Monday, 28 March 2016

SitP 2016 Part 2 - Talks by Philip Moriarty and Sean May

Following on from Part 1, chuffed by be able to have a guest post by Gav, who attended a couple of the talks at SitP and written rather nice blog posts about them (to which NSB has added a little linkage and a few pictures).

Talk by Philip Moriarty
Science in the Park did something a little bit different this year and arranged two science talks. First up was Professor Philip Moriarty from the School of Physics and Astronomy at the University of Nottingham talking about "How do we see what we see?"

As a physicist, Professor Moriarty is often asked some questions that sound quite simple on the surface but are actually very complicated. For example, "why is glass transparent?" The science to explain this is actually PhD level physics.

But before we get on to glass, we have to attack the Death Star. In films we see laser beams but in real life we only see light when it interacts with something. For example if you have a light pointer, you usually only see the point on a surface. This is because there is nothing for the light to bounce off to come to our eyes. However, if you shine it through liquid nitrogen then you can see the beam.

Glass is made of silicone and oxygen atoms. If you arrange these atoms in one way, you get sand. If you arrange them in another then you get glass. As we know, these atoms contain electrons and when you give electrons energy they absorb it. Since light is a form of energy, when a photon hits an electron, its energy can be absorbed.

This is why glass is transparent - it's all to do with how the photons of light interact with the electrons in the molecules of glass. Visible light doesn't contain enough energy to interact with the electrons and so passes straight through glass, hence we can see through it. On the other hand most ultra-violet light is actually absorbed by the glass.

Similarly, if we look at why gold is gold, it's a similar story, it's all down to how the light interacts with the electrons. However, in the case of gold, if you make the pieces of gold really, really small then it actually appears to be red. As you change the size, you change the colour.

Differing sizes of gold nanoparticles have different colours

So, how do those glasses that go dark when you go outside work? There are photochromic - when UV light hits them they change colour. The shape of the molecule determines how they absorb light. When the UV light hits, the energy in the light is absorbed by the electrons and the shape of the molecule changes so they go dark.

There are also thermochromic particles that change colour with heat. The energy that these absorb is from hear rather than light.

Finally Professor Moriarty talks about invisibility cloaks. Light travels in straight lines but we can refract it. So if we can "bend" it in just the right way we could make something appear invisible to a viewer. Scientists have already used lenses to create a very simple version but it only hides things when you look at them from a certain angle. Looks like a true invisibility cloak might be some way off yet.

Talk by Sean May
The second talk at Science in the Park is from Professor Sean May from the School of Biosciences at the University of Nottingham. His talk is on four different monsters - zombies, dinosaurs, dragons and triffids and how we might go about making these creatures.

First up it's zombies. Now, in the US, they have guns so it's easier to deal with a zombie outbreak. Here in the UK, we have pointy sticks and bad language. So, how can we stop zombies? Can we crush their skulls with our feet as seen in Pride & Prejudice & Zombies?

Well, force - mass x acceleration. Acceleration due to gravity is 9.8 m/s2, so 1kg produces around 9.8 Newtons of force. Professor Sean May produces around 890N. Unfortunately, you need around 2,300N to crush a skull. Hence, if you want to do what you've seen in that film then you need to weigh as much as a polar bear.

With our only option being hitting zombies with pool cues a la Shaun of the Dead, maybe we should look at how we protect ourselves instead. How about a fencing outfit? The under layer can withstand forces of 800N and the jacket 350N.

Could a zombie bite through this though? To get though 800N you need a bite with 180lbf (a force of 180 pounds) and to get through the jacket you need 78lbf. The average human bite is 150lbf and this is based on the back teeth. While a lion, polar bear or a gorilla could bite through your fencing outfit, a zombie couldn't. However, there's no guarantee that a zombie would have perfect teeth. You can push a needle through the fencing gear so what if the zombie teeth are broken and have a sharp point?

Fortunately, there is some official documentation to help us deal with an outbreak. The Centre for Disease Control wrote Preparedness 101: Zombie Pandemic. Even the US military are interested - CONPLAN 8888 is their zombie survival plan. There are also scientific papers written about zombies. One, written by Robert Smith? et al (yes, he does actually have a question mark in his name - I guess he should be in The Who rather than The Cure) paints a very pessimistic outlook.

