36 Symptoms of Science Geekery

Science geekery is a deadly disease, not least because it makes you so happy you never want to give it up.

These are 36 of the symptoms I've encountered - and I don't think this is all. Most are mine; a few are other people's. What are yours?

1. You look for constellations in freckles and moles on your skin. And your boyfriend's/girlfriend's - and point them out when you find them. They may be a little disturbed, which is saddening because you mean it as a compliment.

2. One of the most upsetting and bewildering things you can hear is the sentiment that science takes the beauty or poetry out of something.

3. You start quoting Tom Lehrer at length when drunk. Or, indeed, sober and having a good time.

4. Carl Sagan's Pale Blue Dot makes you well up.

5. You have a mental list of all the science things you didn't understand in school. If you're organised you read up on them. If you're not, you just feel annoyed about them and keep planning to read up on them some day.

6. You have your own mental list of what you would put on the science curriculum, if given dictatorial powers!

7. Bookshops are incredibly dangerous places to enter. (For your bank account, not your physical self - unless you do your back in, of course, or indeed sit on the floor and get so absorbed reading something that somebody trips over you.)

8. Once shy and lonely, you suddenly become a very talkative and enthusiastic person!

9. Other people's responses to this vary. They might remark, "You get all animated!" or "You light up when you talk about . . .". However, more commonly they'll object to "these things you just blurt out" as if you've said something exceedingly offensive. Other remarks may include: "You're very passionate about . . ." in a telling-off sort of voice; "You're obviously really shy. Only shy people talk that much all in one go" and "You really remind me of my autistic relative/friend X" or gently take it upon themselves to diagnose autism or Aspergers. You tell them that is very interesting.

10. Fellow geeks are always to be cherished.

11. Your Facebook wall shows rather a lot of links to APOD pictures. You can't help but hope that some of the desperately boring people you can't acceptably unfriend will be even a little inspired. They aren't.

12. Stories such as the idea of "open science" (1st chapter here!) or the children's bumblebee paper put a silly grin on your face for hours.

13. You sneak onto a geeky website, or at least Twitter, when clothes, make-up, alcohol and X-factor become a topic of intense and opinionated discussion in the workplace. Or, if forced to participate, you come out with all the conversation-stoppers.

14. This makes perfect sense!

15. When your friends discuss the inevitabilities of nuclear war or the futility of trying to feed the starving or combat corruption, or treat as completely reasonable the idea of no country agreeing to reduce their carbon dioxide emissions until everyone else does (because it would be bad for their economy), science seems the obvious solution. For example, putting more money into science will drive our renewable energy, and then when everyone else runs out of fossil fuels we'll be in the lead. "Yes," they shrug, meaning "If only", or less.

16. Seeing the cruelty and stupidity of a lot of the world is, every so often, a horrific shock - because you've been concentrating on science, which is so beautiful and makes you so happy.

17. Indeed you feel that more science for everyone would make the world a much happier place.

18. Glow-in-the-dark stars are a very good idea.

19. Remarks such as "But we didn't know how electricity worked for ages, but we still used it" and "We used to think the world was flat" (usually said as excuses for thinking something unscientific and being too lazy to listen to reason) drive you up the wall.

20. When someone claims that some alternative remedy works just fine, you immediately prepare a firestorm of questions about studies, evidence, the placebo effect, and the mechanism (sadly, that usually has to remain inside your head - unless you're a lot braver and more patient than I am).

21. It deeply upsets you to see an inaccurate scientific article.

22. The best clothes and other accessories are those containing an excellent science slogan/joke/diagram.

23. After years, when young, of being personally desperately committed to all your arguments, you grow a virtue of detaching yourself from your scientific work, in order to look at it properly. That ties in with the dry, detached language of scientific journals - although you can't help agreeing they would be much more accessible if written in more ordinary language. (Now if only there was a job requiring that type of translation . . .)

24. You look back on the times you weren't doing science and ask yourself, "What was I doing all that time?"

25. The world becomes full of toys. Clouds change shape before your eyes, whiteboards invite you to write a science joke, broken machinery is there to be pulled apart, Lego is perfectly acceptable at all ages, and your glasses (if you wear them) turn the edges of everything red and blue. And when you arrive early for a meeting, and are conveniently there to help pour the coffee, you first arrange all the polystyrene cups (which you disapprove of, because they're not recyclable, although you wonder if you ought to check that is still true - but cool mugs are still better) into the shapes of a barred spiral, an unbarred spiral and an elliptical.

26. You then excuse yourself by explaining that, now you are into science, the world is suddenly full of toys, and everyone around you grins and nods, because they all feel the same way!

27. You see galaxies in your coffee. And everyday objects in galaxies. And point them out.

28. You can't help but check for flawed methodology in every claim and every study you see. And you see a lot.

29. Organisations or groups whose principles support sometimes see you as the enemy when you point out the flaws in their methods or reasoning. This is tragic, because you want them to produce the best data and arguments.

30. You are occasionally reminded that you have forgotten to do something important, such as turning off the oven, because you were so busy thinking about supernovae or similar.

31. When you suddenly understand a concept or equation you began struggling with a long time ago, it's difficult not to jump or dance. You have to settle for texting your geeky friends or blogging about it later.

32. Sooner or later, you will come across someone who feels that there is something childish about facts and being "right or wrong". This is a lot to do with their own maturity and having learnt to compromise and respect everyone's opinion. You think about this and go through a long thought process concluding that your own maturity about knowledge has passed various stages. As a child, for instance, you might have thought in black and white, and that is what this person usually thinks you are doing. As a teenager, you learnt to think like them (and some people never get beyond that stage). As a science geek, the maturity is error bars, acknowledged uncertainties, and a healthy respect for facts which you know can never be entirely proved, only disproved - who knows how or when?

33. When people ask you to recommend Christmas presents, you give them a list of science books. You genuinely found them funny and delightful.

34. You tell your beloved to paste this equation into Google: (sqrt(cos(x))*cos(200*x)+sqrt(abs(x))-0.7)*(4-x*x)^0.01, sqrt(9-x^2), -sqrt(9-x^2)

35. A science lecture, a Skeptics in the Pub night or a stargazing/telescope session is a much better night out than getting pissed.

36. You use the word "geek" as a compliment. Other people think you're putting yourself down. This needs explaining.

The train tracks

Before you read this post (or choose not to), please bear in mind it might be distressing or triggering - that is, bring horrible memories to the forefront of your mind. It's not something I would have intended to blog about before this happened, but now it has, I think it's important - hopefully, you'll see why. There's some help sites at the bottom of the page.

It's the 11th week of a 12 week term in my postgraduate course. My blogging has gone out of the window, as has a lot of my attention on other projects such as Galaxy Zoo. I'm stressed about getting work to support myself and about my not-easily-cured lack of mathematical knowledge. I love the course but I'm just exhausted now and want to sleep, but I have to get off the train to wait for the next one because the line is branching.

It's freezing out. I was having a fascinating e-mail conversation earlier and completely forgot to change into warmer clothes before leaving the house. The platform's shiny black with rain and I think about latent heat and how it can be both raining and so cold. I walk up the platform to try and get warm, my bag batting on my back. I turn back and - what?

