Wednesday, 25 March 2009

"Welcome to the zoo . . ." The galaxies that made us love them

Messier 109 as seen on SDSS

I often suspect that, in science lessons at school, most observant people have this nagging sensation that deep down something is wrong. They're writing out neat equations on paper, measuring the lengths of springs or the oscillation times of pendulums, typing mysterious formulae into their calculators to bring out results that, whilst they may show a satisfactory pattern, they in themselves don't mean much. They're learning the names of the colours of the rainbow using the mnemonic "Richard of York gave battle in vain", while out of the window last week, across the horizon tomorrow, might well be a breathtaking, ethereal stripe that makes the most blase student gasp and point it out.

NGC 2785 and UGC 4867

We know there are the most thrilling things out there. We know, because we've been told, that there are little molecules vibrating and doing all sorts of funny things with their electrons that we can't see. We know that out of our cities roam wonderful animals, whose lives, from the majestic tiger to the tiny little beetle under the windowsill, are complex and would be marvellous to watch. We know there are stars and great sights above our head at night, if only the streetlights and clouds and tiredness at bedtime would go away - we remember what we hear about black holes and warped space-time . . .

Galaxy Cluster Abell 2151

The trouble we have with all this is that the older we get, the less we feel we can touch it. The childhood excitement we felt for science is akin to that we'd feel for a toy that got taken away and given to someone younger. Sour grapes such as "oh well it's boring" feels better than missing it. As Chris remarks in this podcast, most people drop science after GCSEs. Most of the handful of A level students go on to something else. Only a few science undergraduates go on to do a PhD, and after their PhD, only those who remain are entitled to be called "scientists" and wear white coats and make discoveries. That doesn't mean the public don't respect science. If you believe the papers, "a scientific study" is gospel. It was done by people who managed to get through all those formulae, whose experiments went right, whose application of key words pleased the examiners - again and again and again. These are people most of us will never become. Many of us wouldn't feel entitled to touch science for ourselves, even if we did know how.

NGC 2403

But for over 50 years we have had The Sky at Night. We've had the Moon landings. And for a shorter, but substantial time, we've had the digital revolution and international efforts such as the Hubble Space Telescope. These pictures appear in books, on TV, in newspapers. There's no mistaking that astronomy is real. So when the Internet calls, "Scientists Seek Galaxy Hunt Help", with assurances that you need no astronomy background to take part, how could that not be exciting? (After teaching hundreds of children, I have yet to hear anyone say it sounds boring!)

Besides, we're spending more and more of our time on the Internet. As Clay Shirky pointed out in the Web 2.0 Conference (an excellent article, by the way - a must-read in my opinion!), sitting back and passively watching TV isn't good enough for everybody any more. In a society whose corporations are getting huger and huger, where the most rebellion most of us can enact is playing Solitaire and pinching the company's paperclips rather than working, people like to be part of their entertainment - to contribute as well as to receive. So citizens are now contributing to web pages and public collective efforts. This includes Wikipedia as well as things like lolcats and youtube.

NGC 3945

Wiki? Our temple of accuracy and reliability? Ha ha, yes, I know. But what a resource, and it's free to all! That brings me to my next point. Knowledge is the greatest thing we can have. We have hands, we can buy things for pleasure, we can party, we can build and destroy. I don't think there's anything as thrilling or as worth striving for as knowing exciting things.

(Picture: NGC 3718.)
Knowledge is so valuable that is has become a market exploit. It is a commodity - to be packaged and abused and chopped into regulation sausages and spread as thinly as it can for the most money.

At school, the point is passing exams. The original point of these were to prove you knew something. Now, of course, the point is to impart as little information as possible to get the maximum exam results. Universities are now market-driven, to scoop up as many students as possible for higher and higher fees. "Learning styles" and "multiple intelligences" are heavily probed as new methods to wring higher and higher exam results out of bored or confused children. Having a qualification depends very little on knowledge really, if you ask me. It's a way to separate the wheat from the chaff when it comes to the job market, and minimise the number of annoying application forms people have to read - to keep society heterogenous and prevent dangerous things like too much democracy. Yet knowledge is still the excuse. It's still the most beautiful tool we know.

And we still want it. We still read . . . we still go to the Open University . . . we still watch documentaries and talk about them . . . and now, 200,000 of us classify galaxies.

Two of the most important things to people in Galaxy Zoo are the beautiful pictures, and the contribution to science. Because people still respect science - it's the truth, or the nearest we can get to it. To be part of it, totally unexpectedly for most of us, is an honour and a deep awe and exhiliaration.

And this is real science. We're not rehearsing - we're the ones drawing up the data! People often worry about whether they've made the "right" classification, and we explain that the answers are not there in the back of a textbook - we're the first ones here. We're like artists learning to paint by painting, rather than just reading and writing about doing so. We're at the cutting edge.

IC 749 and IC 750

The zookeepers share the data with us all. We're treated as collaborators. People often complain that they don't hear things very quickly or often, but most of us are getting used to that being part of science - that you don't just rush ahead, you have to be 100% sure it's correct, and that takes time. And it's pretty exciting to have discovered a so-far-unique object, and revolutionised galaxy morphology and colour. And all this due to citizens! Very well summed up in this topic on the forum: "Research power to the people!" It is my hope that, now that science education has become (to many) so unsatisfactory, citizen science will replace it.

