Pluto “Fans”

The recent fly-by of Pluto by the New Horizons spacecraft has reignited a debate that should have stayed buried forever. I’m not saying the IAU’s 2006 definition of planet wasn’t lacking, it’s just that this specific debate should have died and stayed dead.

Plutesters, hehehe.


The problem is that it is entirely unclear why we’re defining “planet” to begin with. Categorization of phenomena is supposed to help us organize them epistemologically. This is why we have a taxonomy of species. Any definition of space objects should be designed to help us classify and study them, not contrived for cultural reasons. We shouldn’t try to exclude KBO’s or other minor bodies because we don’t want to have 15 planets, and we shouldn’t try to include Pluto because we feel bad for it. The classifications we come up with should mirror our current understanding of how similar the bodies are. On the other hand, our precise definitions should produce the same results as our imprecise cultural definitions for well-known cases. As evidenced by the outrage caused by the IAU’s “exclusion of Pluto from planethood”, people don’t like changing how they think about things.

Images of Pluto and Charon.


Which brings us to the current debate. Fans of Pluto seem to be hinging their argument on the fact that Pluto is geologically active, and that it’s diameter is actually larger than that of Eris. Previously it was thought that Eris was both more massive (by 27%) and larger in diameter than Pluto (with the flyby of New Horizons, we now believe Pluto has the larger diameter). This is what moved the IAU to action in the first place; if Pluto is a planet, then so is Eris. There is no world in which we have 9 planets. We either have 8, or 10+.

Then you have Makemake, Haumea, Sedna, and Ceres. How do those fit in? It’s possible we would end up having far more than 15 planets, based on current predictions of KBO size distributions. This illuminates a fundamental problem: what is the use of a classification that includes both Sedna and Jupiter? These two bodies are so different that any category that includes both is operationally useless for science within our solar system. But continuing that logic, the Earth is also extremely dissimilar to Jupiter. The Earth is more similar to Pluto than it is to Jupiter. So having Earth and Jupiter in the same category but excluding Pluto also seems weird.

Unless we consider our definition of similarity. There are two ways to evaluate a body: intrinsic properties (mass, diameter, geological activity, etc), and extrinsic properties (orbit, nearby bodies, etc). One would be tempted to define a planet based on its intrinsic properties. After all, at one time Jupiter was still clearing its orbit, and in the future Pluto will eventually clear its orbit. Does it make sense for the same body to drop in and out of statehood. Well… yes. The fact that a human stops being a child at some point doesn’t make the category of “child” any less useful for a huge range of societal and cultural rules.

In fact, “intrinsic properties” is sort of a gray area. Rotation rate doesn’t really count, since tidal locking is common yet caused by extrinsic forces. Geological activity is also not necessarily intrinsic. Io has extreme internal activity caused by tidal heating. One can imagine the same for a planet close to its parent star. Composition can change as atmosphere is blown away by the parent star, and even mass and diameter can change through planetary collisions.

Regardless, defining a planet only on its intrinsic properties means that moons are now technically “planets”. “Moon” becomes a subcategory of “planet”. This is actually a great definition, but too radical to get accepted currently, so thus functionally useless.

So we must define a planet at least partially based on extrinsic properties. The rocky inner planets and the gaseous outer planets are similar in that they make up the VAST portion of the mass within their orbital region. Earth is 1.7 million times more massive than the rest of the stuff in its orbit. On the other hand, Pluto is 0.07 times the mass of the rest of the Kuiper Belt. Yeah, it makes up less than 10% of the Kuiper Belt. This is a pretty clear separation.

After that revelation, everything falls into place. We have large, orbit-clearing objects, and we have smaller objects that are still in hydrostatic equilibrium but are part of a larger belt of objects.



It turns out, this definition is already in place. For all the hub-bub about the IAU’s definition, most everybody agrees with the splitting of bodies via two parameters that measure likelihood of a body ejecting other bodies in its orbit (the Stern-Levison parameter Λ), and a body’s mass relative to the total mass of bodies in its orbit (planetary discriminant µ). The split occurs at a semi-arbitrary Λ=1 and µ=100.

What everybody is really arguing about is whether or not we get to call both types of bodies planets, or just the big ones.

Stern and Levison propose the terms überplanet and unterplanet, but I think major planet and minor planet is more adoptable.

Finally, just plain old “planet” should refer by default to major planets only, but can contextually refer to both classes in some cases.

Problem solved.

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NASA’s Asteroid Retrieval Mission…

…is actually pretty damn cool. People who are un-enthused by the idea (including many NASA employees) are clearly focusing on the wrong aspect.

