Why I'm Not On Twitter And Never Will Be

I don't use Twitter. But if I did, I imagine my posts would go something like this :


I am looking for hydrogen.

I am looking for hydrogen.

I am looking for hydrogen.

I am looking for hydrogen.

I am looking for hydrogen.

I am looking for hydrogen.

I am looking for hydrogen.

I am looking for hydrogen.

I am looking for hydrogen.

I FOUND SOME HYDROGEN !

I am looking for hydrogen.

I am looking for hydrogen.

I am looking for hydrogen.

I am looking for hydrogen.

I FOUND SOME HYDROGEN !

I am looking for hydrogen.

I am looking for hydrogen.

I am looking for hydrogen.

I am looking for hydrogen.

I am looking for hydrogen.

I FOUND SOME HYDROGEN !

I am looking for hydrogen.

I am looking for hydrogen.

I FOUND SOME HYDROGEN !

I am looking for hydrogen.

I am looking for hydrogen.

I am looking for hydrogen.

I am looking for hydrogen.

I FOUND SOME HYDROGEN !

I am looking for hydrogen.

I am looking for hydrogen.

I am looking for hydrogen.

I am looking for hydrogen.

I am looking for hydrogen.

I am looking for hydrogen.

I am looking for hydrogen.

I am looking for hydrogen.

I FOUND SOME HYDROGEN !

I am looking for hydrogen.

I am looking for hydrogen.

I am looking for hydrogen.

I am looking for hydrogen.

I am looking for hydrogen.

I am looking for hydrogen.

I am looking for hydrogen.

I am looking for hydrogen.

I am looking for hydrogen.

I am looking for hydrogen.

I am looking for hydrogen.

I am looking for hydrogen.

I am looking for hydrogen.

I am looking for hydrogen.

I am looking for hydrogen.

I am looking for hydrogen.

I am looking for hydrogen.

I am looking for hydrogen.

I am looking for hydrogen.

I am looking for hydrogen.

I am looking for hydrogen.

I FOUND SOME HYDROGEN !

I am looking for hydrogen.

I am looking for hydrogen.

I am looking for hydrogen.

I am looking for hydrogen.

I FOUND SOME HYDROGEN !

I am looking for hydrogen.

I am looking for hydrogen.

I am looking for hydrogen.

I am looking for hydrogen.

I am looking for hydrogen.

I FOUND SOME HYDROGEN !

I am looking for hydrogen.

I am looking for hydrogen.

I FOUND SOME HYDROGEN !

I am looking for hydrogen.

I am looking for hydrogen.

I am looking for hydrogen.

I am looking for hydrogen.

I FOUND SOME HYDROGEN !

I am looking for hydrogen.

I am looking for hydrogen.

I am looking for hydrogen.

I am looking for hydrogen.

I am looking for hydrogen.

I am looking for hydrogen.

I am looking for hydrogen.

I am looking for hydrogen.

I FOUND SOME HYDROGEN !

I am looking for hydrogen.

I am looking for hydrogen.

I am looking for hydrogen.

I am looking for hydrogen.

I am looking for hydrogen.

I am looking for hydrogen.

I am looking for hydrogen.

I am looking for hydrogen.

I am looking for hydrogen.

I am looking for hydrogen.

I am looking for hydrogen.

I am looking for hydrogen.

I HAS FOUND ALL OF THE HYDROGEN. I HAS THE WIN.

I am downloading FITS files.

I am downloading FITS files.

I am downloading FITS files.

I am downloading FITS files.

I am downloading FITS files.

I am downloading FITS files.

I am downloading FITS files.

I am downloading FITS files.

I am downloading FITS files.

I am downloading FITS files.

I am downloading FITS files.

I am downloading FITS files.

I am downloading FITS files.

I am downloading FITS files.

I am downloading FITS files.

I am downloading FITS files.

I am downloading FITS files.

I am downloading FITS files.

I am downloading FITS files.

I am downloading FITS files.

I am downloading FITS files.

I am downloading FITS files.

I am downloading FITS files.

I am downloading FITS files.

I am downloading FITS files.

I am downloading FITS files.

I am downloading FITS files.

I am downloading FITS files.

I am downloading FITS files.

I am downloading FITS files.

I am downloading FITS files.

I am downloading FITS files.

I am downloading FITS files.

I am downloading FITS files.

I am downloading FITS files.

I am downloading FITS files.

I am downloading FITS files.

I am downloading FITS files.

I am downloading FITS files.

I am downloading FITS files.

I am downloading FITS files.

I am downloading FITS files.

I am downloading FITS files.

I am downloading FITS files.

I am downloading FITS files.

I am downloading FITS files.

I am downloading FITS files.

I am downloading FITS files.

I am downloading FITS files.

I am downloading FITS files.

I am downloading FITS files.

