Feb 02 2010

Why is that butterfly blue?

Some colours come from the properties of individual molecules, some colours come from the shape of things. This is a post about the colour from the shape of things – structural colour, like that found in the Morpho rhetenor butterfly pictured on the right.

To understand how this works, we first need to know that  light is a special sort of wave known as electromagnetic radiation, and that these waves are scattered by small structures.

For the purposes of this post the most important property of a wave is it’s wavelength, it’s “size”. The wavelengths of visible light fall roughly in the range 1/1000 of a millimetre to 1/2000 of a millimetre. (1/1000 of a millimetre is a micron). Blue light has a shorter wavelength than red light.

The Spectrum of visible light (Image from Wikipedia)

Things have colour either because they generate light or because of the way they interact with light that falls upon them. The light we see is made of many different wavelengths, the visible spectrum. Each wavelength has a colour, and the colour we perceive is a result of adding all of these colours together. Our eyes only have three different colour detectors, so in the eye a multiplicity of wavelengths is converted to just three signals which we interpret as colour. The three colour detectors are why we can get a full colour image from a TV with just three colours (red, green and blue) mixed together. Some other animals have more colour sensors, so they see things differently.

The problem with viewing the small structures that lead to the blue colour of the butterfly wings is that they have interesting features of a size about the same as the wavelength of light, and that means you can’t really tell much by looking at them under a light microscope. They come out blurry because they’re at the resolution limit. So you resort to an electron microscope, electrons act as a wave with a short wavelength so you can use an electron microscope to look at small things in much the same way as you would use a light microscope except the wavelength of the electrons is smaller than that of light so you can look at smaller things.

So how to explain resolution (how small a thing you can see) in microscopy. I would like to introduce you to a fresh analogy in this area. Summon up in your mind, a goat (tethered and compliant), a beachball (in your hands), and a ping-pong ball (perhaps in a pocket). Your task is to explore the shape of the goat, by touch, via the beachball, so proceed to press your beachball against the goat. The beachball is pretty big, so you’re going to get a pretty poor tactile picture of the goat. It’s probably going to have a head and a body but the legs will be tricky. You might be able to tell the goat has legs, but you’re going to struggle to make out the two front legs and the two back legs separately. Now discard the beachball and repeat the process with the ping-pong ball. Your tactile picture of the goat should now become much clearer. The beachball represents the longer wavelength of light, the ping-pong ball the shorter wavelengths of electrons in an electron microscope.

And now for scattering; retrieve your beachball; step back from the goat. You are now going to repeatedly throw beachball and ping-pong ball at the goat and examine where the balls end up having struck the goat. This is a scattering experiment. You can see that how the ball bounces off the goat will depend on the size of the ball, and obviously the shape of the goat. This isn’t a great analogy, but it gives you some idea that the shape of the goat can lead to different wavelengths being scattered in different ways.

So returning to the butterfly at the top of the page, the iridescent blueness doesn’t come from special blue molecules but from subtle structures on the surface of the wings. These are pictured below, because these features are smaller than the wavelength of light we need to take the image using an electron microscope (we are in ping-pong ball mode). The structures on the surface of the butterfly’s wing look like tiny Christmas trees.

Structures on the surface of a morpho butterfly wing (scale bar 1.8 micron)

These structures reflect blue light really well, because of their shape, but not other colours – so the butterfly comes out blue.

Another example of special structures that interact with light is this is a *very* white beetle:

Cyphochilus beetle (Image by Peter Vukusic)

The cunning thing here is that the beetle manages to make itself very white, meaning it reflects light of all wavelengths very efficiently, using a very thin scales (5 micron). This is much better than we can achieve with synthetic materials. The trick is in the detail, once again the scales have a complicated internal structure as you can see in this image from an electron microscope:
Cross-section of a beetle scale (scale bar is 1 micron, Image by Peter Vukusic )

It turns out that the details of the distribution of the scale material (keratin) and air in the scale conspire to make the scale highly reflective. Making things white is something important to a number of industries, for example those that make paint or paper. If we can work out how the beetle does this trick then we can make cheaper, thinner, better white coatings.

