Summer with the open windows: 4. A rotation of blankets

IV. A rotation of blankets

I remember in Santa Cruz when I bought my first real comforter. It felt like a monumental investment. We drove to Ross on River St.; my roommate waited while I deliberated in the “Home” aisle.

I was down to $140 in my bank account, from $2000 when I first arrived. But I had a job, finally, and had just received my first paycheck. At night, I slept in a sweatshirt and jeans on the floor of my attic room which I rented for $500 a month, wrapped like a burrito in my one thin blanket, which served as padding and cover.

But the fog had come in, the nights were actually cold now, and the rains had started.

At Ross I picked out a white comforter, for $29. That night I didn’t sleep in my sweatshirt. The next morning, I woke up warm for what felt like the first time in a long time.

I spent the fall nights out on the slanted roof of the house which sloped away from my window, which looked to the south, to the sea. Life, then, felt as big as the winter sky. I tried to find my way around it, starting at the belt of Orion, up to the eye of Taurus, through the Pleiades cluster bluish and pale, until the dark, hard edge of the rooftop. I felt myself at the helm of a ship at sea, navigating by the stars, seeing in the random patterns of light and dark a ladle, a dog, a Greek hero carrying the head of a monster, a rock, a bull, a queen…

Sometime around midnight, I would reach over to the window sill and pull the covers over my knees.

The summer with the open windows, saw a rotation of blankets. That Boston summer was busy with storms, which announced themselves by a sudden darkening of the sky in the west, then arrived with a billowing of a curtain. And when the rain came at an angle it would wet a particular patch of rug or linoleum.

The old Ross comforter, a bit yellowed by now, on the colder nights, played a part. But most of the time it sat in a heap between my bed and the wall, with the rest of the spare bedding. This fall it went out, finally, in a bag of old clothes and linens I left on the curb for the Salvation Army.

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It’s morning and I haven’t had any coffee yet.

Summer with the open windows: 3. The heat

III. The heat

12am, and it was still 85 degrees. Two fans ran on high, positioned at opposite ends of my apartment, but not a lick of wind it seemed. There were only so many cold showers, only so dark one could keep the room. From my fire escape, I thought I could see the heat, clinging like a net to the city; the air was gelatinous.

I deliberated, then I threw on a shirt, the only place to go was lab.

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Read this too, though it’s short, just for sake of completeness.

Summer with the open windows: 2. The situation with the maggots

II. The situation with the maggots.

Mid-July: flies. It started one Saturday when I was cleaning. I swatted at them with my rag, chased them around the kitchen with a Lysol spray bottle, and took a few down. But soon more came through the hole in my screen. After dinner one evening Larisa rolled up a magazine and went to work with a business-like ferocity I’d only seen once before in my mom, in her early forties, when late one night I went to the kitchen of our one-bedroom apartment for a glass of water, and under the one bare light, found her smashing cockroaches with a vengeance, armed with a shoe.

In the days that followed it seemed that Larisa had eradicated the fly problem. I put tape over the hole in the screen.

Then: a smell. The trash needed tending, I thought; I lifted the lid. A mass of maggots moved on the underside. I had disturbed them, had turned the light on. They blinked and twisted anxiously. Several dropped to the kitchen floor.

For a minute I stood there with the lid in my hand and my mind completely blank. Then, I turned my apartment over. What the hell kills maggots? I sprayed them with Lysol; they kept moving. I tried to squish them with a paper towel but lost heart on the approach. Finally, I emptied a bottle of acetone into the underside of the lid. Did they dissolve or drown? Did I get them all? I washed everything with OxiClean. Then I mopped and re-mopped the floors. And mopped them again. For the next few days the trash bin lived in the stairwell, just in case.

Was it over? No, it was not. A week later: Baby flies.

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Sorry for laughing. It was so gross.

Summer with the open windows: 1. J.P. Licks

In May of last summer, on a sunny, windless day, I threw open all the windows in my third floor apartment. It wasn’t meant to be some kind of experiment, at first; winter had been interminable, the spring had hurried by. My finals over, I was happy, hopeful. I was cleaning.

