Tuesday, December 15, 2015

New: Clash of Ideologies: Communism, Islam, and the West

Western politicians say, “We're not at war with Islam.” But Islam is more than a just a religion. Its scriptures specify a political system, civil and criminal law, economics and trade, laws of war, and other matters which other major religions leave to civil authority, and some of these policy prescriptions conflict with Western values. Clash of Ideologies: Communism, Islam, and the West explores whether the West should treat these aspects of Islam as an ideology, like communism, fundamentally incompatible with its values, and how best to confront it.

Posted at 01:19 Permalink

Monday, December 14, 2015

Reading List: Rocket Ranch

Ward, Jonathan H. Rocket Ranch. Cham, Switzerland: Springer International, 2015. ISBN 978-3-319-17788-5.
Many books have been written about Project Apollo, with a large number devoted to the lunar and Skylab missions, the Saturn booster rockets which launched them, the Apollo spacecraft, and the people involved in the program. But none of the Apollo missions could have left the Earth without the facilities at the Kennedy Space Center (KSC) in Florida where the launch vehicle and space hardware were integrated, checked out, fuelled, and launched. In many ways, those facilities were more elaborate and complicated than the booster and spacecraft, and were just as essential in achieving the record of success in Saturn and Apollo/Saturn launches. NASA's 1978 official history of KSC Apollo operations, Moonport (available on-line for free), is a highly recommended examination of the design decisions, architecture, management, and operation of the launch site, but it doesn't delve into the nitty-gritty of how the system actually worked.

The present book, subtitled “The Nuts and Bolts of the Apollo Moon Program at Kennedy Space Center” provides that detail. The author's research involved reviewing more than 1200 original documents and interviewing more than 70 people, most veterans of the Apollo era at KSC (many now elderly). One thread that ran through the interviews is that, to a man (and almost all are men), despite what they had done afterward, they recalled their work on Apollo, however exhausting the pace and formidable the challenges, as a high point in their careers. After completing his research, Ward realised he was looking at a 700 page book. His publisher counselled that such a massive tome would be forbidding to many readers. He decided to separate the description of the KSC hardware (this volume) and the operations leading up to a launch (described in the companion title, Countdown to a Moon Launch, which I will review in the future).

The Apollo/Saturn lunar flight vehicle was, at the time, the most complex machine ever built by humans. It contained three rocket stages (all built by different contractors), a control computer, and two separate spacecraft: the command/service modules and lunar module, each of which had their own rocket engines, control thrusters, guidance computers, and life support systems for the crew. From the moment this “stack” left the ground, everything had to work. While there were redundant systems in case of some in-flight failures, loss of any major component would mean the mission would be unsuccessful, even if the crew returned safely to Earth.

In order to guarantee this success, every component in the booster and spacecraft had to be tested and re-tested, from the time it arrived at KSC until the final countdown and launch. Nothing could be overlooked, and there were written procedures which were followed for everything, with documentation of each step and quality inspectors overseeing it all. The volume of paperwork was monumental (a common joke at the time was that no mission could launch until the paperwork weighed more than the vehicle on the launch pad), but the sheer complexity exceeded the capabilities of even the massive workforce and unlimited budget of Project Apollo. KSC responded by pioneering the use of computers to check out the spacecraft and launcher at every step in the assembly and launch process. Although a breakthrough at the time, the capacity of these computers is laughable today. The computer used to check out the Apollo spacecraft had 24,576 words of memory when it was installed in 1964, and programmers had to jump through hoops and resort to ever more clever tricks to shoehorn the test procedures into the limited memory. Eventually, after two years, approval was obtained to buy an additional 24,000 words of memory for the test computers, at a cost of almost half a million 2015 dollars.

You've probably seen pictures of the KSC firing room during Apollo countdowns. The launch director looked out over a sea of around 450 consoles, each devoted to one aspect of the vehicle (for example, console BA25, “Second stage propellant utilization”), each manned by an engineer in a white shirt and narrow tie. These consoles were connected into audio “nets”, arranged in a hierarchy paralleling the management structure. For example, if the engineer at console BA25 observed something outside acceptable limits, he would report it on the second stage propulsion net. The second stage manager would then raise the issue on the launch vehicle net. If it was a no-go item, it would then be bumped up to the flight director loop where a hold would be placed on the countdown. If this wasn't complicated enough, most critical parameters were monitored by launch vehicle and spacecraft checkout computers, which could automatically halt the countdown if a parameter exceeded limits. Most of those hundreds of consoles had dozens of switches, indicator lights, meters, and sometimes video displays, and all of them had to be individually wired to patchboards which connected them to the control computers or, in some cases, directly to the launch hardware. And every one of those wires had to have a pull ticket for its installation, and inspection, and an individual test and re-test that it was functioning properly. Oh, and there were three firing rooms, identically equipped. During a launch, two would be active and staffed: one as a primary, the other as a backup.