There were two men on the train tracks. They appeared to embrace briefly, and then walk slowly and carefully back across to the platform opposite. Something stopped inside me, as if I was watching a film that had suddenly gone silent, the screen shrunk, my breathing switched off. What if a train came? They were standing on the rails - would they be electrocuted? A bunch of people had gathered at the edge and held out their hands to pull them up again. I took this to be a prank, or one of them having dropped something. I was quite far away but wandered nearer, suddenly nosy.

One of the men was holding his hands up, as if the others were pointing a gun. There was some jostling and pathetic wails of "leave me alone". It was then that I realised what was happening. Would they calm him down? Talking helps usually, doesn't it? There were a few moments of rising jostling and then calm. And then the man broke away and ran. Towards me. I was just wondering if there would be any point jumping onto the tracks myself when another man ran after him, caught him up, grabbed him, and was joined by two others who held him tight. They ended up on the ground. The man was howling now. He wanted them so much to get off so he could . . . do it again.

I looked around me. Most people were standing still, staring. No, I didn't see anyone obviously calling the emergency services. Suddenly it occurred to me that the men holding him couldn't, there were no staff around, and nobody was in charge. Nobody was going to come along and make everything all right. How could they? British Transport Police. What was their number? There were signs everywhere normally saying "If you see a train being vandalised, call . . ." I couldn't find one. Right. Can't waste any more time. You might have seconds. Action stations.

I pulled my phone out of my pocket. For some reason, dialling 999 - the first time I've ever done that - made me feel very foolish and embarrassed. Also I had started to shake wildly and it affected my voice.

"Emergency services," came a recording. Then silence.

Then "What emergency service do you require?"

"Police please."

Ring, ring. Oh, a long ring, ring. "Police, what is your emergency?"

I almost said "Hello, good evening," on autopilot. The guys still had the man held down, against the wall. His howls were just incoherent howls, like a baby crying. I couldn't even see him. I was right opposite them now, just those two horrifying railway tracks in between.

It was a very clear-voiced, calm lady. I told her which Tube station I was at and that someone had tried to throw himself onto the tracks. She asked if he was still on the tracks and I said no. I described as best I could what was going on. She asked me what he looked like. I had to be honest and say it had all happened so fast and I couldn't see him any more, I couldn't be sure. My mind was suddenly full of a list of features David Allen Green explains here: "Sex, height, hair colour, build, jacket, bottoms, trainers, fabrics, colours of clothes." (I could remember most of those, not all, and managed to come up with height, hair colour, jacket, colours of clothes. I won't repeat them because I don't want this poor guy to be identified this way.) She asked me the most obvious, race.

"What platform is he on?" Oh God. I couldn't see. I paced about trying to find the sign. I told her that he was "on the one in the middle". I found out I was on Platform 3 and told her, adding that he was opposite me, but she thought I meant he was on Platform 3. I was later able to interrupt her and say Platform 2 - I had walked to the right place and was able to see a tiny sign. She clarified with me that there were people holding him. I said there were but I thought he might well do it again if they let him go. All this while people were standing rooted to the spot. A few were on their phones but it seemed to be to friends. I really couldn't tell. None of them seemed to be aware I was calling the cops. I can't remember what she asked that prompted me to respond at one point that he basically just seemed terribly upset and needed some looking after. I still felt really silly and apologised for wasting their time if they'd received other calls about this. She said "No, no," and really sounded like she meant it. "The police are on their way," she told me after a surprisingly short time, "and an ambulance, too, just in case."

She asked me if I wanted a reference number. I told her I couldn't write it down but if it was short I could try and memorise it. I think I have! She asked for my name, but no further details. She thanked me for calling and we hung up.

I longed to yell across to the struggling guys that I had called for help but I knew my feeble, shaking voice wouldn't get to them and it would hardly impress the guy they were holding. I was contemplating finding my way to that platform but it proved unnecessary: within a wonderfully short time several policemen arrived. Slowly they seemed to be taking over the holding down, and doing some talking. The guy stayed on the floor. I couldn't make out what the police were saying but at one point one asked, "And have you taken anything with that?" I noticed a girl had her arm around him - did she know him? I got the impression nobody else did. At one point the police told people brusquely to move away, apparently including the folks who'd held him down. But in general it was all very politely executed.

It had to be ten or fifteen minutes since I'd seen the two men on the rails - of course it's so hard to tell - but it did occur to me that no trains had come, though mine had been due for a long time. Although I hadn't seen any staff, they must have been stopped. I was sort of loathe to get onto mine when it did arrive. I wanted to stay and see what happened. But it wasn't as if anything I did, or knew about, would help him now. Calling the police had been in my hands: now everything was out of them. I went home.

* * *

I was shaking a lot as I got onto the train and sat between people who had no idea what had happened. It seemed very odd that none of the dozens of folks watching had exchanged any communication. I guess it was because it wouldn't have helped. What was passing through the minds of those who hadn't pinned the guy down, hadn't called 999? Had they been appalled at the thought of him dying or was it just something to watch? Had they seen me call 999 and did they think I was doing the right thing? It didn't matter, of course. It's just that . . . well, this hadn't seemed how people are, usually. The number of times someone's spontaneously helped me drag a suitcase upstairs, or even spotted me looking lost and come to see where I was going. Or just happily begun a chat. Yes, in London.

I walked home fast, as always. It was still cold, but my own shaking had I think warmed me up. This kind of thing lets loose all kinds of emotions. I wanted to call my parents, but as they're doctors and saving lives is routine to them, I was afraid they wouldn't be impressed. I hoped that guy would be taken to hospital and get what he needed. And, of course, I wondered what the hell he'd gone through.

He must have been out of his mind to do something so publicly. Did that mean it was just attention-seeking (a cry for help), or that he was so far gone that he wasn't thinking, or that he honestly didn't think anyone would stop him? Four years ago, during that teaching course, I had three detailed suicide plans and all of them involved ensuring I was alone and, if anybody turned up, they wouldn't have time to stop me.

I certainly didn't begin this blog expecting that I would reveal anything so personal, but what the heck - once something's public anyone trying to use it against me would look bloody silly. (And if you are for example an employer who'd turn me down for a job because I've once felt suicidal, I don't want to work for you anyway.) Suicide does happen, it does affect people, and there is no point in not talking about it.

At the time, it seemed that nothing was within my control, and it was only going to get worse. I was far away from home with no real friends anywhere remotely near me, and no time to contact those who mattered. There were so many documents being demanded of me that were intrusive and personal and gave people with power too many more weapons. The reasons I wanted to teach were just the things the teaching profession seemed to wish to attack - in fact my very self as well as my dreams seemed to be their target. That and really obvious bullying, such as criticising me loudly in front of the pupils, teachers and teaching students, or the technicians keeping me waiting for 45 minutes and, while I was still standing there, greeting the other student enthusiastically and helping her immediately when she came in without an appointment. And a teacher, knowing this had happened, charging me with booking equipment that he knew I knew the technicians would refuse to provide. I reported all this and was told "oh, how sad" by the course director. My mentor and his colleagues blamed me, informing me that either this had not happened or that it was my fault it had, and upped their vigilance and destructive criticism of my teaching. I knew that nothing I did would make them pass me - that everything I did I would have to write about and that they would state that it was a failure. In short, I was dependent entirely on the judgment of other people. Home was no respite; I was sharing a very cold grubby house with a girl who among other things almost constantly played music so loud that my body and furniture shook, and screamed her head off if I asked her to turn it down. I was the only person on the course without a car and a nice place to live, and one of only two without a family or partner living in the same house being a constant support. No rest, no control, no hope, no alliance, and a weird sort of grief - that's not a combination you can easily solve.

