Follow the reluctant adventures in the life of a Welsh astrophysicist sent around the world for some reason, wherein I photograph potatoes and destroy galaxies in the name of science. And don't forget about my website, www.rhysy.net
"Atomic hydrogen is the reservoir of fuel for star formation." "Neutral hydrogen is a galaxy's fuel tank." These stock phrases are a mantra I fall back on for beginning both public outreach and journal articles. But are they accurate ? A recent paper has got me wondering if we've got something terribly, terribly wrong. It seems that when galaxies merge, although star formation rates increase, the gas really doesn't do a lot at all. It's a bit like pulling the plug out and not seeing the water level drop.
We Need To Talk About Hydrogen - Well, I Do, Because They Pay Me Money To Look For This Stuff, But You Can Just Listen If You Like.
Atomic hydrogen (HI, pronounced, "H one" since it's a Roman numeral 1, not an I) is the simplest element there is. One electron orbiting one proton. That's it. Electrically neutral overall, since the proton and electron have equal but opposite charges, it should be as simple as you can get.
In reality things can be a great deal more complicated if you want to bring quantum into it, which I don't. Anyway this simple picture is good enough for what I'm going to discuss here.
That picture is a little over-simplified for what we'll need though. For example, two hydrogen atoms can bond to form an H2 molecule :
The electrons from each atom are now associated with both protons, forming a covalent bond.
Or the hydrogen can have its electron stripped away by an energetic photon (i.e. light, often near hot young stars) to become HII (confusingly also pronounced "H two"), which is really just a cloud of protons and unbound electrons. It can even gain an electron to become the negatively charged hydride ion, though this is not thought to be important in astronomy.
The current working model (I would not call it a consensus by any means) is that it's usually only the H2 that's important in forming stars. Atomic hydrogen is generally so hot (1,500 - 10,000 Kelvin) that its own internal pressure prevents it from collapsing into stars. Molecular hydrogen is colder, which means it's less able to hold itself up and more prone to collapsing. That view is by no means certain, and there are some hints that in some circumstances, HI can indeed collapse into stars without forming molecular hydrogen first.
When we go looking for atomic hydrogen, we mostly find it in blue, star-forming galaxies (they look blue because the most massive stars are blue and don't live long).
Random sample of galaxies detected by their hydrogen emission from a large survey. True, many are red, but when you look at them more closely they usually have blue star-forming regions as well.
Looking in more detail, we see "holes" in the atomic hydrogen, where it looks as though the gas has cooled to become molecular and is forming stars. We also see a few cases where there's atomic hydrogen but no star formation. And that's the (simplified) version of why we think atomic hydrogen is usually just a sort of reservoir : ultimately it will cool into molecular hydrogen and form stars, but it doesn't normally form stars directly.
OK, That's Enough About Hydrogen, Please Tell Me About These New Results Now Or I Will Become Cross.
When galaxies merge, the gas collides and things get seriously messy. Not for nothing was a Hubble press release entitled, "Galaxies Gone Wild !"
Needless to say, galaxy collisions and mergers are complicated. But generally if the galaxies both contain gas, collisions result in a massive increase in star formation as the gas compresses and cools. So the atomic hydrogen becomes molecular hydrogen which becomes stars, and everyone's happy, right ?
Oh, would that 'twere that simple. The new paper shows that when you stick two galaxies together, the atomic hydrogen does sod all. Well, it might get splashed about a bit, but its mass doesn't decrease and in fact it might even increase slightly. Which as far as the "fuel reservoir" idea is concerned is like being poked in the eye with a sharp stick.
How Do We Know This ?
Galaxy collisions are slow, grand affairs that can last for billions of years - so we can't just watch galaxies merge and see what their HI does. The metaphor that's usually used is that if you want to learn about how trees grow, you look at many different trees. So it is with galaxies. By finding enough isolated galaxies and galaxies which have already merged, the authors try to look at what happens to the gas statistically.
That's not any easy process. After the merger happens, a lot of information about the original galaxies gets lost. So unfortunately there's just no way to know what sort of galaxies were involved in the original collision. But most mergers are thought to occur between spiral galaxies (because these are far more common, except in galaxy clusters), and spiral galaxy gas content doesn't vary very strongly depending on their precise morphology.
What the authors do is define a sample of post-merger galaxies, then for each of these they find isolated galaxies which have the same mass in stars. Then they measure the gas content of all the galaxies in both samples using existing data from the ALFALFA survey and their own Arecibo observations (They've got me to thank for that since I supervised Derik Fertig (second author on the paper) at an Arecibo summer school. The fact that the other authors are far more experienced senior astronomers has, obviously, absolutely nothing to do with it whatsoever).
What they find is that the amount of gas is the same in both samples. That is, a galaxy with a billion stars that's quietly minding its own business has the same amount of gas as a post-merger of a billion stars. Even though new stars are forming*, somehow the gas just nonchalantly sticks its hands in its pockets and goes, "meh".
* Before the galaxies merged they would have had less than a billion stars in total.
It's not quite as simple as that though. It's not terribly likely that all of the mergers are formed from equal-mass galaxies. And less massive galaxies tend to have higher gas fractions - that is, more gas relative to their stars. So if you stick two unequal-mass galaxies together, and none of the gas gets turned into stars, you'd expect the gas fraction of the post-merger object to be a bit higher that a normal galaxy of the same stellar mass.
There isn't really a handy analogy for this, so let's make one up. And let's bring Worf back into it, why not. Suppose Worf goes to a party at Starfleet headquarters and brings a bottle of strong Klingon blood wine. Captain Picard is making do with regular human wine. When his glass is half-empty, a waiter asks if he wants a top-up. Worf, however, is honour-bound to offer the captain a refill from his blood wine instead. If Picard chooses the blood wine, he'll end up with a stronger drink than if he accepts the regular wine, even though the same amount would have been added.
It's the same with gas fractions. Smaller galaxies are more "potent", they contain more gas per star, so merging them with a larger galaxy is like topping up orange juice with vodka. You'll get a lot more drunk that way.
As long as one bottle is of Klingon blood wine, obviously.
When reading the paper I thought to myself, "man I could sure use a glass of wine right about now !". But then I thought, "well, maybe you could account for the mergers of unequal-mass galaxies by choosing random galaxies from the isolated sample and adding up their stellar and gas masses". Lo and behold, the authors did exactly that in the next paragraph ! What they found was that the difference in gas fractions of the initial galaxies would increase the gas fraction in the post-mergers quite considerably, not by a very dramatic amount but easily enough that they should have been able to measure it in their sample.
So, does that mean that some of the gas is being consumed after all ? The gas fraction may not have changed, but it is less than if you stuck two unequal-mass galaxies together. Well, maybe, though it seems a bit suspicious that all of those tremendously complex processes that happen during the merger just bring the gas fraction down to that of a normal, isolated galaxy. We had a saying during the undergraduate course on general relativity : it all cancels and equals nought - an awful lot of work needed to find out that nothing's happening.
At this point the team turn to numerical simulations to figure out how much gas should be consumed by star formation. This is perhaps the weakest aspect of the paper. Ideally, they'd set up their own simulations and track the evolution of the atomic and molecular gas and the stars, but this is tremendously difficult to do. We're talking about many months (or more) of extra work, so it's perfectly understandable that they don't do this.
Instead they use an existing set of simulations which are (it must be said) vaguely-described here (again this is understandable since that publication is only a letter, not a full article). What they do is track the total mass in stars, then use the known gas fraction relation (from observations of isolated galaxies) to calculate how much atomic hydrogen there is during the whole merging process (presumably because the simulation itself doesn't distinguish between the different forms of hydrogen we discussed earlier).
What they found by doing this is that the star formation process shouldn't change the gas fraction much at all. So the fact that the post-mergers don't have as much gas as expected can't be due to star formation.
