Above The Air, Below The Red

Vinnie and I walk into Al’s coffee shop just as he sets out a tray of scones. “Odd-looking topping on those, Al. What is it?”

“Dark cherry and dark chocolate, Sy. Something about looking infra-red. Cathleen special-ordered them for some Astronomy event she’s hosting in the back room. Carry this tray in there for me?”

Vinne grabs the tray and a scone. “Sure, Al. … Mmm, tasty. … Hi, Cathleen. Here’s your scones. What’s the event?”

“It’s a memorial symposium for the Spitzer Space Telescope, Vinnie. Spitzer‘s been an infra-red workhorse for almost 17 years and NASA formally retired it at the end of January.”

“What’s so special about infra-red? It’s just light, right? We got the Hubble for that.”

“A perfect cue for Jim’s talk. <to crowd> Grab a scone and settle down, everyone. Welcome to our symposium, ‘IR , Spitzer And The Universe.’ Our first presentation today is entitled ‘What’s So Special About Infra-red?‘ Jim, you’re on.”

“Thanks, Cathleen. This is an introductory talk, so I’ll keep it mostly non-technical. So, question for everybody — when you see ‘IR‘, what do you think of first?”

<shouts from the crowd> “Pizza warmer!” “Invisible light!” “Night-vision goggles!”

“Pretty much what I expected. All relevant, but IR’s much more than that. To begin with, many more colors than visible light. We can distinguish colors in the rainbow because each color’s lightwave has a different frequency. Everybody OK with that?”

<general mutter of assent>

“OK. Well, the frequency at the violet end of the visible spectrum is a bit less than double the frequency at the red end. In music when you double the frequency you go up an octave. The range of colors we see from red to violet is less than an octave, about like going from A-natural to F-sharp on the piano. The infra-red spectrum covers almost nine octaves. An 88-key piano doesn’t even do eight.”

<voice from the crowd, maybe an Art major> “Wow, if we could see infra-red think of all the colors there’d be!”

“But you’d need a whole collection of specialized eyes to see them. With light, every time you go down an octave you reduce the photon’s energy capacity by half. Visible light is visible because its photons have just enough energy to cause an electronic change in our retinas’ photoreceptor molecules. Five octaves higher than that, the photons have enough energy to knock electrons right out of a molecule like DNA. An octave lower than visible, almost nothing electronic.”

<Vinnie’s always-skeptical voice> “If there’s no connecting with electrons, how does electronic infra-red detection work?”

“Two ways. A few semiconductor configurations are sensitive to near- and mid-infra-red photons. The Spitzer‘s sensors are grids of those configurations. To handle really low-frequency IR you have to sense heat directly with bolometer techniques that track expansion and contraction.”

<another skeptical voice> “OK then, how does infra-red heating work?”

“Looks like a paradox, doesn’t it? Infra-red photons are too low-energy to make a quantum change in a molecule’s electronic arrangement, but we know that the only way photons can have an effect is by making quantum changes. So how come we feel infra-red’s heat? The key is, photons can interact with any kind of charged structure, not just electrons. If a molecule’s charges aren’t perfectly balanced a photon can vibrate or rotate part of a molecule or even the whole thing. That changes its kinetic energy because molecular motion is heat, right? Fortunately for the astronomers, gas vibrations and rotations are quantized, too. An isolated water molecule can only do stepwise changes in vibration and rotation.”

“Why’s that fortunate?”

“Because that’s how I do my research. Every kind of molecule has its own set of steps, its own set of frequencies where it can absorb light. The infra-red range lets us do for molecules what the visual range lets us do for atoms. By charting specific absorption bands we’ve located and identified interstellar clouds of water, formaldehyde and a host of other chemicals. I just recently saw a report of ‘helonium‘, a molecular ion containing helium and hydrogen, left over from when the Universe began. Infra-red is so cool.”

“No, it’s warm.”

Image suggested by Alex

~~ Rich Olcott

The Sight And Sound of Snow

<ring> “Moire here.”

“Uncle Sy! Uncle Sy! It’s snowing! It’s snowing!”

“Yes, Teena, it started last night after you went to bed. But it’s real early now and I haven’t had breakfast yet. I’ll be over there in a little while and we can do snow stuff.”

“Yaaay! I’ll have breakfast, too. Mommie, can we have oatmeal with raisins?” <click>


<knock, knock> “Uncle Sy! You’re here! I wanna go sledding! Get my sled out, please?”

“G’morning, Sis. G’morning, Teena. Get your snowsuit and boots on, Sweetie. Want to come along, Sis? It’s a cold, dry snow, not much wind.”

