Mini Spinni: The antics of atoms in space

I'd been wondering about emission spectra for a while. To summarise it, what happens is this: electrons exist in "orbits" round atoms. You can think of these orbits simply, like planets orbiting the Sun, or in a more sophisticated manner, as a "wave of probability" of where the electron will be at any given time. There are fixed orbits for the electrons (imagine Mercury being able to jump into Venus or Earth's orbit, but not to a random place in between), and being struck by a photon can boot an electron up into a higher one. This is an unstable, i.e. higher-than-minium-energy state, so at some point later the electron will fall back down again, re-emitting a photon as it does so.

My dilemma was this: if the electron needs a certain amount of energy to move up one or more orbits, and emits exactly the same amount when it returns to its ground state, shouldn't the two cancel out? I.e. why should we see any absorption and emission spectra at all?

I asked our wonderful Chemistry tutor, Tim, this in Brighton two years ago. He told me to think of it as light travelling in particular directions. In the case of absorption spectra, it absorbed it at a particular angle (the light travelling between the source and your eye via it) and radiated it out in a halo, so you didn't really see the re-emitted radiation. And with emission spectra it's vice versa.

Quite by accident I came across some information about hydrogen in space. The interstellar medium is full of hydrogen. Even in regions of "empty" space, i.e. not clouds, hydrogen is present in individual atoms (HI in astronomy notation; a new language to learn after many years of thinking of that as an H-radical). When the temperature is below 100K, or in a denser region, the atoms form molecular hydrogen, or H2, as we find it on Earth. In hotter regions, with starforming activity, the hydrogen is likely to become ionised. In chemistry terms, it is H+ (+ should be superscript!); in astronomy notation, it is HII, or ionised hydrogen. Ionised means that a photon has hit the electron with enough energy that it has knocked it clean off the atom.

So that's the HII galaxies Tom and the zooites are collecting. Hang on. HII emission lines? Emission lines from a proton all by itself, without the electron to be booted up and down any orbit at all? I don't know why I didn't think of it before, but there you go. I asked in the thread, and mukund vedapudi soon came up with the answer. In short, in regions that are hot enough (the vicinity of massive blue stars you get in bright blue galaxies), hydrogen nuclei (protons) and their electrons are constantly recombining as well as ionising. The recombining releases a characteristic emission line just like the Balmer or Lyman series (when the electron drops down to the second and innermost orbit respectively).

But we also detect hydrogen in space with radio waves. How? Photons which fire electrons up into higher orbits need (to the best of my knowledge) to be more energetic than radio waves. Take this picture, from an article about it.

(Credit: sciencedaily.com - the detection of 5 hydrogen clouds in space.)

You can detect hydrogen in clouds and out. In fact there's a specific way to detect cold (but above 100K) lonely HI atoms, because they emit radio waves of 21cm.

I just found out the way they do this. It's to do with spin. I learned enough about that to establish that the Pauli exclusion principle states that no two electrons can exist in the same orbit with the same spin. They can spin one way or the other. That's why you get the s-orbital in hydrogen, and then another s-orbital and three p-orbitals in lithium to neon in the Periodic Table. Each orbit contains room for 2 electrons, provided they're spinning opposite ways.

I hadn't consciously realised that atomic nuclei have a spin as well. But they do. And in the simplest atom we know, hydrogen, which is just a proton and an electron, it's simple enough to keep track of the spin of each. And just like electrons in orbits, when more than one state is available, the system will prefer the one with the lower energy. That is when the electron and the proton's spin are opposite, not equal.

(Credit: odin.physastro)

In a moderately warm environment, not cold or dense enough for H2 to form, hydrogen atoms can collide, the energy of which knocks them into the state of parallel spins. They will later revert to opposite spins, emitting radiation with a wavelength of 21cm. This allows us not only to detect that there is warm-ish, thin, atomic HI about, but also (using redshift) to measure the radial velocity - i.e. whether it is coming towards us, or heading away.

Why doesn't this work for molecular hydrogen? Basically because molecular hydrogen works quite differently. Both electrons are in a hazy cloud of probability around both protons, and the molecule has a great deal more symmetry. This makes dense hydrogen clouds harder to detect (which is probably why it made the news when 5 were detected in the story above). This is also true of most gases, such as oxygen, in space, because they tend to exist in pairs.

Except, for instance, in the important case of carbon monoxide.

Carbon and oxygen have a different number of protons, neutrons and electrons, which makes them behave differently. Oxygen, for instance, is just dying to grab two electrons to fill up its remaining p-orbitals; we call it "electronegative". (In water it is quite greedy and the electrons spend more overall time around it than around hydrogen, which is why water molecules are dipoles.) This means that carbon monoxide will not have that symmetry which insulates it from our beady eyes.

Carbon monoxide undergoes rotational transitions like atomic hydrogen, HI, so we can detect radio waves from it, at the higher frequencies than HI of 1.3 and 2.6mm. It is relatively common in space. Astronomers believe that it is also found pretty much where hydrogen clouds are, so it's a useful tracer for them. For molecules to form, gas has to be cold. And for a cloud to become dense, it has to be cold. And for stars to form, a cloud has to be dense. Isn't it ironic that star formation can't take place unless the environment around it is cold enough?

That is why radio waves, the longest wavelength of the electromagnetic spectrum and its lowest energy, can forewarn us of some very energetic events in the future. It is because of some of the smallest particles in the Universe altering the way they move around.

Update, 14th May: EigenState on the forum has had a chance to read this post, although I promise I did warn him it might make his hair stand on end. He kindly gave me some great science feedback, well worth a read - he knows a lot more than I do. Here it is.

The Red Button

Whatever you do . . .

Where do people get the ideas for things like this?

Hat tip: Stellar.

A whole train of pinwheels!

One of the ways in which astronomy (and, in my humble opinion, galaxy astronomy especially) is revoltingly lucky compared to a lot of science is the outrageous beauty of our subject - though a lot of biology could make use of that too. Most weeks I could begin a blog post with "It's obviously pretty pictures week on the forum right now!" This week is certainly one such week, and I just feel like giving a tour.