I am downloading FITS files.

I am downloading FITS files.

I am downloading FITS files.

I am downloading FITS files.

I am downloading FITS files.

I am downloading FITS files.

I am downloading FITS files.

I am downloading FITS files.

I am downloading FITS files.

I am downloading FITS files.

I am downloading FITS files.

I am downloading FITS files.

I am downloading FITS files.

I am downloading FITS files.

I am downloading FITS files.

I am downloading FITS files.

I am downloading FITS files.

I am downloading FITS files.

I am downloading FITS files.

I am downloading FITS files.

I am downloading FITS files.

I am downloading FITS files.

I am downloading FITS files.

I am downloading FITS files.

I am downloading FITS files.

I am downloading FITS files.

I am downloading FITS files.

I am downloading FITS files.

I am downloading FITS files.

I am downloading FITS files.

I am downloading FITS files.

I am downloading FITS files.

I am downloading FITS files.

I am downloading FITS files.

I am downloading FITS files.

I am downloading FITS files.

I am downloading FITS files.

I am downloading FITS files.

I am downloading FITS files.

I am downloading FITS files.

I am downloading FITS files.

I am downloading FITS files.

I am downloading FITS files.

I am downloading FITS files.

I am downloading FITS files.

I am downloading FITS files.

I am downloading FITS files.

I am downloading FITS files.

I am downloading FITS files.

I am downloading FITS files.

I am downloading FITS files.

I am downloading FITS files.

I am downloading FITS files.

I am downloading FITS files.

I am downloading FITS files.

I am downloading FITS files.

I am downloading FITS files.

I am downloading FITS files.

I am downloading FITS files.

I am downloading FITS files.

I am downloading FITS files.

I am downloading FITS files.

I am downloading FITS files.

I am downloading FITS files.

I am downloading FITS files.

I am downloading FITS files.

I am downloading FITS files.

I am downloading FITS files.

I am downloading FITS files.

I have downloaded ALL of the FITS files. I R A WINNER !

I am doing photometry.

I am doing photometry.

I am doing photometry.

I am doing photometry.

I am doing photometry.

I am doing photometry.

I am doing photometry.

I am doing photometry.

I am doing photometry.

I am doing photometry.

I am doing photometry.

I am doing photometry.

I am doing photometry.

I am doing photometry.

I am doing photometry.

I am doing photometry.

I am doing photometry.

I am doing photometry.

I am doing photometry.

I am doing photometry.

I am doing photometry.

I am doing photometry.

I am doing photometry.

I am doing photometry.

I am doing photometry.

I am doing photometry.

I am doing photometry.

I am doing photometry.

I am doing photometry.

I am doing photometry.

I am doing photometry.

I am doing photometry.

I am doing photometry.

I am doing photometry.

I am doing photometry.

I am doing photometry.

I am doing photometry.

I am doing photometry.

I am doing photometry.

I am doing photometry.

I am doing photometry.

I am doing photometry.

I am doing photometry.

I am doing photometry.

I am doing photometry.

I am doing photometry.

I am doing photometry.

I am doing photometry.

I am doing photometry.

I am doing photometry.

I am doing photometry.

I am doing photometry.

I am doing photometry.

I am doing photometry.

I am doing photometry.

I am doing photometry.

I am doing photometry.

I am doing photometry.

I am doing photometry.

I am doing photometry.

I am doing photometry.

I am doing photometry.

I am doing photometry.

I am doing photometry.

I am doing photometry.

I am doing photometry.

I am doing photometry.

I am doing photometry.

I am doing photometry.

I am doing photometry.

I am doing photometry.

I am doing photometry.

I am doing photometry.

I am doing photometry.

I am doing photometry.

I am doing photometry.

I am doing photometry.

I am doing photometry.

I am doing photometry.

I am doing photometry.

I am doing photometry.

I am doing photometry.

I am doing photometry.

I am doing photometry.

I am doing photometry.

I am doing photometry.

I am doing photometry.

I am doing photometry.

I am doing photometry.

I am doing photometry.

I am doing photometry.

I am doing photometry.

I am doing photometry.

I am doing photometry.

I am doing photometry.

I am doing photometry.

I am doing photometry.

I am doing photometry.

I am doing photometry.

I am doing photometry.

I am doing photometry.

I am doing photometry.

I am doing photometry.

I am doing photometry.

I am doing photometry.

I am doing photometry.

I am doing photometry.

I am doing photometry.

I am doing photometry.

I am doing photometry.

I am doing photometry.

I am doing photometry.

PHOTOMETRY IS DONE ! IT IS DA SHIZZLE.

I am looking for trends in data.

I am looking for trends in data.

I am looking for trends in data.

I am looking for trends in data.

I am looking for trends in data.

I am looking for trends in data.

I am looking for trends in data.

I am looking for trends in data.