“No, I’ll just stay warm and get the hot chocolate ready.”

“Bless you for that, Sis. OK, young’un, ready to go?”

“Ready! Pull me on the sled to the sledding hill, Uncle Sy!”


“Ooo, it’s so quiet. Why’s it always quiet when snow’s falling, Uncle Sy? Is the world holding its breath? And why is snow white? When I hold snow in my hand it melts and then it’s no-color.”

“Always the good questions. Actually, these two are related and they both have to do with the shape of snowflakes. Here, hold out your arm and let’s see if you can catch a few. No, don’t try to chase them, the breeze from your arm will blow them away. Just let them fall onto your arm. That’s right. Now look at them real close.”

“They’re all spiky, not flat and pretty like the ones in my picture book!”

“That’s because they grew fast in a really cold cloud and didn’t have time to develop evenly. You have to work slow to make something that’s really pretty.”

“But if they’re spiky like this they can’t lay down flat together and be cozy!”

“Ah, that’s the key. Fresh spiky snowflakes make fluffy snow, which is why skiers love it. See how the flakes puff into the air when I scuff my boot? Those tiny spikes break off easily and make it easy for a ski to glide over the surface. Your sled, too — you’ve grown so big I’d be hard-put to pull you over wet snow. That fluffiness is why <hushed voice> it’s so quiet now.”

“Shhh … <whispered> yeah … <back to full voice> Wait, how does fluffy make quiet?”

“Because sound waves … Have we talked about sound waves? I guess we haven’t. OK, clap your hands once.”

<CLAP!>

“Good. When your hands came together they pushed away the air molecules that were between them. Those molecules pushed on the next molecules and those pushed on the next ones on and on until they got to your ear and you heard the sound. Make sense?”

“Ye-aa-uh. Is the push-push-push the wave?”

“Exactly. OK, now imagine that a wave hits a wall or some packed-down icy snow. What will happen?”

“It’ll bounce off like my paddle-ball toy!”

“Smart girl. Now imagine that a wave hits fluffy snow.”

“Um … it’ll get all lost bouncing between all the spikes, right?”

“Perfect. That’s exactly what happens. Some of the wave is scattered by falling snowflakes and much of what’s left spreads into the snow on the ground. That doesn’t leave much sound energy for us to hear.”

“You said that snow’s white because of what snow does to sound, but look, it’s so bright I have to squint my eyes!”

“That’s not exactly what I said, I said they’re related. Hmm… ah! You know that ornament your Mommie has hanging in the kitchen window?”

“The fairy holding the glass jewel? Yeah, when the sunlight hits it there’s rainbows all over the room! I love that!”

A beam or white light passing through two prisms.  The first produces a spectrum and the second remixes the colors to white.

“I do, too. White light like sunlight has all colors in it and that jewel splits the colors apart so you can see them. Well, suppose that jewel is surrounded by other jewels that can put the colors together again. Here’s a picture on my cellphone for a clue.”

“White goes to rainbow and back to white again … I’ll bet the snowflakes act like little jewels and bounce all the colors around but the light doesn’t get trapped and it comes out and we see the WHITE again! Right?”

“So right that we’re going home for hot chocolate.”

“Yaaay!”

~~ Rich Olcott

PS – A Deeper Look.

Solving Sleipnir's Problem

Vinnie leans back in his chair, hands behind his head. “Lessee if I got this straight. The computer’s muscles are its processors. It can have a bunch of them, different kinds for different jobs like a horse has different muscles for different moves. Computers got internal networks to connect the processors like a horse has tendons and ligaments. Me and Sy got a beef going about the bones, whether it’s data or memory ’cause nothing happens without both of ’em. That a good summary?”

“That’s about the size of it.”

“So what was that crack about some eight-legged horse being the most interesting case?”

Sleipnir image adapted from the Tjängvide runestone
from Wikimedia Commons under CC 4.0 license

Robert grabs a paper napkin. Coffee shop proprietor Al winces. “Consider the kangaroo. It has two legs and it uses both at the same time when it hops around. I’ll diagram its feet with 1 and 2 and color them both red, OK?”

“Kangaroo hopped through some red paint, gotcha.”

“A human has two feet and we alternate between them when we walk. Like this second pattern — red foot, blue foot, over and over. Then there’s your standard horse with four legs — many more possibilities, right? For one, the front pair and the back pair each can act like a simple walk but independently, like the third row here.”

Meanwhile, I’m fiddling with Old Reliable and find this video. “That’s a good description of the basic gait that the horsemen call the walk, no surprise.”