Earlier today, Geoff put up a collection of pictures of the aurora, which are well worth a read. A few days ago, one of our newbies, Terry, started a thread called "space candy", many of which are SDSS treats we have tasted and loved. Incidentally, Terry's special web page about his experiences as a technician at the Mauna Kea Observing Site was fascinating. We know the big names like Newton and Herschel. Just like we know the names of kings and gallant generals. But history doesn't record all the technicians, the teachers, the mothers, the helpers on the forum. Without these quiet souls, the big names wouldn't have done so well. So I was glad when Terry got a round of applause!

Never mind; whether history records us or not, we'll have a great time. Take Tuesday's Astronomy Picture of the Day: the familiar Pinwheel Galaxy, also known as M101.

Credit: APOD.

It's often seen on the Galaxy Zoo Forum, looking like this:

Credit: SDSS.

The two pictures both show it as blue, because of its high star formation rate (mentioned in APOD). It's also an emission line galaxy - no surprise! Countless billions of atoms are so hot that their electrons are falling, radiating light energy of a very specific wavelength, as unique as a bar code: our way of telling what substances are there.

APOD also mentions that the galaxy is large enough to distort its neighbours. But look at M101 itself. Its own arms are hardly symmetrical - the one starting at six o'clock appears to be flying off into space altogether, the one trailing along behind at nine o'clock seems to fancy doing the same thing, and the one starting at twelve o'clock has a great gap and then a bunch of star formation on the far side of that gap. (Isn't it a good thing the galaxy is anticlockwise so the "timing" I'm using appears logical?)

Anyway, Waveney had the sense to zoom out on the Pinwheel Galaxy and showed us what might have happened:


M101 is very near to us, which means it's easily studied. You can have a look at it in gorgeous detail, though without the blue, on Hubble. Here is a huge file - and I mean seriously huge! This is a smaller copy:


Why do spirals so often turn up in nature? Whirlpools, ammonites, hurricanes . . . We argued endlessly about anticlockwise galaxies (which the bias study proved no more common than clockwise in the end), we worry about viewpoint of galaxies and from opposite ends of the Earth . . . and if you search for the Pinwheel Galaxy on APOD, this is what you get.

(Credit: APOD.)

Now looking at M101 in a new light: the Chandra X-ray telescope. (The good folks at which, incidentally, I wrote to recently with a question - I hope to hear from them soon!)

X-rays in space are just the same sort we use in hospitals: a kind of light whose wavelength is far too short for our eyes to see. That means its frequency and its energy are very high, and they're not something we'd like to get in the way of too often! (Hence, doctors and nurses leave the room when they give you X-rays - repeated exposure would definitely harm them.) X-rays are given off by high energy nuclear fusion - we get a few from the Sun, but most photons created in there have spent too many thousand or million years banging into one particle after another to still be that energetic when they reach the Sun's surface.

(Credit: Chandra. That page is well worth a look in detail - for example, it has a nice little video.)

The visual and the infra-red seem pretty similar, spanning pretty much the whole galaxy. That's to be expected; they're weaker forms of light radiated by stars. The X-rays mostly clump together in the middle, in definite dense and less dense areas - with just a few bright X-ray spots in the very places where the arms look very blue and bright. Chandra has another composite image helped along by Spitzer, which was excited enough about a discovery of its own concerning our familiar Pinwheel last year.


One last picture, specially from Spitzer. This is an infra-red image, the pink areas showing dust clouds and the starlight in blue. That one shows what happened in the least disrupted arm with all the star formation occurring outside a "gap" - it looks like a lot of dust got flung out there . . . The more disrupted arms appear to have little gas left. I wonder if that means they'll disappear in a few million years?

(Credit: APOD.)

Finally, I'm delighted to notice that in the Spitzer image, and in Chandra's infra-red, we can see the tiniest little bar. Just as Johan Knapen said at Astrofest, infra-red light is the best way to find bars. Now after all those pictures you will probably want to head to a real bar. Bring some space candy with you!

Insulation from Physics

Stellar is having her time wasted by CGP Physics from the looks of things. Here is a GCSE Physics question she has to answer:

"Tom decides to insulate the loft. This costs him £350, but reduces the amount he spends on wasted heat to £255 per year. Calculate the payback time for fitting loft insulation in Tom's house."

If Stellar will forgive me for a comment like this, that is about as appropriate for her age as it was of my History teacher, when my class were 15 and 16, to show us a cute Walt Disney version of "Animal Farm" and spend the next several lessons with a worksheet to "put all the events in order". Instead of the terrifying message and the analysis of the tyranny, divisiveness and dishonesty, we got sparkly-eyed bouncing farm animals.

Is that GCSE question physics? Isn't it economics, building, arithmetic and environmental science? All of which are important. And all of which have a tenuous link to physics. And all of which is frankly just boring grown-up stuff on a par with the stock market and income tax. Physics is widely criticised as being boring and inaccessible. The least we can do, therefore, is to keep it about what it's supposed to be: how our incredible Universe works.

Paul Lockhart wrote about how miserable it is to "make math relevant to everyday lives . . . people enjoy fantasy". Same with physics. Physics is deep thought. At least let's keep some of the mystery and excitement of the world going before we start worrying about wall cavities and loft insulation. There will be adult years enough to stress about that.

If there are some physics principles to teach about insulation (after all, everyone should know about conduction, convection and radiation - how can I get this bottle to the other end of the classroom? I could throw it, carry it, or pass it along), at least make them intriguing. What about fat versus fur, the way different members of the animal kingdom insulate themselves? What about how to insulate an astronaut in a space suit - keep the dangerous radiation out, and keep their heat in?

I concede that there are many important and useful topics that don't quite fit into any lesson, environmentally friendly building being one of them. (It was a running joke when I was at school that the exam boards changed their minds every year about whether plate tectonics was chemistry, geography or physics.) This is where things like citizenship and general studies come in. Because, nearly two years ago - just when I was about to start teaching - I read a very serious off-putter by Wellington Grey.

Much of what he says turns out to be just too right. I disagree on one point - about the calculations. He was probably teaching a different course, but I watched many difficult and essentially unfulfilling calculations taking place in GCSE Physics lessons. They didn't make inherent sense to me, because - just like with Lockhart's experiences in maths - students were given a formula and told to apply it, rather than encouraged to prod the world and derive it for themselves. Rather than make students learn "F = MA", what about having, "OK, now what if one of you gets very cross and throws their pencil case at somebody's face. You want maximum impact before you get sent to the Head and expelled, so you might just as well make it worth it. What should you do?" Students would advise throwing something heavy and fast. And then: Why? Why why why? Does one have more effect than another? (Before the let's-point-out-the-obvious troops descend, I am not advocating that such behaviour be encouraged!)

