the Ummm… Drive

figure19

So, there is now a peer-reviewed paper on the fabled EmDrive, which empirically measured a statistically significant thrust. The important results are in Figure 19 up above, and here is what the paper has to say about it:

Figure 19 presents a collection of all the empirically collected data. The averaging of the forward and reverse thrust data is presented in the form of circles. A linear curve is fitted to the data and is shown with the corresponding fitted equation. The vacuum test data collected show a consistent performance of 1.2±0.1uN/kW

It’s not clear if the fit was to the averaged data or the raw data. I suspect the averaged, because looking at the raw data, at no time did thrust exceed 130 uN, even when power was increased from 60 to 80 kW. In fact the data at 80 kW points averages out to the same thrust as at 60 kW, and the error bars are a textbook example of the difference between accuracy and precision.

These results are peer-reviewed, and there is a “statistically significant” linear fit to the data that does demonstrate a correlation between the input power and the observed thrust, but this data does not show that the EmDrive actually works. As Chris Lee at Ars Technica put it, the drive still generates more noise than thrust:

The more important point is that the individual uncertainties in their instrumentation don’t account for the variation in the thrust that they measure, which is a very strong hint that there is an uncontrolled experimental parameter playing havoc with their measurements.

Lee also points out that there are a lot of experimental questions left unanswered, including:

  • Why are there only 18 data points for an experiment that only takes a few minutes to perform?
  • Where is the data related to tuning the microwave frequency for the resonance chamber, and showing the difference between on-resonance mode and an adjacent mode?
  • What is the rise-time of the amplifier?
  • What is the resonance frequency of the pendulum?

on that last point, Lee elaborates:

The use of a pendulum also suggests the sort of experiment that would, again, amplify the signal. Since the pendulum has a resonance frequency, the authors could have used that as a filter. As you modulate the microwave amplifier’s power, the thrust (and any thermal effects) would also be modulated. But thermal effects are subject to a time constant that smears out the oscillation. So as the modulation frequency sweeps through the resonance frequency of the torsion pendulum, the amplitude of motion should greatly increase. However, the thermal response will be averaged over the whole cycle and disappear (well, mostly).

I know that every engineer and physicist in the world knows this technique, so the fact that it wasn’t used here tells us how fragile these results really are.

This is really at the limit of my empirical understanding, but it’s a question that the authors of the paper (not to mention anyone over at /r/emdrive) should be able to field with no worries.

Basically, this paper doesn’t answer any of the substantive questions. But it does at least validate the notion that there is something going on worth investigating. But let’s be real about the outcome – because we’ve seen this before:

For faster-than-light neutrinos, it was a loose cable. For the BICEP2 results, it was an incorrect calibration of galactic gas. For cold fusion, it was a poor experimental setup, and for perpetual motion, it was a scam. No matter what the outcome, there’s something to be learned from further investigation.

and that’s why we do science. It’s not as if scientists are fat cats out to protect their cash cow. (Seriously. I wish it were so). Maybe we are on the verge of another breakthrough, but it will take a lot more than this paper to convince anyone. And that’s as it should be.

Prayers for Steven DenBeste

via Ubu, SDB has been out of contact for over a week, since the big storm. An escalating investigation by the Otakusphere led to this by Brickmuppet:

A few minutes ago I was contacted by the Beaverton police. My information was quite limited and so there were three addresses that could have been Steven’s. As it happened, the second was Steven’s family. The officer had offered to escort them to Steven’s house, but they said they would handle things in the family and declined further assistance. That is all I know at this time, and, as I’m not family, it’s all I am likely to discover.
It does not sound at all good.

Follow here.

UPDATE: Steven has passed away. Indeed we belong to God and to Him indeed we return. Expressions of sorrow by Pete, Ubu, Brickmuppet, Ed Morrissey, Bill Quick, and others at the thread on Chizumatic. Please share links to other tributes in comments.

Like everyone else, I encountered Steven via his blog, USS Clueless, and appreciated the depth of his analyses even as I disagreed with nearly everything he wrote. He was an incredible writer with a gift for condensing complex ideas into teachable form. He forced me to be more rigorous and think through my positions, strengthening me and making me a better writer and blogger about politics. In a strange way he was akin to a mentor, despite our differences.

And then he retired and became an anime blogger, which opened up an entirely new vista, for myself and also my children. Steven’s recommendations of Bottle Fairy, Someday’s Dreamers, and Sugar Snow Fairy truly delighted my kids and enriched them. His recommendations of darker, sometimes offbeat fare such as Kino and Haibane Renmei resonated with me, to the extent that I named the blog after the latter, which is a honest example of something that truly blew my mind. And Steven plied me with his fair share of guilty pleasures, of which Ranma is easily the standard bearer 🙂

Steven was a kind soul whose opinions and passions were grounded in his essential humanism. I wish I’d had the chance to tell him at least once what he meant to me and how much I appreciated him.