Vinnie’s looking at the video over my shoulder. “Huh! Look here at the trot. The front and rear legs on opposite sides work together but in-between the beat of the other pair. I suppose you’d draw it like this fourth sketch, right?”

“That’s the idea. I’m only keeping track of which feet get used at the same time or opposite times. I’m sure there are other combinations that don’t fit the two-color model.”

Vinnie’s still watching the video. “Say this one. The gallop is like it’s walking with its front feet and kangarooing off that beat with its back ones.”

“Well, there you go. On to my point. Sy, what’s a horse’s most important decision if it’s not going to trip up?”

“Which foot it’s going to move next, I suppose. Oh, I see where you’re going. Odin’s eight-legged horse would have a serious coordination problem — which legs to pair together and what order they’d work in.”

“Exactly. No surprise, a computer has the same coordination problem unless it’s extremely specialized. As soon as you have multiple tasks demanding service, yet another task has to direct traffic. That’s basically where operating systems come into play. An OS has low-level code that stands between the application programs and the hardware resources.”

“What’s it doing there besides getting in the way?”

“Simplifying things, Vinnie. You don’t want to recode your program or buy a new version of your spreadsheet software when you plug in a new hard drive. When your application issues a call to transfer some data to or from your hard drive, the OS translates that into bit-level instructions the hard drive understands. A different device from a different manufacturer probably uses different command bits. No problem, your OS satisfies your next I/O call with whatever instructions that device understands. But an OS does more than that.”

“Like what else?”

“Lots of things. Security, for one — it makes sure you’re authorized to logon and touch certain data. Network interfacing for another. But for system performance the critical OS functions involve choosing who gets how much resource to work with.”

“Like disk space? I keep hitting my limit in the Cloud.”

“The Cloud’s a whole ‘nother level of complicated, but yeah, like that. The OS addresses performance by managing CPU time, throttling back low-priority tasks to give more time to high-priority work.”

“How’s it know the difference?”

“Depends on the OS. Generally it boils down to a list of privileged program names and user-ids versus everyone else.”

“How’s it do the throttling?”

“That also depends on the OS. Some of them meter out time slices, others fiddle with dispatch priority. Tricky business.”

“Tricky as running an eight-legged horse.”

~~ Rich Olcott

Memories: The Corners of Your Mind

Vinnie doesn’t let go of a question. “OK, Robert, I got that a computer’s internal network is sorta like a horse’s sinews, tying muscle and bone together. An’ I got that a computer’s processors of whichever kind are like a horse’s muscles. But what does for a computer what bones do for a horse?”

“The ‘bones’ are a bit of a stretch, Vinnie. Data’s one possibility, memory or storage is the other one.”

Vinnie takes the bait. “Horse muscles move horse bones. The processors move data, so data’s got to be the bones.”

For the sake of argument, I come back. “But when the electricity turns off, the data goes away, right? Memory’s still there, so memory must be the bones. Or is it storage? What’s the difference between memory and storage?”

“You’ve put your finger on it, Sy — persistence. If the data’s retained when the power’s off, like on a hard drive, it’s in storage. Otherwise it’s in memory. Setting aside power glitches, of course — a bad glitch can even kill some kinds of storage and the data it’s holding, which is one reason for doing backups. As a general rule, memory is smaller, more expensive and much faster than storage so there’s a trade-off. If you want a lot of speed, load up on fast memory but it’ll cost you cash and resilience.”

“I’ll bet that’s where your special skills come in handy, right, Robert?”

“Pretty much, Vinnie. The trick is to get the right data into the right kind of memory at the right time.”

“The right kind…?”

“Ohhhyeah, there’s a whole hierarchy out there — on-chip memory essentially inside the processor, on-board memory on separate chips, off-board memory and storage…. It goes on all the way out to The Cloud if you’re set up that way. There’s even special memory for keeping track of which data is where in the other memories. The internal network plays into it, too — the data bus to a given memory could be just a byte wide or many times fatter, which makes a big difference in access speed. The hardware takes care of some data placement automatically, but a lot of it we can affect with the software. That’s mostly where I come in.”

Horse skeleton from Wikimedia Commons by CC license

“Doin’ what? The hardware’s pretty much what your boss already bought, not much you can tinker with there. The bits are zoomin’ around inside at electronic speeds, you can’t pick and choose where to put ’em.”

“Yes, we can, if we’re smart and careful. You know Michael Corleone’s line, ‘Keep your friends close but your enemies closer‘? With us it’s ‘Keep your next data byte close but your next program instruction closer.'”

The Memory Pyramid

“Whuzzat mean?”

