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,

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."

Tuesday, 15 September 2015

Sun, Sea, and Science

Let Italy boast of her gay gilded waters
Her vines and her bowers and her soft sunny skies
Her sons drinking love from the eyes of her daughters
Where freedom expires amid softness and sighs.

The first twenty minutes or so of "Scotland the Brave" are basically all about mocking the Italians for being a bunch of pansies. Well, I suppose they're just still bitter over the battle of Mons Grapius, Hadrian's Wall, etc. Actually, on arriving in Soverato I quickly realised why the Romans conquered most of Europe whereas the Puerto Ricans have had about as much impact on world affairs as the Scottish : it's really frickin' hot in Italy, but not all the time.

I mean, during the winter months, the ancient Romans probably sat around saying things like, "Seriously guys, remember how awful it was here last summer ? How we all nearly died ? Let's try invading Gaul this year, it's less dangerous." Whereas in Puerto Rico it's like, "nah, it's far too hot to do anything today, let's not do anything tomorrow instead." Much as Britain conquered a quarter of the world in search of better food, so Rome probably expanded just to have a nice cool summer holiday home somewhere up north.

This theory works quite well considering a couple of exceptions that prove the rule : neither Scotland nor Wales bothered conquering England because the weather there is just as bad, which would put us back on a level playing field except that they're bigger than us.

Welsh rain, English rain... betcha can't tell the difference.
Anyway, for the first two days in Soverato the temperature was 34 C and the humidity level reached Puerto Rican standards, i.e. hell. My flight was delayed so I arrived at about 12:30am and found my hotel (a B&B) was shut. The owner didn't answer my call. So the shuttle bus driver took me to another hotel, which, on reflection, wasn't any better than sleeping on the beach. Worse, probably.

There was no air conditioning. There was a fan, but that provided limited benefits. There was no wi-fi. The shower room was tiny yet somehow contained not only the shower but also a toilet, sink, and bidet. Activating said shower resulted in freezing cold water soaking the entire room instantly because it sprayed water uniformly in all directions. Fortunately, this didn't last long, because it was soon replaced with nice scalding hot water instead. It was by far and away the most bizarre and dreadful shower I've ever encountered.

After enduring this freezing, scalding, cramped torture chamber, I discovered that the "double" bed was actually two incredibly saggy single beds stuck together. So uncomfortable was sinking about three feet into the mattress, which provided essentially no support at all, that I ended up lying exactly in the middle, balanced precariously across the two halves in a pose very much like the Vitruvian Man and hoping against hope I'd be able to sleep like this. This particular conference trip was not going according to plan*.

* For the record, I'm told that other rooms in the hotel do have air conditioning and that later they even had wi-fi as well.

It's a little-known fact that Leonardo drew this picture while hanging Tom Cruise style from the
ceiling above the bed of a disgruntled sweaty astronomer.
Things brightened up the next day. The hotel situation was quickly resolved with some translation (the owner speaking nearly no English) and I moved to my pre-arranged hotel which had air conditioning. But still no wi-fi, which is apparently as rare as gold dust in Soverato. Even the conference venue wi-fi was so poor I resorted to using my phone's expensive roaming 3G access.

Then I swam in the sea and forgot about the internet for a while. The sand at Soverato may be rather coarse but the sea temperature is perfect. It's certainly a natural choice for the University of Birmingham to host a conference, as opposed to, oh I don't know, Birmingham. The conference welcome bag even came with a customised beach towel instead of an umbrella, which would otherwise have been an... optimistic choice for a dreary, rainy city that's 40 miles from the sea.

Even the insane humidity didn't last long, unlike Puerto Rico. After a day or two it had dropped to the point where things became quite pleasant, thus explaining why the region was inhabited at all.

As for the conference itself, this was, as usual, a mix of really interesting and really uninteresting presentations (with a bias quite strongly toward the former). With 80 talks, this is inevitable. The worst are people who sound like they're talking about something very interesting but don't have any enthusiasm for speaking about it and yet for some reason they refuse to shut up. And least people who are genuinely unenthusiastic won't bore you to death. People who simply can't convey their enthusiasm are much more dangerous.

Then there are the classic mistakes :
  • Graphs with axes labels too small to read. Come on people, spend 5 minutes re-making your figures for your presentation. Please ?
  • Not explaining really basic things. There was one talk that was all about the UltraVISTA survey which didn't bother to explain what the heck the UltraVISTA survey is. Aaargh.
  • Not keeping to time. Irritatingly, one particular chair kept saying, "We have plenty of time for questions". No you do not. You're running ten minutes behind time !
  • Cutting into breaks. In an intensive schedule where it becomes difficult to concentrate, breaks are just as essential as when revising for an exam. If you don't have them, you don't learn anything and the whole thing becomes counter-productive. 
I don't know why people keep doing these things. I suggest a "guideline for authors" section on any conference website.

