Merry Naked Christmas!

Look what Santa has brought - a bulging sack of your science questions! If you've ever wondered about the aerodynamics of reindeer, how fast Santa would have to travel to...
22 December 2008


We look back on the greatest science news of the year, discuss our top science facts and take on your festive questions in this festive edition of the Naked Scientists. We find out how scientists can recreate a picture as you're looking at it, just by reading your thoughts, why shape-memory metal could make bridges earthquake-proof and how a simple process could make the cheapest, nastiest wine palatable. Plus, we look into the science of champagne to find out if the bubbles really do go straight to your head and in Kitchen Science, we build a vortex cannon from a plastic bottle, then use it to snuff out candles from across the room!

In this episode

Mind Reading a Reality?

Scientists in Kyoto have reproduced an image based on how the brain responds - effectively reading the brain.

Yoichi Miyawaki and colleagues at the ATR Computational Neuroscience Laboratories have published a report in the journal Neuron, where they used functional Magnetic Resonance Imaging (fMRI) to observe the changes in brain activity when a subject is looking at an image.  Using complicated computer modelling, they were able to train the system to recognise what happens in the brain in response to certain images, and the system was then able to accurately reproduce images that the subject had not seen before.

The images were simple, high contrast pictures, a 10 by 10 grid with each 'pixel' containing a shade from white to black, on which they could produce random patterns called a contrast map, geometric shapes or letters.  In the training stage, they showed the subject 440 random images for 6 seconds each while observing the fMRI, which recorded brain activity by looking at blood flow in the visual cortex, which is located at the back of your brain.

Their computer model went to work by analysing small, overlapping portions of the fMRI in 3 dimensions, and then putting together the data from each portion to reconstruct how the brain responded to each image.  Using multiple portions allowed them to build up an idea of the brain's response, with the overlaps reducing the error, as each section was sampled more than once.  Once it was trained on the random contrast maps, they moved on to showing the subject more defined images, such as letters and geometric shapes.

From the fMRI data, the computer model was able to reconstruct the images as seen by the subject, such as spelling out the word Neuron.  It's only able to work in black and white at them moment, and relies on the images having quite high contrast, but the team think that improving measurement accuracy should enable it to work in colour, and one day may be able to produce images from dreams, or even a direct readout of someone's feelings.

This is a good start, but they have a long way to go before you can upload your dreams at night to watch later on!

How to give your cheap plonk a boost

The festive season is upon us, many of us will no doubt be raising a glass or two of wine in celebration. And this week there is news of a novel way that scientists have found to give a boost to a bottle of cheap plonk. A revolting young table wine can be transformed into a refined tipple simply by zapping it with electricity.

red wineYou might expect it would be the French, the Chileans or perhaps the Californians who have come up with this new bit of wine trickery, but in fact this study was the brain child of Xin An Zeng and colleagues from South China University of Technology in Guangzhou in China, a relative new-comer to the world of fine wine making.

Zeng and his team have been experimenting with Chinese cabernet sauvignon wine, passing it through a pipe with two titanium electrodes hooked up to a electric field and found that the optimum time to do this was for just three minutes - no more, no less.

They can't yet explain just how applying an electric field alters the wine's chemistry but it seems that just this short exposure is enough to make a new wine quaffable. A three month old wine would normally be undrinkable, but after Zeng and his team ran it through an electric field, it passed a taste test with a panel of wine experts.

Normal wine can't be drunk for at least six months, and of course the finest wines keep getting better and better for decades.

Somehow, zapping the wine changes its chemical make up in a similar way that happens slowly over time as wine ages. These changes include the reaction of ethanol with bitter-tasting organic acids in the wine, creating fruity flavoured compounds called esters. Proteins also breakdown to form amino acids, which also contribute to the taste of a good wine and the researchers also measured a reduction in the concentration of nasty-tasting aldehydes.

Just whether or not wine connoisseurs will embrace this new technique remains to be seen, but wine producers in China are already rolling out large scale trials of this new electro-wine treatment. And if you are feeling a bit impatient for a tasty glass of wine this Christmas, please, don't try this out at home.

Damage to the Yamabe bridge in the 2004 earthquake at Chuetsu, Japan

Earthquake proof bridges

The destruction produced by earthquakes can be devastating in its self, but often the knock on effects of this destruction can be even worse. For example if an earthquake damages a bridge beyond repair there are not just problems for the poeple on and around the bridge. It also means that the emergency services can't get across the bridge to help put out fires, and generally support people on the other side. In the longer term the lack of bridge could slow down the rebuilding  after the disaster.

