Spacetime for amateurs

I've been enjoying a Great Courses lecture in my car lately, a highly popularized explanation of special and general relativity with only the most moderate use of math.  The lecturer stresses a popular misconception that the theory of relativity means that "everything is relative."  It would be more accurate to say that the speed of light is absolute, with the consequence that space and time have to be squished to account for things like the fact that two light beams passing each other like trains in the night still have a relative speed of c, not twice-c.  (That's not just a wild idea, by the way, but something than clever guys have proved experimentally.)

I grew up with science fiction stories that grappled with the speed of light, sometimes treating it as an inviolable barrier and sometimes as an inconvenience to be papered over in the interests of advancing the story.  Viewed as a natural law, the inability to exceed the speed of light somehow comes across as a traffic ordinance that's begging to be violated.  We know light can go slower, as it does through glass or water, for instance, so why not faster?  Learning a little bit more about it as an amateur, I now gather it's more a question of light-speed as an inherent quality of a specific thing, like the length of a pencil, that only seems to have maximum and less-than-maximum manifestations because we're looking at it in more or less foreshortened perspectives, so to speak.  So your pencil might look longer or shorter depending on your angle, but it's always as long as it is, and no longer.

My Great Courses lecturer used an analogy that leapt out at me.  Drawn from an excellent 1965 popular textbook by Edwin Taylor and John Wheeler (Spacetime Physics, 1st ed., PDF link to 1st chapter here), the analogy is "the parable of the surveyors."  The king asks his surveyors to figure out how far the smithy is from point "X."  One uses a coordinate system based on true North, while the other uses magnetic North, so they get different recipes for "go so many feet East, then so many feet North."

No matter what N-S-E-W coordinates we choose to measure the distance from "X" to the smithy, the straight-line diagonal distance will be the same.

But the two vectors we add to get to the straight-line distance can be nearly anything, depending on how we rotate the frame of reference.  The analogy is to space and time as the elements that make up the speed of light:  from some points of view, the distance will be one thing and the time elapsed another, but those two elements can change.  What will never change is the speed of light.  It's not so much that light isn't "allowed" to go faster; it's more like the fact that the smithy is a certain distance from "X."  Would it be allowed to be farther?  Sure, but that's not where it happens to be.

The way the lecturer puts it is that space and time are aspects of the same thing, and the speed of light, c, is the conversion factor needed to switch back and forth between them.  Similarly, mass and energy are aspects of the same thing, and the speed of light squared is the conversion factor needed to switch back and forth between them.  Why is one just c and the other c-squared?  No idea.

Advent

(H/t: D29).

Bad Day Between the Hedges

Now that just shouldn't have happened. But it did, in overtime.

Congratulations to the victor.

News in spoons

This spoon adjusts instantly to cancel out tremors.

The Deep South

I realize that for some the Deep South is eternally guilty as somehow the source of all racism, radiating it outwards perhaps by its poisonous presence. Nevertheless, Colbert I. King, neither of your stories happened in the Deep South. Neither Oklahoma nor Missouri is plausibly part of the Deep South, nor do they share much with the culture of that produced Sidney Lanier (of Georgia), William Faulkner (Mississippi), or Flannery O'Connor (born in Savannah, Georgia).

Let us atone for our own sins, which are surely serious enough in your eyes, without asking us to carry those of others.

UPDATE: Geingo (Gringo?) points out that my eyes have deceived me, and that the first story is not set in "Oklahoma" but in "Okolona," a town in Mississippi. Mississippi certainly is in the Deep South, though Missouri remains well outside of it.

May both sides lose

As my husband says, time to sit back and watch both sides destroy each other.  This is not a link about Sunnis vs. Shia, but about two arms of the Nanny State:  employers want to use the ACA to nag their employers about smoking and diets, while the EEOC sues because medical testing of employees is prohibited.

Cthurkey

My husband found this, but doesn't remember where, so apologies to the source:

Blues states and black jail rates

In order of the greatest in-state discrepancy in incarceration rates by state:

How Would They Know Where We're Going?

No holiday travel for me this year, thanks to... whatever you call "Scrooges" at Thanksgiving time. But at least I'll be able to watch my favorite Thanksgiving movie:



Hope you have a good day, all.