It's a pretty basic feeling, desperation, and a pretty basic factor that stopped me. I wrote a goodbye letter to my family - at which point I saw my mother's face with an expression of knowing what I was going to do. I couldn't do it. Simple as that. In fact, I decided if I was willing to destroy my own life, I might just as well cripple myself financially, so I moved house. That did improve things. It only delayed the inevitable as far as the teaching went - but it was very uplifting to realise how very easy it was to make a major change.

There was a massive shift in my thinking. I realised this a year later when I finally found a sympathetic doctor. He asked me if I was suicidal. I said no, and meant it, but mentioned that I had been a year previously. He asked me what I would do and I told him. It occurred to me that I had absolutely no idea then (I had moved back home by then) what I would do. If I ask myself now, I have no idea.

If you're feeling like that, it does end. And no, you're not the only one. I have read of, and been told of and confided in, too many similar situations to feel that posting this is somehow going to expose me as a freak. There are so many hopeless situations, so much cowardice and bullying, so many power games in this world. And of course there are so many other reasons other people have for feeling like that; I doubt my case is remotely unique, but nor do I think it a descriptor for other people.

It does pass.

I wonder what happened to that guy. I worried all the way home that he would do the same thing again tomorrow. Can he be helped? Do we have the resources to do so? Will the right people be in the right place at the right time? Can he make a drastic change to his life - is he in a position to do it? I don't know. I would love to know if he's OK but I guess I'll never find out.

Suicide has been much in the news lately - this is written not long after the death of Gary Speed. Comments on Facebook and other such treasure troves of wisdom ask: "How could he have been so ungrateful? He had a family, didn't he realise he had any responsibility to them?" A frequent response, which is probably true, is that he was no longer in a position to think in that rational way - perhaps he felt, if anything, that they'd be better off without him. Prior to 1961, suicide was illegal - a book I read in my early teens, "Tell Alice" I think it was called, included a family which had lived in permanent shame because a daughter had attempted it.

Stigma and shame solve absolutely nothing. Same with disability and mental illness. Making an act shameful will not prevent someone from falling victim to circumstances that will make them carry out that act - and stigma and shame includes responses such as "he was irresponsible to do that to his family". Yes, a person in full happiness and control would be, but the very point is that that person has lost such happiness and control and needs to get that back before such things can be expected of them. This page sums it up perfectly: the unbearableness has outweighed the ability to cope.

At this point I know I'm treading on very thin ground, being utterly inexpert in such matters, and I don't want to go and put out any misinformation or distress anyone for no good reason. So I won't attempt to analyse any further.

The other thing that prompted me to write this honest and soul-bearing post (although frankly what happened to me could happen to anyone, so it's not even as personal as all that) is the deluge of positive and honest reactions I got on Twitter when, still shaking, I got home and shared this story.

Several sent me virtual hugs and sympathy for having seen something so awful. A few sent me blogposts linking to their and their friends' stories, about how someone's suicide or attempted suicide had affected them, and what happened - they were frightening and painful, but life-affirming: we are all people, most of us care very much about each other, including complete strangers. So many congratulated me for calling 999, which was a little embarrassing as the heroes in the story were surely the blokes who reacted so fast and held him and particularly the one who got down on the tracks. So many expressed sorrow and empathy for the man who wanted to die. And so very many told me, publicly and privately, that I was right to bring up suicide and that it affects so many people and should be talked about more. It chokes me up just how many people have come closer, much closer, to ending their lives than I did.

If you are feeling that way, or you know someone who is, please take other options first. Talk to someone about it, contact an organisation. Don't worry about wasting their time. Don't think your needs are less than others who call them. They're there for you as well as for other people. If you feel guilty, just acknowledge that you do.

These are a list of organisations I've come across, heard of, been sent - please add to them in the comments if you wish.

Metanoia - "If you are thinking about suicide, read this first"

The Samaritans - you can phone them, write to them or walk in

Mind - information for families and friends as well as individuals

Suicide Forum

NHS Choices has a range of phone numbers and websites, including some listed here. They also suggest seeing your GP. Other places suggest going to Accident and Emergency.

The Calm Zone, specifically this page

And, if it's already too late, Survivors of Bereavement by Suicide

And a bit more lighthearted, Questionable Content. Yes, really. This arc in the story starts here (five pages earlier) and Jeph Jacques, the author, recommends an American site, Suidology.

I've decided to edit this paragraph as I felt so bad about it. I initially was terrified someone suicidal might come to me for help and I would need a miracle to save them, so would fail. (After I did my First Aid course I was warned that if I tried to help someone I might make a mistake and be sued. That sort of thing.) But whatever I wrote looked like I was saying "Sorry, but whatever you feel, I can't help." I then came across this list of things you can do if you get a suicidal call and none of them require a miracle - they're all quite simple. I recommend a read - it contains good news for both parties: that the important things are talking and listening. It's surprisingly simple to ask for help, and it's surprisingly simple to give it!

If my distressing evening and my witnessing what that man did leads to one person reading this who will pick up the phone when they need help, then that's all I can possibly want. Back to astronomy at some point - honest!

Space's Explosive Candles

This blog post is an adaptation from this Object of the Day, which is an adaptation from my course at Queen Mary. Here will go back a lot further into the history of the violent events in space that prove vital to astronomy: the standard candle.

A hundred or so years ago, a computer went every weekday to Harvard College Observatory's plate stacks, and compared plate after plate of glass. That computer was a determinedly selfless lady named Henrietta Leavitt; "computer" was the job title of one who analysed astronomers' results, from plates to notebooks to calculations. "Plates" in this case were sheets of glass onto which projections from telescopes had been collected by a light-sensitive silver nitrate solution, capturing the patterns of stars. This meant both greater accuracy in measurements, and a permanent record. (Today, Harvard College Observatory holds thousands, although obviously they are no longer used for observing.)

A "positive" and "negative" plate could be taken of any sky area - white stars or black stars - and laid upon each other. These average out - if the two plates are exactly the same. But if anything has changed in that area of the sky, the object in question will leap out, starkly black or white against the grey.

In fact, this is pretty much the same technique as Ice Hunters uses; more on that in this post from June.

Women were not at that time permitted to use the telescopes themselves. However, as she worked - at first, without pay - on the thousands of plates, Leavitt spotted many variable stars. (Variable stars are stars that change in brightness; they had been objects of interest for some time, but regarded with as something amateurs rather than professionals studied.) The discovery she made that earned her a nomination for the Nobel Prize - but only three years after she died, by someone who was not aware that she was dead - was Cepheid variable stars, a type of star whose brightness rises and falls in direct correlation with its mass.

Stellar mass is directly proportional to its luminosity, and as light's intensity falls in direct proportion to its distance - the inverse square law - it is possible to tell how far away a star is. There are three factors, and if you know two, you can deduce the third. There's a brilliant explanation here at Hyperphysics about how the inverse square law of light (and gravity) works:

Leavitt did not know exactly how far away each Cepheid was, but she had a very useful sample to study: those in the Magellanic Clouds.

