21st century issue.

0 comments on “K is for Kepler”

K is for Kepler

“Truth is the daughter of time, and I feel no shame in being her midwife.”¬†Johannes Kepler

These words, written by Johannes Kepler in 1611, are profound.  At the time, Galileo had just discovered the Galilean moons (including Europa) in Florence but was being persecuted for his belief that the Earth orbits the sun.  Kepler, a staunch supporter of heliocentrism, was working as the Imperial Mathematician in Prague.  When word that Galileo had used a telescope to find the moons reached Kepler, he was so fascinated and impressed that he wrote an enthusiastic letter of support and scrawled that pithy aphorism.

While Kepler enjoyed some social status as Imperial Mathematician and was much more free to contradict Aristotle¬†than his Italian counterparts, his life was by no means a charmed one. ¬†The son of “an immoral, rough and quarrelsome soldier” (his own words), Kepler managed to carve himself a place in history¬†based on his skill as a mathematician and astronomer. ¬†He kept on working through many family disasters, including the deaths of his wife and his seven year old son and a witch trial about his mother.

Kepler was a devout Christian and grew up Lutheran but was excommunicated due to his rejection of the Augsburg Confession.  This left him neither a Lutheran nor a Catholic and between sides when the Thirty Years War broke out in 1618.

You've got to love that frilly collar.  Just like Shakespeare!  Actually, come to think of it, Kepler actually lived at the exact same time as Shakespeare.  I wonder if they ever met and what they might say to each other at a dinner party.  Image is public domain.
You’ve got to love that frilly collar. Just like Shakespeare! Actually, come to think of it, Kepler lived at the same time as Shakespeare. I wonder if they ever met and what they might say to each other at a dinner party. Image is public domain.

Despite all of this, Kepler revolutionized astronomy by formulating mathematical laws that accurately describe the motions of the planets. ¬†These are still taught in astronomy today and are called Kepler’s Laws.

The first law is that planets orbit in ellipses with the sun at one focus.  Before Kepler, most Western astronomers modelled the orbits of planets as circles and had to invoke a strange concepts like epicycles and equant points.

1. Planets orbit in ellipses, not circles.
1. Planets orbit in ellipses, not circles.  Image my own

The second law is that a line between a planet and a star will sweep out equal area in equal time. In other words, planets move faster when they are closer to their star and slower when they are further away.  This law is better understood with a diagram:

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2. Planets don’t have constant speed ¬†Image by RJHall

The third law, formulated after the first two, is that the time it takes a planet to make an orbit (orbital period) is directly proportional to its distance from the star.  This law allows astronomers to calculate how far a planet is from its star based only on information about the length of its year and the mass of the star.  Remember this one, because it will become important later.

As you can see, Kepler’s Laws are fundamental to our understanding of how planets move, or orbital dynamics. ¬†It will come as no surprise then that every young astronomer is all too familiar with Kepler’s laws. ¬†This isn’t the only reason he’s familiar though. ¬†He is also shares a name with the most successful exoplanet hunter the world has ever produced. ¬†The Kepler Space Telescope.

Kepler: Planet Hunter is kind of Like Abraham Lincoln: Vampire Hunter.  Except more real.  And frankly, a little more impressive.    Image by Wendy Stenzel at NASA
Kepler: Planet Hunter is kind of like Abraham Lincoln: Vampire Hunter. Except more real. And frankly, a little more impressive. Image by Wendy Stenzel at NASA

Launched in 2009, the Kepler Space Telescope used 42 image sensors to continuously observe over 145,000 stars. ¬†Unlike a lot of other telescopes that try to take magnified images, Kepler wasn’t interested in images. ¬†It wanted accurate data on brightness. ¬†It basically had a staring contest with these 145,000+ stars, waiting for them to blink. ¬†I say blink because Kepler was waiting for the brightness to go down and back up. ¬†The brightness of stars can vary for all sorts of reasons, but planets passing in front of their stars make the brightness dip in a particular way. ¬†This dip is called a transit and finding transits¬†was Kepler’s mission.