Any caption here is, frankly, superfluous

Maybe we shouldn't be looking at creating zombies then. What about dinosaurs? Well, we already have dinosaurs alive today - birds. But what about if we wanted to re-create some like in the Jurassic Park films? (ignoring the recent Jurassic World since the Indomitus Rex wasn't actually a dinosaur)

But what is genetic engineering? Well, it's different to selective breeding, which is things like domesticating dogs, changing corn from a small grain that only grew in Central America in 2000BC to the huge grain that grows everywhere that we have now and the cross-breeding of strawberries in the 1700s.

Before 2000, most genetic engineering consisted of deliberate mutation. Radiation was used on rapeseed in 1953 and flax in 1965. Most white beans are x-ray induced mutants as is 70% of pasta wheat. Most barley used in beer production and most rice is also engineered.

Another option for genetic modification is transgenics - adding DNA from one species to another. We've been doing this since the 1980s but it can also happen in nature, for example grafts or plant parasites such as mistletoe. 80% of ferns in the world today are naturally transgenic from genes that they acquired 100 million years ago.

Meanwhile genome editing just got even easier (with technology called TALENS and CRISPR) and recently was used in a case of a child with leukaemia. With this new technology genome editing is invisible. If advancements continue and it becomes trivial could we resurrect the dinosaurs?

But if we were to do that how important would authenticity be? Would people really want to see realistic dinosaurs with feathers? Would people get blasé about seeing regular dinosaurs just like in Jurassic World? Since there are a number of creatures in existence already such as the Hoatzin that are already very similar to dinosaurs, why would we even bother?

Maybe if we do decide to bring dinosaurs back from the dead then we should take some cues from Jack Horner's chickenosaurus project. Jack is trying to see if you can make a chicken with a snout rather than a beak. When they've tried this the snout automatically starts growing teeth and all they did to create the snout was to make the mouth wider. This reverses millions of years of evolution as all birds lost their teeth in the Mesozoic era.

Ichthyornis victor  - A Mesozoic bird who still has some teeth!

So, what about dragons? Well, they're very similar to birds with tails and snouts. Wyverns look a lot like avian dinosaurs if they lost the feathers. In the far east, dragons keep the feathers but lose the wings for an extra pair of legs. In older societies such as Egypt and Aborigine we see a lot of feathered serpents.

While all of these dragons aren't that different to real animals, we would have more problems creating a Welsh dragon. This is because they have four legs AND wings. Due to the way that everything evolved from fish, it's very difficult to create something like this although there are a few real creatures that have four legs and wings where the wings grow out of the ribs.

Looking at Game of Thrones a big issue with creating dragons would be their size and how hard they are to domesticate. In the past three years in China they have managed to create miniature pigs so we could perhaps apply the same technology to dragons. The keys to domesticating cats is their fear threshold and their reward threshold ie does it run away from you and will it come back for food? Would dragons be similar?

Finally onto Sean's favourite monster - Triffids. Invented in 1951 by John Wyndam, they were the world's first genetically modified fictional creature - they produce oil, have a venomous sting, eat people, photosynthesise, walk and can communicate. The book even came out before people started eating rapeseed which wasn't even edible until scientists started modifying it.

Botanical illustration of a Triffid

There are already large carnivorous plants, the most famous of which is the venus fly trap which closes its trap very quickly using electrical impulses. Clearly plants can move then but could they ever walk? But according to the text, Triffids have three legs (hence the prefix "tri") and it's very hard to make a creature with three legs. In fact the nearest that we can see to a creature that can efficiently move on three legs is a kangaroo when it uses its tail as a third leg (in fact kangaroos have been seen moving on anything between one and five "legs") But if you have a plant that walks on three legs, how would it get back up if it fell over?

So, clearly it's not going to be easy to create any of our four monsters. In fact, rather than asking how we could create them, maybe we should be asking whether we should create them.

Image sources

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