EarthquakeEngineers at the university of Nevada are trying to reduce this problem by using modern materials. The cause of much of the problem is the steel that is used to reinforce the concrete in the bridges. During a large earthquake this is designed to bend so that it absorbs some of the energy in the vibrations. This is quite effective at stopping the whole structure collapsing catastrophically during the actual earthquake but  afterwards it can mean that the bridge needs really searious repair if not being knocked down to start again.

To reduce this problem the engineers have replaces important pieces of steel reinforcing with Nitinol, an alloy of nickel and titanium which acts as a shape memory metal. This means that it will spring back to its original sape after being bent.

This means that after an earthquake the reinforcement will be the same shape it started as, and although the concrete will still be cracked it should still be able to support loads with minimal if any repair. In the longer term you would have to make some repairs but the clear up of the city could start a lot earlier.

Jools Holland at the Tsunami Relief concert in the Millennium Stadium, Cardiff.

Let your mind wander

Scientists have used brain scans to uncover what happens in the minds of jazz and other improv players when their creative juices start flowing.

Jools Holland at the Tsunami Relief concertWriting in the journal PLoS One, US research duo Allen Braun and Charles Limb recruited 6 trained jazz pianists and asked them to play scales, some pre-learned blues music and also improvise in their own styles whilst inside an MRI scanner.  The musicians used a keyboard adapted specially for the scanner and what they played was relayed back to them via headphones.  The aim of the study was to understand the neurological basis of the almost trance-like state adopted by jazz musicians when they improvise.

"They often play with their eyes closed in a distinctive personal style that transcends traditional rules of melody and rhythm," says Lamb. "It's a remarkable frame of mind during which, all of a sudden, the musician is generating music that has never been heard, thought, practiced or played before. What comes out is completely spontaneous."

To pinpoint the brain regions responsible, the researchers subtracted the scan results obtained when the musicians played scales or learned pieces of music, since they're common to any musical activity, from the pattern of neural activity when they improvised.

The results showed that improvisation was associated with a significant drop in activity in the brain's dorsolateral pre-frontal cortex, an area linked to self-censoring, inhibition and planned actions, such as deciding how to respond at a job interview.  At the same time the medial pre-frontal cortex, which controls self-expression and individuality, increased in activity.

So it seems the musicians are disinhibiting themselves and at the same time boosting their creative brain centres.  "What we think is happening is when you're telling your own musical story you're shutting down impulses that might impede the flow of novel ideas," says Limb.  He and Braun are now planning to find out whether members of other creative professions, like writers or painters also show the same patterns of brain activity when they go to work.

Let's just hope the work of any poets scans correctly...

A SpaceX Dragon capsule structural test article on display at the 2007 X-Prize Cup at Holloman Air Force Base, New Mexico


A story from earlier in the year which hopefully will be the start of big things to come was the news that a small california based company called Space X has managed to build a rocket to put a satellite into orbit. This may not sound particularly impressive as governments have been doing this for 50 years, but what is new is that this has been done by a private company without state support.

SpaceX Dragon CapsuleSpaceX was started by Elon Musk who is a South African entrepreneur who made hundreds of millions from publishing software and then PayPal. When PayPal was sold to ebay he and wanted to do something interesting with his money, first he thought that he wanted to start a mars program, but found that space launch costs were far to high to make it practical even with his immense wealth.

So he decided to try to bring launch costs down to something more reasonable by starting his own space rocket business. This has been tried before and previous attempts have failed, and so did his first 3 launches, but in september at thefourth attempt hs Falcon 1 rocket made it into ortbit. This is capable of launching half a tonne into orbit, but in the new year he is intending on launching his first Falcon 9 rocket which should be capable of putting up to 12.5 tonnes into orbit which is comparable with some of the larger rockets available today.

He is on record as saying that the thing about rocket science is that it is very difficult, so he may not be sucessful with this new rocket first time, but I have to hope that he gets there as if getting into space is cheaper all sorts of exciting scientific possibilities open up, allowing us to go to new places and to look at the universe in new ways.

Seahorse - Hippocampus sp.

Deep sea treasure in the Thames

How could I resist talking about a story that hit the headlines this week - the discovery that there are seahorses living in the busy waters of the Thames Estuary in London.

Seahorse - Hippocampus sp.Over the past 18 months, researchers from the Zoological Society of London have encountered a population of short snouted seahorses (Hippocampus hippomcampus) - tiny creatures that could lie on the palm of your hand.

