German Researcher Discovers Most Efficient Path to Mars

A civil engineer in Essen, Germany has determined the transfer orbit which will get astronauts to Mars the quickest.

Walter Hohmann, a civil engineer, spent several years studying physics and astronomy before publishing his book The Attainability of the Celestial Bodies. It may become required reading for NASA mission planners.

Fuel requirements will be central to the architecture of interplanetary spaceflights, Dr. Hohmann expects. To account for this, he solved for the trajectory which requires the least amount of velocity change, or what scientists call “delta V”. Spacecraft produce this acceleration by firing rocket engines.

The most efficient orbit between two planets turned out to be an ellipse that lies tangent to the planets’ orbital paths.


Source: University of Arizona

Such an orbit requires the least amount of energy to achieve when starting from Earth, but has a serious drawback. Least-energy trajectories are also the slowest. For a crewed mission, taking along enough food and oxygen could make a less efficient path ultimately cheaper.

Another problem is waiting for planets to be in the right place for launch. Because Earth orbits the sun faster than the outer planets and slower than the inner planets, the possible alignment for such a transfer trajectory only occurs occasionally. The window to leave for Mars only opens every two years, for example. Launching interplanetary spacecraft at other times would require vastly more fuel.

Nevertheless, astronomers and aerospace engineers find Dr. Hohmann’s discovery extremely useful for designing space missions.

Happy Amazing Breakthrough Day!

Book Review: Your Inner Fish

This book is not what I expected, but quite pleasurable to read nonetheless. Your Inner Fish does not detail the ichthyologic nature of the human body. Rather, it explores how fish moved onto land, where many now-ubiquitous adaptations came from, and how scientists figured it out.

Dr. Shubin begins with the story we all came to hear: how his team of paleontologists discovered Tiktaalik Roseae. This ancient, shallow-water fish  Tiktaalik is an important transitional fossil because it was one of the first discovered with rudimentary hands. Biologists comparing the limbs of species noticed pattern in the limbs of land animals as far back as the mid-1800s. This patter held only for land-adapted species—reptiles, amphibians, mammals (including aquatic mammals that returned to the seas).

For a long time, it was believed that fish don’t exhibit this pattern. Then lungfish were discovered: living fossils which exemplify, in some ways, the transition from ocean to land. As their name implies, they possess basic lungs, and, interestingly, the beginnings of limbs.

Tiktaalik was an improvement on the lungfish. It had a flat head, for swimming in shallow water, and fin bones that show the beginning of a wrist. Together, we see why fins evolved into arms: shallow water fish needed to do pushups. In their fish-eat-fish world, the ability to push oneself through extra-shallow patches was likely a critical advantage.

Let me tell you, exercising seems a lot less mundane when you consider that your lungfish ancestors did it to survive. That’s what your arms evolved to do. It’s only more recently we found further applications for them.

Throughout this book, Shubin is trying to explain how scientists managed to figure out our evolutionary history. He has perhaps a unique perspective to explain this process, as a paleontologist turned anatomy professor. Knowing what came before helps explain the ways in which earlier species were contorted to become the ones we see today.

Comparative anatomy and the fossil record tell us a lot about how modern species came to be. But genetics also offers considerable insight. Looking at the differences between genomes can tell us a lot about how recently certain categories of features evolved. In many cases, we can take genes from mice or fish and insert them into the DNA of invertebrates like fruit flies and get the same result. Such experiments are strong evidence that features like body plans and eyes evolved a really long time ago.

To be clear, there’s a lot of uncertainty which can probably never be resolved. We can prod algae in tanks to evolve the beginnings of multicellular bonding, but we have no idea if that particular direction is the one that our forerunners took.

Nevertheless, Your Inner Fish gives a good overview of how bacteria became bugs and fish, and how those bugs and fish became the bugs, fish, and people alive today. I certainly came away with an improved picture of how weird our bodies are and their many imperfections, though far from the whole picture. My curious is fairly sated, however—I’ve no plans to read the kinds of human anatomy texts I would need to really appreciate the magnitude of making men from microbes.

