Friday, September 23, 2011

Moving Violations

There's an old physics joke: 186,000 mi/s. It's not just a good idea. It's the law.

If this week's announced results prove out, they may just have to issue speeding citations to the staff at CERN, in Switzerland. To summarize, a neutrino experiment appeared to result in speeds 20 parts per million above the speed of light in a vacuum.

That ... is damn weird. It calls into question some fairly fundamental assumptions we've made about how we think the Universe works. By fairly fundamental, I mean some of them go back a couple of hundred years. Allow me to explain.

There's a fairly simple thought experiment we can run through to demonstrate why we think nothing can go faster than light. It relies on just three basic assumptions, that I will list below:

1) There is no universally-preferred frame of reference. A slightly less fancy way to put that is that there's no such thing as absolute motion. Motion only makes sense if you can measure it relative to something else. A corollary to this is that, if you're out in the middle of nowhere and have few or no reference points, you can't tell the difference between sitting still and moving at a uniform speed in a straight line. This is called Galilean invariance.

2) Light moves at the same speed in all inertial frames of reference. Another way of saying that is that light always moves at the same speed in a given medium, no matter where or how you measure it. This is one of the cornerstones of the Special Theory of Relativity.

3) All particles that have zero rest mass, like photons, are constrained to move at the speed of light, and only at the speed of light. They cannot accelerate or decelerate, but they can gain or lose energy in frequency.

Now, bearing those three assumptions in mind, let's imagine two spaceships out in intergalactic space. They're far enough away from any other points of reference that they can't really measure their motion all that well against them, so their only points of reference are each other. Which means, they have no real way of telling if they're at rest, or moving. For all they know, they're sitting still while the other ship zips past them. Now, let's also assume that one of the ship is charged up with several million volts, so that when they pass close enough, a spark jumps between the two ships. We won't say anything about how fast they're moving relative to one another. The speed can be arbitrarily high.

From the first ship, what you see is that you're sitting still, then this other ship zips by, and then FLASH! You're at the center of an expanding shell of photons. The situation looks the same from the other ship -- you're sitting still, zoom, FLASH! You're also at the center of an expanding shell of photons.

Again, the speeds of the ships haven't been specified. It doesn't matter how fast they think they're moving, because no matter which way you slice it, a wave-front of photons is racing out ahead of you. The only logical conclusion is that both ships must be moving slower than the speed of light.

That's all well and good. But now we have, at least potentially, a very sticky problem.

If this recent experiment is correct, if the Swiss scientists haven't made any errors, then one or more of the three basic assumptions above must be wrong.

The implications of this...

On one hand, it staggers the mind. Such fundamental notions about the Universe just don't fall every day. But on the other hand, this only involves such high energies that most of us will never see any kind of difference. And on the other other hand, I'm really only certain about three things anyway[1], so it won't bother me too much if the Swiss scientists are right or wrong. And even if they're right, it'll take quite some time for them to figure out exactly which of the above assumptions are wrong, and in what way. It'll be interesting to watch the commotion no matter how it turns out.

Still. That's going to be one hell of a speeding ticket, and I'm glad I don't have to pay.

[1] Conservation of Mass, Conservation of Momentum, and Conservation of Energy. As far as I'm concerned, everything else is open for speculation.

Sunday, September 11, 2011

Ten Years.

The relentless fury of the August sun has retreated. I believe I've said elsewhere that Autumn in Texas is usually a time when God apologizes for leaving the oven on Broil for a few months, and the apology takes the form of cool mornings and warm sunshine. Ten years ago today, it was almost exactly the same kind of morning. But with a difference.

That Tuesday morning began for me like any other: I was at my job, wrestling with a pile of code that was stubbornly refusing to do what it was supposed to be doing. The company I was working for had a piece of the FAA's Free Flight Phase 1 project. The specific piece I was working on was the adaptation of pFAST (Passive Final Approach Spacing Tool) to the Minneapolis-Saint Paul International Airport. It was hard sledding, but that's a tale for another day. After a couple of hours, I'd reached an impasse, and decided to check the news as a bit of a break.

That was as much productive work as I, or anyone else in my office, got done that day.

The news that an airplane had collided with one of the towers didn't really register yet. I thought it was an accident. Something like that had happened once before, back in the '40s, when a B-17 hit the Empire State Building. How something like that happened with modern navigation equipment, though, was a mystery. Then, the second airplane hit, and all doubt was gone.

Once could have been an accident. Twice? No, twice meant it was deliberate action. And what's more, I knew who was responsible. I'd been following the story for years. I remembered the 1993 World Trade Center bombing. Khobar Towers. I remembered his 1998 fatwa against Americans, and the attack against the USS Cole. This was his way of finishing the job. A cold fury gripped my heart. They must be made to pay. And I was not alone in that sentiment.

Five years ago, the memory still stung with the ache of unfinished business.

Today, the memory still stings. But at least there is some closure, some completion.

The architect of those attacks is in custody and will never again be a free man, and the man who gave the order is part of the marine food chain. Both lived long enough to see their ideology utterly discredited. The crowds that mobbed Tahrir Square, the citizen-soldiers who liberated Libya inch by inch, they had no use at all for the theocratic state Osama bin Laden championed. The throngs who overthrew one-time strongmen from the Atlantic coast to the Arabian peninsula weren't chanting his name, or that of his movement. Rather, they wanted democracy and self-determination. They had weighed his ideas in the balance, and found them wanting. Bin Laden did not die in glory, but in defeat and despair.