The Magellanic Clouds, so named for a Portuguese explorer, Ferdinand Magellan, who used them to navigate while sailing around Africa, are a couple of nice little dwarf irregular galaxies in the southern hemisphere. Leavitt did not know the distance to these, but did realise that they were far enough away that she could treat all the Cepheids in them as being effectively the same distance away.

This APOD shows the Magellanic Clouds over the Very Large Array during a lunar eclipse. The link will show you a map of what everything is in the sky.

Extrapolating her results led to a bombshell. As telescopes improved, Edwin Hubble was able to spot Cepheids in the Andromeda galaxy, and calculate their distance. Andromeda was completely separate from the Milky Way. Harlow Shapley, who while showing that Earth was not at the centre of the Galaxy was nonetheless convinced that our Galaxy was the only one, was shattered when he heard. He thrust Hubble's letter to him at his young colleague Cecilia Payne, saying, "Here is the letter that has destroyed my universe."

It turned out that there are several subclasses of Cepheid variables - and not knowing this led Hubble to wildly overestimate how fast the galaxies are receding from each other. Nineteenth century geologists, biologists and physicists had rocked the world by showing, through geology and evolution, and radioactive decay, that the Earth was over four billion years old rather than a few thousand as religious history taught; and Hubble's figures suggested that the Universe was only two billion years old!

Henrietta Leavitt had started a new way of looking at the Universe: she revealed the first set of standard candles. It was Walter Baade and Fritz Zwicky who discovered the next sort: supernovae.

Zwicky and Baade were close colleagues in the 1930s, but at the advent of the Second World War, some scientific friendships fell apart (the most famous being that of Heisenberg and Bohr) and theirs was one of them. But they both made outstanding contributions. Zwicky predicted gravitational lensing and dark matter, and Baade identified Population I and Population II stars, which taught us a lot about galaxies. But they had time to separate the already known novae from the much more impressive supernovae, and to predict the neutron star - the complete collapse of an object that had reached the Chandrasekhar Limit.

Chandrasekhar, known as Chandra, had predicted a strange but inevitable law of white dwarfs. A white dwarf is what is left of a star once it has burned all the hydrogen fuel in its core (the hydrogen at the edges is too far away and too cold), and it has stopped shining - though it will remain extremely hot for billions of years. However, should this white dwarf have a mass more than 1.4 solar masses (a solar mass is the mass of the Sun - about 2,000,000,000,000,000,000,000,000,000,000 kg, if you care) its gravity will be stronger than that of the repulsion between electrons which basically gives everything its solidity. This idea was not widely accepted, and he could not predict what would happen. Baade and Zwicky, with more observations and probably more knowledge of nuclear physics under their belts, predicted that protons and electrons would fuse into neutrons. This gives off a staggering quantity of energy, and because electron orbits make up virtually all the volume of an atom, the white dwarf shrinks to a tiny, unimaginably dense object only about 20km across.

A neutron star is what is left after a supernova. (Supernova 1987A, on whose rings the Galaxy Zoo logo is based, has confused astronomers by not so far appearing to have left one.) As with Cepheids, there are different types of supernovae. The most important difference is type I and type II. Both basically involve the collapse of the star's core. (Stars don't automatically collapse when their cores are over the Chandrasekhar limit because of the furious heat of nuclear fusion maintaining an outward pressure.) Type II is the explosion of a star between nine and and up to fifty times heavier than the Sun.

A type II supernova still has an outer layer. A type I supernova does not. These are divided into the subclasses of type Ia, Ib and Ic. Type Ia is the collapse of a white dwarf that has accumulated more material since the star's outer layers were puffed off into space. Types Ib and c are the core collapse of a star, making them more similar to a type II explosion, but their outer layers do not contain hydrogen. Type Ia supernovae have a very special property: the transition from white dwarf to neutron star always happens at precisely the same mass - 1.4 Suns, the Chandrasekhar limit.

And because they are of the same mass, the explosions are of exactly the same brightness. Therefore, they are an ideal standard candle. And because they can outshine entire galaxies, these candles can be seen billions of light years away.

It was examining those that are fairly far away that led to the Nobel prize winning discovery of the accelerating expansion of the Universe. By "far away" I mean with a redshift of under 1, so not exactly at the edge of the observable Universe: far enough to get a really large scale of what is going on, but not so very far that we're looking back at ancient history. Near enough to give a picture of modern times. Naturally that discovery is still being questioned, but the papers (Perlmutter et al and Riess et al) were extremely thorough - indeed, thorough enough to be held up as examples worth learning from, as well as critiquing, as part of my course!

What they found was that the supernovae were fainter than we would expect. And because this is, basically, a local effect - though one over huge scales - it means that expansion is going faster than we thought it is. We know that inflation, unfathomably rapid expansion, took place when the Universe was less than a second old. But we had been assuming the Universe's expansion was slowing down ever since - like a ball thrown up into the air, ready to hover for a moment, and then crash through the greenhouse windows or into a paddling pool or similar.

It turns out the ball has a booster rocket, which is dark energy. The density of dark energy never changes - but, as the volume of of the Universe is ever increasing, the density of matter decreases all the time. There isn't much dark energy about per given volume. But there's more all the time. And we found all this out through standard candles.

Just how standard is a standard candle? Science is never as straightforward as would be convenient - though that only contrives to make it even more interesting!

Not all Type Ia supernovae are made quite the same way - or, to put it in more scientific terms, they may have different progenitors. A white dwarf may start off as under 1.4 solar masses, but accumulate enough material to pass that limit. There are two ways it can do this, and both ways are through starting off as a binary star system. Its companion may still be a star, and it may drag off its outer layers. Or its companion may also be a white dwarf, and they might merge.

(It used to be predicted every so often in astronomy that a star might grow by passing through a nebula, but in practice nebulae are far too rarefied for this to be more than negligible - and the star's stellar wind drives off surrounding gas anyway. Also, two white dwarves merging will not make a type Ia supernova if the both their masses add up to less than the Chandrasekhar limit. If that happens, if they have enough hydrogen, they will become a star again!)

This little theoretical paper predicts that the "single degenerate" supernova - the star plus whit dwarf - will explode in the direction of the host star, and contain hydrogen from the star in its spectrum; while the "double degenerate" supernova - the two white dwarves - will have a different shape and contain no hydrogen. (They are called "degenerate" because the term "electron degeneracy" refers to "degenerate matter", i.e. matter crushed to a point where it only stops being a neutron star because of the electrons holding it apart.) It predicts, in the latter scenario, that the lighter white dwarf will break up and form a ring around the heavier - like Saturn's rings - and the resulting explosion, when it occurs, "may be expected to be axially symmetric, but predominantly of the form m = 2. That is, there is an additional reflective symmetry about the equator. Here the character of the explosion changes monotonically as the viewing angle moves from the pole to the equator." (I think I know roughly what that means, but I'm not quite sure how to describe it! Also, we do not yet know whether or not that paper's predictions are correct. Science will, hopefully, find out.)

It also depends on what the white dwarf is made of, as pointed out by Robert Gagliano, who is one of the major posters on Supernova Zoo. Even if the explosions have roughly the same characteristics, their spectra will not, for white dwarfs may be made of carbon, sometimes oxygen, and may or may not also contain hydrogen and helium, which may or may not be ionised - all these affect the spectrum.