Copeland's Septet

What about my favourite place in the world - the forum? (You knew I was going to get onto that. I'll oblige . . .)

Everybody gets greeted with "Welcome to the zoo!" Many people are astonished, not to mention relieved. "What a nice place!" Now, there are some particular freedoms to the Internet - that you can be anonymous, and therefore get away with saying all kinds of things you don't generally say. (I once heard about a Korean tradition where every so often everyone can put on a mask and say just what they think.) You can be like a child again: trying on new faces, being a fireman or an astronaut . . . You can also work off the rage and frustration you feel at the world. Look on most websites - people talk as they would never dare speak to others in real life. There's something thrilling about the mixture of liberty and venom, but it's mostly just depressing.

People who are used to this are genuinely shocked - and feel as if I've played a malicious trick on them when they "get Aliced" - to discover that Galaxy Zoo doesn't work that way. We won't have swearing, violence, insults, adult language, etc. What we also don't tolerate is selfishness or unkindness. Perhaps that's partly my fault for being extremely strict in the early days - with a lot of confidence and encouragement from zookeeperKevin. Posts that are merely smileys or greetings, which would be deleted as spam on other forums, will stay; on the other hand, any trolling is immediately pounced on. I don't think I quite intended Galaxy Zoo to be so "different" - perhaps the very fact that I'm generally rather ignorant of the Internet helped me along, that I had few examples to follow. I've found myself telling people off for minor name-calling and making assumptions about each other, for example, "you think this because that is your background/level of education". I've been stunned and moved to see people actually apologise later for doing this. I've been lectured at length about "other forums", that I'm a cowardly censor, power crazed, etc. etc. by people who disagree with my decisions about what stays and what gets deleted. There doubtless are times I have been a bit too strict. I certainly don't claim to have done everything right . . .

NGC 6340

I think that what we have at Galaxy Zoo is the opposite type of freedom. This modern world doesn't call for much niceness. Niceness is seldom admired in the office, up the corporate ladder, in business transactions. Traditional recipients of human kindness, such as children, are herded well away from adults - regarded by some as dangerous vandals, by others as legal liabilities too dangerous to so much as look at without fear of prosecution. More and more of us live alone. Many of us are depressed. There's this great upwelling of goodness and kindness and effort in so many people with nowhere to draw on it. But . . . the Galaxy Zoo community has a place for it.

People come along needing picture-posting help every day. People all want galactic signatures. People talk about their lives, their hospital appointments, the deaths of their pets, the annoyances of their bosses and jobs. People are dying to learn. There are beautiful pictures ready for creative art. Things happen every day - the daily routine of Object of the Day means there is something new on the site daily, and now that zooites are involved in it, the amount of research and effort going in is incredible.

And we definitely learn a lot together. As Weezerd put it perfectly: "The beauty of this site is that it is so level. There is no status attached to newbie, oldie, zooite, zookeeper...we all try to work on an equal footing. Of course, some know more than others, but in here that knowledge is made available for sharing, not for overshadowing." For me, that is education as it should be.

Messier 60 - two overlapping galaxies

Together, we do the great and small. Together, we participate in the largest citizen science project there is; together we probe the Universe and build the best thing I know. Together, we swap jokes and post pictures of cakes and cups of tea. I hope that citizen science spreads, and the culture we have here with it. Sattareh Farman Farmaian points out in her wonderful book "Daughter of Persia" that the Islamic Revolution took place because there was no strong alternative for the people to follow - no well-known democrats, only dictatorship or religious extremism. Citizen science is a strong alternative for marketed knowledge and exams.

Galaxy Zoo is an escape from the nastiness of the world - it is the ideal I gave up looking for years ago, and still hardly dare believe I've found. But it's real. It's a place that needs me. It's where you can know you're safe, that nobody will attack you (at least not without a few consequences), where you can be curious without being called uncool, where you can be ignorant without being called stupid. I feel that EdV sums up our Zoo perfectly in his breathtaking thread "Humbled", and Caro does likewise in her artwork (below). We are all so different on the forum: bonded by one common instinct, the special human need to look up and reach for the stars.

"In the heart of most of us there is always a desire for something beyond experience. Hardly any of us but have thought, some day I will go on a long voyage, but the years go by and still we have not sailed."
- Richard Jeffries

Monday, 23 March 2009

Grazie Half65 for ARP 142

I'm insanely excited today over a 16 by 16 pixel picture: a favicon from Half65! It is the beautiful ARP 142 galaxy system, the individual galaxies known as NGC 2936 and NGC 2937.

Credit: SDSS. To zoom in and out and explore around, look at Navigate.

This was the first really "interesting" galaxy I found at Galaxy Zoo No. 1. Ah, the old days - I was living in Brighton, classifying in the computer room when I should have been revising for my chemistry exams. (Actually I did much better than I expected - I thoroughly recommend reading 1 page of notes, doing some classifying to relax the brain and let it sink in, and then reading another page of notes, rather than cramming it all in at once!) The forum which changed my life had not yet been born. Fortunately, a temporary blog was set up by a kind enthusiast, Salmon Chase, and it was one of the first things I posted. My friend Gill's husband named it "the penguin galaxy" and it seemed to catch on!