The level of detail here is just fantastic and may be overwhelming if not taken in small doses. Did you know, for example, that in the base of the Saturn V launch platform there was an air conditioned room with the RCA 110A computer which checked out the booster? The Saturn V first stage engines were about 30 metres from this delicate machine. How did they keep it from being pulverised when the rocket lifted off? Springs.

Assembled vehicles were transported from the Vehicle Assembly Building to the launch pad by an enormous crawler. The crawler was operated by a crew of 14, including firemen stationed near the diesel engines. Originally, there was an automatic fire suppression system, but after it accidentally triggered and dumped a quarter ton of fire suppression powder into one of the engines during a test, it was replaced with firemen. How did they keep the launcher level as it climbed up the ramp to the pad? They had two pipes filled with mercury which ran diagonally across the crawler platform between each pair of corners. These connected to a sight glass which indicated to the operator if the platform wasn't level. Then the operator would adjust jacking cylinders on the corners to restore the platform to level—while it was rolling.

I can provide only a few glimpses of the wealth of fascinating minutæ on all aspects of KSC facilities and operations described here. Drawing on his more than 300 hours of interviews, the author frequently allows veterans of the program to speak in their own words, giving a sense of what it was like to be there, then, the rationale for why things were done the way they were, and to relate anecdotes about when things didn't go as planned.

It has been said that one of the most difficult things NASA did in Project Apollo was to make it look easy. Even space buffs who have devoured dozens of books about Apollo may be startled by the sheer magnitude of what was accomplished in designing, building, checking out, and operating the KSC facilities described in this book, especially considering in how few years it all was done and the primitive state of some of the technologies available at the time (particularly computers and electronics). This book and its companion volume are eye-openers, and only reinforce what a technological triumph Apollo was.

Posted at 21:43 Permalink

Friday, December 11, 2015

Reading List: The Miskatonic Manuscript

Suprynowicz, Vin. The Miskatonic Manuscript. Pahrump, NV: Mountain Media, 2015. ASIN: B0197R4TGW. ISBN 978-0-9670259-5-7.
The author is a veteran newspaperman and was arguably the most libertarian writer in the mainstream media during his long career with the Las Vegas Review-Journal (a collection of his essays has been published as Send In The Waco Killers). He earlier turned his hand to fiction in 2005's The Black Arrow (May 2005), a delightful libertarian superhero fantasy. In The Testament of James (February 2015) we met Matthew Hunter, owner of a used book shop in Providence, Rhode Island, and Chantal Stevens, a woman with military combat experience who has come to help out in the shop and, over time, becomes romantically involved with Matthew. Since their last adventure, Matthew and Chantal, their reputation (or notoriety) as players in the international rare books game bolstered by the Testament of James, have gone on to discover a Conan Doyle manuscript for a missing Sherlock Holmes adventure, which sold at auction for more than a million dollars.

The present book begins with the sentencing of Windsor Annesley, scion of a prominent Providence family and president of the Church of Cthulhu, which regards the use of consciousness-expanding plant substances as its sacraments, who has been railroaded in a “War on Drugs” prosecution, to three consecutive life sentences without possibility of parole. Annesley, unbowed and defiant, responds,

You are at war with us? Then we are at war with you. A condition of war has existed, and will continue to exist, until you surrender without condition, or until every drug judge, including you, … and every drug prosecutor, and every drug cop is dead. So have I said it. So shall it be.

Shortly after the sentencing, Windsor Annesley's younger brother, Worthington (“Worthy”) meets with Matthew and the bookstore crew (including, of course, the feline contingent) to discuss a rumoured H. P. Lovecraft notebook, “The Miskatonic Manuscript”, which Lovecraft alluded to in correspondence but which has never been found. At the time, Lovecraft was visiting Worthy's great-uncle, Henry Annesley, who was conducting curious experiments aimed at seeing things beyond the range of human perception. It was right after this period that Lovecraft wrote his breakthrough story “From Beyond”. Worthy suspects that the story was based upon Henry Annesley's experiments, which may have opened a technological path to the other worlds described in Lovecraft's fiction and explored by Church of Cthulhu members through their sacraments.