I am looking for trends in data.

I am looking for trends in data.

Bored now. Writing code.

Codin'.

Still codin'.

Code is done. Took 3 days. Has just made last 6 months of work obsolete.

Sigh....

I am writing a paper.

I am writing a paper.

I am writing a paper.

I am writing a paper.

I am writing a paper.

I am writing a paper.

I am writing a paper.

I am writing a paper.

I am writing a paper.

I am writing a paper.

I am writing a paper.

I am writing a paper.

I am writing a paper.

I am writing a paper.

I am writing a paper.

I am writing a paper.

I am writing a paper.

I am writing a paper.

I am writing a paper.

I am writing a paper.

I am writing a paper.

I am writing a paper.

I am writing a paper.

I am writing a paper.

I am writing a paper.

I am writing a paper.

I am writing a paper.

I am writing a paper.

I am writing a paper.

I am writing a paper.

I am writing a paper.

I am writing a paper.

I am writing a paper.

I am writing a paper.

I am writing a paper.

I am writing a paper.

I am writing a paper.

I am writing a paper.

I am writing a paper.

I am writing a paper.

I am writing a paper.

I am writing a paper.

I am writing a paper.

I am writing a paper.

I am writing a paper.

I am writing a paper.

I am writing a paper.

I am writing a paper.

I am writing a paper.

I am writing a paper.

I am writing a paper.

I am writing a paper.

I am writing a paper.

I am writing a paper.

I am writing a paper.

I am writing a paper.

I am writing a paper.

I am writing a paper.

I am writing a paper.

I am writing a paper.

I am writing a paper.

I am writing a paper.

I am writing a paper.

I am writing a paper.

I am writing a paper.

I am writing a paper.

I am writing a paper.

I am writing a paper.

I am writing a paper.

I am writing a paper.

I am writing a paper.

I am writing a paper.

I am writing a paper.

I am writing a paper.

I am writing a paper.

I am writing a paper.

I am writing a paper.

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I am writing a paper.

I am writing a paper.

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I am writing a paper.

I am writing a paper.

I am writing a paper.

I am writing a paper.

I am writing a paper.

I am writing a paper.

I am writing a paper.

I am writing a paper.

I am writing a paper.

I am writing a paper.

I am writing a paper.

I am writing a paper.

I am writing a paper.

I am writing a paper.

I am writing a paper.

I am writing a paper.

I am writing a paper.

I am writing a paper.

I am writing a paper.

I am writing a paper.

I am writing a paper.

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I am writing a paper.

I am writing a paper.

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I am writing a paper.

I am writing a paper.

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I am writing a paper.

I am writing a paper.

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I am writing a paper.

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I am writing a paper.

I am writing a paper.

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I am writing a paper.

I am writing a paper.

I am writing a paper.

I am writing a paper.

I am writing a paper.

I am writing a paper.

I am writing a paper.

I am writing a paper.

I am writing a paper.

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I am writing a paper.

I am writing a paper.

I am writing a paper.

I am writing a paper.

I am writing a paper.

I am writing a paper.

I am writing a paper.

I am writing a paper.

I am writing a paper.

I am writing a paper.

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I am writing a paper.

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I am writing a paper.

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I am writing a paper.

I am writing a paper.

I am writing a paper.

I am writing a paper.

I am writing a paper.

I am writing a paper.

I am writing a paper.

I am writing a paper.

I am writing a paper.

I am writing a paper.

I am writing a paper.

I am writing a paper.

I am writing a paper.

I am writing a paper.

I am writing a paper.

I am writing a paper.

I am writing a paper.

I am writing a paper.

I am writing a paper.

I am writing a paper.

I am writing a paper.

I am writing a paper.

I am writing a paper.

I am writing a paper.

I am writing a paper.

I am writing a paper.

I am writing a paper.

I am writing a paper.

I am writing a paper.

I am writing a paper.

I am writing a paper.

I am writing a paper.

I am writing a paper.

I am writing a paper.

I am writing a paper.

I am writing a paper.

I am writing a paper.

I am writing a paper.

I am writing a paper.

I am writing a paper.

I am writing a paper.

I am writing a paper.

I am writing a paper.

I am writing a paper.

I am writing a paper.

I am writing a paper.

I am writing a paper.

I am writing a paper.

I am writing a paper.

I am writing a paper.

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I am writing a paper.

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I am writing a paper.

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I am writing a paper.

I am writing a paper.

I am writing a paper.

I am writing a paper.

I am writing a paper.

I am writing a paper.

I am writing a paper.

I am writing a paper.

I am writing a paper.

I am writing a paper.

I am writing a paper.

I am writing a paper.

I am writing a paper.

I am writing a paper.

I am writing a paper.

I am writing a paper.

I am writing a paper.

I am writing a paper.