When a transit occurs, the size of the brightness dip corresponds to the size of the planet and the length of the dip corresponds to the time it takes a planet to orbit (as well as the size of the star). ¬†Remembering Kepler’s third law,¬†¬†if we know the time it takes to orbit, we can figure out the distance to the star. ¬†And if we know the brightness of a star and the distance, we can figure out how much energy¬†the planet receives. ¬†Plug all that in to a¬†simple(ish)¬†equation, and out pops temperature.

Stars, just like planets and people, come in all different shapes and sizes.  That means light curves also vary widely.   Image from Planethunters.org
Stars, just like planets and people, come in all different shapes and sizes. That means light curves also vary widely. Image from Planethunters.org, a great citizen science project that combines people’s natural pattern-finding ability with Kepler data to find planets.

So thanks to the Keplers (both Johannes and the Space Telescope) we can start to look for alien worlds that have temperatures similar to the ones we find here.  The hope is that one day we will find evidence of life on another planet.  And then we can begin our transition into any one of several sci-fi galactic civilizations (my personal favourite is Foundation, but some people prefer Star Wars, Star Trek, or Eve Online).

Unfortunately, in May 2013 one of the components that kept Kepler (the telescope) stable failed, meaning the mission was apparently over.  The mission had been hugely successful, discovering over 1000 confirmed planets, with 4000 other planet candidates waiting to be confirmed.  It turns out that most stars probably have planets and that a lot of planets in the galaxy might be the right temperature to be habitable.

Astronomers are nothing if not persistent though, so an ingenious method was devised to make sure Kepler can continue observing even without its stabilizer.  This new mission, dubbed K2, uses the radiation pressure from the sun itself to balance the telescope.  Instead of continuously observing the same 145 000 stars, K2s targets will change periodically as it orbits the sun.  There will be far less data coming down, but as of this writing four new planets have already been found since K2 began in earnest in June 2014.

There's a lot of information there, but I think the most impressive bit is that K2 is metaphorically balancing a pencil on a fingertip, remotely, from 150 million km away.  Image by NASA
There’s a lot of information there, but I think the most impressive bit is that K2 is metaphorically balancing a pencil on a fingertip, remotely, from 150 million km away. Image by NASA

Currently, while there are all sorts of really interesting exoplanets out there (from hot jupiters like 51 peg b to mirror earths like Kepler-438b), we have yet to find signs of life.  But I think that before too long, we will.  Just as the truth of heliocentrism eventually came out thanks to Kepler, a telescope with his name will be instrumental in uncovering the truth of life elsewhere in the universe.  Just like he said,

“Truth is the daughter of time, and I¬†feel no shame in being her midwife” Johannes Kepler

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F is for Faraday

By Jonathan Farrow from The Thoughtful Pharoah

The year is 1791. ¬†On a crisp autumn morning in South London, Margaret Hastwell, a blackmith’s apprentice, gives birth to her third son. ¬†With her husband, son, and daughter crowded around, she decides to name the newborn¬†Michael. ¬†Michael Faraday.

Margaret had a lot on her plate, what with two young children, a husband who was often sick, and quite a few bills to pay. ¬†She probably didn’t have much time or energy for idle thought or daydreaming. ¬†I doubt if she much considered what Michael might do with his life other than get by. ¬†There is no way it occurred to her that Michael would grow up to revolutionize the world of physics, make electricity a viable source of mechanical energy, and inspire countless scientists, engineers, and young people (including but not limited to Einstein, Rutherford, and this young science communicator, 223 years later). But that is exactly what he would do.

Faraday went to elementary school and learned to read and write, but by the time he turned 13, he had to start work in order to help his parents make ends meet. ¬†He was apprenticed to a local bookbinder and spent the next 7 years diligently mending books. ¬†But that wasn’t all he was doing. ¬†He was also reading. ¬†Over those 7 years, Faraday read voraciously and became interested in science, particularly the topics of Chemistry and Electricity. Luckily for him, George Riebau, the bookbinder to whom he was apprenticed, took an interest in young Faraday’s education and bought him tickets to lectures by¬†Humphry Davy¬†at the Royal Institution in 1812. ¬†This was only¬†shortly after Davy had¬†discovered calcium and chlorine through electrolysis. ¬†Davy was a big name in science¬†at the time, comparable to today’s Stephen Hawking, Neil Degrasse-Tyson, or Jane Gooddall, so it was with wide eyes that young Faraday attended. ¬†He was so blown away by what he saw and heard that he faithfully wrote notes and drew diagrams. ¬†These meticulous notes would prove to be his ticket into Davy’s lab.