But that assumes that there really is a decrease in the gas content as the galaxies merge. Now I mentioned earlier that there was some suggestion that the gas fraction actually increases a little bit from the mergers. That's a little more tentative. The thing is, not every galaxy in their sample had detectable atomic hydrogen at all, but the detected fraction of the post-mergers was double that of the isolated galaxies of the same stellar mass. That is, if you randomly choose a post-merger and an isolated galaxy of the same mass, you're much more likely to detect gas in the post-merger than the isolated galaxy. Which suggests that post-mergers actually have higher gas fractions than their parent galaxies did.
Another important factor is that the ALFALFA survey isn't as sensitive as we might like. That means it's only detecting particularly gas-rich objects which, say the authors, reduces the expected difference in gas fractions between the isolated and post-merger galaxies - so their calculated differences are probably too large. Many of their isolated galaxies that have no detected gas from ALFALFA probably do contain some gas, just not enough to be detectable. When you run the numbers, say the authors, that means that it's very possible that smashing galaxies together increases both their star formation rate and their gas content.
Which is a lot like pulling the plug out and seeing the water level rise. It's weird.
Believe me, if you Google image search "weird" you'll get far stranger stuff than this.
What ? How Could This Happen ?!? What Does This MEAN ?!?!?!?! To summarise, it seems that when galaxies merge their atomic gas content remains (at best) unchanged, even though part of their gas is turned into stars. Simulations suggest that the fraction that forms stars is very small, but it looks plausible that the atomic gas content actually increases, somehow.
One thing this study doesn't look at directly is the molecular gas, which is what we think is more directly responsible for star formation. Could it be that the stars which form as a result of the merger do so from the existing H2, perhaps due to the shock of the collision increasing the density ? Unfortunately, say the authors, previous studies have found that the molecular gas content also increases during mergers, so, nope.
It just seemed really wrong not to include a picture of the famous merging "Antenna" galaxies in this post somewhere, so here we go.
But before we go saying, "a wizard did it !", the authors suggest a possible explanation for where this extra gas comes from. Galaxies, it's thought, may be surrounded by large halos of ionized hydrogen. Just how much is not known. Normally it could be slowly trickling down, keeping the reservoir's topped up, but during a merger it might cool more rapidly. Simulations say that's possible, so, maybe. Whether this is the correct explanation or if it's due to something else entirely, we just don't know.
If it's true, then atomic hydrogen is just the middle step in the process - a complex system of dams rather than just one reservoir. It's not a totally unprecedented idea, but it will mean quite a rethink. We'll have to wait and see what other observations and simulations have to say : this one study is important, but not enough by itself to prove what's going on.
Then there are elliptical galaxies. They're thought to be formed by mergers, as this rather nice simulation shows :
But they usually don't have any atomic hydrogen. Where's it gone ? And yet, sometimes they do - occasionally they have very large amounts of it. It's a mysterious mystery, right enough. As usual, we need more data. But the more we learn about galaxies, the more complicated they become. Eventually, perhaps, we'll have enough data and good enough theories to have a real explanation. For now, we're still learning. And that's fun.
Last year I had my views of the medieval Catholic church smashed into tiny pieces by James Hannam's God's Philosophers. So when I stumbled upon Jim Al-Kahlili's book and read the blurb, there wasn't much chance of me holding on to my money.
Oddly enough, this book doesn't challenge my existing views nearly as much as Hannam's does. But then I was already aware that science in the Islamic world was, for several centuries, far in advance of anything the West was coming up with. Although Hannam's book challenges that, Pathfinders reaffirms it. Hannam still did a great job of convincing me that the medieval Church wasn't some terrible system to oppress freedom of thought, but the extent to which the Islamic world advanced science was far greater than anything happening in Europe.
Like God's Philosophers, Pathfinders is very accessible to a general audience and obviously intended primarily for a Western readership. It does have some mathematical parts (even the odd simple equation or two), but there's nothing you can't freely skip.
Generally speaking, it has less of a theological/philosophical bent than Hannam's book (except for bits about the scientific method). Hannam went to great lengths to spell out exactly what the Church and its teachings did to support and suppress science, directly comparing religious and scientific thinking; Al-Kahlili doesn't really attempt this. For me the book suffers a little because of this. As an agnostic astronomer I work with those of moderate religious leanings on a daily basis, and in the current social climate I don't think it can be emphasised enough : the religious moderates pose no threat to science whatsoever.
The book's main problem is that it's slow to get going. Not until page 62 do we actually get anything about the science that was being done in the Islamic world. Until then we're given (with one very important exception) a not particularly interesting potted history of the East and the rise of Islam, and there's very little attempt in the rest of the book to relate the science to the political context. It would have been far better to reduce this to ten pages or less, or mention the politics in passing throughout the whole book.
But when it does pick up, it's a very good read indeed. Since it doesn't go much into the philosophical side of things too much, I'll just give some brief highlights of stuff I learned :
"Gibberish" is a term originating from the 8th century (al)chemist Jibir ibn Hayyan. Although there was no distinction between the two subjects yet (though there soon would be), Jibir "stressed careful observation, controlled experiments and accurate records." He pioneered techniques in crystallisation, distillation, and evaporation. Unfortunately he was apparently a monumentally bad communicator, hence the modern term.
9th century Muslim scientists weren't content with taking ancient Greek texts on faith : they made their own observations to check and improve upon them. They accurately measured the circumference of the Earth (the idea that ancient peoples believed it was flat is pure nonsense) and used an improved knowledge of geometry and mathematics to make massive improvements in cartography.
The study of optics in the 10th century was done in such mathematical detail that it wouldn't be improved upon until Newton came along 600 years later. Islamic scientists discovered Snell's Law (no mean feat), understood how light, mirrors and lenses work well enough to design "burning mirrors" to focus light, as well as how the human eye perceives the world. They were even engaging in debate as to whether light is particle or a wave, something which is still not really settled today.
Arab mathematicians pioneered the use of zero, the decimal point (it didn't catch on, the numerical system in use was far different to that we use now), algebra (an Arabic word) as a means of general problem-solving, and were deriving formulae as complex as the cosine rule. It may be only GCSE maths today, but deriving it from first principles ? That's tough.
In terms of explaining the science that was done in the Arabic world, Al-Kahlili does a faultless job. He also clearly explains how and why Islamic science developed : the translation movement. The early Arabs became obsessed with translating Persian texts into Arabic, which included many earlier Greek texts. The reasons were a mix of political (wanting to integrate with their Persian subjects), mystical (astrological - interestingly, as with chemistry and alchemy, there was a clear divide between astrology and astronomy far earlier in the Islamic world than in the Christian), and practical (e.g. knowledge of geometry for engineering projects). And he puts forward a very reasonable case that Islamic science was ahead of (or at least on par with) European science for rather longer than is generally supposed.
There are a couple of areas where he's far less clear and/or convincing. The first is how important the "Dark Age" Arabic scientists were in influencing medieval Europe. There came a point in a book where he mentioned that he hoped he had by now made this clear, but it came as a bit of a shock to me. If that's a goal, he needs to use far more examples and explain them in more detail. It felt to me like the book only really hinted at this, except at the end when he does describe in some detail how useful Arabic maths was to Copernicus and Galileo.
The most disappointing part of the book was the severe lack of explanation as to why Arabic science fell (Hannam's book was better in this regard, but still needed more of an epilogue). Strangely, he doesn't seem think it was due to a rise in conservative, fundamentalist Islam, for reasons he doesn't make clear. Sure, he dismisses the argument that Al-Ghalazi alone was responsible for turning the tide - fine. But today in many Islamic countries we do see (as Al-Kahlili himself says) more fundamentalism, and he fails to address how this came about.
More convincing is his case that the Mongols weren't responsible, since science continued to flourish in other parts of the Muslim world long after their devastating invasions. He also dismisses Western colonialism, since Arabic science was already in a crappy state by the time Europeans arrived to cause trouble (though he notes that it was in Western interests not to educate their new subjects about their own enlightened past).