All told, I’d recommend Your Inner Fish as an entertaining and informative read about how human beings came to be. Neil Shubin has packed a lot of interesting scientific research into it, and with the exception of an example about hypothetical clown people in the final chapter, does a pretty good job of explaining it clearly. Definitely worth your time if the history of life on Earth intrigues you.


Do You Hate Math or Just Counting?

Last weekend KU held their annual Engineering Expo, a fairly typical sort of event for trying to get little kids interested in science and engineering. If you’re unsure what that might entail, come drop by next year.

Presumably this is fun for the little kids—most of them seemed pretty enthusiastic, and I never went to such events myself. And it’s fun for most of the students putting it on. We get to hang out with our friends, tell people about our majors, and get a day off class (though could you maybe have not scheduled it during midterms this year?). Half the fun is getting set up beforehand.

Because we’re nerds, we covered most of the leftover whiteboard space in the SEDS room with various engineering equations: thermo, flight dynamics, orbital mechanics, even the definition of a derivative. This predictably elicited a number of comments, mostly from parents but also from the kids themselves, about how much they hate(d) math.

This was particularly striking to me because when I was that age, I hated math. Or rather, hated what I thought was math. In elementary school, I didn’t know very much math. Pretty much all I knew how to do was glorified counting.

Addition? Counting. Subtraction? Backwards counting. Multiplication? Fast counting. Division? Backwards fast counting. Medians and means? Counting!

This pattern holds when we move onto the secondary school subjects. Algebra is almost entirely about counting graphically. Not all of geometry is counting, but a good fraction of it—vectors, for example—is. The same goes for a lot of trigonometry.

Only when you get to calculus, a senior year subject if it’s on the table at all, do you really start focusing on relationships versus the raw numbers. Calculus was the first math class which I enjoyed. That was the first time math became a tool rather than an obstacle. (Consistently, at least.)

A lot of students abandon mathematics long before they get to the stage where it becomes useful and meaningful. This concerns me. While there are plenty of people whose brains just aren’t made for math, there’s also a lot of great minds being lost because they aren’t made for endless dull arithmetic.

Spend years struggling away with contrived problems, truth held outside of grasp, and well, yes, giving up is certainly a reasonable response. You spent the last fifty years making science and math inaccessible and now, dear politicians and school administrators, you lament that more kids aren’t studying engineering. Behold the completely predictable consequences of your actions.

But this is not just an intellectual problem, or even an economic one. It’s a political nightmare.

Learning integral calculus completely rebuilt my perception of government finance. Just gaining an appreciation for statistics made me rethink dozens of policy positions. And yet I’d bet half our sitting Senators don’t even know what “differentiation” means. This should scare us shitless when they’re trying to plan for the next year, yet alone the next ten or twenty.

I hope that we changed a few minds last weekend, or at least planted a seed of doubt.  If technological civilization is going to survive the next 100 years, we need to rethink the way our culture approaches math and science. I’m severely tempted to do pro bono math education out of fear, but a few college kids can’t do it alone.

So, for your children’s sake: Do you hate math, or just counting?

Book Review: All The Birds In The Sky

[Note: I read this book on the recommendation of my now ex-girlfriend, and I can confidently say that that affected my reaction to the novel. Consider that as you will.]

I have mixed feelings about this one.

On the positive side, the writing is pretty good. I was sufficiently engaged to keep reading, even when I wanted to sit down the characters and lecture them about their life choices. For the most part, the plot was coherent and didn’t tend to lose me.

But those characters. My opinion of them turned negative in the first few chapters and never really recovered. Once the plot got rolling my feelings ended up relatively neutral, which is….less than one would hope for, given such explicit protagonists. The building action felt kind of drawn out, so this non-negative period was somewhat protracted.

One could justify such extended exposition in the service of extensive worldbuilding, but we don’t really get that. I spent a good part of the book wondering about the details of the disasters unfolding out-of-frame and the magical world Patricia disappeared into. We get a pseudo-explanation of the latter in the final chapter, but the resolution felt pretty forced and didn’t clear up very many loose ends. The denouement was about two pages.

Maybe there’s going to be a sequel that explores these things further. The book only came out this year, so who knows.