Of course, I didn't know anything about galaxies at the time, or how to search SDSS, and it was a while before I found out it was called ARP 142. What can we tell about it just from looking at it?

The "egg" the "bird's head" is "looking at" is an elliptical galaxy; the "bird's head" itself is a wonderful merger, with dark dust lanes and bursts of star formation at the top towards the "beak". My impression is that it has been dragged round anticlockwise in a quarter-circle. It's quite peculiar that the elliptical appears so unaffected, but perhaps its stars are closely bound enough not to be so disrupted - or perhaps there's something I'm missing. I checked their redshifts, to see if perhaps the elliptical was further away and looks bigger than it is. It isn't. It's closer to us: z=0.023, while the merger is 0.024. Behind the star at 1 o'clock is a small irregular galaxy known as UGC 5130. Apart from that, it seems to be a relatively empty area.

We can also look at the spectrum. This is an emission spectrum (drat - I haven't written about those yet, though I covered absorption spectra and their history this week*):

What exactly does an emission spectra mean for a galaxy? It means it is very energetic. It probably indicates star formation. Well, we can see that from the blue splodges anyway. And why should that be?

When a hot light source - an energetic photon - hits an electron in an atom, the electron leaps up to higher orbit. Perhaps the next-highest (think of the Earth leaping up to Mars's orbit), or several orbits higher (Earth leaping into Saturn or Neptune's orbit). It has to be of a very, very specific energy - a particular wavelength of light - just the right amount of energy to boost the photon to a specific place. Too high or low and the photon will be sent on its way. But even then, atoms and subatomic particles don't like to be in a higher energy state than they have to be, so eventually the atom falls back down again, emitting that photon again. But since the photon's gone off in any old direction rather than the one it was originally heading in - towards us - that wavelength of light is missing in the spectrum.

That's a hot light source and a cool atom. What about a cool light source and a hot atom? That's where emission spectra come in. That's when the electron was already up in a higher-than-necessary orbit - "in an excited state", as we say - and shoves the photon off in our direction. And that's when the spectrum shows huge peaks.

In this case, the highest peak is of H-alpha, or Hα. That means the electrons are falling from the third orbit to the second, rather like Mercury falling from Earth's orbit down to Venus's. There is also a bit of H-beta (from the 4th to the 2nd) and an even littler bit of H-gamma (from the 5th to the 2nd). That clump of star formation the camera is focussed on in this case is not as violent as some galaxies. The peas, for example, have high OIII emissions - oxygen with two electrons knocked off. I'll write about them in another blog post!

All the above I was able to get out of my eyes and SDSS. Doubtless somebody smarter than I currently am could get a lot more, such as the exact data for the colour filters . . .

The galaxy system is from the ARP catalogue: the Atlas of Peculiar Galaxies, drawn up by Halton Arp. Its number is between 102 and 145, into which category fall the elliptical and elliptical-like galaxy types (of which there's a lovely catalogue here).

ARP 142 is in Hydra. There's a fantastic picture you can zoom right in on on this site, in which it looks more like a bird than ever! That site describes it as "emanating", though is not specific on what is being emanated. You can also find it on skyfactory.

A paper has been written by McCain et al on "ARP 142: Another interacting galaxy with very large internal motions". (As again is clear visually, I think!) Intriguingly, the Hα is not coming off the elliptical, but off the merger - which was once, according to their research, a spiral which is gradually being stripped by the elliptical - not quite the same as my quarter-circle impression above! They state that there is a massive "velocity difference", but I'm not clear on whether that means of the galaxy's movement, or whether the Hα is moving at that speed. Evidently that means ionisation is taking place, but shock waves are unimportant. (Recall they are very important in barred spirals and are often a trigger for star formation in spiral arms . . .) Looking at it visually backs up this conclusion; blue galaxies are full of star formation while ARP only has the odd burst of it here and there.

There's just so much to learn!

P.S. Happy Mother's Day.

P.P.S. Grazie Half for correcting my spelling :D

P.P.P.S. *But I did later. Here is the story of emission spectra, and a wonderful story it is too.

Wednesday, 18 March 2009

Galacticats and Citizen Science

The Galacticats Researchers wish to thank the many citizen scientists who have contributed their galacticats for our second paper, which goes out to the Journal of Astronomical Zoology's editor today.

Authors: Alice, NGC3314, Georgia, Caro, Sophie 378, Milk_n_cookies, Archi, Infinity, Paddy, Pat, Scaryitalian, Thornius, and their furry families thereon.

Abstract: Yes, very.*

Introduction: The serious illness, Galaxyzooitis, allows us to see not only everyday objects in galaxies, but galaxies in everyday objects. Rather like synaesthesia, we present here a case that this is not an illness or disability but rather an enhanced intelligence - and also that galaxies are so spectacular that they really should get into everything.

Method: I wrote a bunch of silly captions, called in the volunteers and made a lot of people laugh.


We first present the commonest finding: a selection of spirals with 4 or more arms.

From Archi: "Barred spiral, more than 4 arms."
From Caro, first an example of a tight spiral and a loose one:
followed by the effect of gravity:

"These two appear to be in close proximity but not interacting. The larger object could be showing some signs of disturbance however."