For a real example, the head of science at one school I worked in was sighing one day about the experiment to measure the Earth's gravity using a pendulum. You set up the equipment, you get them to use such precision - "and then you give them a formula which they don't understand", i.e. G. Conjuring rabbits out of hats isn't science either. OK, I'm off on a tangent now. I wonder if the syllabus even includes why air is a poor heat conductor?

I particularly agree with him on one point - the pointless debating. I'm not sure that precision attracts many pupils - actually, it's a very frightening prospect for most, though probably magical for a few. It is particularly pointless to get kids to have an opinion on something without allowing them to know anything about it. People debate things if they find them interesting, not because they're told to. I watched a first year "humanities" lesson once in which they were told to put ten statements into "order of importance". The teacher's instructions were: "It doesn't matter if you get it right or wrong, so long as you can explain your reasons". Even if writing skills was the point here, wouldn't it be more satisfying if they had some reasons to assess? That must have felt like walking on air rather than the ground. You can't ask me whether I think peace, the environment or starvation is the most important crisis on Earth without giving me some data about which is harming how many (even if they weren't all interlinked).

I wasn't at all surprised to see the footnote at the article, that Mr Grey has given up teaching. I sympathise. As for the "how science works" bit, I think that is important. But that means doing it, not talking about doing it - which, incidentally, is just what is wrong with "practical" subjects like technology nowadays, which children good with their hands but not so good at writing used to find such a relief - and the same will go wrong with these flashy new diplomas, too, now that they're "going to be more academic than A levels". Do we learn to play football by writing down the rules? You don't learn physics, or how to look after the world, by being bored out of your mind by it all at the age of 14. Hardly surprising that as soon as people get to university, they can't remember a thing they did at school, and have to start with basic algebra all over again.

* * *

PS Am I being thick, or is the question even answerable? It doesn't give a figure Tom was originally spending, in which case how can anyone calculate the payback time? Or does "to" mean "by"?

Book Review: "Copenhagen" by Michael Frayn

I got punched in the throat a few weeks ago. No, not literally, but by a piece of literature: not even a book, but a play by Michael Frayn. Not only that, but I fear I have let myself get drawn into a bitter historical argument. I generally try hard to avoid doing this - I refuse to read "The God Delusion" because I believe such debates are a complete waste of time, changing nobody's opinion and merely causing hurt.

Copenhagen was the occupied capital of Denmark which Werner Heisenberg visited, watched closely by the Gestapo, one night in September 1941 to visit and talk to his old mentor and close friend Niels Bohr. It is the title of a play both historical and scientific, and the most fascinating I have ever read. It is the home of the Niels Bohr Institute, where the Copenhagen Interpretation - the new way of describing atoms, using quantum mechanics - was born, after difficult but exhiliarating years of debates and struggles between physicists all over Europe.

I love the story of those scientists. Most of them were young, and breaking new ground, and they fought to the point of tears and avoiding each other for weeks. They were spaced all over Europe, yet operating closely - "Everyone in and out of each other's departments." "Papers and drafts of papers on every international mail-train." I wish I'd been there! I feel the same way about Galaxy Zoo. I honestly believe we might change the face of science and in the long term science education. But my God I get het up if there's the slightest sign that our standards are at risk.

It was Chris's fault that I ordered a copy of this play. I read it again and again at the time - early November last year. The science was enthralling, as was the story. (I didn't feel a need to watch the play, let alone a film - the dogma that "it is always easier to understand when you see it" has never applied to me.) It took several reads to establish exactly what they were talking about, how much each character knew. Their perspectives keep flipping from past to present to future (or rather, from the 1920's to 1941 to after the war, since, in the play, they are "all of us dead and gone"), which was an added brain-teaser until I knew all the steps. It was like having to learn a piano piece or a dance back to front before I could start appreciating the finer points.

Anyway, I picked it up again somewhat absent-mindedly a couple of weeks ago. And again I was reading it over and over. Until suddenly one evening it was like being punched in the throat because what happened was so terribly sad. As a teenager, Heisenberg had had a terrifying time towards the end of the war. Aged 20, his university supervisor took him along to hear Niels Bohr speak, which was a thrilling event. "The war had been over for four years, but we were still lepers . . . in Germany we worshipped you. Because you held out your hand to us." Heisenberg challenged the mathematics Bohr was using, and Bohr came to meet him afterwards. It was the start of a seventeen-year friendship; Heisenberg was almost adopted into Bohr's family. "In the whole history of physics no two men were ever closer," wrote Thomas Powers many years later.

But in 1939 there was war again, and soon Denmark was invaded. Bohr and Heisenberg were both patriots and on opposite sides. Worse, Bohr's mother was Jewish, and in 1943 he had to escape being rounded up by crawling down the beach on his hands and knees in the dead of the night to be smuggled away on a sailboat.

"Copenhagen" looks back on an intriguing, eternally confusing event that took place in 1941: Heisenberg visited Bohr and clearly told him that Germany was working on a nuclear project. But afterwards, the two could not agree on what had been said, or even where. Heisenberg was depressed afterwards, and Bohr clearly angry with Heisenberg for the rest of his life. Heisenberg was no Nazi supporter, but he was clearly working for the regime. Bohr concluded that he wished to provide Hitler with an atomic bomb. Heisenberg claimed that he wished no such thing and was in fact trying to avoid it, perhaps even asking Bohr's advice in going about doing so. Today, many scientists and historians disbelieve Heisenberg and feel his behaviour was immoral and arrogant. What did the two of them say to each other?

That is what the characters in the play try to answer. It deliberately takes place in an unrealistic "afterlife": all three characters are dead, but get together - as they both decided not to do in real life, because trying to resolve it only made it worse - to try and work it out. They also fail to work it out in the play, but at least they explore it and at least each man gets his say.