However, this frustration helped me realize something about myself: the reason I can’t write fiction is that I’m far more interested in building up a world than any story that could be set within it. Maybe I should team up with a plotmeister who wants to break into sci-fi. Contact me if you’re interested.

At this point it should be clear, dear reader, that I’m not exactly qualified to comment on the writing of science fiction novels, but in the spirit of the characters, I’m going to offer some recommendations anyway.

Firstly, if major plot issues could be resolved by better communication between the characters, it’s nice to give readers a reason why the characters aren’t having those much-needed conversations. Yes, it is possible that no one thinks to ask. But our protagonists are a genius and a literal witch (whose main character flaw is caring too much). I have questions if nothing else. Like, maybe I’m unusually inquisitive but Laurence seemed strangely accepting that actual for-real magic has suddenly appeared in his life.

Speaking of magic, there was a weird theme of techies-can’t-into-ethics running through the book which doesn’t really make sense in context (the book, or the real world). At one point, Patricia is chastising Laurence’s worldview for thinking that saving humanity is more important than saving the entire biosphere, a mere stretch goal for the story’s counterfactual SpaceX.

Patricia, you can talk to animals. You can heal HIV with a single touch. You can cut deals with space-time itself. Ordinary humans are playing an entirely different game.

This gets back into the communication thing. Convinced a team of mad scientists prodigious engineers are about to destroy the world? Have you tried talking to them about the risks involved?

Not that tech-types are liable to destroy the world, seeing as they’re some of the only people I’m aware of with any serious interest in solving morality, out of concerns that an artificial intelligence needs a coherent ethical system before we turn it on. Nick Bostrom calls this problem philosophy with a deadline. You can dismiss this claim if you want, I can’t stop you, but when one of the characters is an AI, then it’s, well, weird.

To be fair, it was awakened to consciousness and gets a lot of early training from Patricia, so talking to witches might be a good AI safety strategy. Shame MIRI can’t try that.

What was I talking about? Oh, right, YA near-future apocalyptic meets urban fantasy novel. Does it count as Young Adult when there’s a moderately explicit sex scene? I don’t remember if they covered that at WorldCon.

My final recommendation has to do with character development. Namely, if you go through great lengths to make a villain sympathetic, do give them some sort of redemption arc. We’re given a front-row seat to a cold-blooded assassin developing a conscience in the halls of an unsettlingly exaggerated portrayal of middle-school misery, and then—anti-climax. His scheme is foiled and his later appearances show few signs of further development. He’s still harking on the same MacGuffin, which we haven’t exactly forgotten about. So I’m not really sure what he’s doing here.

And it’s not that Anders is just bad at character re-introduction, because she does a pretty good job with several other reintroductions between sections. So I’m not sure what’s going on with him in particular. Perhaps it’s a touch of genre-bending realism.

So is All the Birds in the Sky worth recommending to the young adult reader in your life? As with so many things in life, that depends. Looking for some light entertainment? Go for it. Want a thought-provoking novel? There are better books out there. Expecting a well-developed science fantasy world? You might be disappointed.


Prediction and Primacy of Consciousness

I finished Leonard Peikoff’s Objectivism: The Philosophy of Ayn Rand in 2015, and on the whole, didn’t get that much out of it. It took a long time to slog through, and didn’t answer some of my longstanding questions about Rand’s intellectual history. I’d recommend it as a reference text, but not as an introduction to Objectivism.

This isn’t a review of OPAR; I’ve discussed it elsewhere. Today we’re going to discuss one of the few good new ideas I learned reading it: primacy of consciousness.

Objectivism advocates a worldview based on primacy of existence. Rand holds that consciousness has no power over reality in and of itself—consciousness is the processes of identifying existents, not creating them. Now a conscious mind can decide to alter existents through physical action, or extrapolate the possibility of not-yet-existing existents, but the mere act of thinking cannot produce physical phenomena.1

Primacy of consciousness puts the cart before the horse. Perception can neither create a percept, nor modify it, nor uncreate it.2 Sufficiently invasive methods of inquiry may do that, but the mental process of observation does not.

Let us consider a technical example. When solving engineering assignments, it is often tempting to avoid checking my work. The correct answer is independent of whether I’ve made an exhaustive search for mistakes. Yet, on a certain level, it might seem that not looking will make an error go away.