Thanks

Our neighbor's niece put together a playlist for her to drive home by last week, with a Thanksgiving theme. The first number: Danke schön: Jim Gerraghty advises us today:

You’ll recall that last year Organizing for Action urged its members to talk up Obamacare at the dinner table. My assessment still stands:

Here’s a crazy idea: Treat your family members as people you love and appreciate — or at least tolerate — instead of targets for political conversion. You only get one or two families in this life — the one you’re born into, and the one you marry into. Maybe if you’re lucky, you become “like a son” or “like a sister” to another. There’s a lot to talk about in this world beyond politics, and chances are you’re not going to persuade disagreeing relatives, anyway.

The Media is Evil

When I saw the headline, I totally assumed they meant like the Gettysburg address. The only reason I clicked through was to see what he had to say about all this. Turns out...

Making things up

Our President has admonished us that "Communities of color aren’t just making these problems up." I never thought they were. On the other hand, police officers working in neighborhoods where apparently it's OK to rough up store clerks and get in cops' faces (not to mention loot and burn stores) aren't making up their problems, either. I don't think a police officer is ever obligated to let a furious 300-lb. guy--armed or unarmed--close on him without shooting to protect himself.

Good Speech

The prosecutor took a long time about getting to what he surely knew was the only thing anyone cared to hear him say. Much of that time was devoted to a lecture directed at the news media, at social media, and at the citizenry in general. It was a lecture on the importance of patience and the grand jury process.

It seemed to me that the very structure of these interviews fostered courtesy, a posture of respect, on the part of the person conducting the interrogation. Prosecutors need the cooperation of both witnesses and jurors. They also must do their work in a manner safe from legal challenge. So they are forced to cultivate patience: patience with procedure; patience with witnesses, many of whom are afraid or upset or inarticulate or barely audible; and patience with lay jurors operating on the basis of common sense and whatever bundle of attitudes and information they happen to bring with them into the jury room.

This was apparently a highly unusual grand jury, one conducted with particular patience -- indeed, it sounded from his description almost as if he elected to run it as a second trial, one that would identify which of the witnesses were most credible and how their testimony fit with the physical evidence. That's unusual, although perhaps our system would work better if it were the standard practice.

Will it be as satisfying as an acquittal at trial, which this result strongly suggests would have occurred had the grand jury operated along more standard practices? I expect some will argue that the differential treatment constitutes an unjust preferential treatment for the officer (though if so it seems to me that the way to fix that injustice is to take more time to present a full and fair analysis of the facts at grand juries generally). On the other hand, if the facts are clear, the facts are clear and it is right not to put the public through another year or more of trauma over what was clearly going to be an acquittal.

In any case, the speech strongly conveyed a sense of a governmental authority figure taking pains to make sure that nothing was hidden, that everything was understood, and that the public could see that the system worked in a highly controversial case. Those qualities of competence and transparency we could use a lot more of from government.

UPDATE:

Apparently not everyone was persuaded.

My Guess Is This Means Utah is A Peaceful Paradise

Still, it's really surprising.

In the past five years, more Utahns have been killed by police than by gang members.

Or drug dealers. Or from child abuse.

And so far this year, deadly force by police has claimed more lives — 13, including a Saturday shooting in South Jordan — than has violence between spouses and dating partners.

Clearly, those numbers don't hold everywhere. But who thought they'd hold anywhere?

There's a Real Irony Here

Many of us remember the controversy surrounding Elizabeth Warren referring to herself as Native American. A 1997 article from the Fordham Law Review listed the Massachusetts Senator as the “first woman of color” hired by Harvard Law School.

But in spite of her questionable Native heritage, Elizabeth Warren called the Senate police on Greg Grey Cloud who had tried to honor the legislators who voted against polluted water tables within Native and non-Native communities.

Grey Cloud had sang what’s called an “honor song” but Warren and police said it was a “flash mob.”

Instead, Gyasi Ross explained, it was “an earnest and honest expression of Indigenous love and appreciation for these politicians who decided to be leaders instead of politicians for one day.”

I'm Only A Bill

Woah!

Sarah Hoyt continues to say interesting things.

For instance, take Mister Obama. I don’t deny that he has the outward appearance of a minority that was very mistreated historically. However, in his particular case, he is not the descendent of slaves but the descendant of slave dealers on his father’s side, and slave owners on his mother’s.

I don't know if his family owned slaves (on his mother's side), but he is apparently a cousin in that direction of George Washington. Washington owned slaves too, from what I hear. All the great heroes of that era seem to have been associated with the slave trade. Even the great philosophers, if not by owning slaves then by endorsing the practice.

