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, 13 April 2015



Yay !

If ever there was an excuse for the blog equivalent of a clip show, this is it. I've gone from being a bored student in Cardiff with nothing better to do that write short pointless blog posts, to a bored postdoc in Arecibo with nothing better to do than write moderate-length blog posts, and now a bored postdoc in Prague with nothing better to do than write really long blog posts. There are worse fates. Here are the highlights.

Top Five Most Viewed Posts

5 : The Curse of the SS

A simple tale about getting a social security number and the problems of having a name without any vowels in it. Apparently mentioning the old woman from Monsters Inc generated 2,500 hits. The internet is a strange place.

4 : Learning To Love The Bomb

Nuclear warheads and big shock absorbers
Towering black monoliths and contradictory orders
A deranged computer that's learning to sing
These are a few of my favourite things...

2,900 hits for the blog post, 4,300 for the video (which does not feature the song). An Orion-version of the Discovery originally considered for 2001 : A Space Odyssey but didn't make the grade.

3 : And Yet It Moves (but not like that)

Debunking some myths of a popular space video and some myths that sprang up around that video. No, our Solar System isn't a vortex, but the Solar System does move and the planets do trace helical paths some of the time. No, the video doesn't show the Sun leading the planets. 3,200 hits... but please see this more recent article. The creator of the video and I have come to an entirely amicable understanding.

2 : Infographic : Galaxy Size Comparison Chart

People love novelty, and I happened to notice  that typing in "galaxy size comparison" into Google images found pictures of smartphones. It still does, but at least now the top results are my charts (7,300 hits for the original post), which have nothing to do with Samsung. Much better*. See also the equally interesting dwarf galaxy version, which is also popular with 2,100 hits.

* But if Samsung would like to buy me out, I'm listening.

1 : VY Canis Majoris : Or, Be Afraid. Be Very Afraid.

People also love comparing the sizes of things. And why not. In this case, rather than directly comparing the size of a particularly massive star with other massive stars, I decided to see what it might look like if it replaced our Sun. This got on reddit and consequently resulted in 21,000 hits to date. Which is nice because sometimes I think that the more effort I put into making things, the fewer people appreciate the result.

Top Five Most Liked Posts

5 : Happy Birthday Arecibo !

With a mere 350 hits but 119 + 1's (a.k.a. "likes") this is one of the most highly rated posts. I suspect this is because Google+ includes likes for the posted image (in this case an animated gif) as well as the post itself. Still, it's a nice, short, image-heavy post which is worth a read. The video was used at Arecibo's 50th Anniversary symposium.

4 : Galaxies Suck, Let's Get Rid Of Them

One of those, "hmm, I thought this might attract attention" posts. I can't really complain with 810 hits and 126 likes... but come on, it's an exploding galaxy ! Using a science-class simulation generously provided by a friend who owed me a favour, I examine what would happen if dark matter disappeared. Of course, this wouldn't be true if our theory of gravity is wrong, but it's a graphic way to illustrate why dark matter is so important in contemporary mainstream cosmology.

3 : Blue Marbles

In contrast to the last one, this one was a case of, "oh look, 50,000 hits, how strange". Actually it was the sequel Rocky Marbles that attracted the attention, which got reshared by I Fucking Love Science, the Daily Mail, and innumerable others. And in fact virtually all of the hits were on YouTube, with only 3,000 on the combined blog posts. 133 likes though.

2 : Project Orion : How To Nuke A Spaceship Without Killing Anyone

To my knowledge I hold the honour of creating the first ever animation of an Orion-drive spacecraft. I probably should have jumped on the YouTube bandwagon much sooner, but back in 2005 creating animations of any length on a home PC was a major undertaking so it didn't seem worth it. This one probably took > 6 months from start to finish. Of course, the animation quality in the Space Odyssey version is much better, and the realism of the detonation sequence is much higher, but this one is much closer to the original design spec. 3,500 hits (>140,000 for the video) and 171 likes.

I have frequent delusions that I should remake this in high definition, which is a fine idea if only I could find the time.

1 : Damn That's A Nice Piece Of Gas

Although viewed by a mere 1,000 people, I'm rather pleased that my most liked (189) post is all about the ultra-specialist subject of visualising neutral hydrogen data. And why not ? Neutral hydrogen is ludicrously beautiful. You should like it, or you have no soul, damnit. This view of the hydrogen in the Milky Way at different frequencies is also my most liked (>500) gif.