I am writing a paper.

I am writing a paper.

I am writing a paper.

I am writing a paper.

I am writing a paper.

I am writing a paper.

I am writing a paper.

I am writing a paper.

I am writing a paper.

I am writing a paper.

I am writing a paper.

I am writing a paper.

I am writing a paper.

I am writing a paper.

I am writing a paper.

I am writing a paper.

I am writing a paper.

I am writing a paper.

I am writing a paper.

I am writing a paper.

I am writing a paper.

I am writing a paper.

I am writing a paper.

I am writing a paper.

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I am writing a paper.

I am writing a paper.

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I am writing a paper.

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I am writing a paper.

I am writing a paper.

I am writing a paper.

I am writing a paper.

I am writing a paper.

I am writing a paper.

I HAS SUBMITTED A PAPER. NOW I SLEEP.

I am revising a paper.

I am revising a paper.

I am revising a paper.

I am revising a paper.

I am revising a paper.

I am revising a paper.

I am revising a paper.

I am revising a paper.

I am revising a paper.

I am revising a paper.

I am revising a paper.

I am revising a paper.

I am revising a paper.

I am revising a paper.

I am revising a paper.

I am revising a paper.

I am revising a paper.

I am revising a paper.

I am revising a paper.

I am revising a paper.

I am revising a paper.

I am revising a paper.

I am revising a paper.

I am revising a paper.

I am revising a paper.

I am revising a paper.

I am revising a paper.

I am revising a paper.

I am revising a paper.

I am revising a paper.

I am revising a paper.

I am revising a paper.

I am revising a paper.

I am revising a paper.

I am revising a paper.

I am revising a paper.

I am revising a paper.

I am revising a paper.

I am revising a paper.

PAPER IS ACCEPTED ! MWHAHAHAHAH !

I am looking for hydrogen.

Galaxies Are Pretty

EDIT : This is an old post from 2013, updated as of March 2016 to include new data.

I've always wanted to understand how the Universe works. This is proving rather difficult, so I'm prepared to settle for knowing what it looks like.

Since I already describe the technical aspects of how the video was produced on my website and in an earlier blog post, I'm not going to do it again because that would be silly. EDIT : I will just add a brief note - you might notice in the video that there's a difference in the number of galaxies detected by ALFALFA and actually shown here. That's because some of them aren't galaxies at all, and a few aren't properly identified by the SDSS automatic algorithms.

 Maybe a more interesting question to ask is : how accurate is the video ? Is this really what the Universe looks like ?

Well, no, it isn't. It's an approximation, but it's grounded in reality. Allow me to try and explain, because it's my blog and you can't stop me.

The complete, full HD video. Partially in 3D if you've got those 

old red-blue glasses. The original can be seen here.

How do we know where all the galaxies are ?

We don't. Just looking at an image isn't always enough to tell what's a galaxy and what isn't. For example... THIS

isn't a galaxy. It's just a crummy old star cluster, and therefore useless. Whereas THIS

is a genuine galaxy and no mistake.

Just like with James Spader and Michael Shanks, there's no way to tell the two apart by just ogling them. But if we measure how fast their stars are moving, we can see that all is well with the star cluster, but the stars in the galaxy are moving way too fast. Without some invisible matter to hold them all together, they should all fly apart (unless we've got something very wrong, which is possible, but in the interests of time let's not go there). So galaxies have dark matter, and star clusters don't.

Whereas distinguishing Spader / Shanks is simply hopeless.

Unfortunately we can't always get accurate measurements of how fast the galaxies are rotating. Sometimes, though, we can measure how far away they are, and that tells us if we're looking at a small bunch of stars very nearby (which would be a star cluster) or a big bunch of stars very far away (which would be a galaxy). More on that in a minute.

Still, the upshot is that identifying galaxies is tricky, and we can't be sure we've found them all. In fact, we know we haven't, because the Milky Way is big, bright, and in the way.

And very pretty.

More important is that the galaxies in the video are selected from the ALFALFA survey. This is a hydrogen gas survey, and galaxies which have hydrogen tend to be forming lots of stars and very blue. So the video is missing a lot of the reddest galaxies, even the really bright ones, because these often lack hydrogen gas. This was a deliberate choice, because I made the video to demonstrate the capabilities of Arecibo in a photogenic way, and neither Michael Shanks nor James Spader seemed to fit the bill.


How do we know how far away the galaxies are ?

We may not know exactly where all the galaxies are, but for those we do know about we generally have pretty good estimates of how far away they are - even though we can't directly measure the distances to other galaxies.

The only way we can directly measure the distances to astronomical objects outside of our own solar system is through parallax, where we see how much a star moves relative to the stars behind it. That's good for nearby stars, but for more distant objects we have to use other methods (calibrated on the ones we can get direct measurements for) to create a 'distance ladder'. And that lets us get pretty good estimates of how far away galaxies are.