But the main process he chooses to blame looks very odd indeed : the invention of the printing press. OK, it was difficult to use this for the Arabic script, and early mistakes by Westerners in defacing the Q'ran meant it was rejected for a long time. But that only answers why Western science advanced; it says absolutely nothing about why Arabic science declined. Interestingly, he hints at a shift away from blue-skies research to the purely practical applications (which should serve as a warning to anyone still stupid enough not to understand the value of pure research for its own sake, see below). But how and why this happened are, frustratingly, left completely unanswered. To me, this shift in religious thinking from liberal to fundamentalist is one of the most important aspects of books such as these. A thousand years ago fundamentalism did not, as we are so often taught, dominate thinking in either the Christian or Islamic worlds - where did it all go wrong ?
I've said a lot of negatives, but the truth is I really enjoyed this book. What it does well, it does very well - and its faults are generally things it's lacking rather than things done badly. But I want to end on a positive note, and what this book does best of all is demonstrate unequivocally that the Islamic world pioneered the modern scientific method. A series of wonderful quotes sum things up nicely :
Or to put it another way : screw you, Islamophobes ! But if you refuse to listen to a religious icon, try a scientist instead.
“The seeker after truth is not one who studies the writings of the ancients and, following his natural disposition, puts his trust in them, but rather the one who suspects his faith in them and questions what he gathers from them, the one who submits to argument and demonstration and not the sayings of human beings whose nature is fraught with all kinds of imperfection and deficiency. Thus the duty of the man who investigates the writings of scientists, if learning the truth is his goal, is to make himself an enemy of all that he reads, and, applying his mind to the core and margins of of its content, attack it from every side. He should also suspect himself as he performs his critical examination of it, so that he may avoid falling into either prejudice or leniency.”
-Ibn al-Haytham, c.1025 AD.
If there is a battle-cry of modern science, it is something like, "Rrraaaaarrr ! I don't trust you, myself, or anything except evidence, and even then only provisionally !". Which doesn't sound like a very dangerous battle-cry... until the atomic weapon takes you out from orbit. al-Haytham clearly understood the methodology of science as well as any modern scientist.
One final quote demonstrates that not only did these early scientists understand what they were doing, but they understood why they needed to do it : not only for practical reasons, but for the sake of (for want of a better word) the soul :
"The stubborn critic would say : 'What is the benefit of these sciences ?' He does not know the virtue that distinguishes mankind from all the animals : it is knowledge, in general, which is pursued solely by man, and which is pursued for the sake of knowledge itself, because its acquisition is truly delightful, and is unlike the pleasures desirable from other pursuits. For the good cannot be brought forth, and evil cannot be avoided, except by knowledge. What benefit then is more vivid ? What use is more abundant ?”
-Al-Biruni, c.1000 A.D.
I can't add anything to that. All that remains is for me to recommend anyone who thinks they might like this book to buy it immediately, and I hope that eventually he'll team up with Hannam. Together they could produce something really potent. Given the rise of Islamophobia and the ravings of certain educated people who should know better, it can't come soon enough.
Human beings are incredibly powerful paradox machines. There is no lower limit on how absurd, self-contradictory, and downright stupid our most violently-held beliefs can be. Despite overwhelming evidence, people still insist that the Moon landing was a hoax, the Earth is flat, aliens are travelling trillions of miles to mutilate cows, anything that's natural must be good for you, vaccines cause autism, the Moon is a hologram, etc. etc. etc.
Actually the massive rocket was spreading the chemtrails that
convinced everyone it was going to the Moon.
While science is fundamentally about doubt rather than skepticism in the usual sense, you can't question everything. If you doubt everything, you end up learning nothing. Sometimes you have to draw a line and say, "I have enough evidence, I shall believe that this is true" even when you don't have 100% proof - because if you don't do this, you'll never move forward. Or as the old saying goes, "Keep an open mind, but not so open your brains fall out."
Perhaps a slightly better way to put it would be to paraphrase a famous political comment : you can question some of the things all of the time, and all of the things some of the time, but you shouldn't question all of the things all of the time.
Total doubt and total confidence have the same end result : they prohibit learning. So, today's issue is : when should you draw the line ? When is it a good idea to stop (or at least temporarily suspend) questioning things for the sake of maintaining sanity, and how do you avoid the trap of becoming dogmatic ?
Facts are facts... aren't they ?
The most important point is that unless you have irrefutable proof, you never trust your assumptions completely. Irrefutable proof is rare, arguably impossible. It's always possible that people are just making stuff up. But, as a rule of thumb, if "you're lying !" is the only accusation you can make against an argument, you've probably lost. It doesn't matter what evidence I produce to support my position, you can always, always, always turn around and say I'm a liar. Or : the evidence is fabricated. Everything is photoshopped or due to mind-controlling drugs like, oh, I don't know, fluoride.
Although the "it's LIES, I TELL YA !" argument is very, very annoying, we must establish what we mean by "facts". Let's take a simple example that's way beyond climate change in terms of sheer absurdity. Suppose I tell you that fish are entirely fictional. They've never existed. Fossils ? Made by the government. Yesterday's lunch ? Cleverly-doctored, delicious halloumi. That thing swimming around in your pond ? That's what the government's mind-control drugs are making you think.
IF YOU TELL ME I DON'T EXIST THEN I WILL CUT YOU.
One could argue that because of "logic" like this it is never possible to establish anything with 100% certainty, and that everything is merely a belief and there are no facts. And perhaps this is correct, but it is not scientific. The scientific method assumes that the world is real (not a simulation or hallucination of any kind) and governed by inviolable laws. Thus what we see and measure are facts. I see a fish => fish exist, that's a fact, end-of. Or more accurately, multiple observers document their fish-sightings under carefully controlled laboratory conditions and thus we establish the existence of fish with what we call certainty. If you don't believe in this most basic assumption, then as far as science is concerned :
If the world was a simulation of some kind, or everyone was lying the whole time about everything (more on that later), then anything could potentially happen at any moment for no reason. That would mean that logic itself is utterly pointless, so we might as well all give up and cry. Maybe the Universe isn't real or predictable, but that doesn't help us analyse it. If you believe this, then you've gone beyond the remit of science : you're not even wrong.
...which is not to say you are wrong, exactly, just that your arguments can't be validated scientifically. Debate your position with a scientist and you'll find that they are literallyincapable of remaining rational. It's a little bit like what would happen if a sports journalist started asking a golfer about their team's strategy to get the ball in the net, or, better, how they thought a free trade agreement would affect the mating habits of sea turtles. It's a case of, "why are you asking me ?"
All the scientific disciplines believe in this underlying principle without question, simply for the sake of being able to do science at all. But beyond that there is no particular central idea of science that it's bound to follow. Theories continually change with time; there's nothing that says, "thou shalt not question this model even if thou hast lots of reasons why it is bollocks". With massive irony, people who like to say science is dogmatic often tend to be the ones pointing out that it's made a lot of mistakes in the past, as though that somehow indicates that the process is flawed. Actually that's exactly how it's supposed to work !
Aside from the fundamental tenet that reality is measurable, the "beliefs" of science are evidence-based and provisional. We know that our ideas will change : they are only temporary assumptions, not (or at least they shouldn't be) fervently-held beliefs. So am I saying that actually yes, we should question everything all of the time ? Nope. The facts never change. Our interpretations of what they mean, our theories, are more subtle.
Being pragmatic
It's important to realise that science also has to make other, much less deep assumptions in order to progress. When we assume that processes like sedimentation occurred in the same way in the distant geologic past as they do today, or that radioactive decay hasn't varied with time, or that the laws of physics are the same everywhere, we aren't being dogmatic unless we never test them. Usually these assumptions themselves allow us to make testable predictions which advance us to the next level. If they're wrong, our tests will falsify them.
Making assumptions that some things are true doesn't have to mean that you can't change your mind, it simply means that you've chosen to put the burden of proof onto the opposing viewpoint. Of course the trap to avoid is thinking that your assumptions - especially if they're very good, well-tested assumptions - are actually facts. That's why we test everything... but as individuals we don't have to test all our assumptions all of the time. That approach is wildly impractical and not helpful.
Dogmatism only occurs when you automatically dismiss alternative ideas because you already know your idea is true, and think the alternative is not worth anyone testing at all. This often seems to be a case of people holding their theories above facts*. Relativity can't be right because you think it's weird ? Tough. It is weird, but it's got a heck of a lot of observational evidence backing it up. In the scientific method observations always get the last word. The ancient Greek approach of doing as much theory and as little observation as possible has long since been abandoned on the grounds that it was just... well, wrong. If you want to persuade me that relativity is flawed, you must show me what tests it has failed, not what you don't like about it.