Top Five Most Interesting Posts That Didn't Quite Make Either Of The Above Lists Through No Fault Of Their Own, Because, Like, Seriously, They're Quite Good And You Should Read Them

5 :
Quack Quack

I'm fed up with people declaring their Google skills to be superior to the years of training it takes to do real science. I'm particularly annoyed by people who declare things like, "we should stop searching for dark matter, it's an arrogant and dogmatic belief". Obviously, their arrogant and dogmatic belief that it doesn't exist trumps all the expert opinion that it probably does but might not so we should go and check to make sure. That said, some burden of the blame does lie with the scientists, and I believe we must stop stating opinions as facts - but more importantly the media has to convey science as a process, ugly and full of mistakes, not a stochastic series of amazing breakthroughs.

I'm also particular pleased with my essays on feminism and especially atheism, but any fool can be qualified to rant about them. Quack Quack, however, is an effort by a scientist to help explain the scientific method, so I can at least claim some small level of expertise on that.

4 :
The Best Space Rock Ever

Asteroid 1998 QE2 is an extraordinary place. A few kilometres across, if you fell over it would take you a minute and a half to hit the ground. You could easily jump into orbit around it or even off it entirely - and if you were very careful you could say, "that's no space station, it's a moon" shortly before you landed on its tiny moon (which is barely larger than the ISS). It's also of a size where comparing it to the QE2 is a vaguely-sensible way to get an idea of how large it is. Oh, and it would float.

3 :
Why Star Trek Is Clearly Better Than Battlestar Galactica

Battlestar Galactica was a depressing show, unless you realise that the entire thing was a highly elaborate ploy to explain the presence of a wonderbra in ancient Greece. Star Trek was a very, very happy show that inspired and continues to inspire generations of aspiring astronauts, astronomers and engineers. BSG just doesn't do that, because it's politics/angst in space and barely sci-fi at all. But hope is not lost. Dr Who is in many ways the moral heir to Trek, both in challenging social taboos and promoting how cool and shiny tech can be without anyone worrying if their toaster is actually a teenage emo psychopath. 

2 : Why NASA Paid Me To Photograph A Potato

They didn't pay me very much, you understand, but it did happen. Explaining why they did this at all in the introduction spoils the fun, so go read the article. I think this probably still trumps writing a fairy tale about a princess and a magical moose as a quick start guide and various interpretative dance performances for the title of "weirdest thing my job entails".

1 : Under The Hydrogen Sky

One of those posts I can't help but think, "hmm, I thought this would be more popular than that" (96 hits !). This is, as close as possible, what the sky would look like if we could see light emitted from neutral hydrogen. Unlike most of my other recent posts, it's not overly long and it's full of pretty pictures. It uses real data, matched as closely as possible to the sky in selected locations around the world. If we could see this with our eyes, we'd never have called it space. Being able to see the sky in another wavelength, and knowing that those features are absolutely real - well, I for one think that's pretty neat.

Here's to another 200 rambling posts about astronomy ! And potatoes !

Monday, 6 April 2015

Ask An Astronomer Anything At All About Astronomy

For those who haven't been paying close attention, you might want to take a look at the new Q&A section. Here I collect the questions people have asked on the interweb which I have attempted to answer. The first batch are all those I could remember answering.

Since this is a very regular occurrence, I'll aim to post weekly updates. I only include my own answers where the alternatives provided were wrong or I felt my own answer added something useful.

For those who did notice the Q&A page, you should also notice that there's now a contents section with internal page links to each question, which is nice.

This week's additions with even more concise answers :

1) Are we sure the acceleration of the expansion of the Universe is real ?

2) Could you pee all the way around the Moon ?
No, but you could around a 2km wide asteroid.

3) How many aliens are there ?
Fifty seven. Six. A million and two. How many would you like ?

4) Could galaxies actually be moving because space is flowing ?
No. It's not that wibbly-wobbly.

5) Is the Universe infinite ?
Could be, but I'd rather it wasn't.

6) How can we prove dark matter exists ?
We can't, yet. Lots of evidence says it exists, and direct detection experiments are underway.

7) How can we detect gravity ?
By dropping cats into a black hole, possibly with lasers. Mew mew mew !

8) What's the latest progress in detecting dark matter ?
Nothing conclusive.

9) Will NASA's pet-rock-on-a-leash need a push to keep it in orbit ?
It will need a few pushes to put it in orbit. After that it will run around in circles all day for no reason, just like a real dog.

10) Do stupid astronomy memes matter ?
Yes they do. I wish they didn't, but they do.

Saturday, 4 April 2015

Things That Look Like Other Things

Some potatoes look like asteroids, others look like cartoon dog bones. Some galaxies look like the Loch Ness Monster. And one comet nucleus looks a lot like a rubber duck. If there's any cosmic significance to an asteroid looking like a potato or a comet looking like a rubber duck, I should very much like to know what that is.

Which is why, when I see a meme like this one...

... there can be only one response.

It's just not even wrong. Even making the comparison is pointless. If you're of the opinion that this is harmless trivia, scroll to the end. Otherwise keep reading.