“What you want to do is have bytes ready for the processor as soon as it’s ready to work with them. That means predicting which bytes it’ll want next and getting those to the top of the memory pyramid. Programs do a lot of short loops, enough that standard architectures have separate instruction memories just for that.”

“So how do you do that predicting? Like Vinnie said, things move fast in there.”

“You design for patterns. My favorite is sequential-and-discard. When you’re watching a movie you look at frames in series and you rarely go back. In the computer we deliver sequential bytes in an orderly manner to fast memory but we don’t have to worry about storing them back out again. Easy-peasy. Sequential-and-store is also highly predictable but then you have to down-copy, too.”

“Yeah, either way the data just flows through. What others?”

Periodic is useful if you can arrange your program and data to exploit it. If you know a just-used series of bytes are going to be relevant again soon, you try to reserve enough close-in memory to hold onto them. Data references tend to spread out but sometimes you can tilt the odds by clumping together related bytes that are likely to be used together — like all weather data for one location.”

“What if you don’t have any of those patterns?”

“Worst case scenario. You guess periodic, buy lots of memory and cross your fingers.”

~~ Rich Olcott

Computer Power, Or Not

A voice from the scone line behind me. “That’s like poetical, sayin’ a horse’s sinews tie muscle to bone and a computer’s internal network is like sinew ’cause it ties things together the same way. But what does for the computer what muscle and bone do for a horse? Hi, Robert, I’m Vinnie, me and Sy here go way back. I’ll have a strawberry scone, Al, and these guys are on me.”

“Sure thing, Vinnie, here ya go.”

“Thanks, Al.” “Thanks, Vinnie.” “Thanks — Vinnie, is it?”

“Yeah. Glad to meetcha. So what are they?”

“The computer equivalent of horse muscle and bone? Well, the horse’s muscle activity generates its power so the computer’s ‘muscles’ are clearly its processors.”

Horse musculature from artwork by Jenny Stout, with permission

“Processors, plural? My heavy-duty desk machine only has one CPU thingy in there, I looked.”

“Only one chip package, Sy, but there’s a lot inside that black block. Your ‘Central Processing Unit’ is probably multi-core, which means it has somewhere between four and dozens of more-or-less independent sub-processors, each with its own set of registers and maybe even local cache memories. If your operating system is multi-core-aware, at any given moment your system could be running a different program on each core.”

“Hey, you’re right, I often download emails and browse the internet at the same time I’ve got a big calculation going. Doesn’t seem to slow it down.”

“Mm-hm. I like to call those cores eccentric processing units because they’re not really central.” <Vinnie pretends to grab Robert’s scone.> “You’ve got a video card in there, too, right?”

“Of course.”

“This may come as a shock, but you probably have more raw compute power on that card than you do in your CPU module. The card’s primary chip has hundreds of millions of transistors allocated to hundreds or thousands of simple-minded micro-micro-processors ganged together to do identical calculations on separate inputs. Rotating a 3-D object, for example, requires four multiplications and an addition for each x-, y- and z-coordinate of every point on the object. No if-then logic, just a very small arithmetic program repeated a gazillion times.”

“So the main CPU doesn’t have to do that.”

“Right. Same principle, you may have ASICs in there devoted to certain tasks like network interfacing.”

“A-six?”

Application Specific Integrated Circuits. They’re everywhere from your smartphone to your hobby drone.”

“Don’t have a hobby drone, use mine for business.”

“OK, your business drone, Vinnie. Your drone and its controller both use ASICs.”

“How will the quantum computer play into this, Robert? I’ve been reading how it automagically tries all possible solutions and instantly comes up with the one that solves the problem.”

“That’s hype, mostly. Quantum computing could indeed give quick solutions, but to a very limited set of problems. For instance, everyone talks about factoring special large numbers. When QC succeeds in that it’ll disrupt internet security, cryptography, blockchain applications and a couple more not-here-yet technologies that depend on factorization being hard to do. But QC can only tackle problems that involve a small amount of data. It’s no good for Big Data kinds of problems like weather modeling or fingerprint matching or rummaging through a medical database to find the optimal treatment for a given collection of clinical findings.”

“Why’s that?”

“A quantum CPU works with a set of constraints and inputs. It does its tryeverything thing to generate an output that’s consistent with the constraints and input. The factorization constraint, for example, is just one algorithm. The input is a single number. The output is one set of factors. Compare that with the weather problem where the goal is to calculate the future weather for every kilometer-by-kilometer-by-kilometer cell of atmosphere on the globe. The constraint is a whole series of equations governing atmospheric gases (especially water) together with the topography of the underlying surface. Each cell’s input is all the measurable weather variables (temperature, humidity, wind velocity, clouds, whatever) plus history for that cell and its neighbors. The output per time-step is predicted weather variables for a billion cells. Quantum’s no help with that data flood — you need good networks.”