Finally, this is something a little different. If you’ve got eyes, then you want to get as much light into them as possible. The problem is that some light gets reflected from the surface of an object, even if it is transparent – think of the reflection of light from the front surface of a clear glass window. These structures:

The surface of a butterfly’s eye (scalebar 1micron, Image by Peter Vukusic)

known an “anti-reflective nipple array”, are found on the surface of butterfly eyes. The nipples stop the light being reflected from the surface of the eye, allowing it instead to enter the eye. Similar structures are found on the surface of transparent butterfly wings.

In these cases animals have evolved structures to achieve a colour effect, but more widely we see structural colours in other places like rainbows, opal, oil films and CDs. The sky is blue for a related reason…

Sources
The work on butterflies and beetles was done by a team led by Peter Vukusic at Exeter University:

Jan 28 2010

Mother, do you think they’ll drop the Bomb?

I thought in this post I would touch on science and morality by means of the Manhattan Project.

The picture at the head of the page is of the very early stages of an atomic bomb going off. The roughly spherical fireball is approximately 20 metres across at this point. It was taken using a “rapatronic” camera, invented by Harold Egerton for just this purpose.  The exposure time for this camera can be as short as 1/500,000th of a second (2 microseconds). Cameras were fired sequentially at periods less than 1/1000th of a second (1 millisecond) after detonation, to produce a sequence of images of which this is just one. The camera is triggered by a photocell, which picks up the x-ray flash as the bomb goes off, and a delay circuit. The shutter contains no moving parts, it is a “Kerr cell” placed between two polarizers arranged such that they let through no light. When a current flows through the Kerr cell the polarisation of light is rotated and so can make it through both polarizers – no current and no light gets through. This is all done electronically so can happen really fast.

The bomb was detonated on a gantry tower supported by guy wires, the bright spikes beneath the round explosion are known as “rope tricks“, they are where the metal guy wires have been vapourized by the light from the initial detonation. If you cover the guy wires in aluminium foil the rope tricks disappear because the light is reflected, paint them black and the spikes appear larger because more light is absorbed. The distorted shape of the fireball is a relic of irregularities in the bomb casing, and the small shed at the top of the gantry tower in which the bomb is placed.

To me the story of the making of the atomic bomb is fascinating and exciting. In the period of a few years from 1939-1945 methods were found to extract scarce isotopes of uranium in kilogram quantities; manufacture plutonium; the fundamental radioactive properties of the substance were discovered; calculations were done to work exactly how much uranium you needed for a bang, how quickly you had to get it together and the whole thing converted into a working device that could be carried in an aeroplane. And they did a lot of this work twice, since the bombs dropped on Hiroshima and Nagasaki are quite different in design.The story about the rapatronic camera shutter is just a relatively little-known footnote to the whole endeavour.

The Manhattan Project was served by a considerable number of scientists, including twenty Nobel Prize winners, amongst a staff of around 130,000. These scientists represent a large fraction of the most renowned scientists of the period. I think I can imagine how I would have felt to working on the bomb, I would have been keen to be part of the war effort, I’d have been thrilled by the intellectual firepower of my colleagues, I’d have been excited by the technical challenge of actually making a real thing.

And then there was the Trinity test firing, I think at this point I would have become really aware of the enormity of what I had been involved in. J. Robert Oppenheimer, who directed the Los Alamos site where the bomb was constructed, later said he thought of this line from the Bhagavad Gita:

Now I am become Death, the destroyer of worlds

Which always struck me as being a bit pretentious, but maybe that’s a result of my ignorance. Whilst Kenneth Bainbridge, the director for the Trinity test, is reported to have said:

Now we are all sons of bitches

Which strikes me as a rather more plausible response. I have to say, with a little embarrassment, that I would have been thrilled by the size of the bang I had made.