Davy Notes
“I got a golden ticket!” Image from the Royal Society of Chemistry

Later that year, Faraday sent a letter to¬†Davy asking for a job¬†and attached a few of his notes. ¬†Davy was impressed and so interviewed young Faraday, but ultimately rejected the eager young fellow, saying “Science [is] a harsh mistress, and in a pecuniary point of view but poorly rewarding those who devote themselves to her service.” ¬†Translation: ¬†“Sorry, I don’t have space for you in my lab, but just to let you know… Science really isn’t very profitable.” ¬†A few months later, one of Davy’s assistants got in a fight and was fired, so guess who got a call? ¬†That’s right, Mikey F.

Not only did Faraday get a spot in Davy’s lab, but he also got to go on a European¬†tour with Mr. and Mrs. Davy. ¬†Pretty sweet deal, right? ¬†On the eighteen month journey, Faraday got to meet the likes of Amp√®re and Volta. ¬†If those names are ringing distant bells, it should be no surprise. ¬†Those eminent continental scientists give their names to standard units of electrical current¬†(Ampere)¬†and potential difference¬†(Volt). ¬†Re-invigorated, 22-year-old Faraday returned to London and took up a¬†post at the Royal Institution as Davy’s assistant.

The next two decades saw Faraday make great advances in chemistry, including discovering benzene, liquefying gases, and exploring the properties of chlorine. ¬†He didn’t get much chance to focus on electricity, however, until 1821. ¬†In that year, Faraday started experimenting with chemical batteries, copper wire, and magnets. ¬†Building on the work of¬†Hans Christian √ėrsted, Faraday’s¬†work was some of the first to show that light, electricity, and magnetism are all inextricably linked (we now know that they are all manifestations of the electromagnetic force). He was a dedicated experimentalist and between 1821 and 1831, he effectively invented the first electric motor and, later, the first electric generator. ¬†These two inventions form the basis for much of today’s modern power system. ¬†The electric motor that opens your garage door as well as wind and hydro-electric generators work on the exact same principle that was discovered by Faraday back in 1831: electromagnetic induction.

Faraday’s insight was that when connected¬†by conductive material, an electric¬†current could make¬†a magnet move. ¬†He also found that the reverse was true: a moving magnet can¬†create a flow of electrons: an electric current.¬†The experiment is actually quite simple and you can even¬†try it at home. Induction enables the transformation of energy between¬†mechanical, electrical, and magnetic states. ¬†Before Faraday, electricity was seen simply as a novelty. ¬†Since Faraday, we’ve been able to use it for all sorts of things. ¬†Like writing science blogs!

The famous iron ring experiment.  Two insulated coils of wire are wrapped around an iron ring but kept separate.  Attaching one to a battery will create a momentary current in the other.  Induction!
The famous iron ring experiment. Two insulated coils of wire are wrapped around an iron ring but kept separate. Attaching one to a battery will create a momentary current in the other. Induction!   Image by Eviatar Bach

[While he was definitely a gifted scientist, Faraday knew next to nothing about mathematics. ¬†He observed, took careful notes, and had an intuition for how to design experiments, but could not formalize his theories in mathematical language. ¬†He would have to wait for James Clerk Maxwell, a young Scottish¬†prodigy, to do the math and formalize¬†Faraday’s Law¬†in the 1860s.]

Faraday continued his work on electricity and gained all sorts of recognition, including medals, honorary degrees, and prestigious positions.  This increased pressure may have been to blame for a nervous breakdown in 1839.  He took a few years off, but by 1845 he was back at it, trying to bend light with strong magnets.  He discovered little else after the 1850s, but continued to lecture and participate in the scientific community.