Present in the conversation are, indirectly, the audience, who take the place of the Gestapo, and the people who subsequently interrogated Heisenberg for many years afterwards. Directly present is Bohr's wife Margrethe. In real life she and Niels were devoted to each other. She typed up all Bohr's papers and he plainly discussed all his research with her. She was less enthusiastic about Heisenberg than Bohr was, and discouraged her husband from allowing him to visit in 1941. The play opens with them debating whether or not to invite him, and they agree that he can come on the condition that they don't discuss politics. (But physics and politics, as Heisenberg remarks, are "painfully hard to separate".) Her presence requires the two physicists to use "plain language", so the audience can understand the science; and she disbelieves most of Heisenberg's explanations. "Every time he explained it became more obscure."

Much of the play is told in a sort of monologue, the characters speaking to nobody and everybody simultaneously. "We operated like a business." "Chairman and managing director." "Father and son." "A family business." It sounds as if they are taking parts singing in a choir. During pauses in the conversation, they follow each other's thoughts: "Silence. And of course they're thinking about their children again." "The same bright things. The same dark things. Back and back they come." Many times the play returns to "the same moments I [Bohr] see every day" - his eldest son, Christian, drowning in a sailing accident. Apparently Bohr and Heisenberg could finish each other's sentences, and once you're used to it, it sounds like close relatives talking. At other times, they argue about the things they and the other scientists did in the past - "shoot" each other by beating each other to it writing papers, skiing, piano-playing, hiking, and Schrödinger's visit during which Heisenberg was angry and jealous and Bohr talked Schrödinger to the point of illness. These snippets are both hilarious and some real philosophy to chew on - "that particle that goes through two slits at the same time" being compared to skiing at 70 k.p.h, and making a decision about which way to swerve when necessary!

Even during the most heated moments of the play, Frayn can suddenly make me snort with laughter, by the two men knowing each other so well. "The speed he skis," Heisenberg remarks of Bohr, "he has to do something to keep the blood going round. It was either physics or frostbite." Later, Heisenberg challenges the Bohrs to murder him as an enemy, adding that this would not be immoral in a war, and that all they have to do is tell someone what he said. At white heat, Bohr interrupts: "My dear Heisenberg, the suggestion is . . ." "Most interesting. So interesting that it never even occurred to you." Bohr was famous for saying "this is most interesting". Frayn brings it out very well how widely Bohr was loved. He has the characters mention that Bohr was dubbed "the Pope" by his students, that it is impossible for anyone to accuse him of ever having done anything wrong. I get the feeling that whatever Heisenberg hoped to gain from the Copenhagen meeting, Bohr's kindness would have been a real encouragement to go ahead with it.

That closeness, I think, is the tragedy - that for seventeen years that there was this special cooperation, the shared excitement and science and walking and talking - and then, because of the war, it died.

There is strangeness. There are differences between the characters and the real people, of course. There is eerie unease when they can't agree on what they said or where, or who did what during their science. Some of things they say sound odd. It particularly struck me early on, when Heisenberg has, in their memories, just arrived at the Bohrs' house in 1941. Bohr says: "I believe you had some personal trouble . . . I'm so sorry." It took a few reads of the commentary to establish that this meant Heisenberg had been interrogated by the Nazis for teaching "Jewish physics" (i.e. relativity). He was accused of being a "White Jew" and forbidden ever to mention Einstein in his lectures. Heisenberg's reaction is very odd: "A slight misunderstanding . . . These things happen. The question is now resolved. Happily resolved . . ." Surely he wasn't happy about it. He was still treated with suspicion, and he could hardly have been anti-Semitic or happy with the persecution taking place. In 1933, when Hitler came to power, Hans Geiger dismissed Hans Bethe from his post as assistant without the slightest regret, and Heisenberg offered Bethe a job despite the dangers he must have known this would bring. Bethe sensibly refused and went to work in the USA.

It is so obvious it is almost a cliche that Heisenberg's life, aims and activities are rather a parallel to his legacy, uncertainty. Michael Frayn is clearly fascinated by human motivation. (I read a linguistics book when I was 15 and have since been used to the idea that we have a dozen different motivations at a time for every word we say.) Frayn wrote: "He wanted to distance himself from the Nazis, but didn't want to suggest that he had been a traitor. He was reluctant to claim to his fellow-Germans that he had deliberately lost the war, but he was no less reluctant to suggest that he had failed them simply out of incompetence." Robert Butler, writing in the commentary of the student edition, points out, "The position for many 'good Germans' was that they wanted Germany to win the war and Hitler to lose it."

This is not enough for many critics of the play. Frayn writes two postscripts, in which he baldly details the criticisms, accepting some and refuting others. (He writes with the confidence of one whose work is good enough that he need not really fear any criticism.) There are many, but just as I can't mention every point in the play I liked without this blog post ending up the size of the Encyclopedia Britannicca and spoiling too much of the plot for you, I won't go through them all. I will mention the one I thought was silliest, though: apparently, there were loud calls for more condemnation of the Nazis. As Frayn points out, the evil of the Nazi regime is "a given". For goodness sake, we don't need yet another sermon on what we don't need telling; the physics and the ethical debates and the mixed-up memories are far more fresh and exciting!

Personally I think it's a sort of trendy modern hysteria. Few people alive today remember the war, so we don't know quite what it was like and therefore whether it might happen again. It's not reality to us, it's a nightmare. It must be fended off. Sadly, people are so worried about what other people think of them that one can't even mention the war without ritual condemnation of the Nazis! Tell me honestly, do you really think that unless someone goes out of their way to state otherwise, they're pro-Holocaust? An old friend of mine accused me of sounding so simply for using the word "Jewish", not in a remotely derogatory way. In my father's school days it was quite acceptable to mention the fact that someone was Jewish; it was like mentioning that I wear glasses or that Spain is sunny. (One of the mostly-Jewish school football teams dubbed themselves "The Smelly Yids"!) Another friend of mine was once warned never even to say "black coffee". Oh, and when discussing schoolkids with one another, teachers who wish to avoid trouble must say "pupil", not "boy" or "girl", because apparently any assumptions that might be made are more important than the actual information they wish to give or obtain.

