Episode 5 Bang Goes the Theory


Episode 5

Science series. Liz investigates a common and unwelcome guest - the bedbug. Meanwhile, Yan explains why statistics are not to be trusted, and Dallas goes stargazing in California.


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Transcript


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On tonight's prorpblg. Dallas meets the team who are looking further

:00:03.:00:08.

into space than ever before. Believe it or not, galaxies

:00:08.:00:12.

themselves can act as lens, this may sound a little bit weird. I'm

:00:12.:00:17.

talking about a very real phenomenon, called gravitational

:00:17.:00:27.

lens. Liz comes into contact with a

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bedbug. I give you the bedbug, one of the

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greatest evolutionary bloodsucking bug.

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Stkpwr first up, the bed being, the papers are full of how we are

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facing a global epidemic of bedbug infestation. I thought it would be

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good to find out why these little citers are so good at invading our

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citers are so good at invading our space.

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We share our homes with millions of creepy crawlies, and if we don't

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think about it, they don't cause us any trouble. This little fella is a

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bit different. Ladies and gentlemen I give you the humble bedbug.

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One of nature's most perfectly evolved human bloodsucking machines.

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If a few of these get into our home, you will know all about it. I'm not

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taking any chances with this one, but I want to find out all about

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them. And there's no-one better to ask than Dr James Logan, he spends

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his days trying to work out how to combat the growing bedbug problem.

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His lab is host to thousands of little critters. And James knows

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all too well what it's like when the bedbugs bite. So, what does a

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bite feel like? I'm going to show you what a bite feels like, I will

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get a bedbug out and let it feed on my arm, when it starts to feed, I

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will lift off the pot. There it goes, it can't believe its luck.

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is having a wander around. How do you know, can you feel it? I can't

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feel a thing. It has gone really still. I felt a very, very slight

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nip there. Did it just go in for the kill? It is gone in. Will I see

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his little body fill up with your. Oh my goodness, it is going, it is

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sucking, moving as it is feeling. Bed begs have piercing mouth parts,

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it is like a needle, they inject it in to find a blood Kapilry, they

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start feeding from the blood. you have them you know you have

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them. Your arm will come up with a big red itchy lump. What your

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immune system is doing is react to go the chemicals injected into our

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body in their sallifva, it is a cocktail of chemical that is act as

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an anti-coagulate and anaesthetic. As it is biting the anti-coagulate

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gives you a nice stream of blood. How long will it feed for?

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should take a couple of minutes, you can see the body swelling up.

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God for bid, this one escape, do we have a situation here? We will have

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a situation. This one has probably mated, she has just had blood,

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which means she will produce viable eggs. She will lay her egg, they

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will hatch out and they will start reintroducing. They will leg three

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eggs in a day, and 300 eggs in their lifetime. How easy is it for

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this bedbug if she escapes to make it to my home? These beds are

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tremendous hitch hiker, they could get on your clothes and get into

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our home. This is why I hear because there are more

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international travellers there are more bedbugs in this country. They

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are getting into people's suitcases? That is how they are

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transported around the country and the world. The other reason is

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there has been a bit of an increase in secondhand furniture sale, they

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lay their eggs on the furniture, and the bedbugs themselves can even

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be transported. She's finished. She's moving. She just pooed,

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that's so rude. No only does she feed off you, she leaves a little

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calling card. Can you see she's struggling to walkings because

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she's so fat. I know - She's struggling to walk because she's so

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fat. They defacate on my arm as you say, that is the smell they use to

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get back home. Bedbugs do love a good square meal. In fact they can

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drink three times their own volume in one bite. A bit like me drinking

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180 litres of milk in one go. And it means these amazing creatures

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can live for up to a year inbetween meals.

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Even when they are full they can slip into the tiniest nooks and

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cranies in our homes. It is only at night they emerge to sniff out

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their prey, then they sniff their way back home. James's plan is to

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develop traps to catch bedbugs before they bite you. But to do

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that he needs to understand their amazing sense of smell. Which

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requires a very complex chemistry kit.

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What exactly is this massive box, what's going on in these tubes?

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OK, so this is a gaschromatigraph, we are separating out gases. What

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we have is a sample of human Oder, it is my Oder that I have collected.