* This article, with scarcely credible contempt for so many theories that underpin the modern world, argues that we shouldn't even bother to test their predictions - it's damn tough to imagine a more dogmatic attitude than that. It is convinced these theories are wrong despite the fact that they have been tested innumerable times and offers almost no explanation why the author thinks they're wrong. Yeah, I get how you don't like singularities. I don't like 'em either. But why in the world are you so convinced that the Universe has to make sense to you ? Exactly what compunction does it have to do your bidding ? There is no reason whatsoever to assume that the kilo or so of warm, blood-soaked grey goop inside your skull should be able to understand the Universe.
Yet sometimes, at a less obstinate level, refusing to question is healthy. I personally am never going to conduct any tests to see if the Earth is flat because I know it's round. Uncounted numbers of people have already done tests to prove it's round, the only way to get around (ha ha) this is to say, "they're all lying". If you have so little trust in your fellow human beings that you think this many people are lying, one wonders how you're able to get out of bed every morning. You're not in a healthy state of doubt, you are simply paranoid.
Of course when people really are lying it's extra important that this is exposed, but you need strong evidence that this is the case. "You're a liar !" is a perfectly valid argument, but it should be the final blow, not the opening attack. When people use this as a first response, or if it's the only option left, I tend to stop listening. If you want to accuse me of being a dogmatic round-Earther, go right ahead.
Normally though, even saying, "I believe this is true because evidence" does not mean, "I am certain this is true". I am not certain dark matter exists. I am not even certain the laws of physics are the same everywhere. But I believe dark matter is the best explanation, and I believe the laws of physics don't vary because I see no evidence that they do. 99% of the time in my day job, there's no benefit to me in questioning these assumptions. So I don't, but that doesn't mean I'm going to defend these beliefs to the death. Occasionally I do stop and question them, especially (as regular readers are by now acutely aware) dark matter, but there's no point me doing so all the freakin' time.
Habeas Corpus, On The White House Lawn If Possible
When I was younger, I read a lot - and I mean a lot - of books on the paranormal, from aliens to ghosts, lake monsters and ESP, everything. I've still got tens of books on that stuff lying around. Don't tell me I haven't looked at the evidence, because I have - extensively. What convinced me that all of this stuff is not worth pursuing is that the evidence just never seemed to be that great or ever getting any better. Aliens always seemed to be determined to remain secret (why ?) but happily chose to reveal themselves to some redneck farmer who'd let them take wonderful pictures of their spaceship but never of the occupants. More often even the spaceships were nothing more than very fuzzy blobs in the photographs.
Photos never got any better come the digital age either.
After this extensive background reading I now tend to dismiss any claims of flying saucers out of hand. I'll believe if one lands on the White House lawn, but the argument, "I'm a dude on the internet, trust me !" carries no weight with me. As far as I'm concerned, this is another hypothesis that has already been tested extensively enough that it can be dismissed until much stronger evidence comes along. If other people want to research UFOs, that's fine with me - I just don't want to get involved with this personally, thanks.
Similarly, when something like the EmDrive or cold fusion comes along, the claims tend to be a case of betting on a barely-measurable detections over decades (even centuries) of established results. It's not that scientists will never accept the result. It's just that we require gold standard, "spaceship on the lawn" level of evidence. For most of us it's simply a pragmatic approach to ignore it until that comes along.
I don't have time for this. I need to know what to believe !
Not everyone is prepared to read up on UFOs. Similarly, not everyone has the inclination or indeed ability to become a professional scientist (likewise I have no ability to become a professional bog-snorkeller, swimsuit model, or a toaster). And therein lies the danger : the modern world is highly dependent on and yet very suspicious of science. It doesn't really matter if you believe in flying saucers or not; it does matter if you refuse to believe in the benefits of vaccines.
The thing is, in most ways I'm not a scientist either. I am not a climate scientist, but I believe global warming is likely mostly the result of humans. I am not a biologist, but I believe vaccines work. I am not a surgeon, but I know surgery works. Nor am I a chemist, but I'm pretty sure dynamite works. And I'm not an electrician but I can still use the internet. Is it dogmatic of me to trust the experts on so many issues about which I'm genuinely no better informed than the average man on the street ? No, because I do understand how the scientific method works.
If you want to persuade me that an argument is false because the method isn't being followed correctly, you might have some success. But if you want to persuade me that the method itself is fundamentally flawed, you're basically arguing against every piece of technology in the modern world. Good luck with that.
It's that critical step of "observation" which is so important. Simply put, it isn't dogmatic to believe that well-tested things are true, as long as deep down you reserve at least a small level of uncertainty*. I also know that the results have been tested repeatedly, and if you don't believe one expert, you probably should believe a thousand.
* Well that's true for theories (well-tested but not proven models) at least. For true facts (i.e. the Earth is round) you can abandon all uncertainty. You can't be dogmatic about facts even if you want to.
Really, the level of trust we're asking for is no different to what everyone accepts in everyday life. We all give money for goods and services expecting that the guy behind the counter won't just run off with it. We all get into planes expecting that they won't crash. We all live in houses expecting that they won't just collapse or catch fire or suddenly turn into jelly for some reason, trusting that the builders have done their job correctly. We cannot be certain of any of those things, but if we doubt them all the time we'd end up cowering in a hole or wrapped in bubble wrap or something.
Of course, keeping the possibility of a terrible accident in the back of your mind is perfectly sensible. Ordinary doubt is a very good thing indeed - it's paranoia that's the problem.
So we should all just shut up and trust scientists unconditionally, then ?
Just like with UFOs, the reason I support virtually every mainstream established result is because whenever I've looked in detail at the alternatives, I've found them wanting. Every. Single. Time. If you think it makes me some sort of dogmatic acolyte, I don't care. It's not my fault if I find the mainstream, evidence-based arguments genuinely convincing.
The great thing is that you too are free to examine those findings for yourself, and if you do so carefully and without bias, I honestly believe you'll be in favour of the mainstream results as well. At least in astronomy, it's easier than ever to get unfiltered access to the original results and even the raw data. If you doubt the findings when you first hear them, that's great ! But if you don't go on to examine things in more detail and still persist in insisting that the results must be wrong, then it is you who is being dogmatic, not the researchers. And if you want to spread your anti-science via the internet, at least take a moment to consider the tremendous irony.
They say that in the age of information, ignorance is a choice. And that's true, but at the same time it puts a burden - nay, a duty - on scientists to communicate their findings as clearly as possible to the general public. We have so much information available to us that sifting through the worst of it is undeniably difficult, so any real scientist able to do outreach bloody well ought to*. It's those on the coalface who are best able to judge the strengths and weaknesses of current research.
* Outreach is a skill like anything else. There are plenty of good scientists who are so monumentally bad at communicating that they should be locked in a broom cupboard whenever there's any chance they might interact with a non-scientist. And of course by "able to" I mean, "allowed to as part of their job". We can't force people to do this on their own time.
This is more important than ever because it's becoming increasingly difficult for the public to directly test contemporary research. The days of a lone genius making some breakthrough discovery in a shed are not over, but nowadays testing the theory can require a billion-dollar particle accelerator. If the public can't test the results for themselves, then we at least need to do everything we can to explain what we did and how we did it as clearly as we can. Understanding the scientific method and the philosophy behind it is far more important for establishing trust than the result itself.
Aaaargh ! I'm very confused ! I just want answers !
I understand why this can be confusing. Most people prefer a clear-cut, "yes or no" answer to questions. It just isn't really like that in science, where we've got this odd mix of hard certainty (true facts), hypothesis (models consistent with limited observational data) and theories (very well-tested models). Both of the latter can be disproved, and many have been throughout history. Yet sometimes, just to make it more confusing, we act as though our theories are facts, even though we know they're not !
