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,

Sunday, 11 October 2015


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.

The active galaxy M82.
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.

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. Maybe enough, 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.

Still, 47 galaxies isn't anything like the missing tens or hundreds of thousands. Enter paper II : Approximately A Thousand Ultra-Diffuse Galaxies In The Coma 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.

Enter paper III : Probing The Low Surface Brightness Dwarf Galaxy Population Of The Virgo Cluster. The lead author is my PhD supervisor, so obviously that means this one is far better than those other two papers, which are really pretty crappy amateurish ramblings when you think about it.

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.


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.

Tuesday, 6 October 2015

The Nuclear Option

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 evil people - 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.


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.

Monday, 28 September 2015

Ask An Astronomer Anything At All About Astronomy (VII)

I know, I know. The last time I updated the Q&A page was in June, and I originally wanted to do weekly updates. Well,  I shall try and make more of an effort. Here are all the questions I've cobbled together over the last few months. I suspect I'm missing quite a lot.

1) When UY Scuti explodes, will we all die ?

2) Can we turn back time ?
Not yet.

3) Do we need to use nuclear power for space travel ? What about magnets ?
Yes. Magnetic propulsion (which is a thing) is not the same as magnetic fuel (which is not a thing).

4) How fast would we have to go to get to Mars in 15 minutes ?
Really fast !

5) Will we lose contact with Voyager I when it reaches the heliopause ?
Possibly, if its batteries run out.

6) Could electrical fields explain galaxy rotation instead of dark matter ?

7) What if we moved to a planet with more helium ?
It would be hilarious.

8) Can we measure the Sun expanding into a red giant ?

9) If the speed of light isn't constant, why do we measure distances in light years ?
It's a constant.

Sunday, 27 September 2015


Depending on your point of view, being called a skeptic is either an insult or a compliment. Being called objective is considerably better, but calling yourself objective is sometimes a sign that you're an authoritarian jerk who thinks they know all the answers. One of the problems is that "skeptical" is sometimes used to mean quite different things. Today I want to discuss the various meanings people use when they say "skeptical" and what those different kinds of skepticism are good for.

Skepticism, Belief, Disbelief, And Inquiry

In everyday use, "skeptical" often means, "I think this idea is probably not true". It does not merely imply that you aren't convinced that something is true, rather that you actively believe that something else is true instead (even if you don't know what that something else is).

This difference is a little bit subtle, but it's extremely important. An example should help. If you are totally unaware of something - let's say you've never heard of the concept of the narwhal before - you have no reason to doubt that it exists. You have no reason to believe that it does exist either. You exist in a state of true, pure neutrality, blissfully unaware of those weird ocean-going mammals.

True happiness can only be achieved when you forget about narwhals. Not many people know that.
Then someone comes along and tells you about this weird blubbery thing with a long horn that swims about in the Arctic Ocean. At that point, there are essentially three things that can happen :
  1. You remain truly neutral. You have no other evidence other than someone's say-so, so you don't form an opinion one way or the other*. For you, the question, "why would a whale have a horn ?" is as valid as, "why would a whale not have a horn ?".
  2. You can believe that it doesn't exist, with an arbitrary degree of intensity. Come on, a whale with a horn ? That's as ridiculous as Donald Trump's hair !
  3.  You believe that it does exist, with an arbitrary degree of intensity. A whale with a horn would be able to skewer its luckless enemies, so why not ?
* You might also just not give a damn about some stupid horny fish thing, which has the same end result.

Of course the third viewpoint isn't skeptical at all (well, we'll get back to that), while the second one is pure skepticism (unless you are "certain" that narwhals don't exist). It would also be legitimate to label the first as a sort of skepticism, but clearly it's different from the way the term is most often used in everyday life.

Being skeptical in either of those two senses is essential for rational, scientific enquiry. Without doubt, one cannot learn. Of course, although a degree of skepticism is necessary for rational inquiry, being skeptical doesn't guarantee you're being rational. It's perfectly possible to be skeptical for completely irrational reasons.

In science there are - unfortunately - some words which are used with quite different meanings than in everyday parlance. "Theory" is the best known of these : more commonly understood as "just an idea or model", in scientific usage it specifically refers to a model which has been very well-tested and not yet disproven. It is much more than "just an idea", which in science is referred to as a hypothesis.