Full size image here.

The most important result of this is Hubble's Law. This allows us to use measurements of how fast the galaxies are moving away from us (a relatively easy measurement) and convert it into a distance. And we think this works pretty well... most of the time. The problems start when you get two or more galaxies close together. Like two sumo wrestlers on a trampoline, the force of attraction is irresistible*  and they can't help but fall towards each other. And that screws up the conversion of velocity to distance.

* It's not really irresistible - it's relatively rare for galaxies to collide and merge**, but they do affect each other's velocity.
** Merging is even rarer - and considerably more unpleasant - for sumo wrestlers.

This is particularly bad in galaxy clusters, which are the equivalent not of sumo wrestlers, but a bunch of obese, angry rabid cats on a trampoline, possibly on fire - the Platonic ideal of chaos. Here, the velocity measurements tell us practically nothing about distance. Some galaxies are even coming toward us, which would give a meaningless, negative distance if we were silly enough to take Hubble's Law at face value. So the galaxy distances in the GIF are pretty good, but far from perfect. There's just no way around that, because better data doesn't exist.

Do the galaxies really look like that ?

No they don't. The images used are optical images from the Sloan Digital Sky Survey, but just because they were observed at similar wavelengths that we use to see with doesn't mean they look like what you'd see with your naked eye.

For starters, they're all much too bright. Think about what the Milky Way looks like on a clear, dark night. Does it really look like this ?

Hell no. The real thing looks beautiful, but nowhere near as bright or as colourful - not even in the darkest spot on the darkest night. Images like this are only possible with long exposures, or large telescopes. So out of necessity - because the video would show bugger all otherwise - the galaxies are shown much brighter than you'd really see them.

The colours aren't 'true' either. but that shouldn't bother you. Everyone perceives colour in a slightly different way - it's practically a subjective choice, rather than a measurement. And then, of course, some people are colourblind. The important point is that the colours are relatively correct - things which look bluer really are bluer than things which are redder.

EDIT : Since making the original, the Sloan Digital Sky Survey (which is where the galaxy images come from) updated their data processing techniques. The results make the galaxies look rather redder and blue features almost disappear - especially given the particular technique I'm using to display them in Blender. Fortunately, a bit of simple colour correction restored the galaxies to their former glory.

Left to right : 1) Raw image from the SDSS; 2) Galaxy as displayed in Blender without colour correction; 3) Galaxy displayed in Blender with colour correction.

This makes a very dramatic difference indeed for the whole set of galaxies. Here's what they would look like if I hadn't done the correction :

Flat, dull yellow. Drab, even. In the words of Bart Simpson, "Wow, the Universe is so boring !". Fortunately, that bit of colour adjustment brings out all the shiny details and stops it from looking a particularly unpleasant shade of beige.

A Universe rich in stars, galaxies, flying spaghetti monsters, etc.

What about the sizes of the galaxies ? Like brightness, these are exaggerated out of necessity, by about a factor of 40. That means that you can see the structures in many galaxies at once, without hoping that the viewpoint passes very close to them (otherwise you'd just see a bunch of small, uninteresting fuzzy blobs). However, as with colour, the relative differences are correct : a galaxy that looks twice as big as another really is twice its size.

One thing there was no need to compromise was the structures visible in the galaxies. Each of the 23,935 galaxies in the video is represented by an optical image of the actual galaxy seen at its location. This is pretty unusual - many of these large-scale videos often just use a few hundred template images. Here, there are unique images of every single blasted one. Don't believe me ? Here's the complete sample.

EDIT : This is from the original version of the post, which used a mere 11,710 galaxies. I can't be bothered to remake this.

View this in full, terrifying detail here.

Astute viewers may note that some of the images look strange. Unfortunately, there aren't any good estimates available for how wide the galaxies are. A large survey like this has most of the data processed automatically, and inevitably sometimes something goes wrong - especially on the large galaxies, which are often (incorrectly) broken up in the catalogue into several pieces.

I had a choice here. The first option was to carefully check all 11,710 23,935 images and make sure the galaxies were the correct size. This option was stupid, so I chose the second option, which was to ignore the problem completely.

Finally, we'll never know exactly what some galaxies really look like, because we're seeing them from a jaunty angle. We can correct for this to some extent, but only if we know the minimum and maximum dimensions of the galaxy. Which, for this sample, we don't. And if a galaxy is edge-on to us, there's nothing at all we can do except go home and cry.

In summary then, the video shows what you'd see if you had super-sensitive eyes and all the galaxies were forty times bigger than they actually are, with lots of errors. The large-scale structures of filaments and voids you see are correct, but not complete. That's a correctable problem, and one I might tackle at some point. But since downloading 11,000 images took about 8 hours, it can wait.