We assume theories are correct as a matter of convenience. Sometimes, yes, we do go too far. Individual scientists are indeed capable of clinging dogmatically to disproven ideas. But the wider scientific community is more robust than that. One of the best articles in terms of science communication I've read recently is the BBC's "We want to break physics" :
"The data so far has confirmed that our theory is really really good, which is frustrating because we know it's not !" Prof Shears says. "We know it can't explain a lot of the Universe. So instead of trying to test the truth of this theory, what we really want to do now is break it - to show where it stops reflecting reality. That's the only way we're going to make progress."
YES ! That's perfect. We know out theories are doing a good job - otherwise we'd already have thrown them out - but we also know they aren't perfect.
The best way to change a scientist's mind is to buy them a drink and slip them a bribe... err, I mean, give them hard evidence that they're wrong. If you have some objection to a theory on the grounds that it sounds implausible, that won't get you very far. The Universe is not necessarily a sensible place, and the only way to test how ridiculous it is is through observational testing. If you haven't got that kind of evidence, then I for one will stick my fingers in my ears and sing, "la la la I'M NOT LISTENING !" because the number of alternative, contradictory theories out there is far beyond my capacity to analyse. On the occasions I've looked at them in detail, I've found them to be self-evidently flawed or simply lacking any advantages over mainstream theories.
If it helps, science rarely offers true answers : but it can give you sufficiently-good information that you're able to make a decision. Put it like this - if you want to design an aircraft and risk hundreds of lives, you're better off relying on aeronautical knowledge than crystal-gazing. Both might be wrong, it's just that the chances of the scientific approach being wrong are waaaay lower than staring at a chunk of glass. The difference between the complex equations of mathematics and the arcane symbols of the occult is that the mathematics actually works reliably, repeatedly, and doesn't depend one jot on sacrificing chickens unless the mathematician is hungry and partial to KFC.
Summary
Science assumes the world is real and governed solely by physical laws. If you believe there's more to it than that, then fine, but that position cannot be analysed scientifically.
Scientific facts are established through multiple observations. We require only the most basic level of trust that everyone else isn't lying about them. Doubt is good, paranoia is just another form of certainty.
People who do yell "it's a conspiracy !" tend to be the ones who think scientists are dogmatic, yet when scientists do change their minds they either ignore it or shout loudly about how scientists had been believing nonsense for years because of their dogmatic attitude.
Those same people also tend to criticise scientists for testing theories they believe are wrong, apparently oblivious to how incredibly closed-minded they've become.
You can't be dogmatic about facts. You can, potentially, be dogmatic about theories. However, the position, "I shall assume that this is true until someone gives good evidence otherwise" is not the same as saying, "I'm completely certain about this and I'll never change my mind - in fact I shall now start a crusade to disprove all other viewpoints, ahahahahaha !"
It's OK to assume that something is true, temporarily ignore the doubters and just get on with your damn job for a while, provided that every so often you stop and check what you're doing. You don't have to check every assumption all of the time - indeed, often the research itself will uncover a flaw if one exists. You just have to be prepared that this might happen.
Generally it's safe to ignore people claiming that things are wrong because they don't like them (rather than presenting actual evidence), or claiming from the off that people are lying, or (99.9999% of the time) that they've found an "obvious flaw" in a theory. Check what they're saying once in a while, but if you do so every time you'll quickly find yourself going insane and that's not good for anyone.
If you're looking for solid answers, forget it. Science isn't so much about getting the "correct" answer as it as about being able to make the best decision possible based on usually limited evidence. Aside from measured facts, scientific theories are only ever a guide to the Universe, a way of making decisions, not a decree of Ultimate Truth.
What do you do if you've lost a galaxy ? Declaring the arrival of Doomsday might be a natural first reaction. What about if you've lost thousands of galaxies ? Full on panic and acute embarrassment would seem like the only rational response.
In fact, this has been the case for astronomers for well over a decade. Not the panicking, because astronomers are brave and/or apathetic folk, but the missing galaxies. Cosmological models predict far more galaxies than we actually observe. So what happens when all of a sudden you discover a thousand faint galaxies in a nearby cluster ? Throw a massive orgy to celebrate ? No. Well, ye -NO ! You get very puzzled is what you do.
Feel free to scroll down to the "The New Results" section if you like, but if you want the gory details, keep reading.
Modelling the Universe
Artist's impression of the dark matter (in blue) that is thought to surround the galaxies.
To understand why, we first have to look at those troublesome models. Simulating a galaxy is far from an easy task. Our current idea is that a galaxy is made of gas, stars, a bit of dust and a lot of dark matter. Gas turns into stars, which then heat up the gas and dust. They also fuse light elements (hydrogen and helium) into heavier "metals", which is bizarre astronomy-speak for "anything that's not hydrogen or helium. Why ? Well this is the same discipline which decided it would be a good idea to measure brightness on a backwards scale (with lower values for brighter objects), call different sorts of galaxies "early" and "late" for no good reason whatsoever*, and doesn't bat an eyelid at calling a telescope, "The Very Large Telescope".
* Often people claim it's because Edwin Hubble thought that galaxies evolve from smooth "early" to structured "late" type galaxies. Actually, he didn't. In a footnote in his 1926 paper, he basically says that he's using these terms in order to confuse the heck out of everyone.
Sometimes I wonder if we should make peace with astrologers just to let them think up the names.
Anyway, the stars don't just shine, they also spew metal-enriched gas back into the galaxy, at a rate depending on the mass of the star. Very massive stars eject gas much more rapidly than low-mass stars. They're also hotter, so can fuse heavier elements and hence produce more metals.
Massive "Wolf-Rayet" stars like this one are the drunken louts of the galaxy, projectile-vomiting most of their mass back into interstellar space. Most normal stars are more civilized and just spit a little bit on the interstellar street.
Metals affect how the gas cools and collapses (colder gas collapses more easily, since it has less heat to hold it up against its own gravity), which in turn affects how new stars form. Some stars eventually explode, heating up the gas and injecting even more metals. And in the centers of massive galaxies, gas can pile up around giant black holes, heating up to millions of degrees and blowing itself apart.
Simulating all of this is, needless to say, very difficult. I hope you'll forgive us for not having solved every problem yet.
And I didn't even mention the mysterious dark matter, which we think dominates the mass of the galaxy by around a factor of ten. We think it's there primarily because galaxies are rotating too quickly, which is easiest to explain with a massive amount of unseen matter. That's not the only possible explanation (see, for example, this post), but for today's purposes I'm going to assume dark matter does in fact exist.
As far as we can tell, dark matter doesn't interact through normal matter (or itself) except through gravity. It doesn't radiate heat, it doesn't form stars or planets. By and large, it does bugger all except sit there providing extra mass, at which point I'd be tempted to make a fat-shaming joke if this wasn't now considered offensive.
Thanks, internet !
This means it's very easy to simulate - it's easier to write the computer code, and it doesn't have to do all the slow calculations needed for gas dynamics. And since it's much more massive than the stars and gas combined, someone had the bright idea of running a simulation using just dark matter. Obviously this wouldn't give us much information on how individual galaxies work, but maybe it would be good for studying the large-scale structure of galaxies. On really large scales, the physics of the gas and dust is thought to be unimportant, so it makes sense to use only the dark matter.
The large-scale structure of the Universe : a series of interconnecting filaments of galaxies and clusters of galaxies.
Guess what ? IT WORKED ! Not only that, but it worked really well. You can indeed produce a Universe in a simulation that looks a lot like the real thing on the correct timescale. That's pretty compelling further evidence that dark matter is real.
The Millennium Simulation. OK, it doesn't look that much like the real Universe, but it would if you put a galaxy in each of the yellow blobs.
But on smaller scales, there's BIG trouble with little galaxies*. Back in the 1990's, simulations were predicting that there should be hundreds of galaxies orbiting the Milky Way, whereas in fact we knew of eleven (over a certain mass). Now, because even making simple measurements of distant galaxies is difficult, astronomers are normally happy when theory and observations agree to within even a factor of ten, but this was just too much.
* A dreadful 1980's movie in which a group of PhD students are drawn into an epic race-against-time with a rival group to see who can be the first to simulate the formation of a dwarf galaxy.