The Universe is quite a big place, and contains quite a lot of things. That some of them look like other things is as significant as the correlation between cheese consumption and the number of people who die by becoming tangled in their bedsheets. It's called a coincidence, people. When you have (literally) astronomically large numbers of objects, you're gonna get a few of those.

From the wonderful spurious correlations.
Let's look at each of the three comparisons in the meme, just because why not.


I was not able to find the source of the image of the brain cell in the meme. I'm not a biologist, but since an image search for "brain cell" reveals hundreds of very similar images, I'm going to assume the image is accurate.

I already knew, however, exactly where the "Universe" image came from - the Millennium Simulation. The clue is in the name. This isn't an image of the real Universe at all, it's a simulation. And in some ways it's a very simple simulation, since the only physics involved was gravity. No gas, no stars, no complicated fluid effects, no magnetic fields. Just gravity. That's all that's needed to produce something that, for some amount of time, looks a bit like a brain cell.

Here's what the real Universe looks like... well, as close as is reasonable, at any rate (as I describe in great detail here) :


The simulation image only shows particles of dark matter. Make no mistake, the sheer number of particles (more than ten billion !) makes this an incredibly powerful simulation if you know how to use it. And it does look a lot like the observable Universe if you only count the positions of galaxies, and don't look at the details like actual images of said Universe.

That the simulation was visualised in such a way that it looks a bit like a brain cell is just not interesting  - it was an arbitrary choice by the scientists to (quite correctly) make a nice image for public outreach, and show the details they were interested in as clearly as possible. That simulation was produced by only modelling gravity. And you know what - that simulation did not become conscious or do anything remotely mystical. It couldn't, because at the end of the day a bunch of simulated particles that have no property except mass can't do a lot except fall together in an interesting way.

That one component of the Universe might look a bit like a brain cell for some short (on cosmic scales) amount of time ? Big bloody deal.


But... but... but they don't even look the same !!!

I mean, seriously. Come on people. The cell image shows two uniform-ish spheres pulling apart. The second shows two truncated shells with bright rings at the edges and a big bright thing in the middle. Even without knowing any of the details, they look completely different ! Seriously, who looks at this and thinks, "these two completely different looking things look like the same thing" ? Aaarrrgh.

The only, marginal and completely superficial resemblance is that there are round things in both images. The only conclusion one can draw from this is that round things exist. Bubbles exist. Footballs exist. Various fruits exist. Water drops exist. Planets exist. And various parts of the anatomy exist.

Many years ago I showed the above image of the Eta Carinae nebula (associated with the death throes of a massive star) to a less-nerdy friend. Since were were both about 15 at the time, his response was inevitably "testicles in space !". Does that mean anything ? God, I hope not.

Stars are round. When they die, they sometimes produce large round structures. Who'd have thunk it.

What's really ironic about the meme is that the supernova image is actually an artists impression. So even when you compare the splitting of a cell to an idealised view of an exploding star, you find they don't look anything like each other. Amazing ! Here's what it actually looks like :

There are also quite a lot of supernovae that look even less like cell division than this one. Ironically one of those is used in the very next image.


Lord have mercy. Not only does this fine image of the Crab Nebula make the point that star death doesn't always look like a dividing cell, but with yet more irony there are plenty of nebulae that look a lot more like the overall structure of an eye than this one. But presumably, the intention here is to compare the filamentary structure of the iris with the filaments in the nebula.

As I have made great efforts to point out, the Universe looks completely different in different wavelengths, and no particular wavelength of light is any more real than the visible light we can see with our eyes. Here's the Crab Nebula at infra-red wavelengths, as seen by NASA's Spitzer Space Telescope :

So much for filaments. But OK, there are filaments at some wavelengths. The iris, however, has a size which is controlled by muscles to vary how much light needs to be let in. So if you look again at the iris image, you'll see that the strands near to the pupil are all straight, completely unlike anything seen in the Crab Nebula. Worse, the iris is thin, whereas nebula are complex three-dimensional structures. And, as with the brain-universe, simulations of supernovae can reproduce some of the observed structures quite well based entirely on known physics, which is again completely different to the processes which create an eye.


Come on people. Please stop. The Universe contains hundreds of billions of galaxy filled with hundreds of billions of stars each and who-the-frak knows how many nebulae and planets and asteroids. That some of them have, at best, a marginal and temporary resemblance to everyday objects is the very definition of coincidence. Unless you think there's also a mystical significance between the apparent resemblance of a galaxy to the Loch Ness monster, or a potato to an asteroid, or a comet to a rubber ducky, this doesn't mean a darn thing. Aaargh.