Concept of a ARM robotic spacecraft

First, let me give an objective overview of the mission.

“NASA plans to launch the ARM robotic spacecraft at the end of this decade. The agency is working on two concepts for the capture: one would capture an asteroid using an inflatable system, similar to a bag, and the other would capture a boulder off of a much larger asteroid using a robotic arm. The agency will choose one of the two concepts in late 2014.

After an asteroid mass is captured, the spacecraft will redirect it to a stable orbit around the moon called a “Distant Retrograde Orbit.” Astronauts aboard NASA’s Orion spacecraft, launched from a Space Launch System (SLS) rocket, will explore the asteroid in the mid-2020s.”

NASA

So, to summarize: we are going to move a giant space rock from it’s orbit around the sun to an orbit around the moon. A space boulder. We are moving it into orbit around the Moon. Does nobody else think that is a HUGE FUCKING DEAL? The closest thing we’ve ever done is maybe return little grains of dirt from an asteroid. Except this time its an honest-to-god celestial body. That we are moving from one ORBIT to another. Oh, and then I guess we’re sending people to it or something.

Honestly, the manned mission is just shoe-horned in to appease NASA’s mandated directives. The star of the show here is the spacecraft that is moving an asteroid larger than itself (if you don’t count the bag or solar panels — I’m sure the bag can be swapped out for some sort of thermal lance). The advances in electric propulsion and in-space engineering alone will be astounding. Just think of the applications for ISRU (in situ resource utilization) and orbital manufacturing this will provide.

Probes scanning the surface of an asteroid

The ability to drag a study target into an easier-to-reach orbit is stupendous. For one, it means we can send a number of heavier, less expensive unmanned missions to study different aspects of it, with more launch windows and shorter commute times. We can get an extensive profile of the object (even drilling inside), to a level of detail we couldn’t obtain if we were sending a small probe out to the asteroid’s ‘native’ environment.

Having this technology is great for both diverting hazardous asteroids and studying a number of different asteroids at decreased expense. Instead of sending a heavy science probe off using the SLS, we send a re-director up to drag the asteroid close, even into LEO, and then send up a bunch of heavy science probes using cheaper rockets. Alternatively, dragging an asteroid into orbit would be a great opportunity to prototype asteroid-mining techniques.

The point is that if you think putting an asteroid into orbit around the moon is a stupid excuse to use the poorly-thought-out Orion/SLS system, you are absolutely right. An Apollo-style mission architecture doesn’t work for anything beyond a Moon mission, so it’s pointless to think of this mission as “training” for anything. But just because visiting an asteroid with people is stupid doesn’t mean that dragging an asteroid into lunar orbit and visiting it whatsoever is stupid. There is IMMENSE value in an asteroid retrieval mission. Seriously, it’s as exciting as a submarine to Europa or Titan.

Why Scientific Philosophy Is Important

I recently talked to a person who was convinced that scientific theories, mathematical theories, mathematical theorems, knowledge, truth, and scientific laws were all basically synonymous. He said that physics could not exist without math, because math defined physics. He also was convinced that believing and agreeing were the same thing. I attempted to remedy these misconceptions using some basic arguments, but I was finally written off as “not understanding anything” and “unwilling to do the math”. When I asked him to define the word truth, he merely kept repeating, “I don’t know what you mean. Truth is just that which is.” When I attempted to explain that the word “truth” was a symbol referring to a concept, and that we couldn’t have a discussion if we were referring to different concepts with the same word, he said “you don’t need to define truth, it just is. It’s very simple.” He couldn’t understand why I kept “bringing up philosophy when we’re talking about simple truths here.”

Sigh. If I can’t break through that kind of rhetoric, I might as well just explain my thoughts here.

Why is it important to know about the philosophy behind knowledge, truth, and science when talking about it? Isn’t it possible to rely on a the natural human consensus of truth? Besides, while it is so hard to explain using language, people intuitively grasp the concept. Right?

Well, let’s give some examples. It’s true that if you drop an object, it falls, right? Well, yeah, that statement is true if you are on the surface of a planet, and not orbiting it. Or if you are underwater and you drop a buoyant object — it goes up! But wait, can you drop something underwater if it doesn’t go down? No, that wouldn’t be dropping it would just be… releasing? Hold on, when an object is in orbit, isn’t it actually just falling in a special way? It’s moving sideways fast enough that it misses the ground by the time it’s fallen far enough. But if an astronaut releases a wrench, and it float right in front of him, you wouldn’t call that “dropping”.