I think this is wicked. To forbid mention of someone's culture and heritage is to deny them a face. It's also to subtly imply that there is something wrong with their gender or nationality or what have you, but that you personally are too smugly refined to say so. And similarly, to assume everybody guilty of sympathy with the Holocaust unless they go on and on about it is to contribute to another culture of suspicion.

(Mealy-mouthed-ness - using the correct words, or not - doesn't mean anything, anyway. Genocide goes on today and not only do we not do any more about it than we did for the Jews during the war - I doubt the victims of Darfur for example will get another country to live in - we daren't mention the fact that it does. As Amnesty International pointed out the other day, it's inadvisable to use the word "genocide" even during an admission that it is actually taking place. I'm not kidding about people "not having a face", either, or why would there have been those two films a few years ago about the "human sides" of Hitler and Jesus? Because people are so silly they actually need proof that every human has a "human side". How babyish.)

Getting back to the play, I also hugely admire Frayn's attempt to tackle very difficult science. He describes himself in the postscript as "a non-scientist" who "can't offer any opinion on the physics". He was certainly braver than the newspaper reviewers. Butler offers seven reviews mentioning the reviewer's own ignorance of science and fear that they needed a physics qualification to understand the play - fears which were mostly dispelled, it seems. It's sad that people are frightened of science. I hope citizen science will help put an end to that; we wouldn't be frightened of a play about art or music. Frayn's ability to have the characters talk understandably, but as scientists, about fission, neutrons, and quantum physics, is brilliant. He has a glossary of some of the lines used at the end of the book. For "that particle", he makes a double joke: "One of the mind-bending aspects of quantum mechanics is that when a particle is faced with the choice of going through one of two slits it appears to go through both of them. (Don't ask.)" Because, of course, "asking" - or using light to "see" the particle - would deflect its path anyway!

* * *

Frayn's masterpiece intrigued me enough to get Thomas Powers's "Heisenberg's War: The Secret History of the German Bomb". It seems impossible to get what is politically correctly termed "a balanced view" - Heisenberg has attackers and defenders. P. L. Rose's book, "Heisenberg and the Nazi Atomic Bomb Project, 1939-1945: A Study in German Culture", for example, is an attack, if that is more to your taste.

Now, like the mealy-mouthed folks I criticise, I wasn't there during the war. But I have a relative who's lived in a terrifying dictatorship abroad, and I'm a history fanatic and an Isabel Allende fan, and like most people I've had the odd instance where I've had to be sly to win a fight because to open my mouth too wide would have been disastrous - so I don't consider myself totally ignorant. I feel an intense admiration for and sympathy with Frayn's Heisenberg, and I think the things his fellow physicists and historians feel he should have done were not actually any better than what he did.

We come to a major question now, which I had never really considered before: Why didn't the Germans manage to build a bomb?

When I was younger I assumed it was simply that America was more powerful and advanced. As one learns more, one finds out that Germany had been bursting with impressive physicists - but the expulsion of the Jews, such as Einstein, sent the brains off to America and brought poetic justice. What about the physicists who stayed in Germany? One physicist, Weizsäcker, stated: "History will record that . . . the peaceful development of the uranium engine was made in Germany under the Hitler regime, whereas the Americans and the English developed this ghastly weapon of war."

Hardly. Take this review by Ian Kaplan: "Those [physicists] who remained in Germany fell into one of three categories: (1) they were Nazis, like Nobel Prize winner Johannes Stark; (2) they could not leave, for what ever reason, or (3) they were selectively blind to the regime around them and its implications . . . The evidence of the Farm Hall transcripts is morally damning. Heisenberg and his colleagues knew about the murder going on around them, but they still worked on the German nuclear program. They did not build a nuclear weapon because they did not know how."

Perhaps there was a fourth reason for not leaving Germany: that one's family and friends and students and fellow countrymen were there too, and one does not abandon all these people lightly. Do we call on all Americans to emigrate if they disapprove of the Iraq war or Guantanamo? Am I going to condemn myself to exile over Ian Tomlinson? No, there are people here besides the police and the government, and I'd rather stay and work here with them. Exile is not a happy future. If the scientists had all left, Nazis would have been put in their places anyway, and then goodness knows what would have happened.

It is possible that the scientists did not know how to build a nuclear weapon; Heisenberg claims that he had some idea, though he had actually got several points wrong. But perhaps - and if you think about it, this isn't as pathetic an excuse as it sounds - they did not want to know. Towards the end of Allende's first novel, "The House of the Spirits", a Communist in danger of being murdered by Pinochet's soldiers explains to his lover that he cannot tell her where he hides: "If they find you, it's better if you don't know anything." The German project, when found by the Allies, turned out to be very primitive, and they claimed they only wished for an energy source. If this is true, one can hardly blame them for wanting that much. People were starving and freezing.

Heisenberg claims in the play that he had hoped that physicists across the world could collectively refuse to build atomic bombs, and then mankind would be safe from the worst of destruction. This was a futile hope. There was no way the Allies would agree to that, and his team could hardly tell Hitler later that they refused to cooperate. But I got interested enough to Google the transcripts from Farm Hall, the house in which ten physicists including Heisenberg were imprisoned (though very well treated) for six months, and their horrified reactions after they heard about Hiroshima are hardly "morally damning":

HAHN: . . . For [Uranium-93] they must have an engine which will run for a long time. If the Americans have a uranium bomb then you’re all second-raters. Poor old Heisenberg.
LAUE: The innocent!
HEISENBERG: Did they use the word uranium in connection with this atomic bomb?
ALL: No. . .
HEISENBERG: Then it’s got nothing to do with atoms, but the equivalent of 20,000 tons of high explosive is terrific. . .
HAHN: At any rate, Heisenberg, you’re just second-raters and you may as well pack up.
HEISENBERG: I quite agree.
HAHN: They are fifty years further advanced than we.

. . .

WEIZSÄCKER: I don’t think it has anything to do with uranium. . .
HEISENBERG: I don’t believe that it has anything to do with uranium. . .

. . .

WEIZSÄCKER: I think it’s dreadful of the Americans to have done it. I think it is madness on their part.
HEISENBERG: One can’t say that. One could equally well say, "That’s the quickest way of ending the war."