Finally, and to me the most interesting point of all: as this paper points out, although there aren't necessarily two distinct types of Type Ia supernovae - there is more a continuum (like galaxy shape, really) - it is established that spiral galaxies tend to host brighter supernovae than elliptical galaxies. This paper, from zookeeperKevin, points out that it is correlated with a galaxy's starforming rate. One of Galaxy Zoo's great finds was about galaxies and colour. "Roses are red, spirals are blue, or at least so we thought until Galaxy Zoo": spirals tend to live alone, where there is plenty of free cold gas, and therefore are blue with star formation. Ellipticals tend to live in clusters, where there is no free cold gas, and are therefore "red and dead". I've written more about this here. The exciting exceptions are blue ellipticals and red spirals. What, I would like to know, are their supernovae like?

A normal red elliptical, normal blue spiral, less normal blue elliptical, and less normal red spiral, taken from the Galaxy Zoo Forum.

Now, if all that fried your brain, go and soak it in the music of a Supernova Sonata, or read Alice Allen adapting William Blake to the supernova.

Cults, laws, and free speech

Cardiff Skeptics in the Pub turned a year old on 20th September. The day before - it also being a Monday - we held its birthday party, with crisps, cakes, balloons and two very special guests: David Allen Green and John Dixon to revisit #Stupidscientology.

Thank you @wmjohn for this photo. Are there any more?

It was a good time to be all insane and swoony over the astonishing fact that our baby group had launched a whole year ago - that had been a pretty good day too. Thanks to all the speakers who've been so far: Simon Perry, Ash Pryce, Andrew Holding, Simon Singh, Hayley Stevens, Deborah Hyde, Jon Ronson, Trystan Swale, James Onen, obviously David and John, Rhys Morgan who's every so often had another news snippet for us, and the great comedy cast of July, whose names for which my memory is embarrassingly incomplete. And the people who've helped with lifts and chair stacking and spreading the word, generally being enthusiastic and supportive, and the audience for keeping us going, and the lady who brought along some profiteroles!

Appreciation expressed, to I hope the smiles of those receiving it and not too much boredom from everyone else (Skeptics leaders love it when you visited one of their events!) - we visited the subject that had got John famous. It may look like an idiotic piece of red tape, political correctness gone mad etc on the surface, but the implications were surprisingly sinister.

David has written a brilliantly detailed blog post about it here; I recommend a read. In short, John, in between tweets about what he was up to in London, had tweeted that he was hurrying past a Church of Scientology so the stupid didn't rub off. A while later, a scientology Twitter account began following him. Well over six months after this, someone complained to the council about the tweet, mentioning, I might add, that they thought there might have been two other tweets they objected to but they could now no longer find them on Google. It was a great many months more before his fellow councillors could make the decision what to do. In the end, they did not take it to court, though John gave us the impression that he might rather have enjoyed himself if they had.

John defended himself with great humour and sense: someone having attempted to make him look a bigot, he was able to raise awareness of quite a lot of unsavoury information (links provided by me, not him) about the Church of Scientology that made "stupid" look like the kindest possible description. You might enjoy this video of him standing up to Kirsty Wark, and being much politer than she was in her attempt to make him appear rude. David's knowledge of law gave him expertise in tackling this issue of free speech defense versus "bigotry" accusation, with weapons I would never have thought of - for example, in his criticism of the document by the Ombudsman, he did not mention the author, because "you can't defame a document". John actually skyrocketed to fame whilst in a tedious two-hour meeting. His mobile was switched off, and he had no knowledge that David had brought the case to the country's awareness. When he switched it on, he had 700-odd new followers and umpteen tweets and voicemails waiting for him.

This is of course far from the first time David has got involved with an issue like this. Not scientology, but a case where the law is being treated as a weapon, rather than a means to get justice.

"The Church of Scientology has as much right as anyone else to assert and protect their ultimate legal rights," he writes. "But it is misconceived and illiberal for litigation (or the threat of litigation) to be used by itself as a weapon."

L. Ron Hubbard, who founded Scientology, is quoted as saying:

"The purpose of the [law] suit is to harass and discourage rather than win. The law can be used very easily to harass, and enough harassment on somebody who is simply on the thin edge anyway, well knowing that he is not authorized, will generally be sufficient to cause professional decease. If possible, of course, ruin him utterly."

In other words, the point is not winning or losing. As Simon Singh found out, even if you win, you have lost thousands, sometimes tens or hundreds of thousands, and years of your life. Very few people in their right mind would take that on if there was any way out. The way out is to back down, to apologise, to retract all your statements, to make out that the individual or organisation suing you has nothing to be ashamed of - and your peers will self-censor their own work, too.

I had something like this happen to me 11 years ago, albeit on a much smaller scale. A boss in whose employment I had been extremely unhappy (the guy I describe at the end of this post, if you're interested) took it upon himself to tell the company treasurer I had said I didn't want to be paid for my last two weeks of employment at his firm - at least, that is what she told me when I telephoned to enquire. When I wrote to the firm to challenge this, I was fobbed off for 3 months (the 3 months in which an employee must begin an industrial tribunal), then suddenly accused of theft on the grounds that I had sent an e-mail to a friend with verbal permission. I was informed that there were 4 logged occasions on which I had been forbidden to use the Internet, and that two other employees had wasted four man-hours searching for any viruses I might have allowed into the company's computers, time I was being charged for.

The charges were blatantly ridiculous, since other employees had routinely used e-mails and often sent them to me, one of my duties was using the Internet, the boss was famous for never logging anything or even being able to use a computer, and he had even claimed that each man-hour cost the company £65 after I had spent the best part of a year daily logging man-hours which were £45. And, as Acas told him, it is illegal to deduct pay from an employee under such circumstances; you have to bring a case against them first. If anyone tried this nonsense on me now, I would laugh in their face. But I was only eighteen, I was extremely poorly, I was inexperienced, and I had spent months being bullied and humiliated by him and had had about as much as I could stand. Now obliged to fight for myself when I was least able to do so, I went to the Citizens Advice Bureau (now being cut all over the place), and although I did not win any compensation I was given back most - not all - of the money I was owed. But it took five months, by which time my sickness had become long-term. He never did drop his threat of suing me. My sickness and the worry that he might do it went on to ruin university for me and whenever I start any new employment I still have an undercurrent of alarm that something like this might happen again. Frankly, if I could have foregone my lost wages and allowed the wrong thing to happen, in exchange for having my health and confidence back, I know which I'd have chosen.

(I would love to name the individual and company that did this - and I bet I'm not their only victim - but sadly, I do not dare do so . . .)

The mere threat of litigation is a massive weapon. For me it was merely "civil action", minor but bad enough. For someone like Simon Singh, or Hardeep Singh, or anyone who someone with as much money as Hubbard had to use the law as a weapon as much as he pleased, the consequences could be much, much worse.

The law, there in principle to do a good and essential thing, can also ruin the innocent. That's why I admire David. He dedicates huge amounts of time and energy, often free, to fighting against that, and defending those to whom it happens.

But that's not the only way the law can be used for personal benefit rather than as it is intended.