A statistical analysis of the results generally indicates more arms than average galaxies. An exception was discovered by Milk_n_cookies, namely Mia the elliptical:

The second major sample we present are peas, which are surprisingly common in galacticats:


Another two peas in a red galaxy with dust lanes, from Scaryitalian:

The above is particularly interesting considering that it is also an irregular galaxy, irregulars normally being blue. We have yet to find a blue galacticat, suggesting that their starforming rates are relatively low.

So far, 100% of peas are incorporated into galacticats, rather than being the entire galacticat, suggesting that galacticats are seldom if ever quasars. Unlike zoo peas, galacticats tend to have small localised OIII regions, suggesting some variation in their composition, not to mention very high energy. They are also incorporated only into tortoiseshell (i.e. red) objects, contrary to the usual pattern of the OIII galaxy being an energetic and presumably starforming place. This is likely to back up the point about localised differences within the galacticat.

A far redshifted Low Surface Brightness galacticat was discovered by Pat, SDSS J1NGLE5:

Unfortunately, SDSS J1NGLE5 is too distant and blurred to make out its features in detail and requires further stroking, I mean study.

Our third sample is of a new species of galacticat, namely the general galactipet. We propose that galacticats are merely one cat-egory of this larger species of stellar object, and we ask for more volunteers to help us expand our studying. Galactipets as a whole contain more variety than galacticats so far studied, though we only have a sample of 4 (or 3 if you insist on being boring about it, as two are of Pickle the hamster), this is not a statistically reliable result.

In the constellation of Canis Minor lies a multi-armed merger of galactipuppies provided by Paddy:

Sophie 378 discovered a red two-armed spiral with a dust band, a Hamster Alpha Object:

It was initially believed that Hamster Alpha Objects were capable of incorporating localised "pea-like" areas in the same manner as red galacticats, but a comparison of redshift demonstrates that this is an overlap:

Finally, Thornius found a very low-surface-brightness object, extraordinarily difficult to spot in the night sky and thus not seen on this blog before. He has christened it "Thorny's Voorwerp".

Most of the results can be studied in more detail between pages 99 and 101 of the pets thread, started by Infinity, but a few were obtained by msn.

Discussion: Miaow!

Conclusions: We, or at least I, believe we can collect a lot more galacticats in future.

*Thanks to Dr NK White, professor of Waveney Studies** and randomness expert, for this phrase.
**Long story. I'll see what I can do about blogging that after I'm next in contact with Professor White.

Saturday, 14 March 2009

A trip to Intech: What can we know about the Universe? by Russell Stannard

At 6:30 p.m. on the second Wednesday of each month, Intech Planetarium hold a space lecture by a visiting speaker. I did the October one (the subject of which I'm sure you can't possibly guess), and last Wednesday I nipped back to watch one by a writer who subtly changed things for me at a very early age: Professor Russell Stannard.

Russell Stannard wrote the "Uncle Albert" series which I often recommend to people on the forum when they ask questions about time, space, relativity, black holes etc. I read them when I was about 9 or 10, a good age to be introduced to concepts that don't make intellectual sense - at that age your mind is like a springy sponge, ready to twist and absorb anything; whereas by your twenties it'll be more like a brick, inflexible and it's harder to soak things up (at least if you're out of practice; not if you aren't, that's for sure!). I believe it's due to these books that I drove my GCSE Physics class insane with irritation throughout every unit on waves, and, more importantly, have always been fascinated by physics and astronomy, had some grounding in their weirdness, and always able to accept relativity and quantum physics despite the brain's logical barrier to them. I'll write more about the books themselves another time. Suffice to say I've been grateful to Russell Stannard for more years than I have anyone else, and it seemed well worth spending two days on a train to go and hear what he had to say.

Another Zooite, John, also came to Intech and we had a look around the science centre. It's a nice interactive place where you can bounce cubes around on strings, knock things onto the floor, play with smoke, torches and pulleys, and see pictures of pairs of socks modelling chromosomes and of the SDSS telescope. My favourite bit that particular evening was messing around with what was to me a mysterious machine, but which John tells me is called a harmonograph. It works by having a pen attached to one pendulum, and a clipboard and paper attached to another swinging at right angles. To see how it's built, here's a site John sent!

I didn't manage to make anything spectacular, but I couldn't resist taking my two home with me, and pinching three others that someone else had left behind:

Eventually it was time to dig our tickets out of our pockets and head for the planetarium. It's arranged with seats amphitheatre style, and a beautiful domed roof, dotted with a few stars poking through the rainbow colours the six cameras cast along the ceiling. The Powerpoint bit looked straight, because they cleverly cut out a slightly curved (on a flat screen) black rectangle - and then project the powerpoint onto that.

Sitting and waiting while the guests filed in, I got butterflies in my stomach all over again remembering my own first ever public lecture in this very room. We had a roof of galaxies over our heads: the Hubble Ultra-Deep Field through a fish-eye lens. It looked truly stunning. I told the story of how old they were and how very many galaxies there were in such a tiny, apparently empty patch of sky, as part of my introduction. But I was so nervous that day that Jenny, the manager, told me while showing me how to work the microphone: "And this is the 'off' switch, just in case you need to cough, or to throw up . . ."