Later:

HEISENBERG: We wouldn’t have had the moral courage to recommend to the Government in the spring of 1942 that they should employ 120,000 men just for building the thing up.
WEIZSÄCKER: I believe the reason we didn’t do it was because all the physicists didn’t want to do it on principle. If we had all wanted Germany to win the war we would have succeeded.
HAHN: I don’t believe that. But I am thankful we didn’t succeed.

. . .

KORSCHING: If one hasn't got the courage, it would have been better to give up straightaway.

[At this point, Gerlach, at who this remark was aimed, stormed out and was later found weeping in his room. Meanwhile the debate continued:]

DIEBNER: [The Reich authorities were only interested in immediate results.] They didn't want to work on a long-term policy as America did.
WEIZSÄCKER: We were all convinced that the thing [bomb or reactor? Nobody knows] could not be completed during this war.
HEISENBERG: Well, that's not quite right. I would say that I was absolutely convinced of the possibility of our making an uranium engine but I never thought that we would make a bomb
and at the bottom of my heart I was really glad that it was to be a Maschine and not a bomb. I must admit that.
WEIZSÄCKER: If you had wanted to make a bomb we would probably have concentrated more on the separation of isotopes and less on heavy water.

Why are they discussing what they are thinking now? Why not while they were working together? Well, it's suicidal to say exactly what you think in a dictatorship or war. You don't know if your neighbour might turn you over to the authorities. They were probably all trying to guess what all the others were thinking; Diebner, in "Copenhagen", is criticised as having "ten times my [Heisenberg's] eagerness [to build a bomb]". But after the bomb had exploded, they knew they had lost. It was too late, they had no more to lose now.

In "Copenhagen", Gerlach is described as "our old Government administrator". He does not seem to have been a Nazi, but was afraid of what might happen to him if he returned to Germany now, and felt responsible for the defeat and deaths of his fellow Germans. Otto Hahn, as Heisenberg said, "wants to kill himself, because it was he who invented fission, and he can see the blood on his hands". He had contemplated suicide years before when he realised what fission could do. Major Rittner, their host/warder, and the other physicists, were very worried about Hahn that night, but Hahn also found time to comfort Gerlach:

HAHN: Are you upset because we did not make the uranium bomb? I thank God on my bended knees that we did not make an uranium bomb. Or are you depressed because the Americans could do it better than we could?
GERLACH: Yes.

Powers states at the beginning of his book that the American scientists feel no guilt at working on the atomic bomb, and Frayn reiterates this in his play - Margrethe asks incredulously, "You're not implying that there's anything Niels needs to explain or defend?" - though he later cites two Americans, including Oppenheimer, feeling revulsion at what their weapon has done. But the German scientists appear to be condemned for both having a project to do, and for failing to complete it. "Hands that had actually worked on the bomb wouldn't touch mine," Heisenberg laments in the play.

I still admit there's a lot I don't know, and I must find the courage to read the critical literature as well as the supportive. But I will say one last thing: those who judge Heisenberg and the other physicists harshly might like to read the Göttingen Manifesto.

Sailing Among the Blues

The first name thought up for Galaxy Zoo was "Galaxy Safari". Astronomy is like a journey sometimes - through space and time, stopping at astonishing tourist sites or, further on, the wilderness. It's definitely true that Google Sky tours have suddenly become the height of fashion on the forum - now Half65, Ben Hoyle and Fermats Brother are all making them, and I expect more will follow!

I often also get the feeling that we're a little like biologists - or rather, that we've changed the whole of galaxy science from specialist zoology (sorry about that) to worldwide ecology. Traditionally, an astronomer might spend a lifetime studying up to 30 galaxies, and we've got used to the usual types - ellipticals are red, spirals are blue, galaxies are pretty, in science and view (and sorry about that too). Our discovery of blue ellipticals and red spirals was like discovering a parrot in a penguin colony, or a polar bear spotted like a leopard. We now know that, as polar creatures are white, the environment dictates galaxy colour. Being in a cluster turns galaxies red. And being alone turns galaxies blue.

That isn't due to natural selection, of course - it's due to the available gas in the local environment. And there's one type of galaxy that always seems to be blue, and that's the irregular galaxy. Irregular galaxies might be past mergers, or they might be little splodges or wisps of star formation, far smaller than your average spiral or elliptical, and with no defined shape we can so far describe scientifically.

(Credit: SDSS.)

Our brilliant Waveney wrote an Object of the Day on our irregular galaxies project yesterday. I won't try to cover all our aims or findings in this post, but one result is definite: they are nearly all blue. We've found a few that aren't, but none that are red, like ellipticals in clusters. Generally speaking, they are much, much bluer than your average Galaxy Zoo galaxy.

Irregular galaxies seem very common, although we can only see the nearest few because they're so small. As sepos stated in another Object of the Day, 90% of galaxies are the low surface brightness variety - again, not the sort we're studying. Could we be focussing on the magnificent tigers and elephants and whales of the universe, and missing out on the beetles and plankton? Do large bright galaxies depend on the existence of these dim little puffs as large organisms depend on the existence of bacteria? Or are these lowly little galaxies simply a by-product of far-flung gas, and have no effect on their larger neighbours?

Going back a moment - why are they mostly blue? It's because they're forming stars. As blue light is more energetic than red, that means the hottest stars give off blue light. That doesn't mean stars start off blue and go red later. It means that whenever star formation takes place, a few massive stars invariably form. These hydrogen-guzzling monsters outshine all the red stars in the galaxy, giving the whole galaxy a blue appearance - but they don't live very long. After a few million years, only the more sedate yellow and red ones are left.

Star formation is the subject of yet another game on the zoo (do you think I need to create a "games" label?) - not to mention Chris's current research interest at Oxford, or so the websites say. Intriguingly, his research apparently "focusses on the use of sulphur compounds". Which seems contradictory to me, since such compounds would not survive the heat and fury of stars. Perhaps they're a feature in gas clouds, or a product of something or other. This is the most informative paper Google could provide. If he ever has time, I'll ask him to talk me through it.

(Starforming region Corona Australis. Credit: NASA.)

So are all irregular galaxies young? Or are they simply like lonely blue spirals and ellipticals - continuing to drift through space and always encountering more gas? Is the Universe still too young for any area to be fully empty of gas, and will we see red irregulars in another few billion years? What about irregulars in giant superclusters, assuming they wouldn't all merge with the giant ellipticals already living there?