A few days ago, Steve Jobs lost his battle with cancer. I've never been able to afford any kind of Apple product, but the effect they've had has really changed things - there's an app for Galaxy Zoo, for instance. The Curious Astronomer and the mother of a special needs child whose life was transformed by Apple have written about that. Sadly, certain people affiliated with Westboro Baptist Church were not so graceful.

This piece of utterly hateful loser-ness circulated the Internet quite a lot shortly after Steve Jobs's death. (She then claimed that God created the iPhone purely so she could insult its founder . . .)

Even though I didn't know much about Steve Jobs, and I'm certainly not an uncritical fan of Apple, I exploded with indignation when I read this. Death hurts. How can anyone use the occasion of someone's death to pick on their relatives? As I've just described, to be kicked when down makes you feel desperate. Why do Jobs's relatives deserve to be made to feel desperate when they're saying goodbye, already knowing the world is watching them?

How, I tweeted, was this kind of harrassment even legal?

I was then immediately challenged by someone I hadn't come across before: Donalbaion, a mature student in Physics. He pointed out that I was arguing against free speech. Simple as that. To deny Westboro Baptist Church the right to harrass the grieving was anti-free speech.

Initially, of course, I was even angrier. Honestly, who would be suffering from a deprivation of their rights more: the bullies, who would be told "No you can't upset these people", or, say, someone who might have to hold a funeral in secret (and therefore deny many others the chance to mourn) if they didn't want to be psychologically attacked? What kind of freedom is it when you can't even have a funeral in peace?

But of course, anger alone isn't much of an argument. What would be the consequence if Westboro Baptist Church was not allowed to exercise its freedom of speech by picking on grieving people?

Donalbaion tweeted me this review of the book "When the Nazis Came to Skokie". In summary: in 1977, Skokie was an area in which a sixth of the residents were Holocaust survivors and their near families. In this very area, a neo-Nazi group wished to demonstrate. The residents fought against this, citing not only the worry that violence might erupt from the demonstration, but their right to live without intimidation from a group who presumably supported the horrors they'd gone through. But on the other hand, to refuse the neo-Nazis a right to protest would violate freedom of speech. The review concludes: "Strum's book shows that freedom of speech must be defended even when the beneficiaries of that defense are far from admirable individuals."

In other words, once someone (say) took out an injunction against Westboro Baptist Church, who else might lose free speech as a consequence? It could be anyone, for any reason. It's just too dangerous.

But that's not the end of the story. All that agonising over human rights, knowing that people are going to be bullied and degraded - that is, according to this piece of writing, precisely what they want us to do. Go and read it now.

Apparently, this is not about beliefs at all. Whether or not they honestly think God agrees with all their statements about who is going to Hell, their aim is that someone else will get angry enough to try and violate their rights somehow. And then they can sue them.

As "El_Camino_SS" has written:

I saw that he was way too calm and collected for what he looked like in the media. I noticed that he never made personal statements against a person, which is verbal assault, and an out against a lawsuit. Also, for a religious fanatic, a group of people who pride themselves on personal attacks, he was running a protest so terribly by the books that I was impressed by it. He will not bait a person, ever. He will not make personal attacks. He will make blanket statements. He will look at a person in the crowd that he thinks is gay, walk over to his stack of signs, pull out the appropriate, well designed, easily read, laminated bright board, and hold it up and loudly proclaim that "gays are going to hell" or some such nonsense, and make eye contact, but he will never cross the line of telling that person that they're going to hell. That would be the part that would screw up the lawsuit. He just wants to get them after him, but wants to appear utterly blameless for damages.

. . . They run too tight of a ship to slip up, and at that point, I realized that the objective of the group was not anything religious at all.

Assuming the above is true - and here I do not claim to know for sure - this seems to me another misuse of law, and it's even more cynical than the type of misuse about which Skeptics here in the UK have heard so much. It's not even, strictly speaking, misusing the law. It's not using archaic silly laws that are set up to benefit the already rich and powerful. It's using a hallmark of civilisation simply to try and get money out of people.

And frankly, I'm not sure if there's anything we can do. With the first type, we can sign the petition to change the UK's outdated and embarrassing libel laws. With this type? We can't change that law, because that way almost everybody would lose their rights, rather than in the above case, where so many would gain them. After all, a civilised society does not remove its welfare state because a handful of people abuse it. And Donalbaion was right to point out that we cannot put free speech to a majority at risk because a handful of people abuse that.

I suppose, in this case, that if anything can be done, it could be a grassroots, done-by-the-people effect. For example, stronger people are less bothered by banners which display the words "God" and "Hate" in the same breath - so a campaign to give people strength in some way. Perhaps similar banners could be waved, saying something like "Civilised people don't target the grieving" - using the Phelps' tactics of blanket statements and never coming across as personal. Just showing solidarity. Bringing a society to a point where it no longer cares. Of course, you good folks in the States may already be doing that; I honestly don't know. My post is about law and free speech, not about any particular church.

And there are things that to some extent make up for the worst. For instance, according to that journalist's post, at least the grieving cannot be verbally attacked, and that these folks only stay for a maximum of 30 minutes. And, more importantly, they are a tiny minority. Take a peep at this Apple store in Chicago (photo taken by Arfon from the Zooniverse). We may not all be Steve Jobs, but if your rights have been violated, in most cases in civilised countries it will only be a few people who've done it, rather than an entire society. Often, most people are on your side.

Astrophysics, here I come

Whew! I'm here!

"Here" is London, the city I was born in and still think of as home. Through a friend of a friend I've found some lovely lodgings just outside the North Circular and am getting used to cooking for one again. All of a sudden there are things going on all around me. There are kids playing with remote controlled cars in the streets, there are buses and trains for which I seldom have to wait more than one or two minutes, there are endless food shops, there is shouting and laughter, there are beautiful parks, there are such a huge variety of people, there are all these friends I can meet without travelling for hours. And there is Queen Mary University and a course which, so far, looks as if it's going to be the course of my dreams.

Over the years of running the Galaxy Zoo forum and getting more and more interested in astronomy, I became increasingly aware of the gaps in my knowledge - the more I knew, the more I found there was to know for which knew I needed some training. Absorbing facts is one thing, but mathematics and computer code and the language I call "journalese" (in other words, the very dry style in which scientific papers are written) is quite another. My knowledge contained some of the gorgeous constructions of science, but without the nuts and bolts to hold them together or build on them. The trouble was that neither my undergraduate degree in Environmental Sciences nor my attempt at teaching had been any encouragement to study any more. I had long stopped thinking of myself as academically minded. So I had thrust the idea into the back of my mind and it stayed there for years, until one tedious morning driving to a pretty useless course I was on for work when the idea of doing a masters in astrophysics suddenly popped into my head like a massive bright gold light being switched on.

At work later that day I snuck onto Google and by that evening I knew which course I wanted to do: this one. There weren't very many others, to be honest (at least not without also doing an undergraduate degree), but this seemed both the friendliest and the best tailoured to what I wanted. I began filling out the form, but procrastinated, worried about money and unable to get hold of one of the referees I had in mind. Then it was off to Boston for the 218th AAS Conference and that was it.