They have been seen as far east as Dagenham where the tides are still strong to bring salty water in, since seahorses don't live in freshwater.

Seahorses have occasionally been spotted in the Thames in the past but only one or two, and never such a healthy population.

The really good news is that these seahorses, along with another British species, the long snouted seahorse (Hippocampus guttulatus) are now protected under the 1981 Wildlife and Countryside act, which means it is illegal to take them from the wild and to damage their wild habitats.

Like the arrival of the whale in the Thames a few years ago, Londoners are proud of their newest aquatic neighbours, and it's a good sign that despite its notoriously mucky and polluted history, the waters of the Thames are much cleaner than they used to be and it is now one of the cleanest big rivers in Europe, home also to porpoises, seals and otters.

Although it could also be that waters are warmer than they use to be with global warming, making them more hospitable to these species that are more normally found further south in the Mediterranean.

Can you see space satellites with a telescope?

Dave - You certainly can see satellites with a telescope.

Definitely for live satellites you can get quite good pictures of them. You can also see the International Space Station (ISS) and all the different bits of it with a large telescope.

With your naked eye you can see what look like stars which move across the sky very quickly and don't have a red flashing light - those are normally planes! Anything moving across the sky very quickly is normally a satellite.

Chris - I saw the guys on the BBC website where they've got this tracking software which they've written themselves and some amateur telescope gear. They have got some amazing pictures of the International Space Station. It really looks like a computer game, how good the pictures are.

Dave - And also you can sometimes see satellites which aren't supposed to be there. One of my housemates has got a friend who was taking photos of the sun - he's an astronomer. Occasionally you see satellites going past the sun and you can see them in some frames of this video. There are lists of all the satellites which are supposed to be there and it was one which wasn't supposed to be there. There's definitely more satellites up there than anyone will admit to!

Chris - Also they fool people because some of them come down into lower orbits and then go back up again. You get these interesting iridium flares where the Iridium network of satellites which are telecommunication satellites come down low in order to communicate and then they go back up higher. They park them into higher orbits when they're less in demand. It means they're using less fuel in the long run because they're not having to keep accelerating their orbit.

Why does my dog always poo on the path and not the grass?

Helen - I want to know why you asked me that question, actually. I'm not really au fait, don't have a dog myself and am not necessarily any the wiser for why this might be. It could be all sorts of reasons. We were discussing this before the show. Maybe it was something to do with marking his territory. Perhaps poo as well as wee and lots of other urine and other fluids like that are good for letting dogs know where they are and if that's their territory or not. Perhaps a path where other dog have walked along and left their smells would be a good place to leave their mark. I was wondering if it thought it as a cat. Cats will be more likely to defecate on a path rather than grass. Cats like to try to cover up their mess. Perhaps on a sandy path rather than the grass. Maybe the grass is spiky and it doesn't like the feeling of it.

Chris - A couple of people on our forum have speculated - Dr Beaver says using Occam's razor the pavement doesn't tickle its bottom when it squats, perhaps in the same way as the grass. A person who calls themselves Dent Student says I guess it's because dogs don't have the same social cues and don't consider it to be antisocial to poo on the path. Someone points out saying, 'are you saying that you do poo on the grass?' Helen - I'd say it's pretty antisocial to poo on the grass anyway. I hate treading in dog poo. I hope when the dog poos on the path you do clear it up afterwards!

Old-fashioned diving helmet

Can you breathe liquid?

Chris - Yeah, this is called liquid breathing. It's been experimented on for a little while because also there's some occasions when forcing gas into lungs is bad. If you've got an adult, for example, with respiratory distress syndrome. This can also affect young babies that are premature.

The problem occurs when the lungs have a deficiency of a chemical called surfactant. Because the lungs contain lots of tiny airspaces called alveoli, the linings of those airspaces are kept saturated with water. Water makes something called a hydrogen bond. It's a sticky molecule, and one molecule tries to stick onto another. This would collapse the alveoli down and make them disappear if you didn't have something there to break this water bonding and make it less sticky. This is what these surfactant molecules do. They help it to remain bigger.

When people have some kind of lung condition - premature babies don't have this stuff, adults can have conditions where they lack this stuff - you don't have any surfactant. As a result the airspace is trying to collapse. As a result it becomes very hard to inflate the lungs and so you have to use very high pressures of gas being blown into you in order to keep the lungs inflated. This can do damage, so scientists have been exploring the possibility of using fluids instead of gas under certain circumstances and also in deep-sea-divers.