The human brain has an amazing pattern-recognition ability which is genuinely very useful in astronomy. I would go so far as to say that if you can't see a pattern, there probably isn't one, and if things don't look the same, they're probably not the same. Your brain can detect stripy tigers in dark forests, which helped your ancestors avoid getting eaten. But many of them probably also saw tigers that weren't there, which didn't matter very much. So when you do see things that look like other things, you've got to be much more careful about deciding whether the resemblance is significant, merely a coincidence, or just an outright illusion.

EDIT : Of course, if all you took from the meme was, "these things look nice, and these other things look nice too", then all is well. You probably shouldn't have bothered reading this. But many people do see a deeper meaning here; presumably visual pattern recognition is not a discrete, separate part of the brain. Moreover, that the comparison is about birth, awareness and death, and is so contrived that in two cases it had to use non-real images, is very strong evidence that that was the wilful intent of the creator. At the very least, it's tough to see anyone creating this meme without being aware of how people would react.

Stupid people aren't dangerous; stupid people who spread their stupidity around are a problem.

Saturday, 28 March 2015

The Absurdly Anthropic

The Absurdly What Now ?

The Universe is the way it is because things happened the way they did. That doesn't sound particularly mystical to me.

Yet that is the essence of the anthropic principle. It's more usually stated in a manner that causes all kinds of horrid confusion :

"In astrophysics and cosmology, the anthropic principle (from Greek anthropos, meaning "human") is the philosophical consideration that observations of the physical Universe must be compatible with the conscious and sapient life that observes it." - Wikipedia.

Different people have radically different interpretations of what this means. As you'll have already gathered, I fall firmly into the camp which says, "this is trivial, but sometimes useful". In this viewpoint, there is no "reason" that the Universe has physical properties compatible with life. It just does, and so we're here observing it. If things had been any different, we would not be here. Possibly some other lifeform would be around instead, or possibly not, it doesn't really matter.

The reason the anthropic principle is sometimes useful is best explained using maths - very simple maths, don't worry. Suppose I tell you to work out what x is if 5x = 10. Well, that's easy, x = 2. You solved that equation because there was just one unknown variable.

This also works for what seem like more complicated equations :

5x + sin(p) - cos(q) + (r*r*r) + (z*z*z) = 10

If I tell you that p =90 and q =0 and r =176 and z = -176 , it's now simple to work out x (it's two again). This time there were lots of other quantities involved, but since you knew what they all were it was easy to find the unknown variable x.

Anthropic reasoning is a lot like this. It says that since we know life exists, the properties of the Universe have to be compatible with that. So if we know enough about the properties of the Universe, we can work out values we don't know by assuming that they have to be compatible with the existence of life. In many ways, this is incredibly trivial : the Sun didn't explode yesterday, so stars can't be prone to exploding. We didn't get hit by a giant asteroid, so giant asteroids can't be common. And I didn't get eaten by a bear, so bears are rare in Prague.

Image source.
Sometimes, anthropic reasoning can tell us more profound, non-trivial truths. The best-known example of this was the discovery of an energy level in the carbon atom by the great, controversial astronomer Fred Hoyle. The legend goes that he worked this out in order to solve how carbon is formed in nuclear fusion inside giant stars. He knew carbon existed - because he was made of quite a lot of it - but the only way he could get fusion to produce carbon was if the carbon atom had a very particular energy level.

Let's assume for a moment that that story is exactly true. It scarcely matters that Hoyle was partly made of carbon; it doesn't matter that carbon exists inside Hoyle or inside a wombat, the important point is that carbon exists at all. Moreover, he could equally have done this for another element less important for life. Or, as is very eloquently expressed in The Science of Discworld IV :

"The Anthropic Principle only seems different from the Sulphuric Principle (a universe containing sulphur has to be suitable for making sulphur) because it's about us rather than a lump of yellow rock. But the Copernican Principle cautions us not to imagine that there's anything special about us, and in this case, there isn't. We are just one piece of evidence. An equally convincing case can be made that the Universe is uniquely fine tuned to make sulphur."

Even if you do think we humans are special, the point is clear. We could use anything else as the basis for an anthropic-like principle : monkeys, turkeys, bananas, Justin Beiber, rocks, bum fluff, Sarah Michelle Gellar, candy floss, clouds, lithium, chocolate, volcanoes, sand... whatever you like.

I already promised not to show Justin Beiber and if you really want pictures of bum fluff then you've come to the wrong place.

I'll die before I believe in the Beiber Principle, could easily be persuaded in the Gellar Principle, and won't ever stop believing that the purpose of the Universe is chocolate. And I'll actively go around trying to convince people of the Gellar-Chocolate principle. Mmm. Sorry, what was I saying ?

That we are sentient, or even alive, is hardly relevant for anthropic reasoning. The essence of it is that the Universe has to have the correct conditions to contain the things we observe within it - that it happens to include life is just the way it is. That we can sometimes work out other facts about reality from the existence of life doesn't mean that life is special any more than it means sulphur is special.