After discussing the odd career of Lovecraft, Worthy offers a handsome finder's fee to Matthew for the notebook. Matthew accepts. The game, on the leisurely time scale of the rare book world, is afoot. And finally, the manuscript is located.

And now things start to get weird—very weird—Lovecraft weird. A mysterious gadget arrives with instructions to plug it into a computer. Impossible crimes. Glowing orbs. Secret laboratories. Native American shamans. Vortices. Big hungry things with sharp teeth. Matthew and Chantal find themselves on an adventure as risky and lurid as those on the Golden Age pulp science fiction shelves of the bookstore.

Along with the adventure (in which a hero cat, Tabbyhunter, plays a key part), there are insightful quotes about the millennia humans have explored alternative realities through the use of plants placed on the Earth for that purpose by Nature's God, and the folly of those who would try to criminalise that human right through a coercive War on Drugs. The book concludes with a teaser for the next adventure, which I eagerly await. The full text of H. P. Lovecraft's “From Beyond” is included; if you've read the story before, you'll look at it an another light after reading this superb novel. End notes provide citations to items you might think fictional until you discover the extent to which we're living in the Crazy Years.

Drug warriors, law 'n order fundamentalists, prudes, and those whose consciousness has never dared to broach the terrifying “what if” there's something more than we usually see out there may find this novel offensive or even dangerous. Libertarians, the adventurous, and lovers of a great yarn will delight in it. The cover art is racy, even by the standards of pulp, but completely faithful to the story.

The link above is to the Kindle edition, which is available from Amazon. The hardcover, in a limited edition of 650 copies, numbered and signed by the author, is available from the publisher via AbeBooks.

Posted at 15:03 Permalink

Thursday, December 10, 2015

Reading List: Astérix: Le Papyrus de César

Ferri, Jean-Yves and Didier Conrad. Astérix: Le Papyrus de César. Vanves, France: Editions Albert René, 2015. ISBN 978-2-86497-271-6.
The publication of Julius Cæsar's Commentarii de Bello Gallico (Commentaries on the Gallic War) (August 2007) made a sensation in Rome and amplified the already exalted reputation of Cæsar. Unknown before now, the original manuscript included a chapter which candidly recounted the Roman army's failure to conquer the Gauls of Armorique, home of the fierce warrior Astérix, his inseparable companion Obélix, and the rest of the villagers whose adventures have been chronicled in the thirty-five volumes preceding this one. On the advice of his editor, Bonus Promoplus, Cæsar agrees to remove the chapter chronicling his one reverse from the document which has come down the centuries to us.

Unfortunately for Promoplus, one of his scribes, Bigdata, flees with a copy of the suppressed chapter and delivers it to Doublepolémix, notorious Gallic activist and colporteur sans frontières, who makes the journey to the village of the irréductibles in Armorique.

The Roman Empire, always eager to exploit new technology, has moved beyond the slow diffusion of news by scrolls to newsmongers like Rézowifix, embracing wireless communication. A network of Urgent Delivery Pigeons, operated by pigeon masters like Antivirus, is able to quickly transmit short messages anywhere in the Empire. Unfortunately, like the Internet protocol, messages do not always arrive at the destination nor in the sequence sent….

When news of the missing manuscript reaches Rome, Prompolus mounts an expedition to Gaul to recover it before it can damage the reputation of Cæsar and his own career. With battle imminent, the Gauls resort to Druid technology to back up the manuscript. The story unfolds with the actions, twists, and turns one expects from Astérix, and a satisfying conclusion.

This album is, at this writing, the number one best-selling book at Amazon.fr.

Posted at 16:33 Permalink

Sunday, December 6, 2015

New: Islam and Political Freedom

Is Islam compatible with political freedom? Using data from the Pew Research Center and Freedom House, Islam and Political Freedom explores whether there is a correlation between the percentage of Muslim population of a country and whether it is ranked as “Free”, “Partly Free”, or “Not Free” based upon political and civil rights.

Posted at 16:29 Permalink

Saturday, November 28, 2015

Reading List: The Dorian Files Revealed

Outzen, James D., ed. The Dorian Files Revealed. Chantilly, VA: Center for the Study of National Reconnaissance, 2015. ISBN 978-1-937219-18-5.
We often think of the 1960s as a “can do” time, when technological progress, societal self-confidence, and burgeoning economic growth allowed attempting and achieving great things: from landing on the Moon, global communications by satellite, and mass continental and intercontinental transportation by air. But the 1960s were also a time, not just of conflict and the dissolution of the postwar consensus, but also of some grand-scale technological boondoggles and disasters. There was the XB-70 bomber and its companion F-108 fighter plane, the Boeing 2707 supersonic passenger airplane, the NERVA nuclear rocket, the TFX/F-111 swing-wing hangar queen aircraft, and plans for military manned space programs. Each consumed billions of taxpayer dollars with little or nothing to show for the expenditure of money and effort lavished upon them. The present volume, consisting of previously secret information declassified in July 2015, chronicles the history of the Manned Orbiting Laboratory, the U.S. Air Force's second attempt to launch its own astronauts into space to do military tasks there.