A Muslim crew member on Star Trek: Discovery?

khaaan-startrekii

As this essay at MoviePilot.com puts it, having a Muslim crew member aboard is fulfilling Gene Roddenberry’s mission:

There are many people facing discrimination in the current fraught social climate, and positive representation in the media can go a long way to helping ease these tensions. There’s no denying that Islamophobia has risen in recent years. Without delving into a political discussion of the specifics, suffice it to say that introducing a Muslim character to Star Trek might be the most revolutionary thing that Discovery could do — and this would be the best way to parallel Chekov’s role in The Original Series.

… including a Muslim character in Discovery would go a long way to fulfilling Roddenberry’s aim of easing social tensions between different human cultures and peoples. Admittedly, to do so the Discovery writers would have to flout another one of Roddenberry’s beliefs, but there’s already ample evidence for religion existing within the Federation.

Personally, I would love to see a woman sporting a hijab on the bridge of the Discovery — and not just because it would be neat to see how the scarf is incorporated into the uniform. If the Discovery writers do want to combat Islamophobia with representation, the character in question must be a practicing Muslim, as this isn’t just a racial prejudice, but one against the religion and culture.

I have two reasons for why I dislike this idea. First, I don’t like the analogy of Islam being the modern era’s Soviet Union. I don’t like talking politics here so I won’t belabor this, it’s a topic for City of Brass. Second, I think that social engineering on this sort works better with ethnicity than religion. Pavel Chekov was not a Soviet Russian. He was simply Russian, ethnically, in a way that was unambiguously obvious (ie, his accent). Worf was as Klingon as you could get – an explicit racial presence, also obvious. For Roddenberry’s strategy of de-Otherizing to work in the context of Islam, a similarly obvious approach needs to be taken.

I think including an explicit Muslim would be jarring since tehre is no other “real world” religion represented in Star Trek, at least for the Human society. It was Roddenberry’s world and he chose to eliminate religion from it. Adding a character who is explicitly Muslim complicates canon and introduces tension that undermines Star Trek’s appeal to all of humanity. Then you also need canon explanations for the status of Jews, Christians, Hindus, etc. This mess is exactly why religion was introduced to DS9 using the alien Bajoran society rather than picking one from our own.

The solution is to recognize that Islamophobia is not an intellectual reaction to a religion’s precepts, but rooted in racial and ethnic fears. Having a stand-in on the crew for a “Muslim-y” ethnic type would be great because that way when someone sees a Muslim on the street, they should be able to counter their knee-jerk stereotype by relating that person to this crewmember. Therefore, the ethnic choice of the actor is relevant to maximize that stereotype-defeating analogy. Which ethnicity works best for this purpose?

Arabs seem an obvious choice, because of the long ethnic association with Islam, but are not as visually distinguishable as Muslim due to high in-group diversity. A better choice would be bearded, brown-skinned, and male, ideally played by a Indian or Pakistani actor. But not Faran Tahir, who looks so badass in real-life that he isn’t connectable as a Muslim stereotype. I think Muslim American women are on the receiving end of more Islamophobia than men are, but for a different reason, and one that isn’t as addressable by casting in this way.

Overall, a bearded brown dude on the bridge would be a great nod to Roddenberry’s Bridge tradition, and avoid needless complication of the Trek universe’s canon or real-world appeal.

Saladin at Jerusalem: A Friday story

This is another alternate history vignette, originally posted here and centering on Abdelkader El Djezairi, one of the most fascinating and heroic characters of the nineteenth century.  The story takes place some years after the end of his resistance to French colonization in Algeria, and after an incident in Damascus which ironically made him into a friend of France.  Those who know what happened there might have some idea of where this story will go… or maybe not.

______

Beit Hanina, 1866

Baudouin rode into camp and found that he was late.

“He’s looking for you,” said the sentry as Baudouin swung down from his horse, pointing to the tent at the center of the camp. “The sayyid needs to see you,” said a Taibeh man who recognized his face. “The emir – he’s been asking for you,” said one of the Syrian officers two tents down. And Raymond, his fellow French lieutenant, put down his bottle long enough to say “get in there, because the king is about to send out a search party.”

The Frenchman needed no more warning, and he ducked into the command tent without stopping for breath. As his eyes adjusted to the darkness, he saw that all the staff officers were sitting around the table. They were an even more motley assortment than the last time he’d seen them: some from the great families of Damascus and Aleppo; Bedouin sheikhs who led troops of scouts; mountain Druzes; Algerians; one or two of the other officers who led his five hundred Frenchmen. Men from the local tribes and towns had come to join them: their fathers had rebelled against Mehmet Ali thirty years ago, and now they’d rallied to a new banner in exchange for the promise that they could rule their own affairs.