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You are going to fire that sweat, your sweat, at the antenna? That's

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right. I'm going to use the syringe. I can't believe you have collected

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your own BO in a glass vial, that is little bit dark! We will put it

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in the hole and inject it in, this machine is a big oven. It heats up,

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as it heats up, low molecular weight compound also travel much

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quicker around a column to a flame, that then tells what you the

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chemicals might be. Inside here is a spliter, half of the chemical

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gets split to the flame to tell us what the chemical S the other half

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of the chemical gets blown out, this transfer line here, into

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another air stream, that then gets blown over the an then that of the

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insect. How is the antenna still reacting

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to smells? Even though the bedbug is dead, the receptor cells on the

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antenna stay alive, for about 30 minutes. Like moths their antenna

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will stay alive for hours, we can actually use it, even though it is

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dead, because the receptor also fire and respond to chemicals. They

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are picked up by protein that is carry the chemical across a space

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to the receptor cell, that illicits an electrical response in the

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nervous system, and that make behavesor, the insects are

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attracted and come towards us. That is how they find us. We haven't

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done a lot about bedbugs and human oweders so we don't know a lot

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about it in this way. They have it made, I actually went to an all-

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you-can-eat buffet in Vegas once and I couldn't eat for a year.

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In case you were thinking I was not being a wuss by being not bitten,

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can I show you his arm the day after, and the day after, he said

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it was so sore and nasty. I rest my case.

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What happens now if you're at home and you have bites like that, what

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should you do? Even though bedbugs are on the rise,

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the chances are you are not going to get them. If you get bites and

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you suspect bedbugs, there are tell tale sign, as you saw, they do a

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little poo after they feed. So in your bed you find some bround

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blotchy grainy bits of bedbug deafcation in your bed. There is a

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sweet, musty smell in the environment, they like to he can

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sudden that smell to follow it home - he can sued that smell to follow

:08:22.:08:32.
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it home. The best thing about James's work is it is going on.

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feel paranoid, you think I have bedbugs. Nothing fires the

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imagination like looking up into a star-filled night. I went to

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Caltech in Pasadena, to look into deep space with a telescope that is

:08:45.:08:55.
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We have had telescopes now for about 400 years, although people

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credit Galileo with inventing them, he was not the first, he did play

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with the I arrangement of lens inside a tube, that increases

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magnification, let us see further, and in the process, revolutionised

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science. Since then, astronomers' telescopes

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have grown ever-larger and more powerful. Now they even launch

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giant ones into space, in their attempts to see further and further

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away. OK, so if size matters, just imagine what you would see if you

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had a lens the size of a galaxy. Believe it or not, galaxies

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themselves can act as lens. This may sound a little bit weird, but

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I'm talking about a very real phenomenon, called gravitational

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Lening. Using the effect - lensing, using

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the effect astronomers can create lens so big they span the universe.

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Gravitational lensing was first suggested by Einstien in his

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general theory of relativity. You don't need to be Einstien to

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understand the principle of it. I want you to imagine this is a

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galaxy far, far away. Light from the orange tree galaxy is making

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its way towards earth. I want you to imagine inbetween us is a huge

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cosmic body right here, another giant galaxy or cluster of galaxy,

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billions of stars. You would think by having it here, it would block

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the light heading towards the earth. But because it is so massive, light

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is actually bent around it. Even though our orange galaxy is

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obscured, we can still see it. A giant galaxy is so heavy with

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such a strong gravitational field, it warps the space around it, which

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makes light bend on the way through. So the galaxy acts like a lens,

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revealing and magnifying distant objects, or indeed, oranges, far

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beyond. This monstrous gravitational field

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is acting just like a lens. Gathering, distorting, and

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managefying light from distant galaxies, the whole thing is just

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like one big cosmic telescope. The trouble is, these lensing galaxies

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are incredibly difficult to spot. Some have been identified by a

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project partly based here at CalTech.

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Come on in. This man is part of a team hunting

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for them. That is a foreground lensing galaxy, we are looking at

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the blue as a disturn galaxy. The blue bits are not off to the side,

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they are directly behind the blob. They are. That is how we see it.

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The blob in the centre is the lensing galaxy, it is showing a

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galaxy further away, creating a ring of blue light. That is not

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their real shape, it is the distorted shape? Yes, because of

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gravitational lensing, this galaxy is magnified by about 10/30.