The creation of NASA in 1958 took the wind out of the sails of the U.S. military services, who had assumed it would be they who would lead on the road into space and in exploiting space-based assets in the interest of national security. The designation of NASA as a civilian aerospace agency did not preclude military efforts in space, and the Air Force continued with its X-20 Dyna-Soar, a spaceplane intended to be launched on a Titan rocket which would return to Earth and land on a conventional runway. Simultaneous with the cancellation of Dyna-Soar in December 1963, a new military space program, the Manned Orbiting Laboratory (MOL) was announced.

MOL would use a modified version of NASA's Gemini spacecraft to carry two military astronauts into orbit atop a laboratory facility which they could occupy for up to 60 days before returning to Earth in the Gemini capsule. The Gemini and laboratory would be launched by a Titan III booster, requiring only a single launch and no orbital rendezvous or docking to accomplish the mission. The purpose of the program was stated as to “evaluate the utility of manned space flight for military purposes”. This was a cover story or, if you like, a bald-faced lie.

In fact, MOL was a manned spy satellite, intended to produce reconnaissance imagery of targets in the Soviet Union, China, and the communist bloc in the visual, infrared, and radar bands, plus electronic information in much higher resolution than contemporary unmanned spy satellites. Spy satellites operating in the visual spectrum lost on the order of half their images to cloud cover. With a man on board, exposures would be taken only when skies were clear, and images could be compensated for motion of the spacecraft, largely eliminating motion blur. Further, the pilots could scan for “interesting” targets and photograph them as they appeared, and conduct wide-area ocean surveillance.

None of the contemporary drawings showed the internal structure of the MOL, and most people assumed it was a large pressurised structure for various experiments. In fact, most of it was an enormous telescope aimed at the ground, with a 72 inch (1.83 metre) mirror and secondary optics capable of very high resolution photography of targets on the ground. When this document was declassified in 2015, all references to its resolution capability were replaced with statements such as {better than 1 foot}. It is, in fact, a simple geometrical optics calculation to determine that the diffraction-limited resolution of a 1.83 metre mirror in the visual band is around 0.066 arc seconds. In a low orbit suited to imaging in detail, this would yield a resolution of around 4 cm (1.6 inches) as a theoretical maximum. Taking optical imperfections, atmospheric seeing, film resolution, and imperfect motion compensation into account, the actual delivered resolution would be about half this (8 cm, 3.2 inches). Once they state the aperture of the primary mirror, this is easy to work out, so they wasted a lot of black redaction ink in this document. And then, on page 102, they note (not redacted), “During times of crisis the MOL could be transferred from its nominal 80-mile orbit to one of approximately 200–300 miles. In this higher orbit the system would have access to all targets in the Soviet Bloc approximately once every three days and be able to take photographs at resolutions of about one foot.” All right, if they have one foot (12 inch) resolution at 200 miles, then they have 4.8 inch (12 cm) resolution at 80 miles (or, if we take 250 miles altitude, 3.8 inches [9.7 cm]), entirely consistent with my calculation from mirror aperture.

This document is a management, financial, and political history of the MOL program, with relatively little engineering detail. Many of the technological developments of the optical system were later used in unmanned reconnaissance satellite programs and remain secret. What comes across in the sorry history of this program, which, between December 1963 and its cancellation in June of 1969 burned through billions of taxpayer dollars, is that the budgeting, project management, and definition and pursuit of well-defined project goals was just as incompetent as the redaction of technical details discussed in the previous paragraph. There are almost Marx brothers episodes where Florida politicians attempted to keep jobs in their constituencies by blocking launches into polar orbit from Vandenberg Air Force Base while the Air Force could not disclose that polar orbits were essential to overflying targets in the Soviet Union because the reconnaissance mission of MOL was a black program.

Along with this history, a large collection of documents and pictures, all previously secret (and many soporifically boring) has been released. As a publication of the U.S. government, this work is in the public domain.

Posted at 22:36 Permalink

Sunday, November 15, 2015

Reading List: What If?