Since the simulations use only dark matter, we also have to figure out how much gas and stars we expect to see in each dark matter cloud (normally known as a halo). This is determined in the models largely by the mass of each halo. There is of course some error in this : not all galaxies of the same total mass have the same brightness. Some have most of their mass in gas, some in stars, some have most of their stars more spread out, making them harder to detect. The important point is that the gas and stars aren't simulated, they're only estimated from the model halos. But it still seemed as though the model predicted far too many galaxies.
Weirdly, the model was pretty rubbish around individual galaxies, but seemed to be doing just fine in galaxy clusters - at least at the mass of galaxies it was able to simulate. But we'll get back to that soon.
Observing the Universe
The aptly-named "Dragonfly" telescope, which has played an important role in discovering new galaxies
Over the last ten years or so, quite a lot more galaxies have been found around in our own Local Group. Computers have been upgraded so the simulations have improved... and predicted more smaller galaxies. Where does the balance lie ? Has the difference between models and observations improved or gotten worse ?
Yes, one of those.
By which I mean, predictably, that it's complicated. What the models predict is how many dwarf galaxies you expect to fine around (say) a giant galaxy like the Milky Way, i.e. within some distance from it. The trouble is that even finding galaxies is difficult. If their stars are too spread out they can be difficult to see; too close together and the whole galaxy can look like a star. Crucially, you have to be able to estimate their distance, otherwise you could be finding galaxies which are much too far away. Measuring distances isn't easy at the best of times, but (like most measurements) it's particularly difficult for the faintest galaxies, which are the most interesting.
You also want your galaxy survey to be uniform. That is, you want it to have the same sensitivity across the whole sky... but part of the sky is unavoidably blocked by the pesky stars of the Milky Way, so you can't do that. Not even if you really want to.
DAMN THIS CRAPPY MAJESTIC DUST !
Nevertheless, such deep, uniformly-sensitive surveys as do exist have discovered a lot more galaxies around our Milky Way than was thought until just a few years ago. But not enough. Maybeenough, if you invoke some complicated physics that the simulations don't handle directly, but not everyone agrees.
In any case, the main mechanism proposed to do this is that maybe there are enough supernovae and strong stellar winds to quickly blow out all the gas in dwarf galaxies when they form. That would stop them forming stars later on. The problem is that the dwarf galaxies we know about have a mix of old and young stars, which isn't what that model predicts. More fundamentally, if giant galaxies really are surrounded by lots of invisible dark matter halos, the effect is like being in a swarm of bees : you're gonna get stung. Stinging causes swelling... and that's what doesn't happen to some galaxies. They should have thick stellar discs or central bulges from all those dark halos ploughing through them, but they don't.
The faint streams of stars indicates that NGC 5907 has torn a smaller satellite galaxy to shreds, but it doesn't have a bulge.
What about galaxy clusters ?
I said earlier than simulations didn't have a problem for whole clusters, just individual galaxies. The problem there is that that particular paper used the same number of particles for both the simulation of a single galaxy and a cluster. That means the mass of the particles in both simulations won't be the same. If they were, the end result might be different.
Simulation of a galaxy cluster and an individual galaxy using just dark matter
particles. Can you guess which is which ?
What the simulation did show, however, was that the structure of the dark matter halo is practically identical on small and large scales. So, if you extrapolate the results of the simulation of the individual galaxy (which has the better mass resolution) up to the scale of the cluster, you predict that a cluster as massive as Virgo should have about 150,000 galaxies. Actually it's got somewhat less than 2,000.
Oh dear. Oh deary deary me.
The New Results
There are actually three papers I want to summarise, but don't worry : they're all quite similar, so I won't go through them all in depth.
We begin with a paper from January : Forty-Seven Milky Way-Sized, Extremely Diffuse Galaxies In The Coma Cluster (the second link goes to an excellent press release). The Dragonfly telescope array (shown above) may be small, but its innovative optics make it excellent at searching for very faint galaxies. And can you guess what it found when researchers pointed it at the Coma cluster ?
Coma as seen through a more conventional telescope. The new discoveries are much fainter, and difficult to show alongside these brighter galaxies.
That's right ! Forty-seven Milky Way-sized extremely diffuse galaxies !* *They weren't looking for them though, because that would have been a remarkable coincidence. Actually they were looking for stars outside their parent galaxies, but found these new galaxies instead.
Although the Milky Way is pathetic in size compared to some of the monster galaxies out there, it's by no means a tiddler. To suddenly find 47 galaxies this big in a region as well-studied as Coma is pretty shocking. The reason they were missed for so many years is that they're of extremely low surface brightness, which just means that they have very few stars for galaxies this large : about a thousand times less than the Milky Way.
You might be wondering how we know these galaxies are really in the cluster, and not closer, smaller objects. Reading the paper it's clear that the team initially thought this was probably the case too. But the new galaxies are distributed in roughly the same way as the known cluster members, which makes that unlikely. Also, by sheer luck, a few of these galaxies happened to appear in archival Hubble observations of known Coma galaxies, which I suppose is a case of cosmic photobombing.
The Hubble observations can't say exactly how far away the galaxies are, but they can place a limit on it. If the galaxies had been slightly closer, the super-sharp Hubble would have been able to pick out individual stars in the new galaxies. It didn't. So the most likely explanation is that they are indeed inside the cluster.
Hubble image of one of the new galaxies, with some slight contrast adjustment, taken from the paper.
Combining those two arguments makes a pretty strong case that the galaxies are in the cluster, but very recently that's been put on a much stronger footing. Observations of the redshift of one of the new detections confirms it's at the same distance as the other cluster members. So it's virtually certain that most of these detections are indeed part of the cluster.
The 8m Subaru telescope is rather larger and more expensive than Dragonfly.
A thousand new galaxies ! 300 of them as large as the Milky Way... now we're talking. Just like with Dragonfly, the observations weren't specifically for going galaxy hunting. In this case they were for a bunch of different projects, but since the Subaru telescope has an archive (all data publically available after 18 months) the researchers were able to exploit it for their own sick, twisted ends. Well, if you think finding galaxies is sick and twisted, at any rate.
Determining if nearly a thousand galaxies are in the cluster is considerably more difficult than for a mere 47, but the authors make a very convincing case. Even finding them isn't easy, because for a survey area this large it's not practical to look at the whole thing by eye. Automatic programs have to be used, which cause all sorts of problems : they misidentify other structures as galaxies (like artifacts in the data and stellar streams) and can identify real galaxies which aren't in the cluster at all. So the team went through all the candidate galaxies the program found, carefully checking to make sure it was really finding galaxies and not something less interesting like some stupid graduate student's fingerprints on the lens.
The most compelling argument is that when they looked in a field outside of the cluster, and did all their very careful processing, they didn't find a single candidate galaxy. As with one of the galaxies found with Dragonfly, they also have a redshift measurement of one galaxy that confirms it's a cluster member. So it's pretty safe to assume that the majority of these detections really are in the cluster.
But a thousand galaxies still isn't enough. Not by a long shot.
Actually what this does do that the others don't is try to quantify just exactly how bad the missing satellite problem is. This one looks at the closer Virgo cluster rather than Coma, using archival data from the Next Generation Virgo Survey.
The paper goes into a lot of details about how they find the galaxies, which is complicated. There are hints that the ~300 new galaxies they find are by no means all that's there, but they doubt there could be orders of magnitude more lurking in the data. Interestingly, the galaxies they find in Virgo are all much smaller than the faint giant galaxies found in Coma*. That raises another issue since the Coma cluster is thought to be older and more evolved, whereas Virgo is still being assembled. How, then, have those faint wispy galaxies survived there without being torn apart ? It would make more sense in Virgo where they could be falling in to the cluster for the first time.
*The authors tell me that this could be because of how the data was processed by the original observing team. There could be larger galaxies hiding in the data, but we won't know until the raw data is released and re-processed in a way more suitable for finding large, faint objects.