What the conference organizers did really well were the social events. Tuesday evening featured a free food and wine tasting event with a tour of a 16th century watchtower, from which the Italians hurled down beehives at marauding pirates. "Do we have any bees ?", someone asked. "No", says I, "It's B.Y.O.B."

Well I thought it was funny.

Wednesday was a half-day excursion to Squillace. Since it featured not a single vine, bower, soft sunny sky, let along anyone drinking love from anyone's eyes or anywhere else for that matter, and the waters were neither gay nor gilded, the Scots would have felt right at home.

Roof of the conference venue when the weather turned. Normally coffee breaks, to the organiser's extreme and lasting credit, were held on the beach. So were the closing remarks.
Taken from inside the bus, but I assure you it wasn't any drier outside than it looks through the window.
What it did feature was rain. Lots of rain. I'm sure Squillace is lovely if it's dry, but it wasn't. I think a castle may have been involved at some point, but I couldn't tell because of the rain. I began to think that indeed Birmingham were being optimistic with the beach towel and maybe the umbrella would have been a better choice after all.

After this soggy and rather miserable sojourn, the trip to the conference dinner didn't begin much better. The bus trip took around 45 minutes (leaving 20 minutes late), then it reached a point where it just stopped. For a full twenty minutes it did nothing except move very slightly back and forth, seemingly in an effort to orient itself very precisely with the bus in front, then it would shift out of position and begin again. We didn't actually have any net motion forwards of backwards, we just sat there shuffling around for no reason whatsoever.

Then, without warning, we got onto a smaller shuttle bus to take us down the road that was too steep and windy for the larger bus. It would probably have only been a five or ten minute walk to the restaurant, though it was still raining heavily. It would have been a lot better if the bus had stayed still though.

The meal itself compensated a hundredfold for enduring hours of walking around in the rain. I have never eaten so much food in my life, and I sincerely hope never to do so again. Several local species probably went extinct that night, but rest assured they died a good and worthy death. Six. Full. Courses. And I mean full. The "appetizers" alone would have been enough. We assumed the menu was giving various choices for each course whereas in fact it was just a list of everything we'd be eating. Methinks that most of the conference registration fee probably went not towards hiring the venue but for the wholesale slaughter of the local marine life.

You know how everyone always says after a big meal that they won't eat tomorrow, but never really means it ? Well I literally didn't eat anything the next day. I couldn't face it. The very idea was an abomination.

I'm not complaining, you understand. It was amazing. For the meal alone I rate the whole conference "excellent". I just never want to do it again.

There's not a lot else to tell unless you want the gory detail of the conference, in which case you should have gone yourself you lazy bugger. Though, unusually, it did end on a positive note. For once it seems a particular problem in galaxy simulations has been solved, and while many other problems in the theories remain, people genuinely seem to think we may be getting somewhere. Which is pretty weird to hear at a conference, so I think probably some people may have been suffering from heatstroke.

Soverato doesn't have much besides the beach, so there's not much to tell there either... except for a final "note to self". Do not trust senior academics. In an effort to save money on a taxi back to the airport, I found other people leaving at a similar time to me. I exchanged contact details with one and we agreed to stay in touch. I sent several emails the day before but got no response until 10:20 pm when I was told I should make my own arrangements.

Oh, great. Thanks for that.

Thinking that a senior scientist who'd travelled all the way from America to be there* must be a fairly reliable chap - especially since his flight was at 9:30am - I'd decided to avoid making my own arrangements in the interest of saving the Astronomical Institute the taxi fare. Whoops. Lesson learned...

* Which is one reason, if you're wondering, why conferences are often hosted in nice locations rather than necessarily at the host institution. Astronomy is an international disciple and if you're travelling transatlantic it makes little difference to cost if you go to Soverato or Hull, except that people aren't likely to choose to fly across the Atlantic to visit Hull.

Seeing as how my hotel owner spoke so little English there was no way I was going to risk trying to arrange that by phone. So I walked the 20 minutes back up Soverato to the conference hotel and had them book a taxi for me. Not exactly what I was planning on doing at 11pm, but at least the hotel was able to book one without any difficulty. The taxi driver turned up the next day early, completely defying the stereotype of Italian lack of punctuality.

Oh well. They really do say "mama mia" though, which more than made up for it.

Sunday, 23 August 2015

Twelve Mile Tall Tales

If you haven't seen it yet, I suggest you first read one of the press releases about the Thoth Tower, a proposed "space elevator" system that's supposed to be able to cut the cost of access to space. As I shall show, it won't.