Munroe, Randall. What If? New York: Houghton Mifflin, 2014. ISBN 978-0-544-27299-6.
As a child, the author would constantly ask his parents odd questions. They indulged and encouraged him, setting him on a lifetime path of curiosity, using the mathematics and physics he learned in the course of obtaining a degree in physics and working in robotics at NASA to answer whatever popped into his head. After creating the tremendously successful Web comic xkcd.com, readers began to ask him the kinds of questions he'd mused about himself. He began a feature on xkcd.com: “What If?” to explore answers to these questions. This book is a collection of these questions, some previously published on-line (where you can continue to read them at the previous link), and some only published here. The answers to questions are interspersed with “Weird (and Worrying) Questions from the What If? Inbox”, some of which are reminiscent of my own Titanium Cranium mailbox. The book abounds with the author's delightful illustrations. Here is a sample of the questions dealt with. I've linked the first to the online article to give you a taste of what's in store for you in the book.

  • Is it possible to build a jetpack using downward firing machine guns?
  • What would happen if you tried to hit a baseball pitched at 90% the speed of light?
  • In the movie 300 they shoot arrows up into the sky and they seemingly blot out the sun. Is this possible, and how many arrows would it take?
  • How high can a human throw something?
  • If every person on Earth aimed a laser pointer at the Moon at the same time, would it change color?
  • How much Force power can Yoda output?
  • How fast can you hit a speed bump while driving and live?

Main belt asteroid 4942 Munroe is named after the author.

While the hardcover edition is expensive for material most of which can be read on the Web for free, the Kindle edition is free to Kindle Unlimited subscribers.

Posted at 21:50 Permalink

Monday, November 2, 2015

Reading List: Farside

Chiles, Patrick. Farside. Seattle: Amazon Digital Services, 2015. ASIN B010WAE080.
Several years after the events chronicled in Perigee (August 2012), Arthur Hammond's Polaris AeroSpace Lines is operating routine point-to-point suborbital passenger and freight service with its Clippers, has expanded into orbital service with Block II Clippers, and is on the threshold of opening up service to the Moon with its “cycler” spacecraft which loop continuously between the Earth and Moon. Clippers rendezvous with the cyclers as they approach the Earth, transferring crew, passengers, cargo, and consumables. Initial flights will be limited to lunar orbit, but landing missions are envisioned for the future.

In the first orbital mission, chartered to perform resource exploration from lunar orbit, cycler Shepard is planning to enter orbit with a burn which will, by the necessities of orbital mechanics, have to occur on the far side of the Moon, out of radio contact with the Earth. At Polaris mission control in Denver, there is the usual tension as the clock ticks down toward the time when Shepard is expected to emerge from behind the Moon, safely in orbit. (If the burn did not occur, the ship would appear before this time, still on a trajectory which would return it to the Earth.) When the acquisition of signal time comes and goes with no reply to calls and no telemetry, tension gives way to anxiety. Did Shepard burn too long and crash on the far side of the Moon? Did its engine explode and destroy the ship? Did some type of total system failure completely disable its communications?

On board Shepard, Captain Simon Poole is struggling to survive after the disastrous events which occurred just moments after the start of the lunar orbit insertion burn. Having taken refuge in the small airlock after the expandable habitation module has deflated, he has only meagre emergency rations to sustain him until a rescue mission might reach him. And no way to signal Earth that he is alive.

What seems a terrible situation rapidly gets worse and more enigmatic when an arrogant agent from Homeland Security barges into Polaris and demands information about the passenger and cargo manifest for the flight, Hammond is visited at home by an unlikely caller, and a jarhead/special operator type named Quinn shows them some darker than black intelligence about their ship and “invites” them to NORAD headquarters to be briefed in on an above top secret project.

So begins a nearish future techno-thriller in which the situations are realistic, the characters interesting, the perils harrowing, and the stakes could not be higher. The technologies are all plausible extrapolations of those available at present, with no magic. Government agencies behave as they do in the real world, which is to say with usually good intentions leavened with mediocrity, incompetence, scheming ambition, envy, and counter-productive secrecy and arrogance. This novel is not going to be nominated for any awards by the social justice warriors who have infiltrated the science fiction writer and fan communities: the author understands precisely who the enemies of civilisation and human destiny are, forthrightly embodies them in his villains, and explains why seemingly incompatible ideologies make common cause against the values which have built the modern world. The story is one of problem solving, adventure, survival, improvisation, and includes one of the most unusual episodes of space combat in all of science fiction. It would make a terrific movie.