(Anyway, I don't suppose it went too badly. When I popped back a couple of weeks later for a Telescope Amnesty event, alone, scruffily dressed, gawky and inconspicuous, I overheard one of the guests I'd talked to last time mentioning loudly that he'd been to my lecture. I was standing right in front of him but he clearly didn't recognise me, but he remembered my name! I was clearly luckier than an artist I'd read about once, who saw a noble lord and a museum attendant standing in front of one of his paintings. He crept up to them to hear what they were saying about it. He overheard the noble lord say, "Of the two, I prefer washing up.")

Lecture: What can we know about the Universe?

"We take it for granted," Russell Stannard said in a clear voice, "that science, by its very nature, is progressive and always will be." But it has not always been so; centuries have passed without many new discoveries in the past, and also our brains and experiments are limited in what they can achieve, so ". . . that process will one day grind to a halt." This does not mean technology, and what we can make, but what science itself is able to tell us. "The Universe will always retain an element of mystery."

There are many things that observation - and deduction where observations are limited, but secondary evidence is available - can tell us. For example, we know about our Sun, the planets, galaxies, clusters, and the expansion of the Universe. Apart from galaxies in our local group, of which there are about 30, all galaxies are moving away from us. If Galaxy A is twice as far from us as Galaxy B, then Galaxy A will move away from us at twice the speed. This means that the Universe is expanding in all directions.

We have been able to calculate from the speed of the expansion that the Universe is 13.7 billion years old. We know that increasing the density of a material such as a gas increases its temperature, and from that we can deduce that the Big Bang and the early Universe must have been terrifically hot - a fireball. There is observable evidence from that, namely the Cosmic Microwave Background.

(The CMB. Picture credit:

We have been able to measure the chemical composition of the Cosmic Microwave Background, which is almost entirely hydrogen and helium, in a ratio of three to one (in mass, not number of atoms), and its temperature all around the three-dimensional perimeter of our vision, which is surprisingly uniform. It was an interstellar gas, not yet containing any stars.

We cannot look back to the moment of the Big Bang; we cannot say what caused it. To look back in space is to look back in time. But we cannot see the first 300,000 years of the Universe's existence, because no light could get through the cloud of subatomic particles. It was too hot for atoms to form, and the subatomic particles scattered the radiation that atoms can absorb. Theoretically, we could probe gravitational waves and neutrinos - but at least in present-day technology this is impractical.

How close to the Big Bang in time can we make direct observations? No closer - but we can study the features of today's Universe for clues.

One such clue is the (observable) Universe's homogeneity and isotropy. The Cosmic Microwave Background is remarkably uniform in temperature. For any material to be a uniform temperature throughout, it must have had some contact time to equalise. The nature of the Big Bang suggests that this was unlikely to have happened. In 1980, Alan Guth proposed that there was a very brief "quiet time" directly after the Big Bang, which caused connections between all the matter - such as it was - at the time. Expansion followed this later.

However, if this was the case, Hubble expansion predicts that galaxy clusters would not be in the place they are. The theory accounting for that is inflation. Inflation was very brief - lasting from 10 to the minus 36 seconds after the Big Bang, to 10 to the minus 34 seconds after the Big Bang (sorry for the lack of superscript font available!). This theory accurately predicts the density of the Universe.

(Diagram of inflation. Picture credit:

Many scientists have suggested alternative versions of inflation. The main questions to ask are: Are we sure it took place? And which type is right?

Before inflation began, the Universe would have had no volume, and therefore an infinite density. We call this a singularity. Physics cannot handle singularities - they should be impossible. Therefore, trying to talk about them doesn't really make sense. It wasn't just matter that was a singularity, but space itself. This means there was both no matter and space, and also infinite matter and space . . .

Stephen Hawking has pointed out that "time might melt away". You can't have space without time, or vice versa. So we may not be able to talk about the first instant of the Universe's existence at all. But is there an even stranger possibility?

Was there a singularity which exploded? If so - what did it explode into? Russell Stannard pointed out that we think of an explosion as, for example, a terrorist attack in which someone causes an explosion in a crowded area, causing carnage. That is because it explodes into something. But the Big Bang didn't do that. It created space. That space is still being created, and pushing galaxy clusters apart.

But space is nothing - how can nothing move the most massive objects in existence? For physicists, space is not "nothing". A lot goes on in it.

Einstein pointed out that space and time need each other to exist, hence relativity. Time deals with causes and effects. The Big Bang seems to have been an effect; what was its cause? A cause would have needed to have taken place beforehand - but there was no beforehand! The question itself has no meaning. Another question, which people have tried to answer for at least three or four thousand years, is: Why is there a world? Why does it remain in existence?

Why are there any laws of nature at all? Chaos calls for no explanation. ("Does it?" I thought.) Einstein seems to have stated that the most incomprehensible thing about the Universe is its comprehensiveness. To sustain life, the laws of nature have to be complex. Once the Universe undergoes "heat death", life will be impossible anyway. For a start, the Big Bang was very violent, and threw matter out a long way. If it had been less violent, the Universe would have shrunk and collapsed again quite soon, and we would not be here.

(Star formation in N90 in the Small Magellanic Cloud. Picture credit: the Faulkes Telescope Project.)

