tom thinks

date 2000-11-27:11:08
Physics We aren't supposed to tell you about this part.

In all probability, there isn't supposed to be a this part. We aren't supposed to feel this way. Physics is supposed to be dry as dust, and physicists aren't supposed to have a drop of romance in their souls. How they let me in is beyond me, but they did. It changed me. This is part of how. Some of what follows is not exactly true, but it isn't exactly false, either.

To what in reality does FICTION refer?

Imagine a large, high-ceiling'ed room, all in dun-painted concrete, full of ancient computers, lit in harsh, broken strips by elderly fluorescent lights. Near the center of the room is the open "C" of the control panel, a right-angle of dials and gauges.

The open side of the "C" faces a wall full of computer; that's "computer", singular, and it fills the full wall, rack upon rack of electronics with tens of transistors per chip. You can trace the flow of data by eye--at one end the electronics racks contain custom modules that amplify the signals coming from detectors in the target room, then shape the signals and taste them to see if they are good. If they pass the tests they get digitized and fed into the computer's maw, where they'er masticated and corrrelated and finally excreted onto the big reel of 1600 BPI tape at the far end, just like on a computer in the old movies.

The data come in slowly--not many events taste good to the front-end electronics; most get spat back into the electronic void. There's a little computer there, like a pilot fish hanging around the mouth of a great shark, catching its leavings, eating everything, cleaning up the sea.

In the midst of all this there's a cot that's even older than the computer, and certainly better used. It's stained by the daliances of graduate students now middle-aged with girls they never married, but it's a place to lay your head during the long hours of the night, while the data comes slowly in.

Only time conquers statistics, and the data comes in slowly. We can't make the universe do what we want--we can only make certain outcomes more likely, then sift through the stream of events, looking for the ones we want. Sometimes totally different events can taste the same, like someone adding aspertame to flavor their coffee. When that happens, it's called "background", those events you can't filter out because they're too similar to what you're looking for.

This experiment started life with a background of the worst kind, events that looked identical to those expected but that were unrelated to the processes we cared about. A mistake in a calculation--a dropped negative sign, the bane of engineering--had predicted the signal would be about the size of the background, and no one had realized the background process was there. The real signal was over ten times smaller, and they were measuring almost nothing but background without knowing it.

I'd found the background, and redesigned the experiment to filter it out before it ever became a problem, but at a considerable cost in rate. I had to throw away a lot of the events I wanted to eliminate most of the background events. So the data came in slowly, and the tape went "CLUNK" every ten seconds or so as a new record was written, more events to process later, off-line.

The hum of the fans and the irregular "CLUNK" of the tape kept me company through many nights--we used to run for a week at a time, twenty-four hours a day, slowly accumulating statistical significance. Other students, and sometimes profs, stood watches for me during the day, as I did for their experiments, though I got much more than I gave from that arrangement. But I took most of the night watches, as did Sean on his experiment, which ran even longer than mine.

I used to drag the cot out into the middle of the control room, into the "C" of the control panel, so I could keep half an eye on things in a half-sleep. Every four hours or so I'd have to get up and check the liquid nitrogen in the detectors and the cooling water for the pumps. Sometimes the beam needed adjustment, and more than once the machine would go through some fluxuation and the beam would go off target and alarms would start beeping, rousing me from half-sleep, fiddling with the controls before I was even properly awake. I can do a lot of stuff while not exactly conscious--the one thing I can't do is talk, but by the time I had the problem sorted out I was usually awake enough to write it up in the run log.

On one occassion the janitor came banging through at about 2 am, scaring the hell out of me. This happened to other students as well--problems with machinery we expected and dealt with calmly; a person appearing suddenly and noisily from nowhere was more than enough to get my heart racing.

Waiting is hard. But you get used to it, you become skilled at it. This skill has stood me in in good stead in other times.

And you get used to the idea of putting the universe into a state where some outcomes are more likely than others, and getting ready to catch the one you want like a snowflake on your out-stretched tongue as it falls gently from the winter sky.
Play Anything that involves twin fountains of water spraying unexpectedly up in my face surely qualifies as play.

Jan has redone the downstairs bathroom, which some previous owner of the house felt ought to be decorated with extremely pink pin-striped wallpaper. It didn't look good. She stripped the old wallpaper and put up some textured vinyl wallpaper that she then painted a nice creamy gold color, with a cute border with dancing sandpipers. The sink, however, was still a mess--the drain leaked, it was barely fastened to the wall, and the tap was very hard to turn off.

Because we are on a well drilled in limestone, our water has a mineral content only slightly less than that of a hard-rock mine. It follows from this that the valves to turn off the water to the sink were completely gummed up with calcium deposits, so the first thing to do was replace them. The plumbing is all nearly thirty years old, like the house itself, and so done in the days before swagelock became common. So the valves were soldered on and had to be desoldered.

I turned main valve to the house off and opened the laundry-room taps to drain what I could out of the system. I thought they were lower than the pipes I was working on. I then disconnected the sink from the valves and found they weren't--there was the most remarkable dual fountain that developed about ten seconds after I had the sink cleared out of the way. There must have been some vapor lock in the system that took a few seconds to let go, maximizing the mess created by the subsequent flood. If the sink had still been in place, the water would have just bounced off the bottom of it. As it was, the stuff sprayed about four feet into the air and distributed itself nicely all over the room, spattering the walls and, of course, me.

The kids thought this was pretty funny. Jan got me bucket while I held my thumbs over the pipes, and in fact the system drained out pretty quickly. I then pulled the stems out of the valves to let them drain out properly and desoldered them. Alex was a bit shy of the torch, so I cajoled him in to stand beside me and let him put his hands on it while I desoldered the second one, letting him get the feel of it and understanding that it wasn't going to hurt him if he treated it properly. Paying attention to what you're doing is the important thing--I recall a student in shop-class who carelessly put a torch on a shelf under the bench he was working on while it was still lit, setting fire to himself in the process. Fortunately, those shop aprons don't burn very well.

I swaged the new valves on, and was delighted to find they didn't leak when I turned the main water back on, very slowly. I've been cautious about water-hammers since blowing out a newly soldered elbow-joint on a copper pipe as a teenager, spraying a truly amazing quantity of water across the room in seconds. I don't think I've ever actually done a plumbing job that didn't involve water spraying all over the place at some point.

Remarkably, almost everything fit. Plumbing "standards" are highly individual. Every company does things a little bit differently, just as in software there are the standards industry agrees to and then there are the "standards" Microsoft or Sun or whoever actually implements. One of the good things about the software bazzare is that there really isn't any choice but to implement the actual standard, because there isn't anything else people can agree on. Plumbing needs this too.

The only mismatch turned out the be in the nuts that connect to the new faucet. They are about a millimeter shorter than they need to be, and after fifteen minutes of screwing around I concluded that rather than using the old ones I should get ones from the manufacturer of the fittings I'm using (Moen) and see if they work any better. So the sink is still non-functional, but it's further along that it was, and any progress in plumbing at all is something to be celebrated.

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