Next time you want to say, "it's only a theory", replace it with "it's only a very well-tested model" and see if that still works. Anyone want to make an extension for Chrome that can do that automatically ?

Source. I would slightly disagree with "bias", which can mean a deliberate distortion of the facts - but it isn't always done with a deliberate, sinister motive. Bias can also happen quite accidentally if you forget to look at the whole system, or don't realise that what you're studying is affected by more factors than those which you have direct control over.
But there's no accepted special scientific definition for "skeptical". Just as in everyday life, we use "skeptical" both when we're actively seeking evidence to show that something is not true. but also if we're trying to prove if something is true or not (i.e. without any preference as to which conclusion we want to find). What we really mean by the latter is that we're trying to be purely rational and objective. I think it's useful to differentiate quite explicitly between those two approaches - both have their uses, as we shall see.

With the narwhal, there are several ways you could behave when presented with evidence of the creature, depending on if you initially went for option 1, 2, or 3 and how intensely you cling to your belief (why you react in that particular way is another subject entirely - you may well have no choice in the matter at all). Your skepticism (or lack of) makes a difference to how you respond to evidence.

A photo, you could say, could have been photoshopped so it doesn't constitute useful evidence, so you remain neutral. Or you could say that because it obviously has been photoshopped (because your own belief that they don't exist is so strong that there's no other explanation) that means narwhals clearly don't, or even can't, exist (an example of extreme, self-reinforcing bias that makes it essentially impossible to change your mind). Or that the photograph is damned good evidence that narwhals did exist once, but not necessarily that they still do. All of these are varieties of skepticism or denial.

Of course, you could also believe that the photograph is sufficient evidence to believe in narwhals (though you might stop short of calling it "proof"). Even though that is not a skeptical position, it's clearly rational. It does depend on the exact quality of the photograph though.

Sometimes photographic "proof" isn't all it's cracked up to be. There is actually a whale in this shot, if you look closely. Not a narwhal, unfortunately.
Scientists and non-scientists alike are fully capable of responding in any of these ways. Each have their own virtues and flaws, and it isn't always easy to judge which one is best. It really depends strongly on the details of the evidence at hand.

The Middle Ground And The Importance Of Good Vocabulary

One might think that surely the true neutral position is always the best one if the evidence is inconclusive or lacking entirely. This is how I personally feel towards agnosticism, which is what the above short example is based on. But that's my judgement call, and other people have very different opinions depending on how they assess the evidence. The point is that evidence can usually be interpreted in different ways, and it isn't always possible to be truly objective, no matter how much we might want to be.

Which makes it damn hard to get away with saying "I'm being rational and objective", instead of skeptical, because someone will almost always disagree with you and claim that their position is more rational and objective than yours. All you can do is say, "I'm trying to be objective", which is rather less satisfying than saying, "I'm being skeptical" but infinitely more accurate than claiming you've actually reached an indisputable truth, most of the time.

Without the word, "try", you are basically pronouncing your judgement as infallible and superior to everyone else's, which is almost never the case. Saying that you are "trying to be objective" admits your flaws while making it clear that you don't have a preference for whatever conclusion you end up with. Which is very different from the conventional meaning of "skeptical", which is to seek to disprove something (i.e. debunking) - though if you state this is what you're doing, at least everyone knows where they stand and everyone accepts there is room for doubt.

In an ideal world, the true neutral position probably is the best one. But in reality, it's rare that people can remain truly neutral on all issues : we are not machines. In the case of the narwhal, where we were seeking only to establish its existence, one may argue that remaining neutral is actually the wrong approach. You can go out and catch a narwhal to prove it exists, but it's almost impossible to prove that it doesn't exist without draining the oceans. Safer, then, to believe it doesn't exist until proof is presented that it does.

From National Geographic. Some people would even be prepared to question having the body of a narwhal as proof of their existence, as was done with the platypus. Establishing proof does happen, it's just rare and damn difficult.
This belief that it doesn't exist should not constitute an absolute dismissal of any prospect that it might exist. It's supposed to be a much more moderate position than denying any evidence on the prejudice that they can't exist (a point of view which, however, it is very, very important to remember most certainly does occur). While "skeptical" is not a perfect word, it is at least distinct from "denial", which is an altogether stronger position. It is, however, also quite different from the true neutral position*, which doesn't really have its own separate word.