~~ Rich Olcott

The Lengths We Go To

A new face in the scone line at Al’s coffee shop. “Morning. I’m Sy Moire, free-lance physicist and Al’s steadiest customer. And you’re…?”

“Robert Tobanu, newest Computer Science post-doc on Dr Hanneken’s team. He needed some help improving the performance of their program suite.”

“Can’t he just buy a faster computer?”

“He could if there is a faster computer, if his grant could afford its price tag, and if it’s faster in the way he needs to solve our problems. My job is to squeeze the most out of what we’ve got on the floor.”

“I didn’t realize that different kinds of problem need different kinds of computer. I just see ratings in terms of mega-somethings per second and that’s it.”

“Horse racing.”

“Beg pardon?”

“Horse speed-ratings come from which horse wins the race. Do you bet on the one with the strongest muscles? The one with the fastest out-of-the-box time? The best endurance? How about Odin’s fabulous eight-legged horse?”

“Any of the above, I suppose, except for the eight-legged one. What’s this got to do with computers?”

“Actually, eight-legged Sleipnir is the most interesting example. But my point is, just saying ‘This is a 38-mph horse‘ leaves a lot of variables up for discussion. It doesn’t tell you how much better the horse would do with a more-skilled jockey. It doesn’t say how much worse the horse would do pulling a racing sulky or a fully-loaded Conestoga. And then there’s the dash-versus-marathon aspect.”

“I’m thinking about Odin’s horse — power from doubled-up legs would be a big positive in a pulling contest, but you’d think they’d just get in the jockey’s way during a quarter-mile dash.”

“Absolutely. All of that’s why I think computer speed ratings belong in marketing brochures, not in engineering papers. ‘MIPS‘ is supposed to mean ‘Millions of Instructions Per Second‘ but it’s actually closer to ‘Misleading Indication of Processor Speed.'”

“How do they get those ratings in the first place? Surely no-one sat there and actually counted instructions as the thing was running.”

“Of course not. Well, mostly not. Everything’s in comparison to an ancient base-case system that everyone agreed to rate at 1.0 MIPS. There’s a collection of benchmark programs you’re supposed to run under ‘standard‘ conditions. A system that runs that benchmark in one-tenth the base-case time is rated at 10 MIPS and so on.”

“I heard voice-quotes around ‘standard.’ Conditions aren’t standard?”

“No more than racing conditions are ever standard. Sunny or wet weather, short-track, long-track, steeplechase, turf, dirt, plastic, full-card or two-horse pair-up — for every condition there are horses well-suited to it and many that aren’t. Same thing for benchmarks and computer systems.”

“That many different kinds of computers? I thought ‘CPU‘ was it.”

Horse photo by Helena Lopes on Unsplash

“Hardly. With horses it’s ‘muscle, bone and sinew.’ With computers it’s ‘processor, storage and network.’ In many cases network makes or breaks the numbers.”

“Network? Yeah, I got a lot faster internet response when I switched from phone-line to cable, but that didn’t make any difference to things like sorting or computation that run just within my system.”

“Sure, the external network impacts your upload and download performance, but I’m talking about the internal network that transports data between your memories and your processors. If transport’s not fast enough you’re wasting cycles. Four decades ago when the Cray-1’s 12.5-nanosecond cycle time was the fastest thing afloat, the company bragged that it had no wire more than a meter long, Guess why.”

“Does speed-of-light play into it?”

“Well hit. Lightspeed in vacuum is 0.3 meters per nanosecond. Along a copper wire it’s about 2/3 of that, so a signal takes about 5 nanoseconds each way to traverse a meter-long wire. Meanwhile, the machine’s working away at 12.5 nanoseconds per cycle. If it’s lucky and there’s no delay at the other end, the processor burns a whole cycle between making a memory request and getting the bits it asked for. Designers have invented all sorts of tricks to get those channels as short as possible.”

“OK, I get that the internal network’s important. Now, about that eight-legged horse…”

~~ Rich Olcott

  • Thanks to Richard Meeks for asking an instigating question.

Better A Saber Than A Club?

There’s a glass-handled paper-knife on my desk, a reminder of a physics experiment gone very bad back in the day. “Y’know, Vinnie, this knife gives me an idea for another Star Trek weapons technology.”

“What’s that, Sy?”

“Some kinds of wave have another property in addition to frequency, amplitude and phase. What do you know about seismology?”