What we see is that the word “drop” has a definition, and we need to know what the definition of “drop” is before we can begin to assess the truth of the statement “if you drop an object, it falls”. As it turns out, “dropping” an object consists of releasing it such that it falls away from you. Uh oh. So yeah, “if you drop an object, it falls” is true, but it doesn’t actually convey any physical knowledge; it just defines a property of the word “drop” in terms of another word, “fall”.

So lets look at some more meaningful examples. Most people would say it’s true that planets orbit the sun in an elliptical manner. Except it isn’t true. It’s true that the movement of the planets can be approximated into ellipses, but in fact there are measurable deviations. “Okay, sure. The movement is actually described by Newton’s laws of motion, and the law of gravitation.” Okay, yes, an N-body approximation gets much, much closer to describing reality. In fact, it perfectly matched the observations Newton was working from. However, it’s still not true the Newton’s laws describe the motion of the planets.

We can look to general relativity to describe the motion of the planets even better. We have launched satellites to observe very minor fluctuations in the path of the Earth that would confirm the prediction made by general relativity. As it turns out, general relativity makes predictions that perfectly match our observations. Woof. Finally, we’ve found some truth. The path of the planets around the sun is described by general relativity.

But wait, can we say this in good conscience? No! Just like Newton, we’ve found a set of laws which create predictions that match our observations. But just like Newton, we cannot measure the motion perfectly. All we can say is that general relativity describes the motion of the planets as far as we can observe. We don’t know if there is some unknown mechanic that affects the motion of planets in a way we can’t measure right now. We can’t say that general relativity is “true”, we can only say that it is confirmed by all of our observations to date, much in the same way that Newton could not say that his laws of motion were true; they merely described the all physical data he was capable of obtaining.

This gets to the root of the problem. While mathematical notions can be “true” because they exist within an entirely constructed framework defined through logic, theories in science can never be “true”. The point of science is not to find things that are true, but to find the best explanation for why the world works the way it does. And just to get one thing clear, theories are explanation of “why”, and laws are explicit definitions of how physical quantities relate. So no, we don’t use “math to define physics”, physics uses math to explain the physical universe. But even without math, we can perform a sort of qualitative physics.

For instance, “things stay still until you push them, and things keep going straight unless you push them.” This phrasing of Newton’s first law of motion is simplistic and uses words like “thing” and “push” without really defining them, but it gets the point across. Similarly, “big things move less when you push them, and small things move more.” This is very simplistic, and doesn’t even mention the fact that acceleration changes linearly with force, but it communicates the basic idea of Newton’s second law of motion, without even getting into what “big”, “small”, and “move” really mean.

The point is that the traditional phrasing of Newton’s second law, F=ma (which, by the way, is more accurately ΣF = m * Σa), merely uses mathematical symbols rather than English symbols, which allows us to manipulate it using the rules of mathematics. But just because we are manipulating arbitrary quantities with math doesn’t mean anything physically. Just because I calculate that an object which masses 1 kg should accelerate at 1 m/s^2 when I apply 1 N of force doesn’t mean the thing is actually going to act that way if I perform the experiment. This is because “mass” is really a simplification of a whole range of things, as is “acceleration”. It doesn’t even account for internal forces, and only describes the movement of the center of mass.

Math may be true, but only within the realm of math. When we translate physical quantities into the mathematical universe, they lose they physical meaning. We may translate them back, but the results we get can only be an approximation, not a truth, not a reality. These approximations can be very useful, but we have to remember the limitations of our theories, and our instruments.

Defining Life

I’ve had this conversation a couple of times recently, because it poses an interesting question: can we create a definition for ‘alive’ that encompasses not only known biological life, but also any theoretical lifeforms we can imagine? This might include alternative biochemistry, artificial life (nanites?), and even digital lifeforms.

Obviously there is an inherent problem in this discussion; we are assuming everyone shares a similar definition of life. However, even a skin-deep probing can reveal divisive philosophical questions. Are computer viruses alive? How about self-replicating structures of dust particles in a plasma? Is the Earth alive? We can’t truly resolve this problem without first clearly setting a boundary for what things are alive and what things aren’t alive. For example, scientists seem to have resolutely decided that biological viruses are not alive. Similarly, its clear to our human sensibilities that a car engine is not alive, even if it is highly advanced and has all sorts of sensors and regulatory mechanisms.

For the sake of discussion, I’m going to skip over this roadblock and dive in. Wikipedia gives these criteria for calling something ‘alive’:

  1. Homeostasis: Regulation of the internal environment to maintain a constant state.
  2. Organization: Being structurally composed of one or more cells.
  3. Metabolism: Converting chemicals and energy to maintain internal organization.
  4. Growth: A growing organism increases in size in all of its parts, rather than simply accumulating matter.
  5. Adaptation: The ability to change over time in response to the environment.
  6. Response to stimuli: A response is often expressed by motion; for example, the leaves of a plant turning toward the sun (phototropism), and chemotaxis.
  7. Reproduction: The ability to produce new individual organisms, either asexually from a single parent organism, or sexually from two parent organisms.