* In this case that would state that actively believing that narwhals don't exist, however moderate that belief might be, is misguided.

Generally speaking, it's this modest level of negativity which is what we mean by skepticism in science. But not always. Suppose you establish with certainty the existence of narwhals, say by taking a sonar scan. So you stop "believing" in them because now you know they exist, but you still don't know very much about them.

But if you now go on trying to prove some more specific fact about narwhals, like whether they are grey or brown, it makes little or no sense to actively believe one way or the other. You may as well remain truly neutral until presented with good evidence, because you know you can eventually get it (and in this case it makes little or no practical difference). That's where having a word that means, "I am trying to perform a rigorous, objective analysis to establish the facts and I genuinely don't care what the result will be" would be useful. "Skeptical" has negative connotations, "verify" has positive ones, but there doesn't seem to be an adequate neutral word for an analysis with an explicit lack of an opinion.

When Skepticism Is Better Than Trying To Be Objective

So why does science generally prefer to be modestly skeptical rather than truly neutral ? Well, if you try and disprove something but fail, then it's stood up to a stronger attack than if you weren't trying to disprove it. That makes it more likely to be true, and you're less likely to spin the results in its favour. This requires you to be moderate though, because if you're a denier you can twist any fact - any fact, no matter how obvious the implication would be to a truly neutral observer - to make it mean whatever you want it to mean. You might not like the end result of your investigations, but you have to be willing to change your mind.

But science is built not so much on skepticism as it is on skepticism's socially awkward cousin : doubt. Whether you believe a theory or not is not as important as the ability to change your opinion. It doesn't really matter if you're trying to disprove or prove a theory by testing it, provided you accept the measurements you get and the consequences of those numbers for your theory. So in that sense, trying to prove a theory could be seen as just as "skeptical" as trying to disprove one. Again, I'm not sure the English language is entirely adequate here.

The problem is that it's frickin' hard to prove most theories. You can't really prove something without disproving all other possible explanations. All you can do, in practise, is show that one idea makes predictions which are consistent with observations. On the other hand, it's usually a lot easier to disprove individual theories - a single failed prediction (in an ideal world) will do just that. And so the scientific method favours the skeptical approach as a matter of simple pragmatism. That certainly doesn't mean that individual scientists don't think that some theories are really true though, not by a long shot.

Normally I avoid quoting Einstein because one can never trust quotes from the internet about Einstein, but in this case it really doesn't matter who said it.
While some people mistake theories for simple, unproven models, others have the opposite problem and confuse them with facts. This is just as bad. Being skeptical, or doubtful, of measured facts and figures is stupid (as long as the experiments were performed correctly). Being doubtful of theories - the models that tie a lot of disparate facts together - is the very essence of the scientific method, and if you don't doubt, you don't science. Yeah, English problems again.

(It's probably worth mentioning here that practically everyone is a denier on a least a few issues. I suspect it's impossible to function if you don't have some convictions, even if those convictions aren't fully justified. "Keep an open mind, but not so open your brains fall out..." - if you doubt everything, you learn nothing)

Peer review is an excellent example of the importance of all this in real life. In science you don't just get to publish your findings without at least one other (usually anonymous) expert checking them over. The process is mediated by the journal editor, who keeps an eye on the referees to make sure they're not being overly-harsh or supportive. Ideally, you don't want someone who's truly neutral toward your research : you want someone who's skeptical, but of course not a denier.

Peer review certainly doesn't guarantee objectivity. Nothing does. But, if it's being done correctly, it does make things more objective than not doing it at all. Problems arise if your reviewer is too far from this ideal position of skepticism : if they're a denier (as happened to me once), they can seriously delay* or even prevent your research from getting published; if they're neutral it's less of a problem but they may not question things rigorously enough; if they're too supportive they may actually overlook fundamental errors in your analysis.

* This really matters. Working to correct errors on a paper is a full-time activity. A bad referee could choose to question your every argument in excruciating detail to the point of absurdity, forcing you to spend months that you could have spent on other research instead.