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can see how the ring of light is produced by shining a torch through

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the base of a wine glass a tiny light in the distance is distorted

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into bright spots and a tell tale ring. It is such a simple principle,

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a lens bends light, and now we have light bending because of gravity.

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How rare is it to find these lensed galaxy? It is very rare, maybe one

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or two out of 100,000 galaxies. We have now this telescope that

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operates on the infrared wave length, we have managed to find a

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large sample of lensed galaxies. This is a new orbiting telescope

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launched in 2009, peering further into dark corners of the universe

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than ever before, it has discovered very distant young galaxies,

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bursting with new stars, its secret is infrared.

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We couldn't see them using optical light, because places where there

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is lots of star formation has lots of dust. Optical light cannot

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penetrate through this dust. So with Hirshal we are finding these

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new galaxies that we didn't know existed.

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Hirshal scans vast areas of the sky, picking out the tiny signs of

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distant galaxies that other telescopes miss. What are we seeing

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here? We are looking at the infrared universe. Each speck or a

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dot here is a galaxy. But you can pick out this bright things, one

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here, there is one right here and they actually are priter, because

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they are being gravitationally lensed. These are the lensed

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galaxies discovered with Hirshal. It is truly as ifing, undiscovered

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galaxies billions of light years away, discovered by gravitational

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lensing. Why is it so important to see the galaxies hiding behind the

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other galaxies? We want to understand how stars form in the

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distant universe. We don't understand the physics associated

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with star formation, how the galaxies came to be, how did the

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first galaxy formed, this is one way for us to get handle on that.

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love things that only noticable on scales so vast that they are beyond

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common experience. Who would have thought that if you get a massive

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enough object, it will actually bend the light going past it and

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focus in somewhere else. That is a very beautiful ING this. I want to

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know is when did we first become aware of gravitational lensing out

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there in the universe. We have known g it for a while, since 1979,

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but the idea of what gravitational lensing could do, we are talking

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about the late 1930, as a concept in physic, back to Einstein, the

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theory of relativity, that space could be warped by gravity and

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therefore warped. Historically it is an interesting story, it shows

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how science works, science as a process from big idea through to

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practical application. It is lovely. Nature composes some of her

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loveliest poems for the microscope and the telescope. Follow the links

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to the Open University to learn more about life, the universe and

:15:56.:16:01.

everything, including me and astro physicist Frank Drake talking about

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the search for alien life. Doesn't it seem like every week

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there is another headline that this or that will vastly increase your

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risk of this and that, but as Dr Yan explains, statistics and gut

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reactions aren't necessarily a good reaction.

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When you read medical stories in the press, it is hard to interpret

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what they are telling you, especially where statistics are

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involved, the figures seemed designed to bamboozle us. I will

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show you what I mean, using bacon sandwiches. A few years ago it was

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all over the news that eating processed meat like bacon or

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sasauges every day could increase your chances of getting bowel

:16:42.:16:47.

cancer by about 20%. So let's see how people react to that. And see

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what they make of my cancerous bacon butties.

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Free bacon sandwiches? Always like that. Increase your risk of bowel

:17:02.:17:07.

cancer by 20%, they are literally free, I don't know if you want them.

:17:07.:17:13.

I'm less hungry now I have seen that. Increase your risk of getting

:17:13.:17:21.

bowel cancer! There has been some research that shows regular eating

:17:21.:17:25.

of bacon increases your chances of bowel cancer by 20%. One other

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thing, let me give you a choice, these bacon sandwiches, only

:17:31.:17:36.

increase your bowel cancer of 5%-6%. Which one takes better. Help

:17:36.:17:41.

yourself to either plate, but prefer these ones? I prefer the

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percentage. I think I will take the risk.

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Either way I'm having bacon. don't like bacon any way.

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We're not trying to trick you, I have eaten these. Can I ask why

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this one, why does it increase rather than this one. The ones that

:18:06.:18:10.

are really nice that are not good for you, like all food. Can I let

:18:10.:18:13.

you into a secret, it is no different at all. These two are

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exactly the same. Those risks are exactly the same as well. The

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difference is, just in the way that you present statistics. Do you want

:18:21.:18:26.

me to explain, I will show you. So, normally, your chance of getting

:18:26.:18:31.

bowel cancer is about 5%, OK, that means out of 100 people, some time

:18:31.:18:36.

in their lives, five of them will probably get bowel cancer any way.

:18:36.:18:41.