For the most part, the author gets the details right. There are a few outright goofs, such as seeing the Earth from the lunar far side (where it is always below the horizon—that's why it's the far side); some errors in orbital mechanics which will grate on players of Kerbal Space Program; the deployed B-1B bomber is Mach 1.25, not Mach 2; and I don't think there's any way the ships in the story could have had sufficient delta-v to rendezvous with a comet so far out the plane of the ecliptic. But I'm not going to belabour these quibbles in what is a rip-roaring read. There is a glossary of aerospace terms and acronyms at the end. Also included is a teaser chapter for a forthcoming novel which I can't wait to read.

Posted at 22:24 Permalink

Sunday, October 25, 2015

Reading List: Concrete Planet

Courland, Robert. Concrete Planet. Amherst, NY: Prometheus Books, 2011. ISBN 978-1-61614-481-4.
Visitors to Rome are often stunned when they see the Pantheon and learn it was built almost 19 centuries ago, during the reign of the emperor Hadrian. From the front, the building has a classical style echoed in neo-classical government buildings around the world, but as visitors walk inside, it is the amazing dome which causes them to gasp. At 43.3 metres in diameter, it was the largest dome ever built in its time, and no larger dome has, in all the centuries since, ever been built in the same way. The dome of the Pantheon is a monolithic structure of concrete, whose beauty and antiquity attests to the versatility and durability of this building material which has become a ubiquitous part of the modern world.

To the ancients, who built from mud, stone, and later brick, it must have seemed like a miracle to discover a material which, mixed with water, could be moulded into any form and would harden into stone. Nobody knows how or where it was discovered that by heating natural limestone to a high temperature it could be transformed into quicklime (calcium oxide), a corrosive substance which reacts exothermically with water, solidifying into a hard substance. The author speculates that the transformation of limestone into quicklime due to lightning strikes may have been discovered in Turkey and applied to production of quicklime by a kilning process, but the evidence for this is sketchy. But from the neolithic period, humans discovered how to make floors from quicklime and a binder, and this technology remained in use until the 19th century.

All of these early lime-based mortars could not set underwater and were vulnerable to attack by caustic chemicals. It was the Romans who discovered that by mixing volcanic ash (pozzolan), which was available to them in abundance from the vicinity of Mt. Vesuvius, it was possible to create a “hydraulic cement” which could set underwater and was resistant to attack from the elements. In addition to structures like the Pantheon, the Colosseum, roads, and viaducts, Roman concrete was used to build the artificial harbour at Caesarea in Judea, the largest application of hydraulic concrete before the 20th century.

Jane Jacobs has written that the central aspect of a dark age is not that specific things have been forgotten, but that a society has forgotten what it has forgotten. It is indicative of the dark age which followed the fall of the Roman empire that even with the works of the Roman engineers remaining for all to see, the technology of Roman concrete used to build them, hardly a secret, was largely forgotten until the 18th century, when a few buildings were constructed from similar formulations.

It wasn't until the middle of the 19th century that the precursors of modern cement and concrete construction emerged. The adoption of this technology might have been much more straightforward had it not been the case that a central player in it was William Aspdin, a world-class scoundrel whose own crookedness repeatedly torpedoed ventures in which he was involved which, had he simply been honest and straightforward in his dealings, would have made him a fortune beyond the dreams of avarice.

Even with the rediscovery of waterproof concrete, its adoption was slow in the 19th century. The building of the Thames Tunnel by the great engineers Marc Brunel and his son Isambard Kingdom Brunel was a milestone in the use of concrete, albeit one achieved only after a long series of setbacks and mishaps over a period of 18 years.

Ever since antiquity, and despite numerous formulations, concrete had one common structural property: it was very strong in compression (it resisted forces which tried to crush it), but had relatively little tensile strength (if you tried to pull it apart, it would easily fracture). This meant that concrete structures had to be carefully designed so that the concrete was always kept in compression, which made it difficult to build cantilevered structures or others requiring tensile strength, such as many bridge designs employing iron or steel. In the latter half of the 19th century, a number of engineers and builders around the world realised that by embedding iron or steel reinforcement within concrete, its tensile strength could be greatly increased. The advent of reinforced concrete allowed structures impossible to build with pure concrete. In 1903, the 16-story Ingalls Building in Cincinnati became the first reinforced concrete skyscraper, and the tallest building today, the Burj Khalifa in Dubai, is built from reinforced concrete.