It's a very careful balancing act to get this all right. Keeping reviewers anonymous helps, since they may feel under less pressure to be unduly hostile towards non-mainstream research. But humans are fickle, capricious, and fallible, and it is inevitable that mistakes get made no matter how careful a system of checks and balances is used. Exposing those mistakes is essential, but let's not go all "oh woe is me, science has failed !" because human beings behave like, well, human beings.

I've never seen this happen at a conference, though it's come close on occasion.


There are different meanings of skeptical, from "trying to disprove something" to essentially "trying to establish something". Both sorts of behaviour are appropriate in the right context, and it's unfortunate that we don't have a real word for the second type.

The essence of all rational enquiry, not just science, is not really skepticism but doubt. Actively trying to prove yourself wrong is just one part of that. Trying to prove yourself right is also valid - indeed you should test what your theory gets right as well as wrong - but it's both safer and easier to go for the skeptical, disproving approach.

Being a skeptic is not the same as being a denier. The skeptical position is one that's willing (if sometimes highly reluctant) to change given evidence; a denier wouldn't change their position if a narwhal stabbed them in the buttocks. Of course, the boundary between the two is fuzzy : a really extreme skeptic might require evidence so strong as to be unobtainable. Sometimes it's extremely hard to tell the difference between the two; in my opinion, deniers are often the ones shouting most loudly that they're skeptics.

Doing good science is a very careful juggling act on a tightrope that's also on fire. Being human, you're fallible and subjective. You may not want to be, but you are, so deal with it. The only thing you can hope to be truly objective about are the raw numerical measurements - any theory you create to explain them will inevitably have some subjective bias. But... there's good news !  Because you can make objective measurements, you can objectively test your theory.

There's some bad news as well though. You might be able to falsify your theory, but you'll probably never be able to prove that it's correct. Some doubts will almost certainly remain. But you know what ? That's actually a good thing. It means you've placed one more stone on the road of progress. Your theory was better than what came before, and allows others to go a little further. Maybe one day we'll reach the end of the road and have some sort of final uber-theory that can crush its enemies beneath its mighty feet. Maybe we'll never have complete understanding - but each advancement offers new opportunities and new challenges. Only one thing is certain : if we don't try, we don't learn. The road to the stars is paved with doubt.


Sunday, 20 September 2015

Moderation Squared

Being Offended

If I have a general philosophy in life, it is "moderation in moderation". I believe that most of the time the middle ground is the safe, sensible and above all correct place to be. Occasionally, you've got to throw caution to the wind and go run naked through a field, or something, but most of the time this is a stupid thing to do. Unless you're a cat.

Lately I've been thinking a lot about how this can apply to free speech. I make a point of trying to follow news sources which go against my own staunchly left-wing political bias, if for no other reason than to hear what evil schemes the other side are plotting. And recently it seems the political right has decided that the left, far from being the bastion of tolerance it so strongly professes to be, is actually a remarkably intolerant place.

Well, needless to say I don't believe that, but there are some things I'm concerned about.

The great paradox for toleration is how we respond to those who are themselves intolerant. It's generally reckoned that accepting people who hold discriminatory views is no real form of tolerance, but just a way of allowing their bigotry to flourish, a tacit agreement with what they say. At least that's the general mood of the internet.

And yet it's easy to accept people's views when you agree with them or just don't care. But whenever someone says something we genuinely don't like, there seems to be always a reaction from at least a few people that this is unacceptable*, regardless of whether it's an issue about toleration or not. The word, "increasingly" would fit into that sentence with tempting ease, but I'm not going to even try and analyse whether that's the case or not.

* A very interesting article though I don't agree with all of it.

Whenever someone says, "I find this offensive", I immediately think of Socrates. He would roam the streets of Athens being obnoxious and offensive to everyone he met. He would do this in the most obnoxious and offensive way possible : by telling the truth. In this case, Socrates was concerned that his fellow citizens were becoming lazy, arrogant, and above all, corrupt :
"My very good friend, you are an Athenian and belong to a city which is the greatest and most famous in the world for its wisdom and strength. Are you not ashamed that you give your attention to acquiring as much money as possible, and similarly with reputation and honour, and give no attention or thought to truth and understanding and the perfection of your soul ?"
He also knew exactly how this would turn out, even in that most popular icon of freedom and democracy :
"Please do not be offended if I tell you the truth. No man on earth who conscientiously opposes either you or any other organized democracy, and flatly prevents a great many wrongs and illegalities from taking place in the state to which he belongs, can possibly escape with his life."
Just because you don't like something doesn't mean it isn't true. Then again, most people who are "speaking their mind" aren't great philosophers, they're just jerks (read that link, it'll take you 30 seconds and you won't regret it).