Why does this cause difficulties ?

The alternative, more extreme view is the so-called "strong" anthropic principle - bluntly stated, the idea that the Universe isn't just suitable for life, but designed for it - it has a purpose, as I alluded to with the chocolate example. This rests on the notion that the properties of the Universe have to be almost exactly what they are, otherwise life would be impossible.

Of course, we could invoke the Strong Sulphuric Principle to see how absurd this potentially is : a Universe containing sulphur doesn't necessarily have to have been designed to contain sulphur, any more than a house containing termites was designed to contain termites. Yes, the house was designed, but assuming some particular random feature of it was the purpose of the house is a very silly mistake.

Or, as in SODIV again :

"Why us ? The Strong Anthropic Principle just assumes it's obvious that we are the purpose of the whole thing. Sulphur ? Don't be silly."

An even better example might be a pile of sand that happens to have a stick on it. The pile of sand wasn't "designed" at all, let alone designed for the stick. The mere fact that things exist doesn't tell you they were designed. It doesn't necessarily tell you that they weren't designed either; the one implies nothing about the other.

But what about fine tuning ? Clearly a pile of sand is not at all fine-tuned, or optimised, to contain a stick. A house is fairly suitable for termites, but it's not ideal unless the entire house is made of wood. In contrast, the argument for the strong anthropic principle for the Universe is that the properties for life are so incredibly specific that it's like balancing a pea on a knife edge - move it even the smallest amount and it will fall. The Universe, it says, is not just suitable but optimal for producing life. And that's much more interesting.

Image source.
If the Universe required incredibly specific conditions for sulphur to exist, and changing those conditions in any way would cause there to be much less sulphur, then the strong sulphuric principle might be valid. But if changing those conditions also changed a whole bunch of other things, we'd have to be very careful that we were sure sulphur was really the purpose of the Universe. That's why we ought to have a damn good reason for assuming that we're special - our mere existence and sentience doesn't automatically make us any more important (to the rest of the Universe) than non-sentient objects like rocks and Justin Beiber.

Indeed, one of the most profound discoveries from astronomy is the sheer size of the Universe. We know of only one tiny, pathetic scrap of rock where life like ours can exist. We're special because we're rare, but we're also totally unimportant for exactly the same reason. We matter to each other; the Universe doesn't give a damn.

The problem with the fine-tuning argument, as SODIV point out, is that the Universe is bloody complicated - as are the conditions for life. Change one parameter and you can compensate by changing the others. SODIV present the very nice analogy of a car :

"If you take a car, and change any single aspect even a little bit, the odds are that the car will no longer work. Change the size of the nuts just a little, and they don't fit the bolts and the car falls apart. Change the fuel just a little, and the engine doesn't fire and the car doesn't start. But this does not mean that only one size of nut or bolt is possible in a working car, or only one type of fuel. It tells us that when you change one feature, it has knock-on effects on the others, and those must also change."

Conditions for life aren't balanced on a knife-edge at all : actually, there's a huge plateau containing different combinations of parameters that would give a Universe eminently suitable for life. For example, if the Sun was a little cooler, Earth would be frozen - unless it was also a little closer to the Sun. And smaller, cooler stars live longer than large hot ones, so this might even be better for life in the long run. Similar argument can be made about the particular values of the fundamental constants. So there's not really much indication that ours is the Universe most suitable for life.

Take the carbon example. The energy level did turn out to be close to the predicted value, but you could actually shift that value by around 4% and still get about as much carbon produced as we see. A 4% error isn't precision engineering, it's a wonky stool. In fact you could actually get even more carbon if the energy level was a bit lower.

And then, just for good measure, there's evidence that Hoyle never even used anthropic reasoning and the whole story is a later invention. As I said, the important thing was only that carbon existed, not that Hoyle existed. He could have used an anthropic argument, but a "carbonthropic" principle would have been every bit as valid.

For even more examples of how fine-tuning is a myth, have a look at the Monkey God web program that lets you generate Universes and see how suitable they are for life. And have a read of the author's website too. And of course SODIV's chapter 22 is masterful, even if their discussion on atheism was just plain wrong.

In short, the Universe will always appear to be fine-tuned to contain whatever it happens to contain. Whether that includes life or not is just a detail.


The Earth and the Universe it resides in aren't some wonderful eden. The natural world is, by the standards of human morality, manifestly cruel and unpleasant. Natural selection is a ruthlessly competitive process : you win or you die, or more accurately, you win and you die. Supervolcanoes and asteroid impacts are periodically devastating for the ecosystem - countless species have gone extinct because they were unable to adapt. Life survives in spite of its environment as much as because of it. Arguments that the Universe is uniquely fine-tuned for sentient life don't have much force in the face of tsunamis, earthquakes and hurricanes.