That conference was one of the happiest times of my life. I was invited into what turned out to be a waterfall of astrophysics, flooding me from all sides. Everywhere I went there was more. And miraculously, I found I actually understood a lot of it. Not a large percentage. But I did begin to notice that what I wasn't understanding was the jargon, the mathematics, the acronyms. The concepts themselves were fine. And many astronomers didn't understand the acronyms either: astronomers were specialists, so a cosmologist for example might be bemused by the many Kepler reports on extrasolar planets - and they were quite happy to tell me so. Even more encouragingly, several astronomers wanted to talk to me at their work, and were quite happy to explain things to me in detail. Since I was writing an article for the Astronomy Now magazine, and because the older I get the less self-conscious I become, I never worried about putting my hand up in seminars or press conferences to ask questions. And the upshot of that was that I heard the same thing from umpteen genuine scientists: "Where do you study?" and upon hearing that I was not a student, "Oh, you must do a PhD! Your questions are really good - you've obviously got a great aptitude for this subject!"

(It's really hard work, not aptitude, but we are often reminded that the former is what really makes the difference. For instance, I also used to be one of the worst public speakers I know. I just curled up and mumbled. Seriously. Now, due to repeatedly bludgeoning myself with the task, public speaking is one of the things I'm best at. In fact this was one way I reasoned myself into going ahead and applying: if you can run the Galaxy Zoo Forum, co-found Cardiff Skeptics and learn public speaking, I told myself, you can conquer mathematics. We'll see in the next few weeks if I was right . . .)

This autumn, I'm studying Cosmology and Research Methods. The latter is quite a new course and there is some worry that it seems "soft" and is somewhat hard to teach. It's actually incredibly valuable - everything anyone studying science needs, everything I wish I'd been told as an undergraduate, everything you need to know if you want to back up some claim you've made (or debunk someone else's). The material we are reading for it is also anything but "soft"! Next term will be Astrophysical Plasmas, and Extrasolar Planets and Astrophysical Disks, both of which sound pretty mysterious! Next year will be the Galaxy, the Solar System, Stellar Structure and Evolution, and Electromagnetic Radiation in Astrophysics - these are all more familiar to me and I can't wait to take them, but since it will also be my dissertation that year, I'm glad to be getting the difficult things out of the way now.

It's a part-time course because for one thing I want to go slowly and for another and MSc course is expensive, as is living in London. So I'm also looking for a job. If you happen to know of any science or science communication related jobs, please let me know. Science communication would of course be my ideal, but I realise I can't be choosy! As well as astronomy I have some background in Environmental Science and Chemistry, plus teaching English and Science, plus other supervisory roles, plus an awful lot of admin. Oh, and some experience of working with vulnerable people - which has been the subject of a lot of my outraged-at-injustice posts the last year or so. Oh, and I'm a very good proofreader and editor. (This is not a post in which I'm going to bother to be modest.)

I'm hoping to get myself together and get blogging more; it's been a topsy-turvy year and I haven't done much for some time. Meanwhile, because I owe so much to Galaxy Zoo for getting me into astrophysics, and because it's so much more fun to feel as if I'm doing the course for hundreds of other people as well as me, and because it'll make sure I myself keep up to date, I'm writing about what I'm learning here on the Galaxy Zoo Forum. Please come along to ask questions and join the lively discussions it's prompting!

Apologies, also, for not writing an Ada Lovelace Day post. Today is Ada Lovelace Day, in which we celebrate women in science, and women who have influenced us. Can I make the excuse that I've been busy starting off on what might one day make me, myself, a female scientist? (I don't know if I will aim to do that or not yet. Let's just say that it looks a lot more possible than it used to.) Carolyn Porco recently tweeted a list of inventions you probably didn't know were made by women, and I also want to make a tribute to Wangari Maathai, a Nobel Peace Prize winner who died a few days ago. Her loss to the world is great: she has done amazing things for women, for politics and for the environment; you can read more about her at the Green Belt Movement.

Happy Ada Lovelace Day, and may neither men nor women ever be put off from learning!

Why do stars live in galaxies?

Coma Cluster from SDSS

This post is dedicated to David Allen Green, who asked me after seeing my PubSci talk why the Universe is full of galaxies - stars living in "cities" - rather than stars being evenly spread around, so the Universe is one big galaxy.

People often remark that the Big Bang sounds like an explosion, or is described as an explosion - and that is a violent, chaotic, destructive event, so why did it produce so much order? I have written about the Big Bang itself in more detail here. David knew this was not the case. His question is, in more scientific terms, this: if it produced so much order, and everything expanded - why did it expand with some areas being denser than others?

I'm not going to answer in the traditional way a scientist would expect. I have a tendency to answer things by telling the story in the opposite order from the traditional way. Rather than starting with the Big Bang, I'm going to start with stars.

The Big Bang did not emit stars. It did not even emit atoms. All this stuff came later - when things had cooled and been able to clump. Paradoxically, a star cannot form from hot gas, only cold, because the atoms (or molecules, or ionised atoms and electrons) of a hot gas or plasma are whizzing around too fast to be able to stick together and condense.

So, how can gas cool down? There not being fridges readily available in outer space, it basically needs to be shielded from radiation. This happens in dust clouds. We can't see the centre of our own Milky Way Galaxy because of all the dust in the way. Longer wavelength radiation can get through a lot of it, but not optical (visible light). Where the dust or gas is thick enough, it can cool. And that's when it gets affected by gravity. It contracts.

Star formation typically occurs in clumps, turning the whole area apparently blue. Take a look at these two galaxies and you'll see where the star formation is occurring:

Galaxy Zoo 1 tutorial

In the spiral galaxy (left), the stars are moving in the same direction. In fact, they move into and out of dense areas, rather like cars moving into and out of traffic jams. This allows regular shock waves to pass through gas clouds, triggering their gravitational collapse and setting off star formation. In the elliptical, on the other hand, each star is going on its own route (see here - click the arrow on the right - for some rather silly star orbits which still remain stable, like a ball falling back to the Earth after being thrown upwards). This leads to the gas being in pretty much a mess, too. There's nowhere it can comfortably clump and cool without being disturbed for a while. Indeed there are no gas clouds left - an elliptical is known for having used up all its gas and having no fuel left. (There is some, but it is too hot and thinly spread to form stars.)

When stars do form, they often start in clusters like the Pleiades:

Digitised Sky Survey; Wiki

The nearest area to us where star formation like this is occurring now is in Orion's Belt. Next time you see the familiar hunter and those three stars lined up, you can relish the knowledge that although it looks dark around them, there's a churning gas cloud there and a great deal going on inside it - APOD has a gorgeous picture collection here.

Star formation stops in the cluster once the stellar wind from the young stars blows off the rest of the gas; we know the Pleiades are young because there is still a lot of gas surrounding them. Due to the gravity of stars in their local neighbourhoods, these young clusters then tend to drift apart. While in Boston I heard one theory that we may have captured some of our comets and even planets from our sister stars in the Sun's infancy. It was an odd talk . . .

Anyway - this was not the question, but I hope it demonstrates that star formation is not straightforward, and that things need to happen to get it going. I suppose one could say space needs to settle down and get ready.

It does demonstrate why stars don't live outside galaxies: basically, they need to form from gas clouds, and any self-respecting gas cloud that happens to collapse in space won't just generate one star at a time - it'll generate lots! The closest we can get to these is an irregular galaxy. These are clumps of star formation without a local supermassive black hole, and without a defined structure such as spiral or elliptical. They are also far smaller than the big monster we live in and the sort the Zoo has been studying. (This is why Richard's project is so exciting from a purely scientific as well as a citizen science point of view - well, duh, if it wasn't good science, it wouldn't be good citizen science either. But you know what I mean. He has already found that irregular galaxies are much more starforming even than beautiful blue spirals.)