Galaxy clusters are undoubtedly very dangerous places to be. Super-sensitive observation of Virgo revealed a dramatic image of streaky structures in the very outermost parts of the galaxies, likely due to the other galaxies disrupting their stars :
Intracluster light, with the foreground stars of our own Galaxy masked as black circles.
So how have these large, faint galaxies survived in Coma without being shredded ? It it all depends on whether these are faint giant galaxies or huge dwarfs.
What I mean by this is : what is the total mass of the galaxies ? A "huge dwarf" (my term) would be a galaxy with the same mass in stars and dark matter but just much more extended than "normal" dwarfs. Basically, imagine taking Gimli and inserting an air pump so that his size increases but his mass stays the same, sort of like the Mr Creosote sketch...
Actually don't imagine that because it's a horrible mental image, but you get the idea.
If, on the other hand, the galaxies have a lot of dark matter (so a total mass much greater than dwarfs), this would make them faint giants (sometimes called "crouching giants"). We don't yet have the observations needed to say which of these is correct, but this second possibility does offer an explanation as to how they've survived.
Being massive would make them much more difficult to disrupt, which would explain why they've survived and they all look nice and smooth. Of course if they're too massive then they wouldn't explain the missing satellite problem at all, and we might even end up having far too many massive galaxies. We'll have to wait for new observations to estimate their total masses before we can try and answer this one.
For the galaxies in Virgo, which are much smaller, this scenario is not likely or necessary (since they could just be falling in for the very first time). The analysis shows that, when correcting as much as possible for the various sources of error, there are nowhere near enough galaxies in the cluster as the cosmological models predict. So in Virgo, at least, the missing satellite problem is still a problem, and everyone is still very embarrassed.
Summary
Galaxy formation models have many problems, not least in predicting the number of galaxies we expect to find. They predict we should see far more than we actually do. But the devil's in the details... and it looks like these new discoveries aren't nearly enough to solve the problem. They might, conceivably, make things even worse.
But it's also extremely important to remember just how complicated galaxy simulations need to be, which is why I rambled on about it at great length. We're not even at the stage where we can include all the physical processes we know about - computers are nowhere near powerful enough for that.
Some people would like to use the old axiom, "if it disagrees with observation it is wrong" to say that the whole idea of dark matter-cosmology is fundamentally wrong. The problem is that the simulations are so woefully incomplete that this makes no sense, because we're not even at the stage of being able to say if they're wrong. They might be, that is perfectly possible. But it's ridiculous to claim that we know for certain that that is the case right now.
What I like most about these papers is how much they expose our tremendous ignorance. Suddenly : BAM ! A thousand new galaxies in the Coma cluster, just like that. And not just any sort of galaxies, but a population of objects we thought were extremely rare. No-one had used galaxy formation theories to predict that there should be a huge number of galaxies as big as the Milky Way but a thousand times fainter hiding in some clusters but (perhaps) not others. For the moment, our observations are running well ahead of our theories. If you're hoping that scientists will come up with any sort of grand, profound understanding of the cosmos, I'm afraid you're going to be waiting for a very long time yet.
Following the aftermath of the May 2015 election, I wrote that I personally would quite like a Labour leader who was even more left-wing that Ed Milliband (though I also noted that this might not be a good way for Labour to get back into power). Well, now we've undeniably got one. Whether this will be to Labour's advantage or disadvantage remains to be seen. This has given me a nasty case of confusion, with the ideological part of me wanting to leap up, punch the air, and shout, "BOO-YA YA PIG-F*$*@!ng TORIES !", and the pragmatic part of me quietly sitting down, hands steepled, going, "Hmmm."
The media are telling a lot of lies, half-truths and reporting statements out of context about Jeremy Corbyn - but that's another story. One thing that is absolutely no lie is that Corbyn is a stalwart opponent of nuclear weapons. In this case, the realistic part of me has won the day, but the ideological part is waging a quite successful guerilla campaign. Which means that I'm going to happily vote for the man, would love to give him a hug, but hope he loses the debate on this particular policy.
Nuclear weapons are possibly the worst thing ever devised, and if I could flick a switch that would instantly remove every single one right now, I'd do it without hesitation*. What I am not in favour of isn't disarmament, it's Britain unilaterally deciding to disarm in the current global political climate. Here's why I don't find the arguments that the UK should abandon its deterrent entirely convincing.
*Excepting a very small stockpile in a case labelled, "DO NOT OPEN UNLESS ASTEROID". (Normally I'm a keen advocate of Godwin's Law ("anyone who mentions the Nazis instantly loses the argument") on the grounds that you can prove anything with extreme, abnormal examples. In this case I have to ignore it, because nuclear weapons are themselves extreme, abnormal examples, and anyway they were invented during WWII)
1) We will never use them...
As the classic Yes Prime Minister explains, nuclear weapons aren't much good as a deterrent against warfare in general. No-one is considering nuking Russia because they're disturbing Ukraine any more than Britain would consider nuking Argentina if they invaded the Falkland Islands again. India and Pakistan aren't nuking each other, despite permanent tensions, and Israel isn't nuking anyone despite the fact that no-one likes them very much.
But an argument could be made that nukes are a deterrent against full-on nation-nation conflicts. Would Russia resort to their "salami tactics" if the Western powers didn't have nuclear weapons ? Perhaps not. Would Nazi Germany have invaded Poland if Poland had had nukes but the Germans didn't ? Unlikely. A small state, unable to defend itself by conventional means, threatened with occupation by an much more powerful, evil but non-nuclear invader... is that really such a black-and-white case of, "no, nuclear weapons must never be used, we must surrender to these people and let them exterminate us" ?
That's hypothetical. We don't have any cases of such a situation directly threatening Britain or her allies - currently. Yet the Arab Spring* (amongst countless other historical examples) proves just how incredibly quickly the political situation can change without warning, and we shouldn't underestimate that. Nor should we ever underestimate just how evilpeople - and even whole societies - can become. History tells me that there's probably no limit to how savage people can be, and being prepared for that just seems prudent.
* Read that link.
2) ... because using them would wipe out the world
Using them against, say, Russia, probably would wipe out the world. Using them in a joint operation with Russia probably wouldn't.
The possibility of us actually initiating a justified, joint pre-emptive strike that wouldn't make the situation any worse does seem incredibly far-fetched, and it certainly isn't the main reason we have nuclear weapons. Anyway I would rather that no-one ever needed to use them at all. So why bother keeping nuclear weapons if all they do is limit warfare, rather than deterring it entirely ?
Nuclear weapons are their own deterrent. The doctrine of Mutually Assured Destruction means that no-one ever uses their nukes because that would bring about their own annihilation in a global nuclear holocaust. Even the craziest dictator doesn't want to risk that.
So, the "we will never use them because apocalypse" argument is correct, but misses something. No-one else will use them either, because we've got them too. Now that we have this unfortunate situation, the point of keeping nuclear weapons is, ironically, to prevent nuclear war.
We do not have nuclear weapons so that we can wipe out the planet in the case that someone launches a nuclear strike against us. All that would do is turn an awful situation into a total apocalypse. Rather, we have them so that that situation can't happen in the first place. The threat of our nukes prevent others from using theirs. And, in the highly unlikely but not impossible case that we actually do need to use them without risking the apocalypse, the option is available.
3) Our allies will help us if we ever really do need nuclear weapons
From Yes Minister - The Challenge :
Hacker : Ah, no, no, no, no, no, no, no. I'm not that unilateralist ! Anyway, the Americans will always protect us from the Russians, won't they ? Sir Humphrey : Russians? Who's talking about the Russians ? Hacker : Well, the independent deterrent... Sir Humphrey : It's to protect us against the French ! Hacker :The French ?! But that's astounding ! Sir Humphrey :Why ? Hacker :Well they're our allies, our partners... Sir Humphrey : Well, they are now, but they've been our enemies for the most of the past 900 years. If they've got the bomb, we must have the bomb ! Hacker :If it's for the French, of course, that's different. Makes a lot of sense. Sir Humphrey :Yes. Can't trust the Frogs. Hacker :You can say that again !