Yes, this is obviously an example of how suitable the Earth is for sentient life.
Of course, you could still say that maybe the Universe isn't optimised for life, but it's still the best Universe possible for life to exist in. That's difficult to believe given the huge range of scope available given the number of parameters. More seriously, these arguments are almost always used to invoke the existence of a designer - in which case you ought to explain not why the Universe is so perfect for life, but why it is so clearly imperfect. At which point the arguments are revealed not necessarily as being wrong, but simply unscientific.

Moreover, you don't know what the designer's purpose is. You could very well say, "Sarah Michelle Gellar is so lovely that the Universe must be setup to ensure she exists." But you could equally say, "Justin Beiber is such a complete pillock that the Universe must be setup to ensure he exists"* - or even, "tsunamis are so awful that the Universe is setup to ensure they happen". The Universe is full of wonders and horrors, so there's nothing to say if the the designer was good, evil, or just a complete berk.

* Fun experiment to try yourself : use the anthropic principle for cheesy chat-up lines and scathing insults. As in, "You're so fine / such a douchebag (delete as appropriate) there's no WAY you're an accident !"

The Universe has properties which are sufficient for life to exist, but that's all we can say for certain. There's little to suggest the Universe is the ideal one for life to survive in, let alone that it was designed for a species inhabiting far, far less than 0.00000000001% of its volume. Virtually all of the Universe is completely unaware of our existence and most of it is an environment that would kill us in seconds. That's a pretty odd bespoke Universe if it's supposed to exist for our benefit, if you ask me.

Used to infer properties of the Universe based on other values, anthropic reasoning is perfectly sound. I would even say it's a very basic scientific idea : if I know some things, I can work out others. But using it to infer a design is ridiculous - of course we live in a Solar System where the planets are in stable orbits, of course we live on a planet with liquid water. The other planets in our Solar System are positively hellish for life as we know it : if there was one just star in all the Universe and the Earth its only planet, then there might be a good reason to suppose that the Universe was designed. But in reality the overwhelming majority of the volume of the Universe is dark, cold and incredibly lonely. That we exist somewhere which is light, warm, and not overtly hostile 100% of the time isn't coincidence, or spooky, it's necessary.

Or to put it another way, saying, "isn't it remarkable how perfect conditions for life are here ?" is as silly as saying, "isn't it remarkable that we live on a rock that's suitable for us to live on, instead of out in that immense cold void where we'd be dead in seconds ?".

The fact that an oasis (at least one) exists where we can survive, given the immensity of the Universe and the huge range of environments, is not in the least bit surprising. The Universe is the way it is because things happened they way they did. Being surprised at this is equivalent to being surprised at the existence of rocks.

None of this makes the Universe the slightest bit less wonderful. Whether you think the Universe is magnificent or oppressive, cruel or beautiful, sacred or profane, is entirely up to you.

Friday, 20 March 2015

And Yet It Moves, Quite A Lot Like That

Is our Solar System a vortex ? No, says Phil Plait. "Err, not quite", says I.

If you've just wandered in off the street and have no idea what I'm talking about, here's the short version. Some time back, this gif and video were doing the rounds on the internet. Like a bad penny, they still keep turning up from time to time, with an astonishing capacity to go viral almost whenever they appear.

What Plait (quite correctly) describes is that the model of the Solar System this video promotes is utter nonsense. What I (also quite correctly) pointed out is that yes, the model is wrong, but the planets trace out helical paths through space even so. I even made a (much crappier) version of the gif to illustrate this. I gave the planets the correct 60 degree tilt relative to the direction of motion (which makes barely any difference at all) and put them in the correct order, just for the hell of it.

I've always maintained that it's that aspect of the video (showing our motion through space) that assures its popularity, rather than the alternative (wholly wrong) model it tried to promote. I did, of course, get extremely annoyed by the promotion of this nonsensical alternative model, but I wanted to make it absolutely clear that this helical-path business is perfectly correct.

I'm extremely pleased to tell you that I've just had a delightful conversation with DJSadhu, creator of the original video. I'll admit to a great deal of trepidation about even opening the email. After all, I wasn't particular polite in the original article, and I was fully expecting yet another angry email from a pseudoscientific nutcase. I get such things frequently enough that I strongly considered just deleting the email without even reading it.

Well, let me say this in no uncertain terms : I was wrong. Sadhu has listened to the critics and made a new video. Gone are the claims that the heliocentric model is wrong. Gone are the links to any alternative model of the Solar System created by someone who doesn't believe CFCs are the cause of the ozone hole. And gone are the links to the Fibonacci sequence as a fingerprint of God. What remains are some very nice graphics and a catchy soundtrack. The whole thing looks really well done to me.