But it won’t. As my structures professor often says, in aerospace engineering we have a safety factor of 1.5. In school, that’s just a target to aim for—if I screw up, the grade will point it out and I’ll feel silly for missing easy points. On the job, that’s not the case. If your work has a serious mistake, you’re going to kill people.

Or wreck the global economy.

Since starting Nate Silver’s book, perhaps the most interesting thing I’ve learned so far (besides an actually intuitive explanation of Bayes’ Theorem, contra Yudkowsky) was just how stupid the root causes of the housing crisis were.

I’d recommend reading the book if you’d like a properly comprehensive explanation, but the executive summary would be that, starting in the late 1990s, the value of houses began to skyrocket in what we now know was a real estate bubble. This was basically unprecedented in US history, which should have been a wake-up call in itself, but the problem was compounded by the fact that many investors assumed that housing prices would keep going up. They wanted to bet on these increasingly risky properties, creating all sorts of creative “assets” to bundle specious loans together. Rating agencies were happy to evaluate all of these AAA, despite being totally new and untested financial instruments. Estimated risk of default proved to be multiple orders of magnitude too low. And yet everyone believed them.

Silver describes this as a failure of prediction, of epistemology. Assessors made extremely questionable assumptions about the behavior of the economy and the likelihood of mortgage default, which are legitimate challenges in developing predictive models. Going back to my examples of structural engineering, it’s easy to drop the scientific notation on a material property when crunching the numbers. If you say that aluminum has a Young’s Modulus of 10.7, the model isn’t going to know that you meant 10.7 × 106 psi or 10.7 Msi. It’s going to run the calculations regardless of whether your other units match up, and may get an answer that’s a million times too big. Remember that your safety margin is 1.5.

I don’t think economic forecasters have explicit margins of error, but the same general principle applies. Using the wrong Young’s Modulus is an honest mistake, an accident, which is easily rectified if found early. Lots of errors in the rating agencies’ models weren’t so honest. They made what looked like big allowances for unknowns, but didn’t question a lot of their key assumptions. This speaks to a real failure of epistemic humility. They didn’t ask themselves, deep down, if their model was wrong. Not the wrong inputs, but the wrong equations entirely.

For instance, say I model an airplane’s wing as a beam, experiencing bending and axial loads, but no axial torsion. That’s a very big assumption. Say there’s engines mounted on the wing—now I’m just ignoring Physics 101. If I ran the numbers and decided that propulsive and aerodynamic twisting moments were insignificant for the specific question I’m considering, then it might be an acceptable assumption. But I would need to run the numbers.

Many people, at many organizations, didn’t run the numbers in the years leading up to the financial crisis. Now not all of them were given an explicit choice—many were facing managerial pressure to meet deadlines or get specific outputs. That’s an organizational issue, but really just bumps the responsibility up a level.3 Managers should want the correct answer, not the one that would put the biggest smile on their face.

In aerospace engineering, we have an example of what happens when you do that:


Just because the numbers look good on paper doesn’t mean they correspond to the real world. Empirical testing is where that comes in. Engineers do that all the time, but even then, it doesn’t prevent organization incentives from bungling the truth. If the boss wants to hear a particular answer, she may keep looking until she finds it.

Economists are worse, trying to predict a massively nonlinear system and, Silver reports, doing quite badly at it. Objectivism is very strong on the importance of saying I know, but rationality also depends on saying I don’t know when you legitimately don’t. Try to find out, but accept that some truths are harder to obtain than others.

Existence exists, and existents don’t care what you think.

1Outside of your body, that is. This is where the line between body and mind becomes pertinent and about where I give up over reducibility problems. Suffice to say that if you can create matter ex nihilo, there’s a lot of people who would be interested in speaking with you.

2Those of you with itchy fingers about quantum mechanics are politely invited to get a graduate degree in theoretical physics. We’re talking about the macroscale here.