Some of the fluids they've been exploring are fluids that don't mix with water so they're organic chemicals, and perfluorocarbons are the class of chemicals involved.

They've done experiments with chemicals with six carbon atoms in a line: That's perfluorohexane. They've also done experiments with eight atoms linked together: that's perfluorooctanes. They haven't done experiments on humans. They've been done on sheep, which is a good model for us because they're also big mammals and have lungs similar to ours. They make a good model and what is special about these chemicals is you can persuade lots of oxygen and gas of any kind to dissolve in this liquid. You then pump the liquid into the lung and it then passes the oxygen into the blood, picks up the carbon dioxide and you pump the liquid back out again.

The problem with this is that lungs are made to move gas, not liquid. It's very difficult to move large amounts of liquid like this. Really, the only time it's practical is when you have someone mechanically ventilating you, in other words moving the liquid in and out for you.

One place where it might therefore have a role is in things like intensive care. It might be possible to use it those setting and people with damaged lungs to get lots of extra oxygen and carbon dioxide out.

Another situation where it might be useful is in the context of deep-sea-diving. When you go deep-sea-diving, something you're well acquainted with, Helen, there's a risk of the bends. As you go down underwater the pressure of gas you're having to breathe in is increased from your tank by your regulator to overcome the fact that you're under pressure under water. You're now breathing gas which is at much higher pressure and density than gas at the surface. This forces a lot more nitrogen into the blood. Nitrogen does not dissolve well at all. It's very insoluble in water unlike oxygen. As a result when you take the pressure off the person again the extra nitrogen that has dissolved in their tissues can come out as little bubbles. It forms bubbles in blood vessels and blocks them up. That's why you get decompression sickness, the bends. 

If you used a liquid in the lungs instead of gas, the liquid would not succumb to the increased compression of being down deep. Therefore it would not force extra gas into solution in the same way that air mixtures would. Therefore it might, in theory, be safer if we can overcome the other problems that are associated with it.

Helen - Have you seen the film The Abyss? It's one of my favourites with a diver and I think they use liquid breathing. They put a mouse in a plastic bag and it's fine but that would be fun if it could happen one day...

Rose Champagne Bubbles

26:16 - Bubbles go Straight to your Head

Does champagne go straight to your head? What is it about the bubbles that makes you get more drunk, more quickly? Meera goes in search of the science of champagne...

Bubbles go Straight to your Head
with Fran Ridout

Meera - Fancy cracking open some champagne to welcome in the New Year? It may be worth you noting that the bubbles that make this drink go pop when you open it will get you drunk a lot faster than its wine relatives. I'm with Fran Ridout, clinical research manager for the charity Saving Faces at St Bartholomew's hospital in London. Fran used to be based at the University of Surrey where she looked into the effects that champagne has on our brains. How did you go about looking into the effect of champagne?

Rose Champagne BubblesFran - We used a psychometric test battery which measured people's reaction time, ability to attend to a stimulus while doing something else, their vigilance, their ability to do something for a sustained time and their short-term memory.

Meera - Who did you test it on and how did you go about getting your samples?

Fran - We actually did the tests on volunteers' work colleagues. We had 12 people and they had two different drinks. One of the drinks was ordinary champagne and the other drink was champagne where we'd whisked all the bubbles away from with an electric blender. We had people drink both drinks on different occasions a week apart. One week they'd have champagne with bubbles, the next week they would have the champagne without bubbles which they thought was ordinary wine. They didn't know the purpose of the experiments. Everybody did a baseline test before they'd been drinking. They then drank a measured dose of the champagne or de-gassed champagne according to their body weight. Then they did the tests again 20 minutes after and 60 minutes after drinking.

Meera - What did you find?

Fran - We found that the champagne with bubbles was much more impairing than the champagne without. We found a difference on all the tests between when they did it before they'd drunk anything and afterwards, apart from short-term memory. With the sill champagne the only test that was impaired was a simple test of reaction time.

Meera - You also looked into the actual blood levels of alcohol in the people.

Fran - Yes, we took blood samples after twenty minutes at five minute intervals. We found that the blood alcohol levels of the people drinking the gas champagne were higher for the first twenty minutes suggesting that it had got into the blood stream a lot quicker.

Grape-Shot: 1915 English magazine illustration of a lady riding a champagne cork - From The Lordprice CollectionMeera - You've actually got some of these psychometric tests set up today. I had a go on two of them earlier this afternoon just to give an idea and get the score for what's my ability without alcohol. I'm just going to finish off this champagne and then we're going to have a go on the tests and see if it's impaired my ability at all.