That is five out of 100. What this scientific research showed, was

:18:41.:18:46.

that if you eat about 50 grams of processed meat every day, those

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risks are not 5% but 6%. In statistics that is known as the

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absolute risk, that is what this is telling you, that isen increase of

:18:55.:19:00.

But that's not to say the 20% is wrong, it is just another way of

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expressing the same figure. And this is called the relative risk.

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Relative to the people who would have got it any way, one extra

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person, that's one, compared to five, one fifth increase. Which is

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20%. Exactly. So this figure is right as well, just a different way

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of putting it. Of course 20% sounds a lot worse, doesn't it. Actually,

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most of you, choose the sandwiches from the plate that was labelled 5-

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6%, that shows you how persuasive statistics can be, it is important

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to look behind the headline figures to find out what is really going on.

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I think I will have a bacon sandwich now.

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I have got a bit of a bug bear when it comes to banner headlines and

:19:50.:19:53.

statistic, we have to understand the basics, like Dr Yan showed us.

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We have to realise a lot of the statistics are "cherrypick"ed for

:19:57.:20:00.

effect without being in proper context, we have to remember that.

:20:00.:20:05.

Enough about the bug bears and the bedbug, let's talk about the cake.

:20:05.:20:12.

Because, I think you two both have a birthday this week. 31. 29.5.

:20:12.:20:17.

Statistics I'm unsure of. The lovely Dr Yan has sent this cake,

:20:17.:20:23.

it comes as catch, you can't have any until you figure how to split

:20:23.:20:30.

it into eight equal pieces with only three cuts.

:20:30.:20:37.

That's not possible. Is it: Very easy. If you think you know the

:20:37.:20:41.

answer is on the website. Before I get too distracted by the chocolate,

:20:41.:20:46.

I will get back to the bedbug investigation. We have heard that

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bedbugs have an incredible sense of smell, time for an e permanent to

:20:50.:20:57.

show us how they use it. - - experiment to show us how they use

:20:57.:21:06.

I have two specimens to show what things are attracted to our little

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bugs. These are two of the smelliest

:21:09.:21:18.

people I know. Dallas and Yan. James have - has set up an

:21:18.:21:23.

experiment to see which of the two has the most attractive smell to

:21:23.:21:28.

the bedbugs. Yan and Dallas haven't washed for 24 hours, they are a bit

:21:28.:21:34.

smelly. James is making them stew in their own juices for another how,

:21:34.:21:41.

in hot, sweat, foil bags. There is something deeply wrong with with

:21:41.:21:46.

this picture. What's happening? have them in the thermal bags which

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is used to collect body Oders. You can probably smell it. There is a

:21:51.:21:56.

pierce pong in here, it smells of boys' bedroom. We are pumping the

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body Oder from the bag, up the tiny tubes here, leading to this

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apparatus here into this arena, the behavioral arena, to find out if

:22:10.:22:16.

Dallas is more attractive than Yan to bedbugs. I think I'm going to be

:22:16.:22:25.

more attractive to bugs. The bedbug is released, what

:22:25.:22:30.

happens now? We will turn the pumps on and vacate the room. The one

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thing about bedbugs is they only feed at night, it will have to be

:22:34.:22:41.

done in the pitch dark. No hanky pangy, we are doing the lights -

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hanky pangy, we are turning the lights off. They can't bite them,

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they are perfectly safe in there, I have given them a night vision

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camera to stop them getting board. This is Yan, in his sweating bag.

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Outside we watch on a monitor as the monitor sniffs its way around.

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So there's our friend in his little choosing area, he's going to choose,

:23:05.:23:10.

up there, choice arena there is a camera, you can see him do his

:23:10.:23:14.

thing. There is infrared lights on there as well. That is the sound of

:23:14.:23:21.

the Oder being sucked down the tubes. That is the sound of science.

:23:21.:23:24.