3Not that responsibility is a thing that can truly be distributed:

Responsibility is a unique concept… You may share it with others, but your portion is not diminished. You may delegate it, but it is still with you… If responsibility is rightfully yours, no evasion, or ignorance or passing the blame can shift the burden to someone else. Unless you can point your finger at the man who is responsible when something goes wrong, then you have never had anyone really responsible.
 —Admiral Hyman G. Rickover, USN

Book Review: Guns, Germs, and Steel

For many years, I did not expect to like this book.

Jared Diamond has something of a reputation for primitivism—arguing that hunter-gatherer societies are actually better off than our own. I found this position abhorrent as an Objectivist and wanted to hear nothing of it.

Then, around a year ago, educational YouTuber C.G.P. Grey made a pair of videos* summarizing certain aspects of Diamond’s book. The theory, as presented there, made a lot of sense and piqued my interest. A few months later I purchased a copy of Guns, Germs, and Steel from my local Half Price Books and eventually got around to reading it.

It turned out to be really good.

First of all, Diamond’s position on agricultural civilization is much more considered than many give him credit for. In the course of his anthropological research he’s spent many months living with modern hunter-gatherer societies, experiencing that sort of existence first-hand. Diamond says that his “own impression, from having divided my life between United States cities and New Guinea villages, is that the so-called blessing of civilization are mixed.” He goes on to discuss the various benefits that extremely low-tech societies realize: better family ties, richer social life, and considerably more free time.

His argument, then, is less that industrial civilization is necessarily bad, so much as that it comes with trade-offs. These trade-offs were far more salient for pre-Renaissance agricultural societies, for whom producing enough food to survive took nearly all available resources, and which were subsequently ravaged by war, disease, and famine on a level which pre-agricultural peoples almost never experienced.

But if the hunter-gatherer lifestyle is so great, why didn’t it stick around? The answer is simple enough: agricultural societies out-competed them. Farming allows a much larger population to subsist on the same land, and additionally allows for the development of professions—specialists not directly involved with food production. With a few exceptions, agricultural societies assimilated, displaced, outbred, or simply exterminated their less advanced neighbors.

So why did certain agricultural societies get an upper hand on the others? This is the real question of Diamond’s book.

His answer comes down to one word: geography. The orientation of the continents, the climate at various locations, and similar factors dictated what early humans had available to work with. The Americas and Africa, on their North-South axes, were at a significant disadvantage compared to Eurasia’s East-West axis. Plants and animals spread over a much wider area, increasing the odds that a human population would have the opportunity to domesticate them.

Thus the Americas and Africa ended up with a much slower diffusion of agriculture. (Australia had it even worse.) While industrial civilization might have developed there, it would have been much later. Eurasian colonization cut such trajectories short.

Diamond rejects the notion that certain peoples’ inherent superiority was the fundamental driver of historical progress. Over the course of millennia, cultural and genetic mutation would have been sufficient to make such factors irrelevant. Societies which disregard the advantages of any particular technology don’t tend to stick around very long. Thus human cultures tend to be near the full potential set by their geographic conditions.

We can observe this through natural experiments, the colonization of Polynesia in the last 2,000 years being a prime example. Austronesians, expanding out of Formosa, landed on nearly every Pacific island, and settled pretty much any scrap of land that can support human populations. These ranged from proto-empires in Hawaii and Fiji, to hunter-gatherers on the cold southern Chathams, which were conquered by New Zealand Maoris wielding European firearms in 1835. It also includes tiny Anuta, which despite a population of less than 200 realized an extremely high population density through advanced agriculture.

In a similar manner, Diamond explores the development of African, American Australian, Chinese, and European cultures in the context of geographic determinism. Of particular note is the impact of states on technology. China, a single political unit, abandoned oceanic exploration due to internal factionalism, and never expended the capital costs necessary to resume. Europe, alternatively, was never truly unified, and so never stopped exploration altogether.

Several chapters are devoted specifically to literacy, technology, and political theory. I think a few of my libertarian friends would find them quite interesting, particularly those concerned with what a stateless society might look like. Also noteworthy are the discussions of cultures which had and lost technology—writing being one example, Roman concrete being another. This obviously does not read as a conservative book, but the more intellectual breed of rightists will find something worth considering in Part Three.