Fran - An excellent idea!

Meera - Well we actually have two of those psychometric tests. What am I supposed to be doing here again?

Fran - The idea is to keep the centre of the cross on top of the ball as the ball moves randomly from side to side across a screen. The other part of the test is that you have to watch out for yellow balls which will appear in corners every now and then. As soon as you see those you have to click the button on your mouse.

Meera - Ok so I'm having a go on this test again now and trying to follow this grey ball that's moving around with my green cross. That one's finished. You've got both of my scores up here. Is there a difference between before and after I drank this champagne?

Fran - There are differences between your tracking. You've actually got better but that is a practise effect. When we did our study we made volunteers do it half a dozen times before they started to get rid of that as far as possible. One component of the test is your ability to react to peripheral stimuli: the yellow balls. Your time there is actually longer.

Meera - We've also got this second test set up which is going to test my movement. I'm just going to start this now but can you just remind me again what the rules are?

Fran - This tests reaction times in two parts. There is a semicircle of lights which come on and you have to move your finger as quickly as possible from across a resting point to turn those lights off. It has two components. One is how quickly you lift your finger up to say I've seen the light and the other is how quickly you can get your finger over to put the light out.

Meera - That's finished now and all the lights have come on so I think I'm going to stop. How did I do here, Fran?

Fran - Well you didn't do particularly well. Your reaction time for the lights was nearly 100ms slower. Your score at baseline was 362 and after you'd had your drink it was 452ms. 100ms may not sound much but if you're driving a car it's extra time it takes before you put your feet on the brake. You could have gone quite a few metres down the road in addition to your normal brake time.

Meera - I guess the key question now really is why this happens. Why does the presence of bubbles in alcohol make it affect our brains quicker?

Fran - In order to affect the brain it's necessary for the alcohol to get into the blood stream. The way this happens is you drink the alcohol which goes into your stomach. Not much of it's actually absorbed in the stomach. About 80% of it is absorbed when it carried on into the intestine. The most likely explanation for the champagne having a more intoxicating effect is that it alters gastric emptying - the way that the alcohol or drink goes from the stomach to the intestine in some way. One possible mechanism is that it alters the way that the pyloric valve opens or makes it open more frequently. That's the part that allows the contents of the stomach to carry on its way to the intestine. Alternatively it could be that the alcohol is absorbed as you're drinking it through the nose, through the mouth. That's much less likely. It's almost certainly something that happens once the alcohol gets into your stomach.

What are your top 5 Science facts?

Lee E: E=MC^2

Helen - My first one is that in the dot of a 12pt letter 'i' there are more protons than there are seconds in half a million years. That was quite mind-boggling. If we made a scale-model of the universe and we made planet Earth the size of a pea the nearest star, Proximus Centauri would be 16,000km away.

I love the fact that when caterpillars munch on plants the plants have evolved to emit a smell that attracts other bugs that come and eat the caterpillars.

If you were to take Mt Everest and plonk it in the deepest part of the ocean you'd have to dive down 2km to reach the top of Mt Everest.

There's all sorts of statistics associated with blue whales. I think the nicest one is that their hearts weigh half a tonne and that's the same weight as a mini car.

Kevin, A12: A Pico second is to a second what a second is to 30,000 years. The moon is 400 times smaller than the sun but the sun is 400 times further away. So we get a perfect eclipse. What a fantastic fact.

Chris - The human heart will beat 40,000,000 times every year of your life. If you work out the weight of blood that it pumps around your body it's lifting about 7 tonnes of blood a day and if you tot that up over a lifetime that's about 2 very large aircraft carriers that your heart has lifted in terms of the weight of blood it's pumped in a lifetime; which is pretty fantastic when you think of the work that nature's polymers are doing. Evolution has given us a heart that can do something that can work for so long and so faultlessly in the vast majority of people.

The age of the universe. The universe we live in is about 13.7 billion years old. We can date that and know that was the moment when our universe popped into existence, begging the question what went before? What's this universe is expanding into?

Scientists reckon conservatively there are about 10^22 stars in the known universe. That means there are 10^22 stars possibly a bit like our sun, many of them a bit different, of course. That means the prospect of finding another system like the system we're in with our Earth, at the right distance from the sun, with liquid water and the right recipe for life doesn't seem so unlikely when you think there are 1 followed by 22 0s after it opportunities for that to happen.