And at the head of the table was a bearded man in a hooded cloak. He was nearing sixty, but his hair was still black and his features strong; his burnoose was unadorned and he had a bandolier of ammunition over his shoulder. He looked more like the fighting man he still was than the prince he had become, but still, every eye around the table was on him: Abd-el-Kader, these past ten months King of Syria.

Once, in Algeria twenty years ago and more, Baudouin had fought this man. Now, he called him lord.

#

“Ah, my brave Baudouin, at last you are here,” the king said. “Have you been in the city?”

“I have, lord.” The words came easily, but there was something fearful in them: now that Baudouin had gone to Jerusalem and returned, he realized what a hideous risk he had taken. Pilgrims still came in and out even with Abd-el-Kader’s army approaching, and the garrison still hesitated to molest Europeans, but if anyone had realized why Baudouin was in the city, he’d have died… eventually.

“I suppose it’s too much to expect that the tunnel is still open?”

“It’s closed, and the Turks are guarding its ghost.” The peasant rebels had used the Dung Gate tunnel to break into Jerusalem in ’34, and when Mehmet Ali’s soldiers had retaken the city, closing it had been nearly the first thing they’d done.

“Then what did you see? More than that, what did you hear?”

“The mutasarrif is in the citadel with the regulars. There are men on the wall, but most of them are conscripts, and they’re complaining that they’ll be the first to die.”

Abd-el-Kader leaned in intently. “They don’t think they can win?”

“The officers promise them victory. The men don’t believe. Even the regular troops – in the coffee-houses, all of them say they want to go home.”

“And the people?”

“They have no love for the Turks. They won’t fight, but they’ll welcome you in: the Muslims know the local tribes are with you, the Christians know what you did in Damascus, and the Jews remember how you treated them in Oran.”

Abd-el-Kader’s face broke into a smile. “Then we’ll sweep the Turks out, Baudouin. You and Raymond and Godfrey will enter Jerusalem with me.” The smile, in turn, became laughter: Abd-el-Kader was endlessly amused that his French officers had the names of Crusader kings, and he lamented that Bohemond had gone out of fashion.

“But there’s the Citadel, sayyid,” said Ibrahim Barghouti: he was from Bani Zeid, the newest of the king’s lieutenants, and he knew the city well. “With forty thousand men, we can sweep the Turks from the walls, but the mutasarrif has cannon and his soldiers are well-armed. We’ll have to lay siege to him, and we don’t have time.”

Baudouin nodded involuntarily. The Sultan was gathering another army, and Abd-el-Kader would soon have to guard his northern marches. If Syria’s borders were to meet Egypt’s as its new king intended, he would have to finish the campaign quickly, and that left no time to besiege David’s Tower.

“You’re right, Ibrahim ustaz. I’ll have to consider this. But Jerusalem will be mine.”

#

Outside the tent, Baudouin went to find a meal. The rush of his escape from Jerusalem was behind him, as was the staff meeting, and he felt strangely drained.

The smell of cooking came from the Ta’amirah men’s encampment, and the route there took him past the artillery. Godfrey was there, in the uniform of a French captain: unlike Baudouin and Raymond, he was still a serving officer, and the cannon were a gift from the Emperor. He saw Baudouin and gave him the briefest of acknowledgments: he said nothing, but his opinion of Abd-el-Kader and the Frenchmen who followed him was clear.

He may call himself a king, but he will be the Emperor’s man, was written on his face. Baudouin, as he’d done before, shook his head. He knew enough of Abd-el-Kader by now to know that, while the Algerian honored his debts, he was no one’s puppet. He might take Napoleon’s aid, but he would be a king in truth.

Once, the thought might have given Baudouin pause, but his loyalty was no longer to France, whether empire, kingdom or republic.

#

It had been in Damascus, in 1860… There was fighting between Druze and Maronites in Mount Lebanon, so of course there was fighting in Syria, and Baudouin saw flames and smoke as the mobs rampaged through the Christian quarter. Man, woman and child were put to the sword and driven into the fire, and the air echoed with screams. Baudouin huddled in a small church with his Marie and their six-year-old Thérèse, knowing there was nothing he could do to protect them.

But then Abd-el-Kader and his men had come, driving away the mobs and leading the Christians to shelter. The emir had been exiled by a French government that feared what he would do if he returned to Algeria, but that didn’t deter him: he took French citizens under his wing just as he did the Christian Arabs, and that night, Baudouin’s family had slept in his house protected by his soldiers’ guns.

Baudouin owed Abd-el-Kader three souls, and when the zu’ama of Syria had offered the emir a throne, the Frenchman’s life was his for the asking.

#

Night had fallen and Baudouin stood at the edge of the camp. The hills of Jerusalem stood in the shadows, and on them, he could see the outline of the city.

