Archive for September 12th, 2012
Here is a handy, sometimes whimsical (but always as accurate as I could manage) comparison between two of my favourite scientific endeavours (now version 1.1, with changes detailed in a new post, along with a HTML table version with all the notes visible.) It is too cluttered with information to be a good infographic, so I’m calling it a TMIGraphic. Click on the image for a higher-resolution pdf with links and copious notes. It’s best if you save it and open it in a pdf reader rather than viewing it in your web browser, as the notes didn’t show up in the browser I tried. Click on each information box for the primary or most readable reference, and click the note icons for more explanations, references and interesting links. If you can’t see the note icons in the pdf, or if clicking on them doesn’t do anything, let me know and I’ll try to figure something out; the notes are important.
I’ve wanted to do this for at least three years; I think it started with wondering which was cooler, and immediately answering myself with the relevant temperatures. When I started this round of Writing Cards (and not so much Letters) I thought I’d work on it slowly throughout the year, then finish it when the appropriate cards came up in one of the NASA decks and the CERN deck in the same week. This didn’t work for two reasons: every time I started to work on it slowly (and also, when I first came up with the idea of doing it as an infographic a year or so ago) I got stuck on the vacuum pressure outside the ISS. And even though the week’s CERN card is about LINAC-1, the NASA card seemed like a challenge that I couldn’t resist. Is the International Space Station really the largest, most complex international cooperative science and engineering program ever attempted? Well, I don’t want to choose a favourite. Let’s just say the Large Hadron Collider is the largest, most complex international cooperative science and engineering program on Earth, and the ISS is the largest, most complex international cooperative science and engineering program in space.
This took longer than my usual deadline of a week, but not through procrastination. Also not so that it would be released four years and two days after the first beam went through the LHC, though I’ll use that as an excuse if it helps. Almost every one of those numbers took quite a bit of effort to get right, and you’ll see in the notes in the pdf (that’s the old pdf, corresponding to the TMIGraphic pictured; here‘s the most recent one) that most of them come with various caveats and explanations, because nothing is simple. I’ll have to update some pages in wikipedia after this. I’m certain I still have some things wrong; maybe some obvious things. Please point them out, and I’ll fix them in the next version. Also, feel free to tell me how bad my layout is, iff you have a better suggestion. I know this is not perfect yet and I intend to keep working on it. If you have ideas of information to add, I’d like to hear that too; especially if you have leads on where to get that information. I can provide the original OmniGraffle document if you want to make your own changes, but I’d have to clean it up a bit first; there are a few things that I just made invisible rather than deleting.
The vacuum pressure outside the station gave me the most trouble; I’d hoped it would be a simple equation, or a statistic NASA would publish on their general ISS fact pages, but mainly I just found statements that the pressure inside the LHC beam pipe was the same as at 1000km altitude. For ISS orbit I found values or equations around the place suggesting values that differed by a factor of a billion, and nothing that seemed convincingly more authoritative than the others. Finally, via the Wikipedia page on orders of magnitude of pressure, I found a NASA document with the numbers for 500km, so I used those. It actually varies by a factor of 20. This is still at least 70km higher than the station, so outside the station it’s more likely to be toward the higher end of that range; that is, a less perfect vacuum than inside the LHC beam pipe.
I also had some technical difficulties with the presentation (apart from the clutter and my lack of graphical talent or training.) Firstly, I’m sorry if colour-blind people have trouble distinguishing anything. I wanted to use a colour-blind safe palette, but the paler colours wouldn’t have had enough contrast with white to work with the style I’d chosen. The colours of the information boxes are not essential anyway; they just group them into broad categories and might make it a bit easier for people to find the corresponding information about the ISS or the LHC.
As for finding the corresponding information boxes about the ISS and LHC, it’s really not optimal. There’s a tangled mess of dashed lines connecting them which is really no more functional than background decoration. I thought of making each info box link to the corresponding one on the other diagram, but although that worked in OmniGraffle, in a pdf viewer it did not zoom in enough on the linked box to make it sufficiently obvious which one you’d just jumped to. I also would have liked to make the links in the notes clickable, and add images to some of them. Again, this was possible in OmniGraffle but not in pdf. I’m not sure if there’s a common format that allows all these things.
So, after all that, the important question: Which one would win in a fight?
Of course it depends what the fight is, and here’s where you can get creative. In a weight-loss competition such as The Biggest Loser, I think the ISS would win, having lost about an eighth of its weight by going up to 426km altitude. Though the LHC did lose a fair bit of helium at one point. Meanwhile, the ISS literally runs rings around the LHC, and would certainly win the high jump. If you have an idea, feel free to comment here or, as the TMIgraphic says, tweet it with the #ISSvsLHC hashtag. Maybe it’ll catch on.
As for the ultimate winner, I’ll let Wil Wheaton have the last word. Science. SCIENCE!
Update: I heard back from my friend who had information on the LHC tunnel temperature (actually the temperature of the LHCb cavern, but it should be about the same), and updated that. I also added information in the notes about the exhibition on the AMS detector which you can come see at CERN Microcosm at the moment, and nudged a few things inwards so the preview is a little narrower. If you’ve gone through all the notes in the old pdf you might already have seen this talk given at CERN by the astronauts who installed the AMS on the International Space Station. I was there, and I wanted to ask (for the purposes of this comparison) which they thought was the most awesome out of the LHC and the ISS, but I was in one of the few spots without a microphone.
One thing I’d been meaning to mention is that the path to ‘orbit’ of both things starts with a proton and continues with a booster. The first module of the ISS was put into orbit using a Proton rocket, and many of the rest were taken to orbit on the space shuttle, with its solid rocket boosters. In the LHC, it’s the particle called a proton and the Proton Synchrotron Booster which accelerates it as part of the journey to the LHC.