Irregular galaxy from SDSS

So, stars form when gas clouds collapse. And a good thing too, or we wouldn't be here - not only does the Sun give us light and heat and keep the Earth in a stable orbit, but it's nuclear fusion in stars that creates heavy enough atoms and molecules to form rocks and iron and organic molecules and water and so on that are needed to create life. (As Carl Sagan put it in Pale Blue Dot, it's funny that we consider this the anthropic principle when it might just as well be called "the lithic principle", that the Universe was primed to create rocks, too.)

But why should there be clouds of gas in the first place? If the Big Bang sent everything out in its own direction, and the force of the explosion was equal, sending everything in a sphere (assuming there are three dimensions - in any case, sending equal quantities of everything in equal directions) - then everything should be the same space apart.

Picture a given area of atoms, say of hydrogen. Each is the same weight and has the same gravity. Each is equally spaced from all the others. Each is pulling on the ones around it - so each feels a force from all of its neighbours in every direction. Like a tug of war whose sides are entirely evenly matched, nothing goes anywhere.

But the Universe did not expand quite evenly. Its evenness - its homogeneity - is very, very nearly complete. Especially after inflation. When we look back at the time before any atom was cool enough to get near another, the differences were less than one part in ten thousand.

That time is called "the dark ages" and it's the limit of how far back we can see. There's something in the way. And that's another sort of cloud - or to be exact, a plasma. A plasma is a seething mass of ionised atoms and their electrons - atoms whose electrons have been torn off. (There's probably no net electric charge, since for every negative electron zooming around, there's a positively charged atom somewhere.) The Sun is a plasma. And the one at the edge of the visible Universe is called the Cosmic Microwave Background.

We can't see through it because its edge marks the end of a time in the Universe when it was so hot that light couldn't get through it. (Recall that as you look deep into space, you look back in time. When we look at the Cosmic Microwave Background, we look at a time over 13 billion years ago. When you look at the Sun, you look at a moment 8 minutes ago - and hurt your eyes, incidentally, so I don't recommend that.)

Space was so hot and dense then that whenever a photon of light went anywhere, it promptly collided with an atom or an electron and was sent off elsewhere. It would have been like looking through a thick cloud - or, indeed, the Sun itself, where the same thing happens. (This is why the light that shines down on us is millions of years old. It took that long to escape.) But once the Universe had cooled enough, electrons were able to bind with protons and neutrons, to form neutral atoms. At that point light could get through. We cannot look back any further than that boundary; we have to look at the rest of the Universe and work out what happened before that point.

The COBE satellite, which launched in 1989, made a discovery about the Cosmic Microwave Background that explained our existence: some parts of it were hotter than others. Just a bit. And you've read earlier what hot particles do. They whizz around, they bounce off each other - they don't clump together as easily as cold ones. So everywhere in the Cosmic Microwave Background that was a tiny bit cooler got that tiny bit denser.

And that's where gravity set in. That's where the clouds of hydrogen and helium started to fall together. I have yet to read an astronomy book that doesn't jokingly relate this to capitalism - that the rich get richer and the poor get poorer - in other words, any area with just a bit of density will, over time, attract more and more material. And, conversely, the empty areas get empty. Marcus Chown has written a whole book about how the Cosmic Microwave Background was discovered, and the tiny, tiny fluctuations in it - Afterglow of Creation.

(I once asked Chris if heat alone could account for the fluctuations. Things were very hot then, and as in Brownian motion - the random motion of water molecules that kicked a pollen grain around and therefore allowed Einstein to demonstrate that atoms did exist, and measure their size - there would be a certain amount of randomness: particles moving now one way, now another, like waves on a lake. Would that alone be enough to account for the fluctuations? Chris said no. They were caused by something more, some other irregularity in the Big Bang. I don't know what.)

Stars and galaxies soon formed; the furthest - that is, the earliest we can find - you can read about here. Look at the Hubble Deep Field, a region of space containing vast numbers of very early galaxies, and you'd think that all that uniformity you'd expect from the Big Bang hadn't happened at all.

NASA; Wiki

And yet . . . David was also not wrong. Not at all.

Before writing this blog post, I dug out Horizons of Cosmology by Joseph Silk, which Astronomy Now had kindly sent me in exchange for a review, and which prompted this blog post. I thought it would probably remind me of a few useful things, and it did.

Galaxies live in clusters. Our own Milky Way does - and it is steadily zooming towards a larger cluster, even while the Milky Way and Andromeda circle each other, ready to merge. And clusters live in superclusters. Superclusters are the largest objects in the Universe. They are like bright filaments through the blackness of space. An accident and emergency doctor and dedicated galaxy classifier once remarked to me that they look remarkably like neurones in the brain.

NASA and Universe Today

Silk describes some of the deep sky surveys, the search to understand inflation and the minute differences in temperature that seeded the unevenness, and goes on:

"The larger the region, the more the universe approaches homogeneity. On average, the universe is completely homogenous. There is no dense centre, no rarified boundary region. Yet everywhere there are galaxies. In some regions, there are slightly more than the average, and in others, slightly fewer. We describe these variations as fluctuations in the average density of the Universe. Some are positive, some are negative.

When we measure the strength of the density fluctuations, in other words, we find that the overdensity or underdensity is smaller with increasing scale . . ."

Float away from our world, and look down at it: it will seem huge. Further, and it will shrink, and so too will the Sun, melding into our local group of stars. Later will come our Galaxy's spiral arm, then the galaxy itself. Then the cluster. Then strings of superclusters . . . the further you go, the more you see, the more similarity you will see. It's like when you break the world down to see atoms, and then electrons and quarks. Nature is simple. The Universe is vast. And I love it.

(You may notice I have created a silly new hashtag called Fizzicks Questions. I hope to answer more - and tell you about some good answers I have been given to my own astronomy questions - in the future.)

Shut up and be grateful - that's an order

I confess I'm a regular reader of the Virginia Ironside column at the Independent. The dilemmas are often interesting and indeed have given me ideas for stories, as well as prodding thoughts about real people I meet. However, I don't always agree with what Virginia says, and today's dilemma was no exception. A lady with osteoporosis in many joints is understandably infuriated with people being made anxious by her slowness and asks how to get them to calm down without being rude. Virginia responded with a blast of accusations of rudeness and being "impossible to please" - "people like you irritate me". Other letters published were all to the effect that the person writing in was basically an ungrateful cow.

Since nobody had any practical advice to offer, I gave mine. I also thought of blogging about how all these accusations completely missed the point of the dilemma. About how fussing, while better than the horrific prejudice thousands of disabled people face, is not the solution. And about regardless of how well a fusser means, the questioner had to live with this situation, and was asking about how to live it better - and being made to feel dreadful is not going to help her or anyone else. However, I don't have to, because BrennyBaby at NewsJiffy has already done it for me - many thanks!

(Related post: Blaming the vulnerable, from back in January.)

Update:

It got a lot more interesting than that. I did not really expect the writer of the dilemma to see my comment - but not only did she see it, she's posted her original letter and got a really good discussion going right here, so please check out the comments. And please join in!