Being offended by something doesn't mean you're right to be offended by it. On the contrary, Socrates was particularly offensive because he told people truths they didn't want to hear. This is why if you want to go down the "I'm offended by this" route, if you want anything to actually happen as a result of it then you must also explain what you find offensive, what harm it's doing to yourself or others, and, most importantly, why it's not true. Because if you're offended by the truth, then that's just tough on you*.

* By which I mean, of course, not, "I'm offended by this horribly unnecessary injustice", but cases of, "I'm offended by this unavoidable fact of reality". We'll see some examples of this soon.

Being Free

Take the issue of gay rights. Those opposed seem to be under the impression that they are somehow being discriminated against because they don't agree with the (now majority) position that gay people are entitled to equal rights. Star Trek put this very eloquently :

"We have not injured you in any way". I have not heard a single (remotely credible) counter-argument to this. What exactly is it that gay people have done to straight people that causes such offence ? Answer : nothing. Game set and match - being offended by people being gay is manifestly stupid. The rights deniers are in the wrong, they are not being offended for any logical reason.

... but, on the other hand, the Kim Davis case has me worried. Not very worried, but a little bit worried. Kim was jailed for refusing to issue single-sex marriage licenses. We can't stop Kim from being offended (that is an impossibility), but it seems we can stop her from advocating her position. Now this is perilously close to violating the Takei principle of free speech :

The thing is, government intervention did happen in this case, albeit for actions rather than words. Sure, being offended by homosexuality is stupid, but... really, a jail sentence ? The internet has produced some quite wonderful memes, of which my favourite is this :

... but really an actual jail sentence ? For not doing her job ? It's not like she's a firefighter or an ambulance driver. She issues marriage licenses, for heaven's sake. Jailing someone because their religious beliefs prevent them from this, however stupid I might find those beliefs, does not sit well with me. It seems far too close to jailing people on the basis of their beliefs alone. Or to put it another way, if you don't let people say things you don't like, you aren't really advocating free speech at all.

I mean obviously if someone doesn't do their job, you fire them. In extreme cases you ban them from holding that job again. It's just a bit unusual that you jail someone as well.

EDIT : Important point of clarification. Kim couldn't be fired because she was an elected official. An elected official refusing to obey the law makes the case rather more complicated than I initially realised. Oops ! My mistake. Government intervention in this case was unavoidable. After aggrieved couples filed a successful lawsuit, Kim was found in contempt of court for continuing to refuse marriage licenses. So, the jail sentence is (arguably) another step removed from the root cause of the court case - of course, anyone can be jailed for being in contempt of court.

One could, however, still argue that her continued persistence in following her beliefs rather than the law resulted in a jail sentence. She couldn't have been fired, so the alternative was a fine (which was rejected as it was believed others would pay it for her), or she could have chosen to resign. She did not - so, essentially, she chose to go to jail for her beliefs, which is very different from the state deciding that this was the only course of action. That she didn't choose to resign ties in nicely with the next section.

This particular article, if you want an alternative viewpoint, argues that Kim couldn't resign because that would be like a mathematics teacher being forced to teach that 2+2 = 5. It isn't true, of course, because marriage more than anything else is a social construct, not an objective fact about the nature of reality. That it has historically been between a man and a woman has no bearing whatsoever on what society deems it to be today. Historically, slavery was deemed to be entirely natural. Kim was free to resign - but obviously that option does not leave her free to do her job, which I'll return to shortly.

The reason I'm only a little bit worried about this is that if we apply the classic "what if they were black ?" test, it fails. Individuals are no better or worse because they're gay or straight than if they're black or white, and if Kim had refused to marry a so-called "mixed race" couple she'd have been run out of town (or so one would hope). We'll get back to racism in a moment. Still, using just a little caution here seems prudent.

Then there are the more common cases where no-one was jailed, but forced by angry twitter mobs to resign for saying unpopular things. That worries me far more : a wider trend where freedom of speech results in very public humiliation and resignations. Do we really have freedom of speech if the consequences of that freedom are so extreme ? Surely we need more than freedom from jail sentences for people to express themselves. Yes, you should be fired for not doing your job, but surely not for simply expressing controversial opinions.