Surfing the Fiscal Glacier

For those who have been living in a swamp but have just returned to civilization desperate to catch up with Physicists of the Caribbean (there must be thousands in that situation, right ?) - the US government decided some time ago to agree to disagree. No-one could work out how to do spend all the money, so they more or less opted to just carry on as normal and try and work things out later - a multi-billion dollar, "meeeehhh", if you will.

This might, perhaps, have been a workable plan if the disagreements had been about whether the Capitol building needed an extra water cooler or not. Alas this was not the case. Firstly, for reasons that entirely escape me, the US is going for austerity measures even in a time when its economy is growing. That seems to me a good definition of shooting oneself in the foot, but since I admit to having all the financial acumen of a piece of runny cheese, I'll let it slide.

"Quick, burn it before the poor people can get it any !"

More importantly, while British politics suffers from being really quite breathtakingly dull*, American politics has the opposite problem. In Britain, the two sides will make token attacks on each other's policies, full of sound and fury but signifying nothing. Since these are often the policies they themselves were once calling for, this is rarely convincing. Differences between the parties have become almost Lilliputian.

* But see my earlier, somewhat desperate attempt to liven things up.

Not so in American politics. Here, it seems that everyone hates the other's guts and actively wants them choke to death on a live poisonous snake, or something. At least, that's the impression I get. It's as though every party member really believes that the other side broke their house and burnt their legs down, then raped their pets and murdered their family. Or something very similar.

Actually, this is much as the great Welsh politican Nye Bevan felt about the Tory party 50 years ago. The situation is probably worse here though, because the electorate are split almost exactly 50-50. On the one hand we have the Democrats, a fairly right-wing party by European standards, and on the other, the Republicans. These latter, as far as I can tell, are not so much a political party as they are pantomime villain rejects.

(that said, the Republicans may all be stark raving mad. but if you want to find some seriously messed-up politicians, look to India)

However, the these two groups of mortal enemies, who often seemed quite willing to physically throttle each other, decided that there was a way to reconcile their differences, for the good of the country. And that way was, metaphorically speaking, to lock themselves in an empty room with limited oxygen from which they could only escape by behaving equitably towards each other for several days. And remember, half of this group are bona fide insane.

The non-metaphorical, self-inflicted punishment was to be the fiscal cliff. This was a wonderful, all-inclusive, $85 billion dollar package of cuts to the economy that would hit automatically at some point if an agreement could not be reached. Absolutely no-one wanted this to happen - even the Republicans, who seem think that America deserves as many horses and bayonets as money can buy.

Well, surprise surprise, these two diametrically opposed forces just couldn't reconcile their differences, my goodness me, whoever could have foreseen this ? Still, they weren't about to risk messing with the economy, so with a mighty collective effort they decided to kick the can down the road a bit more. Thus, this is a slowly-advancing cliff : to wit, a glacier.

But not nearly as pretty, or as useful.

Unfortunately on the second or third attempt both sides called the other's bluff. Or to extend the metaphor, they both played chicken with a glacier and lost. This is a singular accomplishment, and really should win them both an IgNobel for economics, although possibly the economic equivalent of a Darwin Award might be better.

The fiscal glacier, then, has calved. For science this is particularly nasty, with the great hunk of icy funding that's crashed into the sea constituting about 8% of the mass of the whole frozen river (that link is worth clicking). So what happens next ? Do we sink, swim, or surf the impact wave to freedom ?

Look closely, and you'll realise how awesome this is.

My guess is none of the above. We'll probably tread water until we all die of hypothermia. Yay.

Beginner's Guide to the Universe

A few days ago I joined the Google+ space community and posted a timeline of the Universe I made a short while back. This proved a popular post, so perhaps it's worth a short overview.

Current thinking is that the Universe stated with a Big Bang about 14 billion years ago. It was very hot, got bigger and then cooled down. Stars formed. Stars became galaxies. Galaxies swirled around and kept crashing into year other. About 5 billion years ago, the solar system formed, though this is a minor detail only of interest to everyone on Earth and probably no-one else in the Universe gives a damn.

So, how do we know that this is true ?  Well, some parts we know definitely, some parts are very likely, and others are downright dodgy. Here I'll try to explain which is which. If you want to learn more, click on the links !

1) The Big Bang

Unfortunately, I begin with the statement that the Big Bang is the moment of creation. This is dramatic, but wrong. In fact, the Big Bang theory is about what happened immediately after that still-mysterious moment. Why the Universe decided to give the whole "existence" thing a shot is anyone's guess, so don't let me tell you not to believe that God / the Flying Spaghetti Monster / pure science wasn't responsible. They're all equally likely at this point.