“Not a whole lot. Uhh … earthquakes … Richter scale … oh, and the Insight lander on Mars has seen a couple dozen marsquakes in the first six months it was looking for them.”

“Cool. Well, where I was going is that earthquakes have three kinds of waves. One’s like a sound wave — it’s called a Pwave or pressure wave and it’s a push-pull motion along the direction the wave is traveling. The second is called an Swave or shear wave. It generates motion in some direction perpendicular to the wave’s path.”

“Not only up-and-down?”

“No, could be any perpendicular direction. Deep in the Earth, rock can slide any which-way. One big difference between the two kinds is that a Pwave travels through both solid and molten rock, but an Swave can’t. Try to apply shearing stress to a fluid and you just stir it around your paddle. The side-to-side shaking isn’t transmitted any further along the wave’s original path. The geophysicists use that difference among other things to map out what’s deep below ground.”

“Parallel and perpendicular should cover all the possibilities. What’s the third kind?”

“It’s about what happens when either kind of deep wave hits the surface. A Pwave will use up most of its energy bouncing things up and down. So will an Swave that’s mostly oriented up-and-down. However, an Swave that’s oriented more-or-less parallel to the surface will shake things side-to-side. That kind’s called a surface wave. It does the most damage and also spreads out more broadly than a P- or Swave that meets the surface with the same energy.”

“This is all very interesting but what does it have to do with Starfleet’s weapons technology? You can’t tell a Romulan captain what direction to come at you from.”

“Of course not, but you can control the polarization angle in your weapon beams.”

“Polarization angle?”

Plane-polarized electromagnetic wave
Electric (E) field is red
Magnetic (B) field is blue
(Image by Loo Kang Wee and
Fu-Kwun Hwang from Wikimedia Commons)

“Yeah. I guess we sort of slid past that point. Any given Swave vibrates in only one direction, but always perpendicular to the wave path. Does that sound familiar?”

“Huh! Yeah, it sounds like polarized light. You still got that light wave movie on Old Reliable?”

“Sure, right here. The red arrow represents the electric part of a light wave. Seismic waves don’t have a magnetic component so the blue arrow’s not a thing for them. The beam is traveling along the y‑axis, and the electric field tries to move electrons up and down in the yz plane. A physicist would say the light beam is planepolarized. Swaves are polarized the same way. See the Enterprise connection?”

“Not yet.”

“Think about the Star Trek force-projection weapons — regular torpedoes, photon torpedoes, ship-mounted phasers, tractor beams, Romulan pulse cannons and the like. They all act like a Pwave, delivering push-pull force along the line of fire. Even if Starfleet’s people develop a shield-shaker that varies a tractor beam’s phase, that’s still just a high-tech version of a club or cannon ball. Beamed Swaves with polarization should be interesting to a Starfleet weapons designer.”

“You may have something. The Bridge crew talks about breaking through someone’s shield. Like you’re using a mace or bludgeon. A polarized wave would be more like an edged knife or saber. Why not rip the shield instead? Those shields are never perfect spheres around a ship. If your beam’s polarization angle happens to match a seam where two shield segments come together — BLOOEY!”

“That’s the idea. And you could jiggle that polarization angle like a jimmy — another way to confuse the opposition’s defense system.”

“I’m picturing a Klingon ship’s butt showing through a rip in its invisibility cloak. Haw!”

~~ Rich Olcott

The Decade Isn't Over Yet

My father was a man of firmly held opinions, although he would be quick to say they were conclusions. Trained as a physicist, he lived a career in chemistry because in the Depression you took what you could get. Never hesitating to carry his sciences into the public forum, he wrote many Letters to The Editor on topics from the chemical hazards of powering automobile air bags with sodium azide, to the optimal size of a wine glass, to the historical connection between Hitler’s Navy sowing the North Sea with mines and the rise of industrial vitamin D production in the US.

He once suggested that the best location for highly radioactive nuclear waste would be the already-radioactive Chernobyl reserve in the thenSoviet Ukraine. Obvious when you think about it, except for the geopolitical part.

Dad enjoyed tweaking the bureaucrats. When he mustered out of the Navy at the end of WWII, he was given a letter stating that because of his extensive top-secret radar know-how, he was to hold himself in readiness should the nation have to call him back to duty. Many years later and in his eighties, he wrote a letter to the Secretary of the Navy. In it he said that his technical skills had deteriorated over the decades and therefore he requested relief from the obligation. He never told me whether or not he’d heard back.

A frequent target of his disdain was the herd of natural foods enthusiasts who abhor “ingesting chemicals.” “We are made of chemicals.” he wrote. “The only thing that is free of chemicals is a perfect vacuum.” He held that the phrase “organic salt” is an oxymoron when applied to any preparation of sodium chloride. I can only imagine his reaction to the displays that advertise gluten-free water.