Less than a month after the Trinity test an untried version of the atomic bomb was dropped on Hiroshima, instantly killing 80,000 people; then a few days later a second bomb, identical to the Trinity test bomb, was dropped on Nagasaki killing another 40,000. Subsequently many more people died of their injuries.

I’m not sure how I would have felt at this point I think I would have been a bit shocked, I struggle to conceive of that many people dying. The world was at war so I would have been familiar with the idea of people dying in, for example, the air raids in the UK. So maybe I would have thought this was justifiable, that the war against Japan couldn’t have been won in any other way or at least any other way would have led to just as many deaths. Maybe it would have been clear to me at the time that the atomic bomb was as much about the Soviet Union as it was about the war with Japan.

After the war many scientists returned to normal life. Some didn’t, Edward Teller enthusiastically promoted the thermonuclear bombs for just about any application imaginable. Joseph Rotblat left the Manhattan Project before the bomb was dropped, and whilst continuing scientific work, he helped found, and run, the Pugwash Organisation and spent the rest of his life campaigning for peaceful conflict resolution.

Do scientists have a special moral responsibility? They certainly took the initiative in terms of highlighting the potential of an atomic bomb before the war, but actually making the bomb and deploying it took far more than just a few scientists. As to the morality of killing people in war, then I don’t think scientists can claim any special moral insight here.

Finishing in this way seems a bit trite, and it feels in some ways an abdication of responsibility. I think the point I’m trying to make is that scientists are just people, and we bear the same moral responsibilities as anyone else. The only difference is that scientists have the potential to open up new moral questions: “Is it more wrong to kill 100,000 people with one bomb, as opposed to many bombs?”. Maybe we have the ability to close old moral questions through evidence.

Jan 23 2010

Caverns measureless to man

I thought this week I would talk about conferences, since they are something that is very much part of life as a scientist and which are perhaps are a little alien to people.

My first scientific conference was in Durham, where I did my PhD, I took the opportunity to find accommodation in the town before I moved up from Bristol. There was a problem with this: the conference supplied us all with name badges on which we were to write our names in our own fair hand. I was sitting opposite to an elderly academic at lunch who felt my name was somewhat small and indistinct. So I re-wrote it in large capitals with my biro, going over the letters repeatedly to get a “bold” effect. Now my handwriting isn’t great at the best of times, doing large-size capitals freehand has the look of the scrawling on the lunatic asylum walls. Later I went off looking at rooms in houses, but felt I was getting funny looks when I asked for directions. Later I realised why: not only did I still have my lunatic-asylum name badge on, I had it on upside down!

In many ways that first conference set the pattern for future ones, accommodation was primitive: in Durham Castle, which is used as student accommodation during term time. I met an old chap who, on hearing what I was doing swore blind he had done it all 10 years ago (I checked, he hadn’t, they never have). I learnt interesting things from esteemed academics in the bar.

For most the price of attending a conference is to present a poster, or a talk. This means I am accustomed to public speaking, just an odd sort of public speaking. In fact when I’ve had to speak at weddings, I’ve felt the lack of an overhead projector and had to resist the temptation to “thank the organisers for inviting me”, this is nearly appropriate but needs rephrasing. Conferences have also given me ninja buffet skills, and an appreciation that if you march off confidently in any direction (in my case in search of lunch), then quite a few people will follow you for no better reason than it looks like you know what you’re doing.

I’m not sure how widespread the idea of a poster presentation is outside of science, the idea is you convert your most recent work into…. a poster, a jumble of text boxes, figures and graphs (see below). If you’re flash, and organised, you print it out as a single sheet on laminated paper at some central service and then carry it around in a special tube. Otherwise you print it out on a load of A3 sheets. Posters are typically viewed in an over-crowded hall whilst drinking warmish white wine and eating finger food, text on the posters is normally too small and you’re too far away – the combination of these things always gave me a splitting headache. Supervisors attempt to get their students to defend their posters, that’s to say chat to anyone who wanders up.