Older Faraday with glass bar
While that does look remarkably like a cigar, Faraday is actually holding a glass tube in his hand. A glass tube… of Science! ¬† ¬†Public Domain image from Wikimedia

So not only can Faraday be considered to be one of the fathers of the modern world because of his breakthroughs in electricity, but he can¬†also be considered to be one of the fathers of modern popular science communication. ¬†In 1825, he decided to give a series of Christmas lectures at the Royal Institution, specifically aimed at children and non-specialists. ¬†He gave these lectures every year until his death in 1867 and was renowned as a charismatic, engaging speaker. ¬†He tried to explain the science behind everyday phenomena and in 1860 gave a famous lecture on the candle, something which everyone had used but which few actually understood. ¬†The¬†Christmas lectures continue to this day and, continuing with Faraday’s legacy, the Royal Institution is one of the UK’s leading science communication organizations.

Doesn't that look fun!?
Doesn’t that look fun!? ¬† ¬†Public Domain image from Wikimedia

It is not simply that Faraday was a great scientist and lecturer, nor that he managed to escape poverty in 19th century England to become world-renowned. ¬†Michael Faraday’s story is so¬†great¬†because by all accounts, he deserved every bit of success he gained. ¬†One biographer, Thomas Martin, wrote in 1934:

He was by any sense and by any standard a good man; and yet his goodness was not of the kind that make others uncomfortable in his presence. His strong personal sense of duty did not take the gaiety out of his life. … his virtues were those of action, not of mere abstention

It’s no wonder that Einstein had a picture of him up in his office. ¬†I think I might just print one off myself.

Faraday painting 1842
Still pretty handsome considering this painting is from 1842, making Faraday 51 years old.   Public Domain image from Wikimedia
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Asimov’s Amazing Assertions

by James Riley

“What will the World’s Fair of 2014 be like? I don’t know, but I can guess.”

Could you predict the future? In the wake of the 1964 World’s Fair, Isaac Asimov, prolific sci-fi writer, made some startling predictions about life in 2014. Published in The New York Times on August 16, 1964, Asimov’s article “Visit to the World’s Fair of 2014” gives us real pause for thought about our life in the Information Age. Let’s explore some of his scarily accurate speculations about the future, and today’s technologies which helped realise these prescient predictions.

“Robots will neither be common nor very good in 2014, but they will be in existence [ . . . ] In fact, the I.B.M. building at the 2014 World’s Fair may have, as one of its prime exhibits, a robot housemaid.”

Robotics has snowballed in the last decade, but the discipline is still in its infancy. What is really interesting here is the housemaid that Asimov speaks of. One such example would be the Roomba autonomous robot vacuum cleaner, sold by iRobotics, which detects dirty spots of floor, avoids falling down the stairs by detecting steep drops and actively avoids obstacles. However there are more novel robots, like TOPIO, made by TOSY, which (/who?) played ping pong at the Tokyo International Robot Exhibition in 2009.

Isaac Asimov predicts future 2014 1964

(Isaac Asimov. Image Credit:¬†“New York World-Telegram and the Sun Newspaper Photograph Collection”/Taken by Phillip Leonian)

“General Electric at the 2014 World’s Fair will be showing 3-D movies of its “Robot of the Future,” [ . . . ] (There will be a three-hour wait in line to see the film, for some things never change.)”

This one is scary. Not only did Asimov predict 3D cinema becoming commonplace (the original 3D film technology being patented in the 1890s), but by a strange act of fate it happens that General Electric bought the controlling stake of Universal Studios in 2004. Universal being the company responsible for the last film in The Cornetto Trilogy, The World’s End, depicting ‘robots’ taking over the world, available in 3D. Of course, the film came out last year, and the invaders weren’t really robots (according to themselves), but it’s still a remarkable prediction.

“As for television, wall screens will have replaced the ordinary set; but transparent cubes will be making their appearance in which three-dimensional viewing will be possible.”

This two-fold prediction is an extension on the last. The wall screens Asimov speaks of have become common place across developed nations with newer variants of screen, such as LCD, taking over the clumpy cathode ray tube displays of the past. Many of these new variants are available with 3D technology.

“Communications will become sight-sound and you will see as well as hear the person you telephone. The screen can be used not only to see the people you call but also for studying documents and photographs and reading passages from books.”