Dad and I worked on different aspects of the Y2K Problem. From mid-1996 through the first month of January 2000 I and lots of other IT colleagues spent most of our working hours making sure that the wheels of our society wouldn’t grind to a halt because the various gears failed to mesh properly. All that work worked, but because we were successful the rest of society decided Y2K had been no big deal. If only they knew.

Meanwhile, my Dad had a different Y2K concern. He expressed it in this note which appeared in multiple publications:

To The Editor:
 There seems to be friction about naming the final year of the current century and/or the first year of the next decade.
 Those who affirm that 2001 is the beginning of the new century are absolutely correct. There was no year 0.
 Also, there is a substantial group who want to celebrate the year 2000.
 OK, the year twenty-naught-naught is the end of the present decade, century, millennium. We can and should have celebrations for the end of world wars, the end of holocausts, the end of homelessness, the end (hopefully) of drugs, reckless driving, etc.
 Even 1999 has been headlined. Let it be the year of preparation for the next two celebratory years. Those who want to capitalize on the final year of the present decade and the first year of the coming century can use 1999 for planning, organizing and even rehearsing the functions anticipated.
 The three-year spectacle will satisfy a substantial majority of those who seem to be unhappily vocal, one way or the other. Let’s make peace.

  • 1999: On your marks.
  • 2000: Get set.
  • 2001: Go.

~~ Irwin Olcott

Just to show how firmly he held to his calendrical conclusion — despite a medical condition that would have felled a less-determined man, Dad held on until Jan 10, 2001 because he wanted to live into the 21st Century. His initials, “I.O.,” drew his attention on the number ten. We in the family think that’s why he stayed with us until the tenth of the month, although there was some mention of waiting that long for tax purposes. Knowing him, it could have been some of both.

In my opinion, Dad had the right of it. The year 2020 will not be the start of the 21st Century’s second third decade, it will be the end of its first second. May the year and the following ones go well with you.

~~ Rich Olcott

How To Wave A Camel

“You’re sayin’, Sy, no matter what kind of wave we got, we can break it down by amplitude, frequency and phase?”

“Right, Vinnie. Your ears do that automatically. They grab your attention for the high-amplitude loud sounds and the high-frequency screechy ones. Goes back to when we had to worry about predators, I suppose.”

“I know about music instruments and that, but does it work for other kinds of waves?”

“It works for waves in general. You can match nearly any shape with the right combination of sine waves. There’s a few limitations. The shape has to be single-valued — no zig-zags — and it has to be continuous — no stopping over here and starting over there..”

“Ha! Challenge for you then. Use waves to draw a camel. Better yet– make it a two-humped camel.”

“A Bactrian camel, eh? OK, there’s pizza riding on this, you understand. <keys clicking> All right, image search for Bactrian camel … there’s a good one … scan for its upper profile … got that … tack on some zeroes fore and aft … dump that into my Fourier analysis engine … pull the coefficients … plot out the transform — wait, just for grins, plot it out in stages on top of the original … here you are, Vinnie, you owe me pizza.”

“OK, what it it?”

“Your Bactrian camel.”

“Yeah, I can see that, but what’s with the red line and the numbers?”

“OK, the red line is the sum of a certain number of sine waves with different frequencies but they all start and end at the same places. The number says how many waves were used in the sum. See how the ‘1‘ line is just a single peak, ‘3‘ is more complicated and so on? But I can’t just add sine waves together — that’d give the same curve no matter what data I use. Like in a church choir. The director doesn’t want everyone to sing at top volume all the time. Some passages he wants to bring out the alto voices so he hushes the men and sopranos, darker passages he may want the bases and baritones to dominate. Each section has to come in with its own amplitude.”

“So you give each sine wave an amplitude before you add ’em together. Makes sense, but how do you know what amplitudes to give out?”

“That gets into equations, which I know you don’t like. In practice these days you get all the amplitudes in one run of the Fast Fourier Transform algorithm, but it’s easier to think of it as the stepwise process that they used before the late 1960s. You start with the lowest-frequency sine wave that fits between the start- and end-points of your data.”

“Longest wavelength to match the data length, gotcha.”

“Mm-hm. So you put in that wave with an amplitude near the average value of your data in the middle art of the range. That’s picture number 1.”

“Step 2 is to throw in the next shorter wavelength that fits, right? Half the wavelength, with an amplitude to match the differences between your data and wave 1. And then you keep going.”