Altogether, I found Diamond’s theory intelligent and well-argued. He does not pretend that it’s perfect. His epilogue is an exhortation for more serious study—history as a science, as he call it. Nearly thirty pages are devoted to suggested further readings. Find a coy, apply a light dose of skepticism, and enjoy.


*The first of these is Americapox: The Missing Plague, which discusses why European diseases were so devastating to Native Americans, but not vice versa. The second is Zebras vs Horses: Animal Domestication, which digs deeper into the causes at play. Disease is only one of the proximate factors Diamond discusses, and I’ve mostly chosen to omit it from my review because Grey explains far better than I could.

The Worst Week of American Spaceflight

On January 27th, 1967,the crew of Apollo 1 was undergoing a simulated countdown when an electrical fire started within the spacecraft. The hatch was bolted tightly onto the capsule. Escape was impossible and the blaze quickly grew in a pure oxygen atmosphere. Astronauts Gus Grissom, Ed White, and Roger Chaffee died on the pad.

On January 28th, 1986, the space shuttle Challenger was destroyed was destroyed 73 seconds after lift off for the STS-51L mission. Cold weather in the days before launch had weakened the rubber o-rings sealing sections of the solid rocket boosters. Flames escaped and penetrated the external fuel tank, igniting an explosion of liquid hydrogen and oxygen that disintegrated the orbiter vehicle. The crew was not killed in the explosion—forensic investigation revealed that pilot Michael Smith’s emergency oxygen supply had been activated, and consumed for two and a half minutes: the amount of time between the break-up to when the remains of Challenger landed in the Atlantic Ocean.

On February 1, 2003, the space shuttle Columbia disintegrated during re-entry over the southern United States after sixteen days in orbit. During launch, a piece of cryogenic insulation foam fell from the external fuel tank and struck the left wing of the orbiter, damaging the thermal protection system. As Columbia streaked across the southern sky, atmospheric gases heated by its hypersonic flight entered the wing and melted critical structural members. Ground observers in Texas could see the shuttle breaking apart over their heads. Rapid cabin depressurization incapacitated the crew.

This is the worst week in the history of American spaceflight. These three disasters are not the only dark spots on that record, by they are by far the worst. We remember them, and vow not to repeat the mistakes that led to their deaths.

After Apollo 1, Flight Director Gene Kranz gave the following address to his mission controllers:

Spaceflight will never tolerate carelessness, incapacity, and neglect. Somewhere, somehow, we screwed up. It could have been in design, build, or test. Whatever it was, we should have caught it.

We were too gung ho about the schedule and we locked out all of the problems we saw each day in our work. Every element of the program was in trouble and so were we. The simulators were not working, Mission Control was behind in virtually every area, and the flight and test procedures changed daily. Nothing we did had any shelf life. Not one of us stood up and said, “Dammit, stop!”

I don’t know what Thompson’s committee will find as the cause, but I know what I find. We are the cause! We were not ready! We did not do our job. We were rolling the dice, hoping that things would come together by launch day, when in our hearts we knew it would take a miracle. We were pushing the schedule and betting that the Cape would slip before we did.

From this day forward, Flight Control will be known by two words: “Tough and Competent.” Tough means we are forever accountable for what we do or what we fail to do. We will never again compromise our responsibilities. Every time we walk into Mission Control we will know what we stand for.

Competent means we will never take anything for granted. We will never be found short in our knowledge and in our skills. Mission Control will be perfect.

When you leave this meeting today you will go to your office and the first thing you will do there is to write “Tough and Competent” on your blackboards. It will never be erased. Each day when you enter the room these words will remind you of the price paid by Grissom, White, and Chaffee.

Gene Kranz is right. Tough competence is what those of us in the space business must strive to be, every day, for lives are on the line, and the future of manned exploration of the cosmos is at stake.

These seventeen are not the only space travelers to die in the line of their work, and undoubtedly more astronauts and cosmonauts will perish in our conquest of the universe. That is no excuse for sloppiness. The Apollo 1 fire could have been prevented. STS-51L should not have launched. STS-107 could have been saved on-orbit. It’s the job of engineers, technicians, flight controllers, and fellow astronauts to see accidents before they occur and prevent them from happening.