It's all too easy to re-write this scene given post-2000 politics :
Hacker : Anyway, the Americans will always protect us from the Russians, won't they ? Sir Humphrey : The Americans ? THE AMERICANS ? Minister the Americans elected a chimpanzee as President ! A man who thinks its a revelation that most of their imports come from overseas ! Who said our Prime Minister was bigger than a poodle ! And now there's a very real chance that they'll elect as the most powerful man in the world someone who's widely regarded as little more than a talking, racist toupee ! Hacker : Yes, well, I see your point.... Still, that leaves us under the protection of the Frogs, eh Humphrey ? Bit embarrassing, but they wouldn't let us down, would they ? If push came to shove... ? Sir Humphrey : [Sighs] Minister the last French premier said he couldn't imagine a situation where Britain would need an aircraft carrier and the French wouldn't want to be involved, a statement which had several political journalists coughing the words, "Falkland Islands" so loudly that they had to be treated for laryngitis.
To be marginally more serious, of course I would hope our allies certainly would protect us by nuclear means if such a situation ever arose. Of course, that would mean that now our allies have to invest in this incredibly expensive system while we do not. Good for us, but not likely to be well-received by countries who don't want to disarm. I also believes it sends out the wrong signal at the wrong time : given the financial crisis, spending cuts, the chaos in the Middle East and the sly manoeuvrings of Russia, I think we would be perceived as weaker, not stronger.
Of the nuclear states (US, Russia, the UK, France, China, India, Pakistan and (just about) North Korea), only France and the US are at all likely to come to our aid in that incredibly unlikely situation that we actually need them. But if such an absurdly unlikely, desperate situation that required nukes did arise, I'd really prefer not to have to rely on anyone.
4) Other countries have disarmed / don't have / don't need nuclear weapons
Most countries have never had any nuclear weapons, but that doesn't mean they aren't defended by ours. It's pretty hard to ignore my Czech colleagues saying, "please don't give up your nuclear weapons". Anecdotal, perhaps, but there we go. If anyone has any international opinion polls on public feeling in non-nuclear states towards those which are so armed, let me know (or equally, the opinion of the military experts in those unarmed countries).
Four countries have abandoned nuclear weapons. Three of them (Belarus, Kazakhstan and Ukraine) gave them up to Russia (those from the Ukraine were disassembled) when the Soviet Union collapsed. Only South Africa decided to get rid of them entirely of its own volition. The country had no more than seven nuclear weapons and probably conducted no actual tests. And, well, of the countries most likely to ever be involved in a major conflict with Russia or China, I wouldn't put South Africa at the top of the list.
5) If no-one disarms first then nothing will ever change
This also neatly explains why Corbyn's, "I'd never use them"
comment was so ill-advised.
The above arguments might make it seem as though I'm implying that we're stuck with these god-awful death weapons that cost billions and which we'll almost certainly never use, because if we decided to disarm then we instantly fling open the doors to our enemies. Of course, that isn't quite what I mean.
Would disarming actually increase the probability of us being nuked, right now ? No. Does it increase the chances that we'll be invaded and/or nuked at some point in the distant future ? That is much, much harder to answer. It would be foolish in the extreme to say, "definitely not". I do not believe anyone is remotely capable of predicting the future with anything like the required accuracy for us to safely opt for unilateral disarmament.
This doesn't mean we're stuck with them forever. But for the last sixty years or so, the sheer horror of what a nuclear war would mean has prevented it from happening. That has been in part due to a balance of power (or rather, in the case of nukes, a balance of terror) between the world's most influential nations. While I don't think that now is the right time to disarm, I do think it's possible - I just want it to be done multilaterally and in as complete safety as can be achieved.
Consider the fictional Sir Humphrey's absolutely correct comment that for most of the last 900 years the French were Britain's arch-enemies. That changed. Which means that Russia, having had a bit of a rough century, aren't guaranteed to be at odds with us forever. I believe that this is an area of foreign policy where Corbyn is absolutely right : we must try and engage with our enemies rather than provoke them, because if we don't we really will remain stuck in pointless hostilities.
War between the nations of Europe has been common for the last 1,500 years. Today it's unthinkable that Norway would invade England or that France would take on Italy. I would like us to be that close with all the other nuclear states before we start talking about disarmament. If we can do this with nations we've fought for 900 years, we can do it with anyone. I just think disarmament is something you do once trust has been established, not as a (in my opinion risky) way to establish that trust initially.
6) Think of all the things we could do with the money instead !
For where your treasure is, there will your heart be also. - Matthew 6:21.
It really is depressing just how much better the world could be without military expenditure. I wrote a while back about all the wonderful stuff we could have had if we hadn't held a stupid sports contest for two weeks. That was a mere £9 billion. Trident costs a lot more, but possibly not as much as the £100 billion that's so often bandied about. That's over the full 40 year lifetime though, so "only" £2.5 billion per year. Still, I was surprised to learn that that's just 5% of the MODs budget (Corbyn claims 25%, presumably referring only to the equipment budget). In any case, £2.5 billion is a lot, but it's hardly unaffordable for one of the richest countries on the planet.
Even Jeremy Corbyn has stopped saying that savings from Trident could go towards "national well-being" and has recognized that Britain needs a strong military (it almost sounded like he was saying, "replace Trident with conventional forces", though that's just my interpretation). The Liberal Democrats, erstwhile opponents of Trident, have changed their stance considerably on the nuclear deterrent.
Yet, while in principle it would be infinitely preferable to spend the money on just about anything else, helping to deter nuclear attacks is a price worth paying. We're not spending billions on weapons of mass destruction we'll never use. We're spending it on a proven method (however stupid) for preventing nuclear war. That's where my heart is, Matthew. Not in investing in the weapons, but in preventing their use.
7) But does it have to be Trident and not something cheaper ?
Like a wooden submersible duck...
A permanently at-sea submarine solution offers the best deterrent. Even if a surprise enemy first strike completely obliterates our land and surface forces, they stand very little chance of also taking out a nuclear submarine hiding God-knows-where in the ocean. So making that pre-emptive first strike becomes a pointless risk that no-one's willing to take, hence it doesn't happen. With the submarine solution, there's not really any need for fleets of bombers or underground missile silos.
Other options considered include a smaller number of submarines. That would mean there isn't always one on patrol, so there's sometimes a risk that a first strike would completely eliminate our ability to retaliate. That rather weakens the whole "deterrent" aspect.
Could we provide a credible deterrent without submarines at all ? Some people think so. Arguably, by having a fleet of nuclear-armed bomber aircraft* instead, we would not only save around £13 billion but also simultaneously increase our conventional capabilities (which we are far more likely to ever actually use). The trouble is that if you want to deliver bombs by aircraft, it's much more difficult to guarantee that those aircraft reach their targets : sub-orbital ICBMs are much harder to shoot down; submarines are "practically invulnerable" to a surprise attack. On the other hand with enough stealth aircraft, and a virtual certainty of having enough time to deploy them, a credible nuclear deterrent without submarines might be possible.
* Though the F35 plane proposed to carry the bombs has been universally panned as being simply utterly awful.
Summary
I want nuclear weapons gone. I really, really do. But more than that, I want to guarantee that nuclear war never happens. That is the priority. Right now, given the incredibly unstable political climate of the world, disarming Britain does not seem like a sensible way to ensure that. I think other countries are more likely to perceive it as saying, "we cannot afford nuclear weapons" rather than, "we no longer need nuclear weapons".
I've never been a fan of the idea that "if you want peace, you must prepare for war". An armed truce is not peace; you can't threaten people into liking you. But you can engage with them with genuinely honourable intentions whilst having a backup plan in case something goes horribly wrong. Turning the other cheek is a laudable principle, but sometimes you just get slapped. Bullies seldom respect what they perceive as weakness.
History teaches us that human beings are capable of almost anything, and as such, predicting the future is nigh-on impossible. There are no guarantees in anything we do. I have great respect for Jeremy Corbyn's pacifism, but I just don't see unilateral disarmament as either currently safe or a way to peace. Peace, however, might just be a route to multilateral disarmament. I think we should first be in a position of genuine, mutually-dependent trust before we disarm, so that we can finally destroy these awful things forever.