“You got the idea. Early physicists and their grad students used up an awful lot of pencils, paper and calculator time following exactly that strategy. Painful. The FFT programs freed them up to do real thinking.”

“So you get a better and better approximation from adding more and more waves. What stopped you from getting it perfect?”

“Two things — first, you can’t use more waves than about half the number of data points. Second, you see the funny business at his nose? Those come from edges and sudden sharp changes, which Fourier doesn’t handle well. That’s why edges look flakey in JPEG images that were saved in high-compression mode.”

“Wait, what does JPEG have to do with this?”

“JPEG and most other kinds of compressed digital image, you can bet that Fourier-type transforms were in play. Transforms are crucial in spectroscopy, astronomy, weather prediction, MP3 music recordings –“

Suddenly Vinnie’s wearing a big grin. “I got a great idea! While that Klingon ship’s clamped in our tractor beam, we can add frequencies that’d make them vibrate to Brahms’ Lullaby.”

“Bad idea. They’d send back Klingon Opera.”

~~ Rich Olcott

How To Phase A Foe

“It’s Starfleet’s beams against Klingon shields, Vinnie. I’m saying both are based on wave phenomena.”

“What kind of wave, Sy?”

“Who knows? They’re in the 24th Century, remember. Probably not waves in the weak or strong nuclear force fields — those’d generate nuclear explosions. Could be electromagnetic waves or gravitational waves, could be some fifth or sixth force we haven’t even discovered yet. Whatever, the Enterprise‘s Bridge crew keeps saying ‘frequency’ so it’s got to have some sort of waveishness.”

“OK, you’re sayin’ whatever’s waving, if it’s got frequency, amplitude and phase then we can talk principles for building a weapon system around it. I can see how Geordi’s upping the amplitude of the Enterprise‘s beam weapons would help Worf’s battle job — hit ’em harder, no problem. Jiggling the frequencies … I sort of see that, it’s what they always talk about doing anyway. But you say messing with beam phase can be the kicker. What difference would it make if a peak hits a few milliseconds earlier or later?”

“There’s more than one wave in play. <keys clicking> Here’s a display of the simplest two-beam interaction.”

“I like pictures, but this one’s complicated. Read it out to me.”

“Sure. The bottom line is our base case, a pure sine wave of some sort. We’re looking at how it’s spread out in space. The middle line is the second wave, traveling parallel to the first one. The top line shows the sum of the bottom two at each point in space. That nets out what something at that point would feel from the combined influence of the two waves. See how the bottom two have the same frequency and amplitude?”

“Sure. They’re going in the same direction, right?”

“Either that or exactly the opposite direction, but it doesn’t matter. Time and velocity aren’t in play here, this is just a series of snapshots. When I built this video I said, ‘What will things look like if the second beam is 30° out of phase with the first one? How about 60°?‘ and so on. The wheel shape just labels how out-of-phase they are, OK?”

“Give me a sec. … OK, so when they’re exactly in sync the angle’s zero and … yup, the top line has twice the amplitude of the bottom one. But what happened to the top wave at 180°? Like it’s not there?”

“It’s there, it’s just zero in the region we’re looking at. The two out-of-phase waves cancel each other in that interval. That’s how your noise-cancelling earphones work — an incoming sound wave hits the earphone’s mic and the electronics generate a new sound wave that’s exactly out-of-phase at your ear and all you hear is quiet.”

“I’ve wondered about that. The incoming sound has energy, right, and my phones are using up energy. I know that because my battery runs down. So how come my head doesn’t fry with all that? Where does the energy go?”

“A common question, but it confuses cause and effect. Yes, it looks like the flatline somehow swallows the energy coming from both sides but that’s not what happens. Instead, one side expends energy to counter the other side’s effect. Flatlines signal success, but you generally get it only in a limited region. Suppose these are sound waves, for example, and think about the molecules. When an outside sound source pushes distant molecules toward your ear, that produces a pressure peak coming at you at the speed of sound, right?”

“Yeah, then…”

“Then just as the pressure peak arrives to push local molecules into your ear, your earphone’s speaker acts to pull those same molecules away from it. No net motion at your ear, so no energy expenditure there. The energy’s burned at either end of the transmission path, not at the middle. Don’t worry about your head being fried.”

“Well that’s a relief, but what does this have to do with the Enterprise?”

“Here’s a sketch where I imagined an unfriendly encounter between a Klingon cruiser and the Enterprise after Geordi upgraded it with some phase-sensitive stuff. Two perpendicular force disks peaked right where the Klingon shield troughed. The Klingon’s starboard shield generator just overloaded.”

“That’ll teach ’em.”

“Probably not.”

~~ Rich Olcott