And for our part? On this anniversary, when we look back and reflect on the very real pain and loss of that day, we can look forward as well. When we think of those who lost lives and loved ones that day, we can take solace in the fact that they have been avenged. When we think of the lives and loved ones lost in the wars, we can take comfort in the fact that they did not die totally in vain. From the Maghreb to the Hindu Kush, people have a chance at freedom and self-determination that they have not had in many years, if ever. Some of those stories will end in success. Some will not end so happily. But the ends of those stories will not be written in English, by an American author. Those stories will be written by the people who live them, as is right and proper.

And for our part, our story will also go on. We have our full share of problems. But on the whole, I wouldn't trade them for anyone else's on this Earth.

May God be with you all, and may God continue to bless the United States of America.

Friday, September 09, 2011

Sesquicentennial, Part XVII: Man in Motion


Only a year earlier, he was the picture of abject failure. Virtually nothing he had turned his hand to resulted in success. He was the husband of a devoted wife, and the father of adoring children, and exactly that much was right with his world. He was a miserable figure, shuffling to and from the only job he could find, a clerk in his father's store. At thirty-eight years of age, Ulysses Grant had hit rock bottom.

His fortunes hadn't always looked so grim. His father, Jesse Grant, was well-regarded though not spectacularly wealthy. Born Hiram Ulysses Grant, he was mistakenly nominated to West Point under the name Ulysses S. Grant. He raised no complaint: he'd secretly dreaded having to go by the initials H.U.G., knowing that would mean no end of ribbing from his classmates. He was an indifferent student, graduating 21st out of 39, with two notable exceptions. He was an outstanding horseman, and he was exceptionally talented in mathematics.

Grant didn't actually want to be a career soldier. Oh, he had no qualms about the job, it's just that what he really wanted was to be a professor of mathematics. And that's what almost happened. He wanted the job, West Point wanted him back as an instructor, but this was 1843, and trouble was brewing down on the border with Mexico. Lieutenant Grant would be a soldier, after all.

As a quartermaster, if he were so inclined, he might have seen no action at all. But that wasn't his style. Twice, he was brevetted for bravery, at Molino del Rey and at Chapultepec. This, despite the fact that he was deeply opposed to the war itself. He thought it terribly unjust, and would later write, "I was bitterly opposed to the measure, and to this day, regard the war, which resulted, as one of the most unjust ever waged by a stronger against a weaker nation."

After the war, Grant remained in the Army. As a result of the Mexican War, the United States had acquired an immense amount of territory, and soldiers would be required to guarantee its safety. Grant's duties were to be as a quartermaster at a succession of forts on the west coast. It was more or less at this point that we'd see a facet of Grant's character that would resurface several times in the future. Grant, in the face of action, was a capable and diligent soldier. Grant, faced with the tedium of garrison duty, did not handle boredom well. It's not known for sure whether or not Grant ever drank on duty, but his commander believed that he had. Grant was given an ultimatum: resign, or face court-martial. He resigned.

For several years, Grant tried to make a go of it as a farmer, on a plot of land his family owned outside of St. Louis, Missouri. But Grant was a poor businessman. After four years, he had to give up farming, and spent a couple of years as a bill collector in St. Louis. This didn't work out, either; and after a string of failed ventures, he was forced to accept a job as a clerk in his father's leather goods store. This is where we find him in late 1860 and early 1861: a broken man, shuffling between his home and his father's store.

His luck began to change in April. After Fort Sumter was attacked, President Lincoln called for 75,000 volunteers to suppress the Rebellion. As it happened, soldiering was something Grant was quite familiar with ... And so it was that Grant helped to recruit a company of volunteers, and accompanied said unit to the state capital at Springfield. This company seemed to be more well-drilled and disciplined than most volunteers, so Governor Richard Yates offered Grant a position to recruit and train new troops. Grant accepted -- this wasn't the field command that he was looking for, but it beat working in his father's store. Besides, if he did a good enough job, perhaps someone would notice.

Someone did notice. Grant's enthusiasm, energy, and efficiency made an impression not only on his soldiers, but on Governor Yates. In June, the Governor promoted Grant to Colonel, and gave him the Twenty-first Illinois volunteer regiment, a particularly unruly regiment of volunteers. Within a few months, they weren't quite so unruly anymore. It's not that Grant was a harsh disciplinarian, or a martinet. He wasn't. But he kept his men busy with drill, attended to their needs diligently, and as is so often the case, his soldiers responded positively to such treatment. This turn-around caught the eye of Major General John Fremont, who'd known Grant by reputation from the Mexican War. He'd been appointed by Lincoln as commander in the West, and Fremont needed someone to take charge of a deteriorating situation in the District of Cairo. Fremont saw Grant as "a man of dogged persistance, and iron will," and tapped him for the post.

What a difference a year makes. From the depths of failure in September 1860, Grant had risen to command of a regiment of volunteers in September 1861. This change of fortunes affected Grant's entire demeanor. He began to walk with a bold, confident step. He was immensely confident of his abilities, but at the same time, kept a fairly solid grasp on the limits of the possible. These two qualities seldom meet in one person.

General Fremont had given Grant orders to venture out and meet the Confederate forces at Belmont. Grant immediately began making the necessary preparations. Soon, he would march out to meet the enemy.

In September 1861, few knew the name Ulysses S. Grant. This was about to change.