Conferences are where you learn all the interesting stuff that people don’t write down, like how it took some poor PhD. student months to get an experiment to work once and they’ve never quite managed it again, or how a little fix is required to get a numerical simulation to work. You also learn lore from the more senior members of the community: how X has been doing Y or small variants thereof for the last 20 years. How Z has been wrong for all of living memory. How W, although publishes great work is not a very nice man. You may get some idea of what someone’s master plan is (you’re certainly not going to get it from journal articles), you’ll get to appreciate that other academic groups work in radically different ways. I also learnt that science transcends barriers of language and culture, the scientists I meet on tour are my tribe, my closest relatives beyond my real family.

All these conferences mean I’ve done a fair amount of travelling, personally I don’t consider this a great benefit. Business travel rarely gives you much time for sightseeing and the places you end up there may not be sights to see, and if there were I’d much prefer to go with my wife rather than a random collection of other scientists. I’ve visited Rhode Island, Boston, Sante Fe, Heidelberg, Sitges, Akron (Ohio), Philadelphia, Cancun and numerous towns around the UK. The only upsides of Cancun were the tropical fish just off the shore, the ever present iguanas and the Mayan ruins, otherwise it’s an overpriced tourist hell-hole.

The best conferences I’ve been to have been the smaller ones, the invitation only ones, the ones where discussion is programmed into the schedule, the specialist meetings for young academics. The larger conferences tend to be soulless and confusing: which of the 10 parallel sessions should I attend? And is it physically possible to switch sessions? There is a fine conference in the UK for the polymer community, which used to be based near Moretonhampstead, but now lives in Pott Shrigley. The presence of the golf courses is significant here, the organisers liked their golf so we had a morning session, an evening session and an afternoon off for golf. The non-golf players went off for walks in the country, which was a fine bonding experience. I remember distinctly my future postdoc supervisor standing on a tussock in the middle of boggy ground suggesting to the rest of the group that we proceed no further. It turns out being a Fellow of the Royal Society does not guarantee good navigation skills!

Is there still a need for conferences, in these days of electronic communication? Although the prospects for online networking via various social media are great, currently uptake by scientists is pretty low in percentage terms and the bandwidth of the communication is low. The amount you learn about a person from just one face-to-face meeting is enormous compared to what you get through electronic media; electronic media are great as an introduction and for maintaining contact but there’s nothing like meeting people.

The “caverns measureless to man” title is in homage to the SIGGRAPH conference I attended in Boston, there were somewhere in the region of 20,000 delegates. It was held in the vast Boston Convention and Exhibition Center.

Jan 17 2010

We are the angry mob

Once again it feels like I’m accused being a member of an angry mob of twitterers. This time by Catherine Bennett in The Observer, over the censure of Rod Liddle, stimulated by his potential appointment as editor of The Independent. As far as I can tell Rod Liddle is a rather unpleasant individual both in terms of his personal treatment of those close to him and in his public writing, actually looking down the first page of his Spectator articles I would appear to agree with him approximately 10% of the time.

Catherine Bennett raised this as an issue of free speech, implying that we are attempting to remove Rod Liddle’s right to free speech and also the rights of those such as Jan Moir, whilst going easy on Islam4UK. As an articulate member of a mob, I’d like to say this is really not what I want to do. To my mind Rod Liddle, Islam4UK and the BNP should all have a right to let their views be known, I just don’t believe they have a right to express that freedom anywhere or any time. However, the corollary of this is that I believe that I also have the right to point out that what they say is stupid, unpleasant and wrong. When given a public platform the BNP and Islam4UK seem to do a pretty good job at making themselves look risible, remove that platform and you risk people imagining that they are eloquent and right  for lack of any evidence to the contrary.