That night as I ate dinner and read by the window, a wind kicked up and blew my papers clear across the room. It was as if a passage was opened, from one end of my apartment to the other. The breeze persisted all night, and I liked the feeling, of the outside inside, of the hard outline of my little apartment blurred, so I kept them open. I finally closed the windows end of September, when there was no more denying that the seasons have turned. These are some stories from that summer.

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I. JP Licks

JP Licks, by nature, is an outdoor cat. When my parents found her in their backyard in the summer of 2008, she was with a boy cat from her litter. They were two skittish, starving little things, probably not 3 months old, climbing trees, digging up gophers, wrecking my mom’s vegetable garden. Every day, teeth marks on the plants, poop in the flower pots, ripped up grass and little rat skulls scattered around the yard.

One morning, I get a call at school. “Do you like cats,” my mom asked. I took them both.

Maxwell, the boy cat, died age 6 months. A girl in my dorm, on the 4th floor of the building, had fallen in love with him. Then, one day, he fell, too, out her window, onto the concrete outside.

Maxwell was the only cat friend JP Licks ever had, but she kept up the habit of going outside, anyways, on her own. She was happiest in San Francisco, after I graduated, where I lived on the first floor of a little row house near the ocean. The door to the backyard I left open, every day, pretty much all year round. From there she could hop the fence to the neighboring yards, and from there, get out to the park, if she liked. I never did find out what she did all day but when I called in the evenings she would come running. Next morning, she’d be by the door again, waiting.

One day, JP Licks was sick with a fever and stayed in bed all day. In the backyard, through the window, just that once, I saw a perfect white cat, long-haired and unmoving. It just sat under our tree and stared at our door.

Then I came to Boston, and my apartment is so small and winter so cold that JP Licks took to sleeping 15 hours a day. The first chance I got, I let her out my window. The fire escape in the back of the building starts at my window, connects the three floors of apartments, and ends at the pavement below. But it’s a skeletal structure, narrow and high, with a huge gap before each stair and bolts that appeared to be pulling out of the wall. Every time I climbed out there, at first, visions of plunging headfirst into the ground were all I could manage, and my cat, too, I assume, since she refused to step out onto the grating. Rather, for days, she sat on a wood board in the corner of the platform, in the sun, and took it all in.

Then, gingerly, inspired by some moth or mouse or bird below, she took her first step.

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Late reading update. Sorry

Ring of Charges

A single charged particle moving in uniform circular motion undergoes centripetal acceleration and radiates light. The phenomenon is well-understood. A charged particle spit out in a jet by a supermassive black hole glows with this light. The Advanced Light Source at UC Berkeley exploits this light. And this light was missing from the atom, invalidating the Bohr theory of electron orbits.

But it’s also well-known that a conducting ring sustaining a constant current, such as a superconducting coil below the transition temperature, does not radiate, though it’s just a superposition of many of these single charges, arranged in a symmetric way. This latter case can be understood as a statics problem. If the ring is modeled as a continuous charge density, its configuration at any point in time cannot be distinguished from any other point in time, therefore, the fields also cannot change. Static fields do not radiate.

I wanted to understand how the transition happens, how, as we add more particles, the light turns off.

Using the equation for the electric field derived from the Lienard-Wiechert potential for a radiating point charge in the non-relativistic limit (Jackson E&M), I plotted the field at a considerable distance from the sources (x,y)=(5,10). As I was only interested in the dynamic component of the field, the plotted values have their means subtracted.

Here’s the field for one charge:

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Two charges, evenly spaced:

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Three charges:

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Four charges:

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Five charges (here we’re starting to run into MATLAB’s floating point number precision limit):

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The single charge case can be understood as a rotating dipole, confirmed by the radiation pattern. Add a second charge and we’ve canceled the net dipole moment, only a quadrupole remains. The magnitude of the field is reduced by some factor involving v/c. The next order in the multipole expansion is an octupole, with the magnitude of the field further reduced by the same factor. We see this geometric progression as we add more charges:

Another thing to notice is that a ring of N charges has N-fold rotational symmetry and the period of the emitted radiation is reduced by a factor of N in each case. As N approaches infinity, the ring approaches a continuous charge density and both the amplitude and period of the emitted radiation go to zero.