Some questions we already seem to have answered, at least to the best of our ability, on Galaxy Zoo so far. For example, we've established that galaxy rotation is generally random, though spirals near each other have a greater likelihood of rotating in the same direction - another indication that environment is very important in galaxy formation. (For more on galaxy rotation, I would recommend all ZookeeperKate's posts on the Galaxy Zoo Blog.) But I don't think we need worry that we've already found out everything. There is a lot more left to come!

Sand, snow, sea, sorrow, and strangeness

To see the world in a grain of sand and heaven in a wild flower . . .

. . . take not only Blake's advice, but now that this is 2009, follow random people on Twitter and you never know what you might find. EarthVitalSigns, part of NASA, just tweeted the depressing Man's Greatest Crimes Against the Earth. These include activities such as wanton slaughter, toxic waste spills, and deforestation. The gallery stays away from the effects of climate change (coral reefs decaying due to increasing carbon dioxide in the oceans, terrible floods in Bangladesh, that sort of thing) and go for tragedies so obviously direct results of human activity that nobody could argue with them. (On a selfish note, for a story I'm writing. I have dim and distant first year Environmental Science memories of something like a massive mud flow into the oceans, due to someone mucking about with a river or something, which can actually be seen from space. Does anyone remember anything more about that?)

Below this picture gallery on the Discovery galleries site was . . . strange fruit. At this point I was glued to the screen and clicking continued from there. What sand grains look like magnified 100 times - and where they came from. An underwater gallery, whose web address would seem to suggest there's a video to watch, too. There are a lot more picture galleries to investigate. That Discover Magazine is a black hole to get sucked into - have you seen their article about time?

And my favourite - snowflakes. I tried to follow the link and was infuriated when "Firefox prevented this site from opening a popup window" and googled their investigator, Libbrecht at Caltech. Here he is.

That was another random post straight out of the blue. Which is Twitter for you. Cheep cheep.

Einstein's wise words

My signature on the Galaxy Zoo Forum is a quote from Einstein: "Peace cannot be kept by force. It can only be achieved by understanding."

It sounds serene and peaceful, and very obvious too. I changed to it from a rather more blatantly political signature, Steve Biko's "The most potent weapon in the hands of the oppressor is the mind of the oppressed", for various reasons - for example, it looked (though is not meant to be) a bit too aggressive for a moderator, and indeed a bit ironic when I had to remove forum posts (at least in the eyes of those who deem it as necessary to swear or use sexual language as to voice their political opinion). And who could complain that I quote the great scientist?

It appears that the riot police would. I've been getting increasingly disgusted with the Independent in the last few years and haven't been paying the attention I should to the news - it's so easy to live peacefully in Pembrokeshire. Good job I started following Amnesty International on Twitter and noticed their daily blogs. This one led me to a very shocking video from my home town of London.

Ian Tomlinson was, according to the Guardian, simply walking home from work. Watch for yourself; can you see any sign that he was involved in the G20 demonstration, let alone the least threat to the police?
This man was killed. He seems to have been beaten 3 times with a baton as well as falling to the ground. He died of a heart attack* a few minutes later. The police claim they tried to resuscitate him and it was all the protestors' fault he died for impeding the ambulance. Can you see much sign that they were concerned for his welfare here? I can't.

Update: It wasn't even a heart attack, but internal bleeding. The newspapers finally released that story a few days ago.

That is not the way to keep the peace. Not only is it evil, it's stupid. Police are there to get people to behave properly, right? Randomly killing innocents won't encourage that.

The passer-by who handed the video in to the Guardian was a New York businessman, who'd wandered in out of curiosity. He states that "the family were clearly not getting any answers". You can read more witness statements here; one of them, "C", states that Ian Tomlinson had already been assaulted by the time he got to the site on video. I wonder if one policeman radioed another to say "trouble-causer coming towards you wearing a blue and white shirt"?

The IPCC first turned the story over to the Metropolitan Police, which sounds rather like a teacher telling a weeping bully victim to take their complaint to the bully, but then changed their mind. The patronising language quoted in the newspapers - such as "raises obvious concerns" and "the unfortunate death" - makes me sick. They'd be using different language about any death of one of their own.

I don't think this is an isolated incident. I did glance through the letters of Monday's Independent - check out the one at the top. Someone in my family used to live in a road next to a London football stadium. After a match, the police forbade him to enter that road. He said, "But I live there." Their reply? "Not today, you don't."

This said, condemning all police officers won't bring Ian Tomlinson back to life, or help next time the riot police are called. There are many very civilised police men and women, who are probably suffering from just the kind of contempt and disapproval I got from some of the public when I decided to try teaching - the resentment of an unfeeling, paper-pushing, bossy bastion of the government who neither knows nor cares about the real needs of the people they're supposed to be serving. It's gruelling to work in a system gone rotten, but trying to smuggle in some good when you can; it wears you down and shortens your life and makes you feel there's no hope. A policeman my family knows says that police successes are never praised; another one's health was ruined by the culture of excessive drinking.

I rather suspect the culture is similar to that of education; it's lost its values. Or rather, values have been replaced by trademarks of how much you're putting up with. Or maybe people just aren't being brought up properly because their parents are forbidden to spend any time with them, and they're not learning civilsation?

It was Robert Peel who thought up the idea of a national police force, which is why they're often called "bobbies". Say what you will about the police, it's far better than the predecessor - rich landowners having their own private armies. But the police should be friends to the public, not enemies. Equipping them with bullet-proof cars with tinted windows, and all that gear and batons, cuts them off like a dictator in an armoured tank. Hmmmm. Now, how to effect a change like that?

But the most important thing is not to be cowardly. Don't accept others' right to attack people because they have a baton and uniform. If by any tiny chance you a) are reading this, b) were there, and c) haven't said anything - please do so. If you don't speak, you're not being neutral; you're propping up injustice. Yes, I have been on demonstrations and will continue to do so when I can. If Blair can spout about how "we will not allow the British way of life to be spoiled by terrorists" (no - only by your Big Brother State, mate), then - protestors, don't allow your protests to be spoiled, either. Cameras for cameras, too. They can film the public and hold data on us, but the public can do the same thing.

Sigh. Wouldn't a bit of civilised co-operation work so much better?