Oders coming from the bags are being pumped through the pots. It

:23:24.:23:29.

is sussing out which side it prefers, which one will be the best

:23:29.:23:33.

blood meal? It is favouring this side more. It is definitely

:23:33.:23:40.

favouring that side now. This is quick it exciting. Having a whiff

:23:40.:23:45.

of the two boys when - quite exciting, having a whiff of the two

:23:45.:23:50.

boys, who would your money be on? Yan, I would escape out of the hole,

:23:50.:24:00.
:24:00.:24:02.

if I was the bedbug, the smell There is some serious science going

:24:02.:24:07.

on here. Because James wants to find out which chemicals bedbugs

:24:07.:24:13.

respond to. Once you discern whether it is attracted to a

:24:13.:24:17.

particular individual's body Oder, do you take apart the body Oder to

:24:17.:24:21.

see what chemicals might be attractive? If somebody is more

:24:21.:24:26.

attractive than someone else, it possible they might produce for

:24:26.:24:30.

attractants than the other. It might be the person not attractive

:24:31.:24:34.

might be producing natural repellant, that their body has a

:24:34.:24:39.

natural defence system against bedbugs. I thought it was always

:24:39.:24:45.

about something in your body Oder that is attractive to insects, I

:24:45.:24:55.
:24:55.:24:59.

never realise you had had repellants. If we can find out what

:24:59.:25:09.
:25:09.:25:10.

it is we can sell it as a repellant. It is definitely spending more time

:25:10.:25:15.

on one side than the other. looks like a clear result, but to

:25:15.:25:25.
:25:25.:25:27.

be sure we run the same experiment again and again. After several

:25:27.:25:37.
:25:37.:25:41.

hours there is no doubt. They look bored now. A game of I Spy. I do

:25:41.:25:47.

feel for them, there has been in the bags them, it gets hot and

:25:47.:25:56.

sweaty and it is not pleasant. There is about a quarter of an inch

:25:56.:26:01.

of water in the bottom of this bag. Do you reckon we have a good

:26:01.:26:08.

result? I'm confident we have an answer. Let's let them out of the

:26:08.:26:12.

cave. How are you. Oh my gosh the pong in here is something else.

:26:12.:26:16.

is a bit ripe. Do you want to who is more attractive to bedbugs. Who

:26:16.:26:23.

do you reckon it is? I reckon it's Dallas. Why do you reckon it is

:26:23.:26:28.

Dallas? I reckon it is Yan, he's a little gamey. Dallas didn't have a

:26:28.:26:34.

shower this morning and the shame T-shirt for two days. James has his

:26:34.:26:39.

money on Yan? I did. After he got a whiff of you, he said it is

:26:39.:26:44.

definitely going to be Yan. We have a categorical, all-out winner, I

:26:44.:26:48.

can announce to you that the person in the room who attracts the

:26:48.:26:55.

bedbugs most s a certain Mr Dallas Campbell. Get in. Bet bug of taste.

:26:55.:27:01.

Clearly has - bedbug of taste. traictive, it is scientifically

:27:01.:27:05.

approved I'm attractive. Draw a line and move swiftly on. I say

:27:05.:27:09.

that, I think I'm attractive to all insect life on earth, because every

:27:09.:27:14.

time I go on holiday I get bitten to shred, whoever I'm with are

:27:14.:27:18.

absolutely fine. Exactly the same experience, I went travelling with

:27:18.:27:25.

mate, we would share a room, I wake up with bites, and he never got

:27:25.:27:29.

bitten. I never could figure out if I was attractive or he was

:27:29.:27:34.

repulsive. Depending on the insect you are giving out an traictant or

:27:34.:27:40.

repellant, we don't know what it is for bedbug, he finds out it was a

:27:40.:27:46.

repellant that Yan wask sueding we can make a - was exuding we can

:27:46.:27:51.

make a spray. Can you imagine, essence of Yan. If you want to see

:27:51.:27:56.

more boy dorm action, if you are in the mood, get on to the website,

:27:56.:28:01.

check it all out. I haven't seen it yet, I can't tell you what it is

:28:01.:28:05.

like. That is it for this week, next week I'm doing something

:28:05.:28:09.

really stupid. In the name of science I will not clean my teeth

:28:09.:28:13.

to see what will happen. I have a smell thing goingen in the series.

:28:13.:28:17.

I'm looking into something we take for granted. Artificial light, only

:28:17.:28:21.

in recent history have we had the ability to flick a switch. But new

:28:21.:28:25.

research suggests that it may also be having an unexpected biological

:28:25.:28:30.

effect on our bodies. Dr Yan will be coming over all health and

:28:30.:28:33.

Liz investigates an increasingly common and unwelcome guest - the bedbug. Meanwhile, Yan explains why statistics are not to be trusted, and Dallas goes stargazing in California.