Rites and spontaneity

An old re-post from Maggie's Farm about civil and religious marriage, and more broadly about sacraments and religious dissension, reminded me of the always-reliable views of C.S. Lewis on the ages-old squabbling over high- and low-church traditions, channeling Old Scratch:

“I think I warned you before that if your patient can’t be kept out of the Church, he ought at least to be violently attached to some party within it. I don’t mean on really doctrinal issues; about those, the more lukewarm he is, the better. And it isn’t the doctrines on which we chiefly depend for producing malice. The real fun is working up hatred between those who say “mass” and those who say “holy communion” when neither party could possibly state the difference between, say, Hooker’s doctrine and Thomas Aquinas’ in any form which would hold water for five minutes.

And all the purely indifferent things – candles and clothes and whatnot – are an admirable ground for our activities. We have quite removed from men’s minds what that pestilent fellow Paul used to teach about food and other unessentials – namely, that the human without scruples should always give in to the human with scruples.

You would think they could not fail to see the application. You would expect to find the “low” churchman genuflecting and crossing himself lest the weak conscience of his “high” brother should be moved to irreverence, and the “high” one refraining from these exercises lest he should betray his “low” brother into idolatry. And so it would have been but for our ceaseless labour. Without that, the variety of usage within the Church of England might have become a positive hotbed of charity and humility.”

Yesterday was my dear husband's birthday. Since 1963, he's had to share his birthday with the anniversary of the assassination of John F. Kennedy. It turns out it's also the anniversary of the deaths of C.S. Lewis and Martin Luther. I have been reading a biography of Luther at Project Gutenberg lately and have been surprised to find that his personality so often gave way to an almost hysterical vituperation, equating Catholic adherence to various doctrines and rites as the worst sort of devil-worship.  (What kind of man thinks that celibacy is inherently evil?  And what was with the obsession with calling his enemies pigs and donkeys?)

In Luther's time people were ready to fight to the death over distinctions that make little or no sense to me today. As Lewis notes, from the Devil's point of view, the more lukewarm I am on points of real doctrine the better, and I no doubt have a lot to learn from people for whom the questions of eternity were daily matters of life and death. Nevertheless, I'm not sorry to be able to regard with indifference quarrels over the precise meaning of sacraments. I have never noticed that questions of this sort much occupied Jesus's thinking. My impression is that He thought sacraments were beside the point except as they brought our devoted attention back to what was always important, which was God.  Nevertheless, I am probably more easily tempted to irreverence than idolatry, so a sect like Episcopalianism, with its emphasis on rites, is a good one for me.

Gutenberg has been full in recent months of works furiously condemning the Reformation. It's a perspective that is fairly unfamiliar to me, so I am reading about it with interest. The common theme is that Protestants (and pseudo-Protestants like Episcopalians) erred in believing we could turn loose hundreds of millions of Christians to decide for themselves what the Bible means and what God wants from us. How, they wondered, will anyone know what to believe if no one can agree on an authoritative source?  I acknowledge the danger of sectarianism, but I'm unable to see how reposing our faith in a single infallible human interpreter helps matters.  As a people, as a body of worshippers, we're always going to have to confront the problems of dissension and error.  Nevertheless, again, because of my strong tendency to contrariness, disobedience, and iconoclasm, it's probably just as well for me to be connected to some kind of apostolic tradition, to keep me somewhat in the straight and narrow.

I always come back to the Sadducees and the Pharisees.  The Sadducees got the rap for a mindless adherence to ritual, as if they were performing magic tricks to force God's hand.  The Pharisees at least understood that our hearts have got to be in the right place, but they were still far too hung up on legalism and formality.  Christ blew all that away, not by abolishing forms but by refusing to be distracted by them into trivialities.  He was forever responding to picky demands to rule in favor of this or that technical rule with parables showing why both rules completely missed the point.  Even with this example, we spent next two thousand years fighting out the question of form over substance.  I don't think we can be all about substance; most of us need form as a reminder and a discipline.  But with form always comes the temptation to obsess on the dead container instead of the living Content.

Priorities

This Golden Retriever performed brilliantly, but his goals were not well aligned with those of his human.  Clearly, he appreciated his human's good judgment in bringing him to such an interesting playground.



There's no question how my dogs would perform in this contest.

H/t Maggie's Farm.

Thanks, neighbors

When Nashville was playing hockey in Canada this week, a professional singer was belting out the "Star Spangled Banner" before the game when her mike cut out. The mostly Canadian crowd didn't miss a beat, but finished the song for her.

Do they have better music training in Canada or something? That crowd didn't even hesitate about what key to sing it in, totally together. Every time I hear a bunch of Americans try to sing "Happy Birthday," they are in as many keys as there are singers present.