The intriguing question with people like Jan Moir and Rod Liddle is that they have liberal backgrounds of a sort, they are clearly pretty smart. So when they write something that sounds illiberal, offensive and pandering to the basest of instincts are they simply being “radical for pay”? Do they really believe what they write, or do they just write what they know will go down well with their employers and their readers, happy in the knowledge that all publicity is good publicity. Writing a blog brings these questions to the fore, because it’s very obvious how frequently a post is read (or at least looked at). Should I write something worthy, but dull to most people and get a few hits or something that people are impassioned about which will get many hits and mentions?

What is it I want from complaint? In a way I want to shout that someone is wrong on an equal footing, I want access to the means of production (okay dissemination, but you have to turn a phrase when you can). In the past the right to provide public comment was a special privilege, available to the few who had a newspaper column or similar. What I have written here contains no more or less research than the Observer piece, I’d humbly suggest that my opinion is of equal value to Catherine Bennett’s. I am happy to accept that her writing is somewhat superior to mine. Is this the message for mainstream media? Ill-informed rant is no longer viable, because anyone can do that – genuine insight, research, knowledge and good writing are valuable because they are hard.

Jan 16 2010

Follow Friday – a post for twitterers…

There is a tradition on Twitter, called Follow Friday in which, of a Friday, you mention people you follow who you think other people would be interested to follow. For me this is a cause of social stress for fear of forgetting someone I should remember, so I thought I’d try doing it in my own way. You can see all the people I follow here, and the people that mention me are here (I think you might need to login to twitter to follow those links).

And here, in alphabetical order to avoid accusations of favouritism, are my micro-biographies of people you should follow:

@alexconnor is an astrophysicist who now works on policy at the Institute of Physics. He shows his weekend DIY exploits to great acclaim.
@Allochthonous is a geologist, he writes the Highly Allochthonous blog. I mis-pronounce is name “allo-kan-thus”, I believe it’s a habit I cannot break.

@andromedababe Observer of shagging frogs, lover of shoosies. Blogs at AndromedaBabe’s Blog on teaching and other stuff.

@BarbaraMaller a closet writer and chatter from California.

@BillyGottaJob originally @BillyNoJob took us on a journey at his now named At Long Last I’ve Got A Job blog.

@Carmenego is a very cheerful musical lady from old London town, who blogs skeptically at Carmen Gets Around (II)

@ChristineOttery a journalist, doing an MA in science journalism, her blog is Open Minds and Parachutes but she is also published in proper media like the Guardian’s Comment is Free.

@Crafthole is a archeologist / historian person engaged married to @ladycrafthole. We share an interested in the scientists of the 18th and 19th centuries

@DaintyBallerina historian, and writer of the Fragments blog, is often the first with a #wine hashtag.
@DanielFurrUK is a libertarian Liberal Democrat, who blogs at http://danielfurr.tumblr.com/.

@deborahshelton is an interior designer, see here. She hangs around with the historians.

@doyle2718 – it’s me mate from work: Doylie! The only one on twitter, the rest just think I’m odd…

@dr_andy_russell is an atmospheric physicist at Manchester University. Writes a blog. Handy for a knowledgeable opinion on climate change.

@DrEvanHarris is former LibDem MP for Oxford West and Abingdon, and was the party’s Science spokesman. He joined twitter recently and immediately gained a massive following of nerds and geeks, he uses twitter like a pro and is responsive to queries. His website is here.

@Drop4three an enigma I have yet to crack, he blogs at dropped

@Duddy an author of several novels of a scientific bent, and Cestrian and Keeper of Snails blog. She has retired from Twitter, but the blog is still well worth visiting

@Essiefox a historian and the writer of the Virtual Victorian blog, we seem to share a taste in music.
@FyreFlye a chatty lady, who I always associate with the big sunflower in her avatar.
@Gelada is a mathematician and makes pretty sculptures with maths, his blog is Maxwell’s Demon.