Another law of nature is called "g" - the strength of gravity. Gravity causes nebulae to collapse and stars to form. If g was larger, all stars would be massive blue supergiants and might only live for a few million years. We have needed four billion years to evolve, so we are lucky to have a smallish Sun which takes ten billion years to burn all its fuel. If g was smaller, nebulae would not clump together densely enough to reach the million degrees required to start nuclear reactions. (I disagreed with this and asked afterwards, what about more or less dense nebulae evening out the effect? Basically, if g was different enough, that just wouldn't work.)

The bodies of living creatures are very complex, containing heavy elements. Only hydrogen and helium could have survived the Big Bang; heavier nuclei would have been smashed up. Forming a carbon nucleus, for example, requires special conditions (more on that when I write a review of "The Magic Furnace" by Marcus Chown). In other words, heavy elements must be cooked in stars - and then they have to be got out of stars to make us! The way to do that is by a supernova. Supernovae are odd enough, because they are actually an implosion; how can an implosion trigger an explosion? It seems that neutrinos are what carry off all the matter - and neutrinos don't usually have the least effect on matter at all. It's likely that while you're reading this, a few thousand are going right through you. You could bounce a neutrino through the Earth from the UK to Australia 100 billion billion times before it had a 50% chance of knocking into an atom! They are very slippery - any more so and we undoubtedly wouldn't be here.

(Supernova 1987A. Picture credit: APOD.)

Planets could not exist in the early Universe: there are no planets around first-generation stars. ("What about gas giants?" I should have asked, but forgot.) Planets such as Earth are made of these heavy elements from supernovae, and form in secondary eddies around stars. Conditions for life are delicate. Russell Stannard quoted Freeman Dyson as saying, "The Universe knew we were coming" (it's up to you whether you agree with that, can't say I do . . .). The Anthropic Principle states that we're here because if conditions were any other way, we wouldn't be here to ponder them! Probability (or perhaps logic) leads us then to ask if there are really lots of universes, each with slightly different laws of physics, and we are in the one which is ideal to support life. We can't contact any other Universes, or prove there is a "multiverse" - if we could, they'd be part of this Universe. We also can't prove there isn't one.

Another thing science cannot tell us is how big the Universe is. We can observe things 13.7 billion light years away. But presumably anyone 13.7 billion light years away can see 13.7 billion light years further on. Where is the edge of the Universe? If we went to the edge of the galaxies and looked out into empty space . . . well, that would still be in our Universe. The current thinking is that it is infinite. "I, personally, am very suspicious of the word 'infinite'," Russell Stannard informed us, and went on to tell us a story about a hotel with an infinite number of rooms. The hotel filled up and did very well. So well that the manager decided to build another hotel with an infinite number of rooms. One night, there was a fire in one hotel. They got everyone out, but this infinite number of guests had nowhere to stay that night. They were all feeling in quite a fix until the manager told the infinite number of people in the first hotel to go to their door, look at its number, double it in their minds, and move all their possessions and themselves into the door they'd see. So the infinite number of guests outside went into the rooms occupied by the infinite number of people in the first hotel, and . . . er . . . I think the moral of this story is supposed to be "er".

Back to the Universe. What is its average density? This is an important question, because it decides the fate of the Universe. If it is dense enough, gravity will halt its expansion. It may stop forever and remain static, like a craft in orbit around the Earth; or, if it's a bit denser than that, the galaxies will fall back together, like a football falling back to the pitch, and a "Big Crunch" will occur one day. But if the Universe isn't dense enough for this, it will go on expanding forever.

It seems that matter itself - stars, gas, etc - make up 5% of the density we need for this to happen. Dark matter accounts for more: 28%. (Science may one day tell us what dark matter is, but we have no way of finding out yet.) Our own local group of galaxies should hold together. The violence of the Big Bang was not enough to pull them apart. Not on its own.

The remaining ~70%* of the "critical density" is dark energy. It adds up perfectly to sustain a critical value (which Russell Stannard seems to find very satisfying, while I find it rather bewildering - doesn't it change?). Not all matter was created during the Big Bang, perhaps. Inflation may have created more. Space expansion creates matter . . . But it looks as if the Universe will expand forever. Look back at the inflation picture. The expansion seemed to slow a little somewhere in the middle. Without dark energy, we would fall back together. But dark energy somehow manages to create more of itself all the time - and it pushes the galaxy clusters apart.

(* Yes, you nitpickers, I have spotted that 5%, 28% and 70% add up to more than 100%. I'm afraid that's what I've got written down in my notebook. I don't remember why. We can make some educated guesses . . .)

Why would a vaccuum have a mass (or an energy)? There's a lot going on in it (virtual particles and antiparticles colliding - Hawking radiation - sprang to my mind). The expansion of the Universe is now actually speeding up, just as populations increase exponentially - the more dark energy is created, the more can be created! Dark energy repels, and repulsion vastly increases with time. The calculated value of expansion is 120 orders of magnitude greater than what we observe, which Russell Stannard describes as "embarrassing" (and "BANG!" describes as the probably the greatest ever discrepancy between the observed and the predicted!). Could a mechanism we don't know about be at work? We don't know.

Is there a connection between today's repulsion of clusters and the early inflation?

One final question: is there other life in the Universe? Exoplanets seem to be being discovered every day; but they are too far away to visit. Where do we rank with ET? The brain size has increased at three times the rate of body size in humans. But Russell Stannard does not believe ET is findable, and they will have to contact us. He also said that the human brain is not designed to do science, but to hunt, gather, find mates, ward off predators, etc - so it's actually a huge achievement that we've got where we are today at all.