The ability to create structures with the solidity of stone, the strength of steel, in almost any shape a designer can imagine, and at low cost inspired many in the 20th century and beyond, with varying degrees of success. Thomas Edison saw in concrete a way to provide affordable houses to the masses, complete with concrete furniture. It was one of his less successful ventures. Frank Lloyd Wright quickly grasped the potential of reinforced concrete, and used it in many of his iconic buildings. The Panama Canal made extensive use of reinforced concrete, and the Hoover Dam demonstrated that there was essentially no limit to the size of a structure which could be built of it (the concrete of the dam is still curing to this day). The Sydney Opera House illustrated (albeit after large schedule slips, cost overruns, and acrimony between the architect and customer) that just about anything an architect can imagine could be built of reinforced concrete.

To see the Pantheon or Colosseum is to think “concrete is eternal” (although the Colosseum is not in its original condition, this is mostly due to its having been mined for building materials over the centuries). But those structures were built with unreinforced Roman concrete. Just how long can we expect our current structures, built from a different kind of concrete and steel reinforcing bars to last? Well, that's…interesting. Steel is mostly composed of iron, and iron is highly reactive in the presence of water and oxygen: it rusts. You'll observe that water and oxygen are abundant on Earth, so unprotected steel can be expected to eventually crumble into rust, losing its structural strength. This is why steel bridges, for example, must be regularly stripped and repainted to provide a barrier which protects the steel against the elements. In reinforced concrete, it is the concrete itself which protects the steel reinforcement, initially by providing an alkali environment which inhibits rust and then, after the concrete cures, by physically excluding water and the atmosphere from the reinforcement. But, as builders say, “If it ain't cracked, it ain't concrete.” Inevitably, cracks will allow air and water to reach the reinforcement, which will begin to rust. As it rusts, it loses its structural strength and, in addition, expands, which further cracks the concrete and allows more air and moisture to enter. Eventually you'll see the kind of crumbling used to illustrate deteriorating bridges and other infrastructure.

How long will reinforced concrete last? That depends upon the details. Port and harbour facilities in contact with salt water have failed in less than fifty years. Structures in less hostile environments are estimated to have a life of between 100 and 200 years. Now, this may seem like a long time compared to the budget cycle of the construction industry, but eternity it ain't, and when you consider the cost of demolition and replacement of structures such as dams and skyscrapers, it's something to think about. But obviously, if the Romans could build concrete structures which have lasted millennia, so can we. The author discusses alternative formulations of concrete and different kinds of reinforcing which may dramatically increase the life of reinforced concrete construction.

This is an interesting and informative book, but I found the author's style a bit off-putting. In the absence of fact, which is usually the case when discussing antiquity, the author simply speculates. Speculation is always clearly identified, but rather than telling a story about a shaman discovering where lightning struck limestone and spinning it unto a legend about the discovery of manufacture of quicklime, it might be better to say, “nobody really knows how it happened”. Eleven pages are spent discussing the thoroughly discredited theory that the Egyptian pyramids were made of concrete, coming to the conclusion that the theory is bogus. So why mention it? There are a number of typographical errors and a few factual errors (no, the Mesoamericans did not build pyramids “a few of which would equal those in Egypt”).

Still, if you're interested in the origin of the material which surrounds us in the modern world, how it was developed by the ancients, largely forgotten, and then recently rediscovered and used to revolutionise construction, this is a worthwhile read.

Posted at 23:30 Permalink

Monday, October 19, 2015

Reading List: The Road to Relativity

Einstein, Albert, Hanock Gutfreund, and Jürgen Renn. The Road to Relativity. Princeton: Princeton University Press, 2015. ISBN 978-0-691-16253-9.
One hundred years ago, in 1915, Albert Einstein published the final version of his general theory of relativity, which extended his 1905 special theory to encompass accelerated motion and gravitation. It replaced the Newtonian concept of a “gravitational force” acting instantaneously at a distance through an unspecified mechanism with the most elegant of concepts: particles not under the influence of an external force move along spacetime geodesics, the generalisation of straight lines, but the presence of mass-energy curves spacetime, which causes those geodesics to depart from straight lines when observed at a large scale.

For example, in Newton's conception of gravity, the Earth orbits the Sun because the Sun exerts a gravitational force upon the Earth which pulls it inward and causes its motion to depart from a straight line. (The Earth also exerts a gravitational force upon the Sun, but because the Sun is so much more massive, this can be neglected to a first approximation.) In general relativity there is no gravitational force. The Earth is moving in a straight line in spacetime, but because the Sun curves spacetime in its vicinity this geodesic traces out a helix in spacetime which we perceive as the Earth's orbit.