Image from TechInsider.

Getting To Space Is Cheaper Than You Think

Probably not this cheap though.
Space, they say, is only an hour's drive away - straight up. The energy required to travel 100 vertical kilometres is actually extremely modest : for a hefty 100 kg individual it's about the same as 100 kWh... which costs all of £3 ($5 US). Why, then, does it take the incredible power and expense of a rocket to launch stuff into space ? Why does it actually cost something like $4,000 per kilo to get into space ?

Well, the 100 kWh is the theoretical minimum you need to overcome gravity. Any launch system is going to be less than 100% efficient, so you'll always need to put in more energy than that. Rockets in particular have to carry all their own fuel, and the fuel is heavy, so they need to carry enough to lift both the weight of the fuel and the payload. And merely reaching 100 km altitude is far easier than going into orbit at 100 km altitude.

To hurl something up to 100 km altitude, you'd have to give it a staring speed of about 1.4 km/s (3,100 mph), ignoring air resistance. But if you did that, it would simply go straight up and then fall straight back down again.

More on this at the excellent xkcd.
To get something to stay in orbit you need to go very much faster, about 7.8 km/s (17,000 mph). Although that's "only" about 5.6 times faster, energy scales as speed squared... so you'll need to give it over thirty times as much energy. Let's say you could float a balloon up to 100 km altitude (you can't, but let's pretend). If you threw something off the side, it would still simply plummet to the ground - unless you threw it at 7.8 km/s sideways. The point is your starting altitude makes almost no difference at all to the huge amount of energy you need to go into orbit. You need just as big a rocket at 100 km as you do on the ground.

Or you can just troll physics.
Wouldn't it be nice if, instead of having to deal with complicated rockets and the need for vast, explosive energies, we could just take the stairs ?

Maybe. Maybe not.

Space Elevators

The idea of a space elevator is nothing new, but traditionally it's very different to Thoth's "plan". A more typical space elevator is a cable stretching 36,000 km out from the surface of the Earth (with a counterweight station on the end to keep it in tension). At that altitude, it so happens that an orbiting object would take 24 hours to orbit the Earth. Since the Earth takes 24 hours to rotate, objects orbiting at that distance never move in the sky : they are geostationary satellites. Below this distance orbiting objects have to move more quickly, so they take less than 24 hours to orbit and aren't always visible overhead.

The dashed lines show the line of sight from each of the satellites to the ground. Watch carefully and you'll see that the satellite at 36,000 km is always above the same point on the Earth, whereas the others move.
And no, I don't know why the background is that yucky grey colour instead of its original pristine white.

Here's the thing. The station at the end of the tether is in orbit, just like any other satellite. "Drop" something from the end station and it won't fall, because it's already in orbit. At lower levels, this isn't true. The tension in the tether forces it to stay up, but the speed of the tether at all points below the station isn't high enough for it to be orbiting. So if something fell off from halfway up, it would simply drop to the Earth below.

... except that it's a bit more complicated than that. You don't simply fall straight down like you would from a very tall building or a mountain, staying parallel to the tower. This thing is so tall that we're out of the realm of everyday experience and into orbital mechanics. Gravity at the top of the tower is much weaker than at the base (more on that soon), so as you fall not only does your speed increase, but your acceleration also increases. And the linear speed at which the cable is moving forwards increases with height.

All of which means that, unlike falling off a cliff, if you fell off a space elevator from a high enough altitude you'd actually move forwards relative to it. And if you were high enough up, you wouldn't hit the ground at all - you'd go into orbit. Not a nice circular obit like at the top of the tether, but a hair-raising elliptical orbit (which in the example shown here would probably graze the atmosphere so you'd die a horrible fiery death).

Note that all the little spheres drop at the same time. But gravity
is so much weaker at the top that it takes them much longer to fall.
The Python code used to generate this is available here.
Anyway, the neat thing about this kind of space elevator is that you don't need a rocket to reach the tremendous speeds necessary for orbit. Instead of an incredibly complicated rocket system, which has to carry all its fuel onboard to travel in the vacuum of space, you can just use an electrically-powered lift. That would get you to orbit for the princely sum of £150 per person. Roughly the price of an EasyJet return ticket from Bristol to Prague. Of course it won't be this good in practise, because nothing is perfectly efficient, but clearly it's many orders of magnitude cheaper than using conventional rockets.

What About Thor ?

He isn't relevant at all. Check your spelling.

Err, OK, what about Thoth ?