The emergence of Skype and FaceTime have revolutionised the way in which we communicate, but the end of this statement is really quite startling. I’m sat in a coffee shop, using a tablet computer screen to read Asimov’s 50-year-old passages of predictions about me sitting here in 2014 using a screen to read passages; and simultaneously writing a document about the predictions, on the same screen which I am studying the documents containing the predictions which Asimov made. The very act of writing this article is one of validating Asimov’s claim. Baffling.

“Much effort will be put into the designing of vehicles with “Robot-brains”*vehicles that can be set for particular destinations and that will then proceed there without interference by the slow reflexes of a human driver.”

The Google driverless car project is doing just that. Using sophisticated laser radar technology, the car’s software creates a detailed 3D map of its environment. Many other companies have created road-worthy driverless cars. In 2010, a European Union backed initiative took four prototype electronic autonomous vans 8000 Miles, from Italy to China, proving that this technology is close to commercialisation.

image

(Google Driverless Car. Image Credit: Steve Jurvetson)

“Gadgetry will continue to relieve mankind of tedious jobs. Kitchen units will be devised that will prepare automeals, [ . . . ] Complete lunches and dinners, with the food semiprepared, will be stored in the freezer until ready for processing.”

Microwave ready meals and frozen pizza: who’d have thought the future would taste so bland? Although, he didn’t predict the obesity epidemics that this would contribute to.

“In 2014, there is every likelihood that the world population will be 6,500,000,000.”

Asimov underestimated the size of the population (only(?) by around 600 million), but he did foresee the potentially disastrous effects of this exponential rise.

“There are only two general ways of preventing [civilisation’s collapse due to overpopulation]: (1) raise the death rate; (2) lower the birth rate. Undoubtedly, the world of A>D. 2014 will have agreed on the latter method. Indeed, the increasing use of mechanical devices to replace failing hearts and kidneys, and repair stiffening arteries and breaking nerves will have cut the death rate still further and have lifted the life expectancy in some parts of the world to age 85.”

The end of last year brought about an easing of China’s one-child policy. A policy originally implemented to curb a population explosion. Asimov does correctly predict the great leaps forward that medicine has taken, furthering life expectancy in some places, such as Monaco, to almost 90 years old.

image

(Photobioreactor producing microalgae, can be used for food or biofuel production. Image Credit: IGV Biotech)

“Ordinary agriculture will keep up with great difficulty and there will be “farms” turning to the more efficient micro-organisms. Processed yeast and algae products will be available in a variety of flavors. The 2014 fair will feature an Algae Bar at which “mock-turkey” and “pseudosteak” will be served. It won’t be bad at all (if you can dig up those premium prices), but there will be considerable psychological resistance to such an innovation.”

A trip to any high street health store will confirm the use of algae as a food product, though it is not yet an international dietary staple. As for the “pseudosteak”, products such as fungi based Quorn and other meat replacements have been around for years. Last year, however, brought us the World’s first lab-grown burger; and Asimov was right about the price, with the patty coming in at ¬£215,000. Would you like supersize?

“The world of A.D. 2014 will have few routine jobs that cannot be done better by some machine than by any human being. Mankind will therefore have become largely a race of machine tenders. [ . . . ] Mankind will suffer badly from the disease of boredom, a disease spreading more widely each year and growing in intensity. This will have serious mental, emotional and sociological consequences, and I dare say that psychiatry will be far and away the most important medical specialty in 2014.”

Asimov foreshadows our seemingly inevitable path towards unskilled labour here, and also to mentally unstimulating work. He would probably be right about the psychiatry part as well, if it wasn’t for the overwhelming abundance of cat videos on the internet (which was one thing he did fail to predict). But on a more serious note, the field of psychiatry is en route for greater leaps forward, and larger public dependence, with more and more people being diagnosed with mental health issues each year.

Asimov leaves us with a salient warning about nuclear warfare, a warning that still applies today. Let’s hope that today’s predictions of the next 50 years are allowed to be realised just as Asimov’s were, without the threat of total annihilation.

“The New York World’s Fair of 1964 is dedicated to “Peace Through Understanding.” Its glimpses of the world of tomorrow rule out thermonuclear warfare. And why not? If a thermonuclear war takes place, the future will not be worth discussing. So let the missiles slumber eternally on their pads and let us observe what may come in the nonatomized world of the future.”