There were holy places within. Thérèse had dreamed of coming here: she’d so wanted to visit Jerusalem and the Holy Land. But business, and Baudouin’s diplomatic post, had never allowed…

He felt the touch of a hand on his shoulder. “Are you thinking of them?”

“Yes, lord.”

“I know what it is to miss a wife and child.”

Baudouin nodded but said nothing. The lives Abd-el-Kader had saved, God had taken three years later when the fever came. That was the other reason why there was nothing tying Baudouin to France, and why he had nothing to live for but the man he’d chosen as his king.

“I will make you whole, Baudouin. We will find a Melisende for you. Maybe in Jerusalem, maybe somewhere else, but she will be there.”

There it was, the Crusades again. Abd-el-Kader’s joke grew old sometimes. But Baudouin understood what was behind the words: it was something that neither of them ever said, but that the Algerian was wise enough to know and that the Frenchman admitted to himself in his moments of clarity. Having only one allegiance was a sickness, and a man needed more than a king: he needed a family.

His answer, when it came, was oblique: “We might both die tomorrow.”

“We might, but with God’s will we won’t, not if the Turks do as I hope.”

“You have a plan then, lord?” asked Baudouin. The staff meeting had been inconclusive.

“Yes, I have decided. You will get your orders in the morning. Now find your tent and go to sleep.”

The King of Syria had commanded, and his French lieutenant gratefully obeyed.

#

Baudouin rode out at dawn, Raymond mounted next to him and his men at his back. His orders, given minutes before, were to advance through the villages west of Jerusalem and invest the city from the south. A Druze cavalry troop rode with him: they, too, were to take the high ground above the Hinnom and Kidron valleys while others garrisoned the western villages themselves. The main body of the army was stirring, and it would soon advance from the north.

“It will be a siege after all,” said Raymond.

“It looks that way.” Baudouin wondered what Abd-el-Kader was thinking. Did he truly think he could reduce the citadel so quickly? Had he decided to use artillery after all, even if it put the holy places at risk? That would go against everything Baudouin knew of the emir’s character, but what other explanation could there be, especially with him leaving a gap in the line to the northeast…

A bullet whistled and cracked past Baudouin’s head, and more gunfire erupted from the Turkish patrol that had hidden itself just south of a village. Men and horses fell, and for a second, Baudouin was paralyzed. But it was only a second, and then he drew his saber and kicked his horse into a gallop.

His men followed and the charge went home. Baudouin was face to face with an officer, trading saber strokes: he narrowly parried a cut at his face and pressed forward in a flurry of strikes. The Turkish captain fought back fiercely, shouting curses and battering at Baudouin’s guard, but then he broke off and fled as a Bedouin troop came to the French soldiers’ aid. The rest of the patrol broke off with him, a few turning to shoot backward at their enemy but most fleeing pell-mell up the valley.

Baudouin called a halt to regroup. He counted five of his men dead and several others wounded, and he told off a squad to carry the injured ones to the rear. A troop of townsmen from Jenin rode past him and their officer called out to see if anything was wrong, but he waved them onward.

There was gunfire elsewhere as other troops encountered the enemy, but none of it seemed to be slowing the investment of the city. “We should advance that way,” Raymond said, pointing at Abu Tor and the ill-named Hill of Evil Counsel. There was a small Ottoman garrison there, but if they took it, they would command the heights that guarded Jerusalem from the south.

Baudouin nodded and saw that his troops had regrouped and were ready to ride. He began to shout an order but trailed off as he saw a scout riding up at the gallop.

The man was from the Fawaghrah tribe – the foie gras, as some of the Frenchmen called them – and his horse was lathered. “Stop the advance!” he called. “Stop the advance! The Turks are leaving the city!”

Baudouin looked and saw that it was true: soldiers were evacuating the citadel and the conscripts were leaving their positions on the walls. Suddenly he understood the reason why Abd-el-Kader had left a gap in the northeast. He hadn’t wanted to surround the city: he’d wanted the Turks to see that they were about to be surrounded. Backed into a corner and ordered by their commander, even demoralized soldiers would fight, but if they were left a path home, they might force their officers’ hand, especially if the officers were uncertain themselves…

“Without a battle,” Raymond said, and for the first time since Baudouin had met him, there was something like awe in his voice.

“Does the king want us to pursue?” Baudouin asked.

“No,” said the Fawaghrah man. “He said they won’t come back. We might need to chase them out of Abu Tor if they don’t leave on their own, but that’s for later – he wants you and the other commanders with him when he enters the city.”

“Think of that, Raymond – we Crusaders will ride into Jerusalem at last.” But this wasn’t a Crusade, Baudouin realized: here was Saladin come again, and this time the Franks would be at his side.

#

The French lieutenant rode north at the command of his Saladin, the king he had chosen. But later, as he passed the gate of Jerusalem, it was Thérèse’s face he seemed to see.