Of course, it's well-known that fundamentalist religious types don't approve of the Big Bang, because the Universe was created when God sneezed sometime in October of 3000 BC, at some point after lunch but before mid-afternoon tea, probably on a Tuesday. Or something. Great*. Yet for a less prominent minority, the Big Bang is far too godly, because it allows room for a an initial divine spark. You just can't win.

*No, not really.

But I digress. The science case that the Universe was once a lot smaller and hotter than it is now is pretty strong, verging on overwhelming. We know that galaxies are all moving apart, so they must have been closer together in the past - that's just common sense. The Big Bang theory predicted the Universe should be filled with background radiaiton, which it is. It also does a pretty good job of explaining the chemical composition of the Universe.

A reassuring point is that the age of the Universe predicted by cosmological models is in agreement with other, independent constraints such as the age of stars. Since dwarf stars are predicted to be able to shine for trillions of years, we really ought to see such old stars if any existed. That we don't see any is a pretty good indicator that the Universe hasn't been around forever.

A final point here is that we're quite sure the Universe really is expanding, and it isn't that all the galaxies just happen to be rushing away from us, as though we were at the center of an explosion (that link has an excellent hands-on project for those who are really interested). Apart from the constraints of cosmological models, geometrical considerations also support this, and the Tolman test proves independently of all this that the expansion is real.

The Big Bang theory is not without problems - but the basic view of a small, hot Universe expanding into the one we see today is pretty sound.

2) Inflation

KABOOOOM !

That is the sound the Big Bang did not make around 14 billion years ago, because it wasn't an explosion in the conventional sense. What it was was a load of really hot material rushing apart at tremendous speed, which amounts to the same thing in many ways.

Explosions are messy. That much is just true. So it seems quite reasonable to expect that the Big Bang would also have been messy, even if it wasn't your typical exploding barrel of gunpowder. The big problem is that Universe we see today is just too damn boring. Or, to be more accurate, it's the same everywhere. Nothing but galaxies, galaxies, and more galaxies, wherever we look. YAWN.

In the immortal words of Bart Simpson..."Wow ! The Universe is so BORING !"

Seriously though, why is it so uniform ? How come we don't see huge parts of it filled with nothing but sheep* or old socks ? In fact, there's quite a lot of structure, but there's nothing that can't be explained by the simple action of gravity.

* Not counting some parts of Wales.

BAAA !

I exaggerated the bit about sheep, of course. The point is the structures produced in the expanding fireball of the Big Bang shouldn't look like structures only produced by gravity - so where are they ? Inflation gets around this tricky problem by saying that the very early Universe expanded very very very rapidly. This means that everything we can see is actually just a minute part of a single, much greater structure. The messiness is there - it's just much bigger than anything we can ever see.

And that's great, except that no-one knows what caused it.

Should that be worrying ? Well, yes, probably. Nonetheless, the evidence for a small, hot early Universe seems too strong for this to be a real concern. We know basically what happened, just not how or why. It's like having a confession from a murderer who doesn't give a reason - and the Universe is bloody complicated, so it doesn't seem at all unreasonable to me that it's going to take a long time to solve, if we ever do.

3) Galaxy Evolution

HAHAHAH !

I laugh because this is what I work on, and I'm only too aware of how controversial the whole thing is. But we do know some things. We know galaxies are very far away, so far it's taken their light billions of years to reach us (so long, Creationism). We also know that they interact with each other, but we've no idea just how important this is. The current line of thinking is that virtually everything can be explained by mergers, but this actually has so many problems I really don't know where to start. That could be a whole other post, at some point.

We are also dead certain that they are pretty.

Another thing we know is that galaxies have different properties depending on how far away they are (which on these scales is the same as how old they are), but it really doesn't matter where they are on in the sky. That's another nail in the coffin for the steady state theory, where nothing much should change over time.

I won't go into details of galaxy evolutionary theory, but it's worth pointing out that we have no idea what 90% of galaxies are made of. We know that they're rotating too fast, and should all fly apart without something else there to hold them together, but we haven't a clue what it might be (many ideas yes, but no evidence as yet). It's also possible that our understanding of gravity is wrong.

5) The Solar System

The solar system was probably formed around 5 billion years ago, based on models of stellar evolution and radioactive dating. These are independent methods which give pretty much the same result, which is always nice. The existence of elements which continuously decay by radiation is also another problem for poor old steady state theory. A Universe that's infinite in time and space really is quite difficult to justify these days.

But. as with everything else, there are still a lot of unknowns. We definitely do know that solar system formed, because we're here. But we're not even sure about some fundamentals as where the gas giants formed or even how many there were. There are also problems with simulations in forming the rocky planets. Yet for all that. we know there must be a solution, because now we know that planetary systems are common around other stars.


6) Dark Energy

Throw a sheep up into the air and will be very surprised, but it will likely come back down again amd run away. That is, unless you throw it upwards with enough speed to escape the gravitational pull of the Earth. In that case, it won't (which is a shame, because the heat generated by air compression would make for instant roast mutton).