@GentlemanAdmn a gentleman and an administrator, he writes an eponymous history blog.

@graemearcher is a statistician and a relatively unpolitical politician who writes an occasional blog post on Conservative Home. He likes swimming, cats and Mr Keith.

@hangbitch always happy with an acerbic comment. She has a blog at Hang Bitch.

@HappyMouffetard is my wife, so I must mention her. Cruelly deprived of twitter at work, when she can she tweets on nature and gardening. Curator of The Inelegant Gardener

@iknowhim I always think of as mysterious, a cause de her avatar. She has a blog, Last Tango in Dulwich. And her twitter background is a very fine, if not sensible, shoe.

@Jackpot73 another friendly soul of the interwebs, who has been sharing my sense of humour, which may or may not be a good idea ;-)

@jme_c is many things including college lecturer at Somerville and MSc Science Communicator at Imperial College, he is suffering geek-envy for my HTC Desire. His website is here.

@jordancdarwin is a fellow code monkey, these things are important. He is also an enthusiastic atheist, as you can tell from his website.

@KateKatV is @PaoloViscardi’s mum! I know this is an impolite way to introduce someone, she also has a blog here.

@laales is a split between Hong Kong and Dorset (which is where I come from), she is a member of the historical faction.

@LadyCrafthole is a photographer who blogs at Lady Crafthole’s Blog. She makes little planet photos.

@lahossner is most mysterious, I believe she is a fan of books.

@langtry_girl was best able to finish the sentence: “Understanding the Periodic Table is very much like making love to a beautiful woman…” is an economist, so nearly a scientist ;-)

@Lesanto is a social media consultant with a difference, speak to him and he’ll speak back: he tries interesting things on twitter. His company is media140.
@localbuilderuk Lover of snowboarding and wine, of which I approve – not so sure about the golf ;-)

@louwiseman joins me from the gardening faction, she seems obsessed with insects at the moment.

@LucyInglis historian and writer of the awarding winning Georgian London blog, she attracts the strangest blog search terms and seems to like cricket, or possibly cricketers…
@Margit11 was living in Edinburgh but is now living in Munich. Blogs at Intercultural Musings, on being a foreigner in the UK but things will change.

@markgfh science editor of the Times, and fellow science-politics geek.

@MarkReckons is a fellow LibDem, and political blogger – you can find him here. A moderate in all things.

@masticatingmanx is a fan of food, no indication as to how this has affected waist-line but his blog looks pretty healthy. An inhabitant of the Isle of Man, which I have only seen as a distant shadow.

@MentalIndigest a macho biologist, proud of his snowsocks, my main competition in the race to identify the Friday Mystery Object (see below). He writes the Mental Indigestion blog

@Morphosaurus a teacher who was able to recognise tunicates from my inept description, keeper of Bastard the Cycad and author of multiple blogs.

@nemski is that rare creature: the American Liberal he comes from just down the road from Malvern (Mrs SomeBeans comes from the UK version). Various sciencey tweets.

@Nora_Lumiere is an animator and writer, and a friend of food. She blogs at Animated Writing, where she has been kind enough to invite me over as a guest blogger.
@opheliacat a member of the historical faction, she is our woman in New York.

@PaoloViscardi biologist and proper curator at a museum. Also master of the Friday Mystery Object, on his blog Zygoma, which provides me with much distraction.

@PatrickBaty and @PapersPaints are one and the same, analyser of historic paints and one-time instructor of tank drivers. He blogs at News from Colourman, he’s been on the TV but was upstaged by his cat, Caspar.

@philipmcdermott is a research associate and software engineer. He blogs at http://number23.org/

@Quackwriter author of Kill-Grief and alumni of the Wirral, curator of the Quack Doctor blog, which reports on the wacky medical adverts of the past.