I share and everyone in this room shares 60% of your genes with a banana. Not because we're particularly vegetable-prone but because of the ubiquity of the genetic code - it doesn't matter whether you're an E. coli bacterium or human, you have the same genetic code running in you. In other words you can take a gene out of a jellyfish, put it into E. coli and the E. coli bacterium will glow green like the jellyfish did because the genes that work in us work in bacteria. What this shows is that we all came from a common ancestor somewhere, probably about 3.9 billion years ago.

Can you guess what the fastest living creature on Earth is? Guinness book of records for the world's fastest creature is a bacterium. Its name is Bdellovibrio. It moves at 60 body lengths a second. It does it with a little propeller called a flagellum - tiny proteins that whip along and force the bacterium along. They're actually predatory and eat other bacteria.

Dave - Light travels at 299,792km every second. Stuff which is hitting your eye is going ridiculously fast. Light from the Andromeda galaxy has been travelling for 2.5 million years. Some of the static the TV picks up - some of it is cosmic microwave radiation which has been travelling since 400,000 years after the big bang. For 13.7 billion years it hasn't hit anything and then it hits your radio!

A typical hurricane uses the same energy as 8 billion tonnes of TNT.

A modern processor has got 580 million transistors. 35 years ago the first processor has just 2500!

47:25 - Eating All Your Sweets at Once?

Is it better to eat all of your Christmas sweets and chocolates in one enormous binge, or make them last all winter?

Eating All Your Sweets at Once?

We put this to Linda Morgan, Professor of Nutritional Endocrinology at Surrey University

Better to eat all your chocolates all in one go or a few at a time? The short answer is that it doesn't make any difference. The extra calories will be the same in each situation. The only effective way to prevent weight gain is to not eat the extra chocolate in the first place, I'm afraid. Evolutionarily we evolved with feast and famine and we needed to build up the body fat that we should have got in feast times to see us through the famine. However, if you do eat all your chocs in one go and you felt queasy afterwards then you would probably be less likely to build up a chocolate habit that lasts well into the New Year. On the other hand if you eat a few chocs each day you may well end up with a habit that is quite hard to break in the New Year. If you have to eat chocolates have them all in one go and make yourself sick!

Does light ever decay?

Dave - These two are actually slightly related. Light will carry on going for an awful long time. As far as the photons which were created at the end of the Big Bang that's when there was a big soup of protons and electrons. As soon as the electrons got trapped by the nuclei of the atoms the universe went transparent. The photons have been travelling since then which is about 13.7 billion years ago. They reach us as part of the cosmic background radiation. They've carried on going. What they have done because the universe is expanding - one way to think about it - they've been stretched so their wavelength has got longer. They've moved further red. It's called red shift which is the reason why the sky is black. If there was none of this effect then you'd see the effect of the Big Bang as incredibly bright gamma rays all around us. The sky would be bright white, bright x-ray really. Because the universe has expanded so much these photons have been stretched so they're actually in the microwave region. The photons can go on forever but they can change their wavelength. Is there a limit to how bright light can be? The only one I've found possibly is you can get incredibly bright lights photons will start to scatter each other. People have suggested than in order to be able to see this effect you'd need an exowatt laser. That's a billion watts of energy - a billion nuclear power stations being funnelled into the size of something a cubic millimetre. Then you'd need photons, instead of just going past each other, bouncing off each other at which point you won't be able to get much brighter than that. There would be a limit somewhere with that.

How far back can we observe in the universe?

Dave - The limit is this point at which the universe became transparent which is about 400,000 years after the Big Bang. Because before that the universe had free electrons in it. Electrons interact with light very strongly so the light would hit an electron very soon and essentially stops. That's the limit.

Is there an antimatter equivalent to light?

Dave - In some sense it does. There is an antimatter equivalent to a photon. It's not an antiphoton. If you have two photons you know are in exactly the opposite phase they can cancel each other out. As far as we know the photon is its own antiparticle.

What do earwigs eat?

Helen - Earwigs fortunately don't eat our brains. That's a bit of a wives' tale. They eat all sorts of stuff. They can eat plants, they can dig out dead things. They're omnivores essentially so plants, flowers and other insects but I think we can rest assured they don't eat you.

Why are flies so difficult to swat?

Helen - Flies are difficult to swat for lots of reasons. Their eyes work much more quickly than our and they also have a clever way of lining themselves up before they get hit because they can hear where the noise of you coming at them is coming from. So they get ready to jump before they actually do jump. So they go in the right direction.


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