This deserves to be everywhere.

The expansion of the Universe is no different, except that it doesn't go "baaa" and is less woolly. That is, by rights the expansion of the Universe ought to slow down, and then it ought to start contracting. That's because everything has mass, and mass means gravity which tends to pull things together.

Even if the unfortunate sheep were put inside a rocket and shot straight up at escape velocity, the unexpectedly intrepid mammal would find itself forever slowing down once the rocket had exhausted all its fuel. It's just that its speed would drop more and more slowly each day, so, although if you waited long enough, it would slow to a crawl, it would never actually stop. Sort of like Zeno's Paradox, only with rockets and sheep instead of Achilles and a tortoise.

Unfortunately, the expansion of the Universe is not slowing down. It appears to be speeding up.

This is allowed by the Einstein's laws of gravity, which is nice. The problem is that no-one knows what the physical mechanism causing the speedup is. It could be some completely unexpected force, or even just a total illusion. It's probably still too early in the game to tell.



Well, that's all I've got. Of course, everything I've just said is a massive oversimplification, but the links contained therein are much better, Inasmuch as I have any conclusions, I suppose they'd have to be the following :

- Anyone who claims that all of modern science is wrong is... well, wrong.
- Anyone who claims that science can already explain everything and thinks there's no more important work left to do is a f***ing IDIOT. Slap them.

I Wanna Be A Pseudoscientist

Some of the greatest discoveries in science have come from crackpots with theories they've obviously thought of while smoking something illegal. Obvious, that is, at the time. With hindsight, X-rays, aeroplanes and rockets seem like very good ideas indeed, but no less an authority than Lord Kelvin poo-poohed X-rays and aeroplanes, while the New York Times decided that rockets couldn't work in space as there'd be nothing to push against.

But the most often-quoted "I told you so" moment concerns Alfred Wegener, who looked at the continents of the Earth and reckoned that they could probably all fit together pretty well. On the face of it, this theory is bloody stupid. Whole continents sailing about the world ? There there Wegener, be a good chap and pass the opium.

Also, he was a vampire.

Of course, he turned out to be dead right. Unfortunately, every crackpot under the sun now uses this to justify their own stupid theories. Much as "Godwins Law" means that anyone trying to draw comparisons to the Nazis instantly looses the argument, so we also need some sort of Wegenerian law to stop lunatics comparing themselves to the genuinely misunderstood Wegener.

Some examples. As as scientist I get fairly regular emails (and occasionally real post) about revolutionary new theories. It's an occupational hazard. The latest is an extremely badly-written and very boring website which can be viewed here. You don't want to though. It's dull. I've no idea if some poor sod has genuinely taken the time to invent a new and pointless theory or if it's just some massively elaborate scamming routine.

Then of course there's the notorious TimeCube, where a very angry man has decided that
a) Everyone is evil apart from him and
b) Something about days being made up of 4 different days happening simultaneously, or something.
I don't know what he's talking about and no-one else does either.

But my all-time favourite has to be the downright strange Space Mirror Mystery. This very well-designed but badly-worded website espouses the theory that there's a giant mirror, 300 million km wide, surrounding the Earth. Nothing exists further away than this, it's all just reflections in the space mirror (I can think of 7 spacecraft off the top of my head further away than this, but never mind). The best bit is that you can download "items" 1-4 for free, but to get item 5 (whatever that is) you have to pay a very specific $101.

Which is why I want to be a pseudoscientist. Not for them the drudgery of sifting through data, endlessly analysing and re-analysing in the hope of making an iota of progress. They don't have to toil away, re-writing the same damn thing over and over again in different ways, or give Power Point presentations to anyone, or have to worry how much it will cost them to publish a paper with colour figures. No, for them it's much easier to claim that it's all bollocks and blame it on the Moon*, or Nazi space werewolves or whatever.

* In the case of astrologers I mean this literally.

This sounds a lot more fun to me. Screw astronomy. I think I'll be the world's first radio astrologer. Sure, we know all about planetary influences, but what about distant quasars ? If Jupiter rising in Scorpios can cause you to feel slightly put-out for a few days, what happens when the Crab pulsar is directly overhead ? Does it make your natural sense of timing much much better ? Does a very bright continuum source cause you to feel all wibbly ? What about when an GPS satellite - which is much brighter than any natural sources - moves through your star sign ?

The last one is obvious - the US government is bent on using the mystical energies of GPS satellites to control the destiny of everyone on Earth. Hell, those jerks are probably using ley lines as well.


EDIT : I drafted this a while ago but it slipped off the front page and I forgot to publish it. Alas, the "space mirror mystery" website no longer functions, so I replaced the link in the text with a webarhive version - fortunately this contains about 90% of the original material.