@rebekahthornton is local. She sometimes has a mathematical air about her and is fond of darts.

@ripplestone is from the gardening tendency, although her name makes me think of geology. She blogs at Ripplestone Review.

@robajackson chemistry lecturer, card-carrying red, and trombone player. He blogs on chemistry and politics.

@rosamundi I associate with a pair of purple shoes, which she used as an avatar for a long time. She is a lady of mystery, and is often found with the historians.
@rose_darling Writer. Editor. Poet. Dreamer. Music lover. Conversationalist. Gastronaut. Traveller. I love it when people write their own biographies! She has a blog here, which I don’t think she pimps enough!

@sallybercow  I started following all sorts of people for the election. Sally, self described #1950shousewifebot with a familiar surname is by far the most fun

@Samiahurst Doctor, teacher, blogger, and sometimes apprentice chocolate maker.

@sarahsiddons seems to come to me from the historical faction, curator of the Weird, Ordinary, Wonderful blog.

@Schroedinger99 is a fellow skeptic, how did I manage not to add him sooner? He has a blog at Bad Reason.

@Sciorama a scientist I know from some time ago, a biological physicist with very red hair.

@Scisu interested in things sciencey, she blogs for BioData.

@smithatcity is a doctor and a Science Communicator in training at Imperial College, she blogs at in bed with medicine.

@Stephen_Curry a fellow scientist, who scatters x-rays from crystals. He blogs at Reciprocal Space.

@stephenemoss a biological scientist, his work was on the BBC website recently. We hang around together at virtual science policy gatherings. He blogs at a little bit at The Mad Professor.

@Steve_P_Knight is the king of lasers. I think we must have met over something sciencey, but I can’t remember what!

@TiggerTherese is of the gardening tendency, her bio mentions being an ex-banker – but she doesn’t like to talk about it.

@thecredo I think may have escaped from The Thick of It. Originally the owner a mad old bearded-man avatar, this is how I will always see him.

@ThetisMercurio is in her own words rationalist, humanist, satirical… Staunch opponent of Steiner-Waldorf schools, the homoeopathy of education.

…and now I find I have shifted my social stress to a different sphere. My plan is to keep updating this post, if you spot any factual errors, find my biography offensive, or feel left out then please let me know.

Added Saturday (16/1/10): @scisu @Stephen_Curry, @Sciorama, @Samiahurst, @Quackwriter, @PatrickBaty, @paperspaints, @PaoloViscardi, @Nora_lumiere, @morphosaurus, @mentalindigest, @lucyinglis, @lesanto, @jackpot73, @happymouffetard, @GentlemanAdmn, @Gelada, @FyreFlye, @duddy, @daintyballerina, @ChristineOttery, @Carmenego, @BillyGottaJob, @BarbaraMaller

Added Friday (22/1/10): @AlexConnor, @Allochthonous, @GraemeArcher, @Rosamundi, @StephenEMoss
Added Friday (29/1/10): @opheliacat, @ThetisMercurio, @rebekahthornton, @LadyCrafthole

Added Friday (5/2/10): @dr_andy_russell
Added Friday (26/2/10): @crafthole
Added Friday (6/4/10): @jme_c, @MarkReckons, @TiggerTherese, @smithatcity, @DrEvanHarris
Added Friday (30/4/10): @hangbitch @nemski @louwiseman @sarahsiddons
Added Friday (7/5/10): @sallybercow @jordancdarwin @rose_darling @markgfh, @Schroedinger99
Added Friday (5/6/10): @laales, @KateKatV, @iknowhim, @doyle2718
Added Friday (30/7/10): @masticatingmanx, @robajackson, @deborahshelton, @lahossner
Added Friday (27/8/10): @ripplestone, @Steve_P_Knight, @Margit11, @langtry_girl
Added Friday (3/9/10): @andromedababe @thecredo @localbuilderuk
Added Friday (17/9/10): @philipmcdermott

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