If you were wondering, they're lorikeets at Paradise Park

This month, there is a 4 page spread in the Astronomy Now magazine about Galaxy Zoo 2. Sadly, it's not available online, but it's worth a read (you should be able to get it at some newsagents or supermarkets). It begins with the wonderful Carl Sagan quote: "Somewhere, something incredible is waiting to be discovered." We start off with the basics of galaxy classification and how Kevin and Chris turned our "problem" of too much data into the public project we now know and love. It then discusses the red spirals, switching-off of star formation and the effects of the environment, and goes on to "odd" features and whether perhaps the Hubble classification should be a continuum rather than discrete "E" and "S" classifications. There's a lot of information in the article, not all of which is on the forum yet. Tantalising hints again . . . !

There is a nice box about the work of one of our new astronomers, Ben Hoyle, and another box about how one zooaholic became addicted, with the following picture:

This is a huge cage named "Flight of the Rainbows" in a conservation zoo named Paradise Park in Hayle, Cornwall. I've been goodness knows how many times in over 20 years, and it never fails to produce that big daft grin on my face. The birds are lorikeets, and they are adorable! They live in a huge flock and scream to high heaven, and love perching on people. You can go and buy a little tub of glucose and cod liver oil for 50p and they'll come and sit on you and often shriek in your ear, climb in your hair, etc. When I was about 16, one of them got very attached to this particular jumper and spent a good hour or so climbing around in it. (Yes, they can be a bit messy, so take a spare shirt and a lot of tissue paper . . .) They have the most amazing tongues, like thick pipe-cleaners with a bit of grey-blue fluff on the end!
Paradise Park is also home to otters, pretty much my favourite wild animal, which used to be very endangered by miserable sadists hunting them (remember Tarka the Otter and Ring of Bright Water?):


Do you remember the red panda who escaped from his zoo in Birmingham? A couple of them live at Paradise Park, too. They have the sweetest faces, but don't turn them to the public very often. I got a shot of the most amazing tail, though . . .

(I knew my cat Cassie reminded me of something . . .)

One of their features is flying displays. There are birds of prey every day - I'll never forget watching a lanner falcon fly; my childhood memory supplies me with a speed of over 100 m.p.h. stated by the devoted keeper and demonstrator. Or their beloved old barn owl, Barnaby. Sometimes children in the audience can try on the glove and have the bird sit on their hand. The only problem is how devastating it is for little ones not to be chosen! More recently they've added demonstrations of parrots flying, and the stories about them - their natural habitats and behaviour, or their mistreatment (or well-meaning lack of luck) with their former owners. They've trained cockatoos to collect pound coins from visitors' hands. Believe me, it is well worth paying £1 to have a cockatoo come and pick it out of your hand with its beak!

There is also a play area called the Jungle Barn, a sweet little steam train (yes, I did go on it aged 26), a nice pub just outside the park (and they stamp your hand with a parrot or monkey so you can go back in again), a flamingo-filled garden, and a farm with goats and pigs. Again, you can buy a bag of food to feed them. (They get a set amount of food every day so presumably feed them whatever people don't buy.) Just before you get to the farm, there is a nice hot washbasin on the left, and a reminder to wash your hands after doing this. And on the right is a shed full of rodents - rabbits, chinchillas etc. The chinchillas have a long, long drainpipe spanning not only all around the shed, but out of the shed and into another little hutch across the path. You never know when a chinchilla might zoom above your head while you amble innocently along, perhaps laughing at the ginger pigs or the goat who ate a hole in your jacket pocket to get at the paper bag! They really zoom, so you can see they need the racing track. I dread to think what happens if two collide - CERN springs to mind - but I expect they hear each other's footsteps . . .

Anyway, it's a wonderful day out, and easy to find. It's also doing a great job with conservation. One of its projects is the World Parrot Trust. A third of all parrot species worldwide are threatened; I remember a heartbreaking statistic from when I was little, showing a beautiful bird with the label "Only 15 left". They're threatened both by the destruction of their habitat and by poaching. Birds are a good indicator of how the environment is doing generally; if they're flourishing, probably the plants and insects and other, less noticeable wildlife is, too. And on a more personable (but less fair or scientific) level, parrots are so intelligent and sweet! The World Parrot Trust is an international effort, with a great many projects under way. So if you ever happen to get a card or letter from me, it might well have a parrot or two for decoration - which will most probably have come from the Paradise Park shop!

2,617,570

. . . classifications were achieved during the 100 Hours of Astronomy at Galaxy Zoo. Yep - in 4 days, we got two and two-thirds million galaxies . . .

We'd been chattering away about the possibilities in the IYA thread. April 1st was getting nearer and nearer and we weren't hearing anything, and in any case I for some reason had the notion that it would be cool for us to have our own separate 100 hours, so that zooites could explore other things during the 100 hours and lots of people could come and try the zoo another time - perhaps I was inspired by a letter-writer's remark about how it had packed more punch for Robin Cook and Clare Short to resign at separate times, giving Tony Blair two crises to deal with rather than one. So I suggested a galaxy marathon on April 28th, which is Kevin's birthday (speaking of whom, nice article about him again!), and Fluffyporcupine's into the bargain. But all of a sudden we did go ahead with the 100 hours.

For the biased images, Kate made what we called a "zoo-ometer". Now we had the next version, a Zoonometer (TM), as I'm supposed to call it. We watched the total climb . . .

. . . and on we raced, click click click . . .

. . . and at approximately 12:50 on Saturday afternoon, we wondered why it didn't burst and speculated upon ways to show it - with just over 28 hours to go.

And we decided to plug on. And bet each other that we'd get to 1.5 million. We just about did, we thought.

Then suddenly this morning Arfon announced we'd got 2.6 million. How did we do 1.6 million in the 28 hours remaining?! It's a great story why, and shows just how fast we were going - you can read a splended and entertaining account by our expert Arfon here. I would go so far as to suggest that we were up at a relativistic speed, making things appear differently between observers . . .

WELL DONE ARFON! You are a star!


Many people are all for the special targets to meet again, though not to have that all the time or we just get used to it. The Hawthorn effect states that people perform better if they know they're being observed, a variation on the uncertainty principle with a bit more certainty about which way things will go generally!