We are hugely privileged to be living in the scientific age, he concluded. The human race has existed without being in the scientific age for thousands of years. One day, all that can be discovered will have been. That doesn't mean we'll know everything, but we'll have come up against all our limits of science. But right now we're in the middle.

Afterwards Jenny gave us a 15-minute planetarium show, incorporating a lot of three-dimensional graphics from our beloved SDSS. According to her show, the Universe is 92 billion light years across. There was a five-minute interval during which Russell Stannard was surrounded by a crowd of children. Good on you all, I thought from my seat. I hope they grow up to be interested in science forever.

As we filed out I couldn't resist going and bothering him. I thanked him for the lecture and told him I'd been an Uncle Albert fan for about 17 years - though I'd never got over the heroine Gedanken saying she was giving up. He merely smiled. His writing is very exuberant and I thought he'd have something to say. He didn't. He was very quiet: perhaps he'd heard it all before; perhaps he was tired, in which case I hope I didn't tire him further. (He did sign my Uncle Albert books, though!) But I feel very privileged to have finally met someone who made such a difference so many years ago. I hope I've done his talk justice.

Friday, 13 March 2009

Spooky mindreaders, space games and a cherry on top of Jodrell Bank

Jodrell Bank is evidently putting its nose out of joint to be as silly as possible for Red Nose Day. If you ask me, it looks like an iced cake. If you're quick you can catch all their ghastly puns on Twitter.

Meanwhile, Tom and Stellar just eerily answered my post whinging out into the ether for a galaxy merger game. They've found Galaxy Crasher, where you alter the size of the galaxies, their number of stars, their angles relative to each other and whether or not they have frictional forces or a dark matter halo. Apparently some people have managed to make collisional rings, which just goes to show they're better at it than me! Check Stellar's blog for how it works.

On the subject of space games, it's surprising how many there are. Many months ago, Edd showed us Orbitrunner, where you choose the position of the Sun to keep planets and moons in a stable orbit (otherwise - BOOM!!!). It has haunting music and is highly addictive, especially on a computer such as this Mac which doesn't run it too fast (my PC laptop ran it so fast I didn't have time to think and got nowhere). Orbitrunner is particularly illustrative of the slingshot effect, which Mariner 10 used extensively to get around and for which there's another game here. I started by crashing the spaceship with Jupiter!

Heading back to the 1970's (apparently), there's also the old favourite Asteroids, certainly containing the least physics and realism, but no less fun. With the four or five relevant keys, bangs and whistling alien spaceships, there's something wonderfully addictive about these super-simple old games. I wonder when they'll be saying that about 2009 ones? (Christmas 2009, I expect.)

If that's enough games for you, more serious stuff will come later, I promise.

Tuesday, 10 March 2009

Thank you Pat for the Pleiades!

A huge thanks to Pat, one of the Galaxy Zoo lens-hunters, for applying her technical genius to getting this picture as a background!

If you're wondering, I found this picture on Google Images, Pat found the instructions on "the cutest blog on the block", and I used Powerpoint (yes - really!) to get the stars and the black in precisely the right place. But neither this Mac nor Photobucket agreed to let the picture get big enough - and you do need to get it the right size in advance. Apparently PaintShopPro will sort it out.

After that, I decided we didn't need any more green and yellow labels over the place. What I'm aiming for is for the stars to be on each side, but the text to be over a black background. Let me know if the Pleiades and the text overlap!

Sunday, 8 March 2009

Book Review: "100 Things to Do Before You Die", edited by New Scientist

Want to make shimmering snow angels in water? Or find out how it feels to be a human comet with a bright tail? Then take a trip to a bioluminescent bay. There are only a few in the world, but one of the brightest and most pristine is Mosquito Bay in the small Carribean island of Vieques, off the coast of Puerto Rico.

Pick a moonless night and use a kayak if you can. Each stroke will light up the water and your boat will be surrounded by the most magnificent bright blue-green glow.

Dip your hand into the water and twirl it around - the more vigorous your movements, the more you'll shine. Cup your hands and reach in. As you lift, look closely at the water. There you'll see the culprits: microscopic organisms called dinoflagellates that release light when they are disturbed.

Nature's pixie dust is all around you.
These are the opening words of the book "100 Things to Do Before You Die (plus a few to do afterwards", which in late 2004 came free with a New Scientist magazine. Over four years on, I still read bits of it every so often. It's a very little volume, each "thing" with an opening title, catchy subheading, and the information rather neatly arranged, I think, by a loose formula. It seems to be an opening paragraph about the activity, followed by some of the science, a bit more detail, and ending with a cool, rather journalistic catchphrase. It's not the least bit rigid, though - the topics are wide-ranging to say the least, and it also has 12 "guest" entries from public science figures such as Sir Patrick Moore (from before he became a "sir" - and his suggestion is a mild surprise!).

I love this book and would give it five stars any day. I've done about seven of the activities, which range in ease from contemplating the size of the Universe to scenarios involving impressing NASA enough to get picked to do an experiment in space. I definitely mean to do more, such as spending all night in the garden to listen to the wildlife. There are some really little things whose value we don't think about until it's brought up short under our noses by books like these. For some reason, I often fall asleep while I'm reading it - not because I'm bored, but I guess because it's familiar, relaxing, and also makes me use my brain. Not with problems, but by making me picture the activities.