"Freedom of speech does not mean freedom from consequences", as xkcd says - but that's only true up to a point. If saying certain things is a guarantee that you'll lose your job, then you're hardly free to say those things.

Social justice... or mob rule ?

The Kim case is only slightly worrying because this was a clear case of not tolerating intolerance. Time for some more examples. There was Rosetta scientist Matt Taylor, who wore a provocative shirt (perceived as, though not actually, demeaning to women) and was forced to profusely apologise. I've already covered that one in exhausting detail (skip down to page 3). More recently there was Tim Hunt, a Nobel laureate who was forced to resign for making a stupid joke. You've probably heard that already. What you may not have heard is the full context of the joke :
“Let me tell you about my trouble with girls. Three things happen when they are in the lab: you fall in love with them, they fall in love with you, and when you criticise them they cry. Perhaps we should make separate labs for boys and girls ? 
Now seriously, I’m impressed by the economic development of Korea. And women scientists played, without doubt an important role in it. Science needs women and you should do science despite all the obstacles, and despite monsters like me."
I refrained from commenting on the quote when it first emerged because we only had the first paragraph. Even then, I found it highly dubious whether this was a hanging offence. People fall in love in labs ? You mean people of similar interests working closely together ? OH MY GOD, THE HORROR !

Yeah, OK, the "when you criticise them they cry" bit is patronising and stupid, but as far as I can determine, in his subsequent interviews he didn't defend this or the (not serious) idea of separate labs - only his opinion that workplace relationships are a problem. Maybe they are, maybe they aren't, but you could say the same about any profession. And to me it seems like one hell of a stretch from "workplace relationships are difficult" to "the lab is not a singles bar". Workplace relationships are going to happen whether you like it or not. Deal with it.
The #DistractinglySexy hashtag was funny but, I venture, somewhat cruel and a classic example of the internet leaping instantly to conclusions that are not really borne out by the facts (I recommend reading that link). 
It seems to me that this was indeed no more than an idiotic joke. Are we feminists so insecure that we cannot stand to have a prominent figure make a one-off* joke, however awful ? Seriously ? Is our position really that weak that we must silence not only the genuine hard-line critics (who are mostly deluded liars) but also those just, very occasionally, being a bit daft ? I hope not.

* This matters. Every single person alive, bar none, has said or done something they later regret. 

Then we have people being genuinely offended by Labour leader Jeremy Corbyn refusing to sing the national anthem. I mean, good grief, an agnostic republican refusing to sing a dull and dreary song about God saving the monarch ! Outrageous. He should apparently "learn to be a grown up", because obviously singing a song about a divine, possibly fictional deity he doesn't believe in, saving an 89 year old obscenely wealthy and powerful woman he's never met from a host of unspecified dangers, is clearly the only sensible course of action for an adult, responsible political leader who doesn't want to be seen as a raging hypocrite. What the hell is wrong with people ? This is a textbook case of people being offended not because something genuinely harmful actually happened, but because they are stupid.

Unless you think it isn't possible to stand in respectful silence ?

Yet of course there are examples of people saying truly awful things who, in accordance with moderation squared, deserve punishment. James Watson remains a horrible racist, despite the fact that the DNA he helped discover indicates that race is largely a social construct. So yeah, when someone like him says something appalling, I think we do have to respond quite forcefully.

The moderation squared approach compels me to tread very lightly. On Google+ I have blocked only 1 follower (out of nearly 1700 at the present time) in the four years I've been using it. That was for the exceptional comment about "black African males making disgusting animal noises". Now, I've got a lot of followers with whom I profoundly disagree about certain topics. I even follow some of them back. But then I've got real-life very close friends with whom I have strong disagreements. However such abject racism* is far beyond my tolerance threshold : if I let this person continue expressing themselves on my stream, I'll be guilty of letting them promote vile, hate-filled, completely disproven pseudoscientific nonsense.

* I am most definitely not talking about real controversies like positive discrimination here. There is a vast and clear difference between that and racial hatred.