Now, if this were a purely qualitative description, one could dismiss it as philosophical babble, but Einstein's theory provided a precise description of the gravitational field and the motion of objects within it and, when the field strength is strong or objects are moving very rapidly, makes different predictions than Newton's theory. In particular, Einstein's theory predicted that the perihelion of the orbit of Mercury would rotate around the Sun more rapidly than Newton's theory could account for, that light propagating near the limb of the Sun or other massive bodies would be bent through twice the angle Newton's theory predicted, and that light from the Sun or other massive stars would be red-shifted when observed from a distance. In due course all of these tests have been found to agree with the predictions of general relativity. The theory has since been put to many more precise tests and no discrepancy with experiment has been found. For a theory which is, once you get past the cumbersome mathematical notation in which it is expressed, simple and elegant, its implications are profound and still being explored a century later. Black holes, gravitational lensing, cosmology and the large-scale structure of the universe, gravitomagnetism, and gravitational radiation are all implicit in Einstein's equations, and exploring them are among the frontiers of science a century hence.

Unlike Einstein's original 1905 paper on special relativity, the 1915 paper, titled “Die Grundlage der allgemeinen Relativitätstheorie” (“The Foundation of General Relativity”) is famously difficult to comprehend and baffled many contemporary physicists when it was published. Almost half is a tutorial for physicists in Riemann's generalised multidimensional geometry and the tensor language in which it is expressed. The balance of the paper is written in this notation, which can be forbidding until one becomes comfortable with it.

That said, general relativity can be understood intuitively the same way Einstein began to think about it: through thought experiments. First, imagine a person in a stationary elevator in the Earth's gravitational field. If the elevator cable were cut, while the elevator was in free fall (and before the sudden stop), no experiment done within the elevator could distinguish between the state of free fall within Earth's gravity and being in deep space free of gravitational fields. (Conversely, no experiment done in a sufficiently small closed laboratory can distinguish it being in Earth's gravitational field from being in deep space accelerating under the influence of a rocket with the same acceleration as Earth's gravity.) (The “sufficiently small” qualifier is to eliminate the effects of tides, which we can neglect at this level.)

The second thought experiment is a bit more subtle. Imagine an observer at the centre of a stationary circular disc. If the observer uses rigid rods to measure the radius and circumference of the disc, he will find the circumference divided by the radius to be 2π, as expected from the Euclidean geometry of a plane. Now set the disc rotating and repeat the experiment. When the observer measures the radius, it will be as before, but at the circumference the measuring rod will be contracted due to its motion according to special relativity, and the circumference, measured by the rigid rod, will be seen to be larger. Now, when the circumference is divided by the radius, a ratio greater than 2π will be found, indicating that the space being measured is no longer Euclidean: it is curved. But the only difference between a stationary disc and one which is rotating is that the latter is in acceleration, and from the reasoning of the first thought experiment there is no difference between acceleration and gravity. Hence, gravity must bend spacetime and affect the paths of objects (geodesics) within it.

Now, it's one thing to have these kinds of insights, and quite another to puzzle out the details and make all of the mathematics work, and this process occupied Einstein for the decade between 1905 and 1915, with many blind alleys. He eventually came to understand that it was necessary to entirely discard the notion of any fixed space and time, and express the equations of physics in a way which was completely independent of any co-ordinate system. Only this permitted the metric structure of spacetime to be completely determined by the mass and energy within it.

This book contains a facsimile reproduction of Einstein's original manuscript, now in the collection of the Hebrew University of Jerusalem. The manuscript is in Einstein's handwriting which, if you read German, you'll have no difficulty reading. Einstein made many edits to the manuscript before submitting it for publication, and you can see them all here. Some of the hand-drawn figures in the manuscript have been cut out by the publisher to be sent to an illustrator for preparation of figures for the journal publication. Parallel to the manuscript, the editors describe the content and the historical evolution of the concepts discussed therein. There is a 36 page introduction which describes the background of the theory and Einstein's quest to discover it and the history of the manuscript. An afterword provides an overview of general relativity after Einstein and brief biographies of principal figures involved in the development and elaboration of the theory. The book concludes with a complete English translation of Einstein's two papers given in the manuscript.

This is not the book to read if you're interested in learning general relativity; over the last century there have been great advances in mathematical notation and pedagogy, and a modern text is the best resource. But, in this centennial year, this book allows you to go back to the source and understand the theory as Einstein presented it, after struggling for so many years to comprehend it. The supplemental material explains the structure of the paper, the essentials of the theory, and how Einstein came to develop it.

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