The book should really have been called "100 things, some of which you might be able to do before you die". I did a quick tally through the book the other day. 32 of them can be done with minimal money and travel; though it feels like fewer, probably because most of these are at the beginning, and their leaves me with an increasing slightly feeling of disgruntlement (is that a word?). 35 require major travel across the world, but all of them sound well worth it! Two involve becoming an astronaut; four depend entirely on luck; three demand you be rather a special person; and three are impossible if you're not a millionaire. Nine depend on a technology in the pipeline being launched and made widely available, four are not possible unless you have a high-up scientist for a friend, and one is medically not to be advised!

Just one guest entry really annoyed me: Anton Zeilinger on time travel:
My dream is to go back in time, say 200 years, and show people a CD player. How glorious to watch their reactions. Would they be shocked? Would they grab it from me and check if there are miniature people inside? Would some even be creative enough to guess that this is a future technology?
- which I can't help feeling is just pointless, as well as very patronising! If I went back in time, I'd want to see how these people lived, and the things they put up with that we're not tough enough to deal with now, and how they spoke (apparently people used to speak slower than they do now), and what skills I could learn from them.
And imagine explaining to these 19th century children how much longer we live today. And that many of today's 60, 70 and 80-year-olds are happier and more active than they are.
That's just cruel. Let's boast about our supermarkets to the starving, too. Anyway, I doubt it's true about more active - kids worked on farms and in factories well over 12 hours a day back then.

Rant aside, the activities are wonderful, involving food, travel, science, machines, books, thought, and simple appreciation . . . but none of these in excess. There's a great range of themes and locations and things to suit various personalities, and it's a great reminder that, as it points out in one entry, we are still animals. It also inspired and explained to me to make liquid nitrogen ice cream for my Chemistry class at Sussex University, and then as a demonstration for primary school children in Brighton!

I thoroughly recommend a read.

ISBN 1-86197-925-8


There is disagreement on the Galaxy Zoo Forum as to whether this galaxy is an overlap or a merger. I don't think it's either. I think it's a cat curled up, with its head and ears on the right, and its tail folded neatly around itself on the left.

(A widespread symptom of Galaxyzooitis is not only seeing galaxies in irrelevant objects such as clouds, coffee and keyboard symbols, but also seeing everyday objects in galaxies.)

I wish to propose an entirely new discipline of galaxy studies: galacticats. I have two excellent research colleagues in this endeavour, Georgia Bracey and Bill Keel, both experts on astronomy and furry felines. We present a sample of galacticats and their contributions to cosmology herewith.

Firstly, A Rare Conjunction of Cats. Astrophysicist Bracey observed a very rare scenario and concluded that, while coincidences are common, this particular incident was achieved under the influence of a comfortable stellar environment. As she explains, "Every now and then things in the universe arrange themselves so that it appears that one thing is very close to another thing. We call it a conjunction. It's a fairly rare event. . . However, even more rare is the conjunction of cats that you see in the picture above." She also points out that it is very well worth keeping your eyes open to spot these conjunctions, and I agree with her even though my powers of observation are something to be . . . er . . . modest about.

Overlapping Guru Keel, who suffers invasions of galacticats whilst packing his suitcases, nevertheless made useful observations of "The Overlapping Technique". He reports: "The overlap technique can be used to tell how transparent or opaque the foreground system is. From this, I conclude that cats are opaque except around the edges. Ahh, the power of science!"

As a follow-up, I will follow this by presenting the following classification of galacticats as follows:

An irregular galaxy, SDSS IZZY2AM, in the constellation of Lynx.
An elliptical galaxy in the constellation of Cassie-opiea.
An edge-on spiral galaxy, overlapping with a fainter one, in the constellation of Orion the Hunter.
This is not a galaxy but merely an artifact from two very bright nearby stars overloading the SDSS camera. Starry-eyed cats not only burn all their nuclear fuel at a terrific rate, but also reflect all the light that goes into them at the correct angle, i.e. have an albedo of 1.0!
This, on the other hand, is not an artifact but a pea, an OIII or doubly ionised oxygen containing quasar!
Cass-Jobs and Half65 positively identified this as a clockwise spiral galaxy.
Galacticats acquire dust lanes by collecting dust from the local environment.
A ring galaxy, probably a collisional ring due to interaction with Galaxy SOPHIE 378, in the constellation of Leo the lion.
Astronomers have reason to believe that these two multicoloured galaxies are beginning to interact.
In the constellation of Coma Berenices, a long tail indicates merging activity . . .
. . . as do strange loops and arcs.
The Galacticats Team would like to request volunteers' help to discover more galaxies; irregulars and four-armed spirals would be particularly interesting, plus whether these galaxies undergo a redshift as they begin to be allowed outside. We propose the pets thread on the Galaxy Zoo Forum as an initial study, to be followed by more specific contributions and classifications from citizen scientists in the future. We thank the public in advance.

This project proposal was written without the knowledge or permission of Georgia or Bill, but I hope you both enjoy it when you see it! Happy classificat-ion!