But the m^2 approach tells me that I should be reluctant to limit someone's free speech in even this small way. Indeed, I didn't delete their comments. I simply don't want that person continue to spread their faeces all over my posts. Moreover, in this particular case, racism is such an utterly disproved notion that it's not controversial, it's just wrong, and I don't even have to mention how damaging it is. I do, however, keep in mind another quote from Socrates :
"You have brought about my death in the belief that through it you will be delivered from submitting your conduct to criticism, but I say that the result will be just the opposite... If you expect to stop denunciation of your wrong way of life by putting people to death, there is something amiss with your reasoning. This way of escape is neither possible nor creditable. The best and easiest way is not to stop the mouths of others, but to make yourselves as good men as you can."
All true, and yet I doubt Socrates would have approved of spreading messages of racial hatred had he lived through the twentieth century. The m^2 approach allows for these rare, exceptional extremes which require quite different treatment from normal criticism. With a force as destructive as racism, I have few qualms about censorship. There are rare times when freedom of speech is not such a noble virtue, and can even become a vice.

On the lighter and more bizarre side, recently there was a call to ban sex robots. Which are a thing, apparently.

Supposedly such robots are demeaning to women and damaging to relationships, despite the fact that they are not. I don't feel the need to explain why this is incredibly stupid, so I won't. Well, except to say that this is basically banning people from fantasising about sex*. It doesn't make any sense at all. But then, as with gay rights, for some reason people do love to try and legislate about what we can and can't do with our genitals. To which I say :

* I'll let you in on a secret : male fantasies don't tend to involve much in the way of fully-developed, loving relationships. GASP !

Slightly more seriously, there are examples of people actively seeking to accuse people of intolerance and radical beliefs as a sort of weapon, which goes far beyond the at least well-intentioned knee-jerk twitter responses to controversial comments. This is a problem which is far from unique to over-zealous feminists or the political left. Currently it's being employed with avengeance against Jeremy Corbyn, with articles featuring statements which are simply factually wrong.

Summary and Conclusions

It would be extremely foolish to say that there's an easy way to tell who's right when someone offends someone else. People most certainly can be offended by things they really shouldn't be offended by at all. The main lesson from "moderation squared" is simple caution and benefit of the doubt : are you quite sure that your opponent is wrong and promoting something that is harmful ? You are, and you can prove it ? Alright then, you may now try to stop them. You're not ? You have even just a little doubt ? Well then, present your counter-arguments, but don't petition for a ban just yet.

There are plenty of horrible people in the world, and social media is an incredibly powerful force for change. Like any source of power, it's dangerous. Is it not reasonable to suggest that when someone says something controversial, it might be better to wait until you have all the facts before jumping to a conclusion and attacking them in 140 characters or less ?

Individual tweets may not be damaging, but the collective actions of thousands can have a serious impact. It's rather disappointing that people are so quick to respond so forcefully to throwaway comments from people they've never even met. How they feel justified in claiming to fully understand people's motives so quickly without all the facts in hand is beyond me.

Three recent articles make some valuable points. The Guardian describes how having "freedom from" means that societies are safer but weaker. In the name of having "freedom from" terrorism, we're safer but easier to control  : governments can take away our "freedom to" express ourselves. The Atlantic has a popular article ostensibly about "trigger warnings", but more importantly about why shielding ourselves from unpopular ideas is self-destructive and dangerous. Finally, Spiked gets a little too cross with feminists, but makes the important point that women are being seen as incredibly vulnerable and in need of protection from even the most minor of misdemeanours.

The m^2 approach doesn't say we must never censor anything - just that we have to be very careful about it. I do not agree with every point in the articles linked throughout this post, but I am worried that censorship (or something close to it) is being used as a first response rather than a last resort. I do not think the left is so incredibly intolerant - but I do think there's a danger of that, and we're not examining our own behaviour closely enough. I'll give the last words to Socrates :
"This is the hardest thing of all to make some of you understand. If I say that this would be disobedience to God, and that is why I cannot 'mind my own business,' you will not believe that I am serious. If on the other hand I tell you that to let no day pass without discussing goodness and all the other subjects about which you hear me talking and examining both myself and others is really the very best thing that a man can do, and that life without this sort of examination is not worth living, you will be even less inclined to believe me. Nevertheless that is how it is, gentlemen, as I maintain, though it is not easy to convince you of it."