When I watched it, I don't mind admitting that I was very pleasantly surprised indeed. I really can't find any show-stoppers with this at all. Really, if there are any inaccuracies in this one, I think this would be nit-picking.

As I pointed out in the first article, I couldn't see any hint of the Sun moving ahead of the planets, despite Phil Plait's claims (but keep reading) which would have been horrendous. Sadhu explicitly confirmed that to me :

"Again, the sun is not leading here, still not convinced it does. Although Bhat's paper put me on the "helical track", I do not take his "cone shaped model" as absolute fact... I've had of discussions with viewers, noobs, trolls, haters, lovers, and scientists, and I kind of doubt the cone shape model to put it mildly."

Seriously, what more can one ask for ? He freely admitted that his second video does show this Sun-leading model, but here he couldn't be any more clear : he's not trying to show that with this video.

Sadhu asked :

"And how come, even though the standard model is 'correct' and 'complete'... you had to come up with a completely new animation to show the old model is okay ?
Because there was no such video... and that's what I find annoying.
"Science" quickly jumps onto the "it's all wrong" bandwagon... and then you have to go and tinker to personally make the first "correct" version (oh the angle is a bit different)
The complete model should have been out there all along!!!!  

Noo, let's debunk DjSadhu, and then make the correct version - for the first time !"

I can see his point. There certainly wasn't a standard-model video out there - at least, certainly not one that's anything like as pretty or as popular. It would definitely seem very unfair to debunk the person who made such a successful video demonstrating (pretty much for the first time) the motion of the Solar System through space.

My response was to explain in some long-winded detail why the the standard-model video didn't previously exist, and what it was about the original that had got some people (myself very much included) riled up. I'll try and keep things a bit briefer here.

First, why there wasn't a video already. Any object moving on a circular path that's simultaneously moving forward must trace out a helical path. This ought to be incredibly obvious, but here's a simple demonstration you can try at home, provided you have at least one functional finger.

Hold your hand out and point one finger to the left. Now move your finger in a circle, and move your hand to the left. You'll see your finger traces out a helical path. There's nothing the slightest bit mysterious or profound about it - it's simple, basic geometry. No-one ever felt the need to make a video claiming "your finger is a vortex !"... err, well, on second thought maybe they did, but I'm not into that sort of thing, thank you very much.

Next. repeat the experiment but this time move your head at the same speed as your finger. The helices disappear ! Your head is now in the same "reference frame" as your finger - that's the heliocentric model, the standard diagrams of the Solar System you're probably familiar with. The heliocentric model is neither wrong nor incomplete, it's simply a choice of reference frame. And at this point, to demonstrate the fact that we've been aware of the motion of the Solar System for some time, here's the Galaxy Song again. Yes, I used this last time... but come on, it's a very good song.

However, while it may be completely obvious to me that the Solar System moves like this, it clearly isn't obvious to a lot of people. So I have to concede - empirical evidence demands it - that Sadhu's video (notwithstanding the alternative model, which we'll get back to shortly) is beneficial in that it does a good job of illustrating this fact.

The second point - it wasn't the video that got me riled up, it was what it was promoting. My response (shortened slightly) was as follows :
  • "First, you presented the idea of helical paths as though it were some revolutionary new model. You could have very easily checked with more or less any astronomer who would have told you that we already know this is the case. 
  • Second, I completely agree with Plait about Bhat - I think he's nuts. His document put me in mind of Moon landing conspiracy theorists and Hollow Earth believers.... Your claim was not, "hey everyone, in this reference frame we're moving on a helical path !" (which would have had people saying, "pretty neat !") but instead, "hey, this totally ludicrous model claims we're moving on a helical path, so I've overturned heliocentricism" (which has people thinking you're mad).
  • Third, you seemed to be strongly implying that you didn't believe the 60 degree tilt of the ecliptic was even possible, because you thought it would mean that sometimes the planets are moving faster than the Sun. Plait's analogy of swinging a ball on a string while walking down the street is correct - this poses no problem whatsoever for classical mechanics.
  • Fourth, you were claiming that in the classical model the planets should be eclipsed by the Sun once per year. This does not happen, simply because the orbits aren't all perfectly in the same plane. An alternative model is not necessary to explain this.
  • Fifth, I don't think it's fair to say that discrediting the other stuff on your website was not relevant. You made quite an explicit link between the motion of the planets and DNA and other organic structures. In effect, you claimed that your alternative source model provides evidence for a pseudoscientific idea about the Fibonacci sequence. That was never going to go down well."

Sadhu's response was pretty much everything I could have hoped for. I've re-arranged his response a little, for reasons that will become apparent soon enough. It deserves to be quoted at length.