I'm so very glad you asked. Thoth's design is completely different. At just 20 km tall, it's not something most people would recognize as space elevator - more of a conventional building. The thing is, 20 km just isn't high enough to convey any advantage whatsoever. At that height gravity is only about 1% less than at sea level. You need to go to altitudes of thousands of kilometres before gravity really drops significantly. Here are some numbers in handy gif form, because maths.

1 g is the gravity we experience : 9.81 m/s/s. The times shown are how long it would take to fall 1 metre under those accelerations, at the altitudes shown at the top. Earth's gravity at 5,000 km is roughly the same as the surface gravity of Mars, while at 10,000 km it's about the same as on the Moon.
Yes, I know this isn't my most sophisticated graphic, but my computer is dying. Gotta keep it simple.
Clearly, you need to go to much, much greater distances than 20 km to get any advantage over gravity. But according to Tech Insider, which gives a critique of the massive engineering challenges of building the tower :
Finally, Quine claims that since rockets eat up about 30% of their fuel during the first 12-mile ascent, the tower will offer the same savings in fuel compared to conventional rockets launched from the ground.
Oh, really ?

I think not. Rockets use more of their fuel in the early stages because that's just how rockets work. The initial mass of the rocket is very large. So if you want to accelerate that large mass against gravity, you have to eject a correspondingly large mass out the other end. Moving the rocket 20 km up makes absolutely no difference to the size of the rocket needed whatsoever, if you still want to reach the same final speed with the same payload with the same gravity.

There's one possible escape for Thoth : the tower would be so tall it would be above quite a lot of the atmosphere. At 20 km the atmosphere is about 13 times less dense than at sea level. Except there's just no way that's going to save you anything like 30%, as this NASA engineer describes, and this helpful random person on the internet explains using maths. Atmospheric drag accounts for slowing the rocket by maybe a few tens of metres per second, compared to the required velocity of several thousands of metres per second. Basically, no.

But Thoth have compounded error upon error. Even if their 30% figure was correct, it's dubious if it would help. It would be like having a 30%-off sale at Harrods : the wealthy are so rich they won't care, and the rest of us still couldn't afford it.

OK, so it would help for those people in the narrow band for whom a space mission was just about out of reach. But the cost of the tower is claimed by Thoth as $5 billion, and others at more like $500 billion, as well as the engineering challenges of its construction being formidable to say the least. So it's a case of one of the most stupendous engineering projects in history for the sake of saving 30% on very expensive rocket launches. Doesn't seem like a great deal to me - and remember, that 30% saving looks wildly optimistic.

Thoth's plan for how the tower would be used looks even worse :
"Astronauts would ascend to 20 km by electrical elevator. From the top of the tower, space planes will launch in a single stage to orbit, returning to the top of the tower for refueling and reflight,” said Dr. Brendan Quine, the inventor.
Righto, first off - when did "inventor" start to mean, "someone who had an idea" ? I've got this idea for a genetically engineered fire-breathing horse that can ride a unicycle - if I patent it do I get to call myself an inventor ? How about a robot that can procrastinate ? Some sort of swimming couch... ?

Anyway, space planes. They don't exist. Well, the Shuttle did, but that certainly wasn't a single-stage-to-orbit vehicle*, and to land it needed a runway 4.5 km long. So Thoth's idea, in summary is to build a tower twenty times higher than any other existing structure using techniques that might not work for optimistic fuel savings for planes that don't exist on a tower that will be too small and cost too much money.

* If it wasn't already clear : being 20 km further up doesn't make it any easier to develop a single-stage-to-orbit vehicle.

All I'm saying is that no-one with an ounce of sense will put a shred of money into this.
There are space planes in development, and they do have the capacity to transform space flight. The British company Reaction Engines is developing the Skylon vehicle, to be powered by hybrid jet-rocket engines. This has been in development for a long time, but finally the technologies appear to be maturing. It would make a much more dramatic saving in launch costs compared to a giant tower - more like 75% by some estimates. That's nowhere near the savings slash a real space elevator might bring, but enough to make a real difference.

So as far as I can tell, Thoth's plan relies on some absurdly fundamental misunderstandings of high school physics. It just won't work.

Bur let's end on a positive note. Private companies have been making ludicrous proposals for decades - Thoth's is nothing new. The difference now is that these absurdities notwithstanding, private space ventures are finally starting to make a difference. Space tourism is a reality - albeit only for the super-rich, but with the prospect of a dramatic price fall no longer a pipe dream. Space X and Orbital Sciences (now known by the less inspiring name of Orbital ATK) have already delivered cargo to the International Space Station, while Scaled Composites claimed the first astronaut launched by a privately-built rocket. And let's not forget : though Thoth's idea is very silly, someday a proper space elevator might really open up the road to the stars.