"About two years ago I heard of this "Bhat model", the cone shaped, helical solar system. It fired up my enthusiasm and I started making these videos. Frankly I was a bit pissed about the 'standard model' (as you can tell by the claims in the first video), because it just did not show properly how things work. For me personally, the difference between a stationary looking dinner plate model and this dynamic, spiralling model was huge. So I made the videos, the first one (solar system) just showed this helical model, and the second one (our galaxy) showed this cone shape and the helical pathway of the sun, and lots of other debatable details. Especially that second video was reason for most resistance and criticism from the scientific community, but it affected how both videos were regarded.

Anyway, that was how it worked back then. Now, two years later, I'm certain of one thing: the huge difference between the stationary looking dinner plate model and the helical model remains.

As long as I leave out the wacky stuff, the cone shaped stuff, leave Bhat out, do not argue about the shape of the sun's path, it could easily be accepted.

So that is kind of what I decided, I want to make this "Solar System 2.0" video, with no outrageous claims, none of the disputable stuff, just the best representation of the helical model that I can make. And make it art.

The video does not claim that the heliocentric model is 'wrong', it puts it into perspective. For most people a new one. Also, the cone shaped stuff is not in the video, not important, and should certainly not ruin the message.

I'm not after words, but after images. So I left the words out. Vortex/helix, wrong/incomplete, all those terms are vulnerable ingredients in a video, and they are not the point !

The point is how people 'see' the solar system. Although the helical paths may have been known to astronomers and astrophysicists (and part of the public), what people 'see' when they think about the solar system is in my opinion incomplete."

It would be pretty damn tough for me to disagree with any of that. In fact, let me state it more explicitly : bravo, Sadhu, I salute you.

He did, however, make two statements I dispute - one is pretty minor, the other major but not as bad as you may at first think.

The minor point : "The only bold move I made was to 'blame' the upward angle in the sun's path for the difference between 90 and 60 degrees. "

I'd say the fact that the planets don't move at 90 degrees to the direction of motion is simply chance - they could be oriented at any angle. A more interesting, related point that someone mentioned to me elsewhere is that there's no reason the plane of the ecliptic (the narrow "sheet" in which the planets orbit the Sun) should always be at the same angle relative to the direction of the Sun's motion around the center of the galaxy.

That's a little bit complicated a statement, so probably an illustration will help. Here's what you might interpret Sadhu's video as showing (he confirmed to me that this is not what he's trying to show, however) :

Here the Sun (yellow circle) and the orbits of the planets (white lines) are shown at different points in their orbit around the galaxy (obviously they're not to scale). If they orbited like this, the paths of the planets would always trace out neat helical paths.

That might not be the case though. The plane of the ecliptic could keep the same angle throughout its orbit around the Galaxy.

In this case, the neat helical paths would only result at two points in the orbit (those at the extreme left and right in the above image). The result of the time there'd still be helices, but they'd be distorted.


At the other extremes (the top and bottom in the image), the planets would trace out something more like a flat, spirograph pattern than a 3D helix :


Which is correct ? Actually, I don't know. Or even care very much - and that's where Sadhu and I have a more profound disagreement. For me, the motion of the Solar System through space is neither very interesting scientifically nor philosophically*. For Sadhu, however, things are different :

* Personally I'd rather there was more interest in my hydrogen sky video or giant nuclear spaceship or exploding galaxy renders, which were far more interesting, labour-intensive projects.

"Yes, in my personal experience the helical paths, DNA, life, Universe is all connected. Hell, I would not be surprised if one day the discovery is made that the entire Universe is conscious."

Sadhu and I are never going to agree on that. And you know what ? That's absolutely fine. I have stated several times previously that I have no problem with people holding irrational beliefs, I don't see them as inherently wrong or amoral. What Sadhu is doing here is making a very clear distinction between his unscientific opinions and objective facts. That is commendable. If more people could do this, the world would be a happier place.


I still stand by my original article. I don't think I was wrong to debunk the claims against heliocentricism at all. As I said, the problems with the original video were minor, but what it was promoting deserved to be shot down.

Sadhu is no longer using his talents to promote anything remotely unscientific. True, he does still have unscientific opinions (and a brief glance at his website shows him to be interested in things I profoundly disagree with). Some of what he says is "disputed" I would say "no, that's just wrong" - but come on, there's no point being a jerk about it. For me to fail to publically acknowledge the virtues of this video, would, I think, make me a complete arsehole.

People, this should be seen as a win-win scenario. The essence of Sadhu's original video was correct, and he's publically declaring skepticism for the second one. His new effort has none of the quackery associated with the first. To me, that seems like the best of all possible outcomes. Demonising your opponents is no way to win them over - and sometimes, it turns out they were saying something valuable all along.