There are some good ones in there, but a few need to go. Let’s throw out Organization (this can almost be seen as tautological — things made of cells are alive because they are made of cells — and exclusive of otherwise potential candidates for life), Growth (one can imagine an organism which is artificially constructed, but then maintains itself perfectly, or a mechanical organism that starts life by being constructed externally, and slowly grows smaller as it sacrifices components to stay operational), and Reproduction (again, imagine a constructed organism that cannot reproduce). This leaves Homeostasis, Metabolism, and Adaptation/Response to stimuli.

However, its clear that Metabolism is important: an organism must take something from its environment and consume it to maintain an internal state. Metabolism and Homeostasis are where biological viruses fail the ‘life test’. While some advanced viruses meet the Adaptation and Response to Stimuli (arguably the same thing, just at different scales), no virus can use resources from its environment to perform internal upkeep. It requires the hijacked machinery of a cell to do that.

Unless you say that living things are part of a virus’s ‘environment’. Then you could argue that in some sense of the word, viruses are alive, because they use resources present in the environment to perform internal upkeep. This raises an important question about context. Indeed, all definitions of life seem to hinge on context. For example, a computer virus’s environment is the computer system. Resources would be computing time and memory, perhaps.

Is a computer virus alive? Advanced viruses can modify their own state (metamorphic code), respond to stimuli (anti-virus, user activity, etc), and metabolize resources from their environment. They also reproduce, although we cut that criterion so the point is moot. If a computer virus meets the requirements for life (albeit unconventionally), then do we have to accept it as a lifeform?

Moreover, there are things we wouldn’t normally call a single entity that fulfill the requirements for life. These are often termed “living systems”. The Earth is a prime example. It has systems that regulate its interior, it absorbs sunlight and that helps fuel the regulatory cycles on the surface. It’s debatable whether the Earth responds to stimuli. Sure, there are feedback loops, but the Earth doesn’t really respond accordingly to changes (say, changes in solar luminosity or meteoric impacts) in order to maintain homeostasis. Quite the opposite, in fact. For example: a decrease in solar radiation produces more ice, lowering albedo, thus lowering albedo further.

So maybe the Earth isn’t alive, but we have to consider nonetheless that systems can be alive. In fact, its questionable whether humans are single organisms. Several pounds of our weight are gut bacteria, independent organisms which share no DNA with us, but on which we rely for survival. We are a system. Call it a colony, call it symbiosis; the entity that is a human is in fact a collection of trillions of ‘independent’ organisms, and yet that entity is also singularly ‘alive’.

Can we trust our initial, gut reaction that tells us what is alive and what isn’t? Moreover, what use is there in classifying life in the first place? We treat cars that are definitely not alive as if they are precious animals with a will of their own, and then squash bugs without a second thought. Is it important to define life at all, rigorous criteria or not?

Separating Science and Religion

I read this article for school:
Lightman’s The Accidental Universe

When asked to write an essay about it, this is what came out. I don’t normally post essays like this, but I’ve been meaning to write a post much like this for a while anyways, so it’s convenient.


Lightman descends into the realm of religion, masking his language with a thin film of scientific consideration, but none of its hard, decisive, rational edge. Lightman never even touches the basic principles of science, but uses philosophical arguments to parade a seemingly-scientific theory around.

Falsifiability is a method for evaluating scientific theories popularized by Karl Popper. It contends that a theory cannot be proved by showing evidence in favor of it. A theory may be shown to be strong if it can make empirically confirmable and correct hypotheses, but a theory can never be proved – only disproved. So to be a scientifically valid, a theory must have a way to be disproven (thus by not being disproven, it continues as the dominant theory). This is one of the problems with the multiverse theory, the theory of intelligent design, and even string theory: it is most likely impossible to disprove them. If an intelligent creator revealed itself, such a turn of events would not inherently make the multiverse theory wrong, per se (a multiverse theory can coexist with intelligent design). It would only make it irrelevant. Of course, this reveals an even bigger fundamental problem with those theories: they don’t explain the mechanics behind physical phenomenon in the traditional sense. Instead, they provide a framework of thought into which actual scientific theories can be slotted. But the multiverse theory is only one framework among many, and there is no way to show that one framework is strictly better than another.

Is it not just as reasonable, just as falsifiable (or not, as the case may be), to conclude that the universe as we know it is the only one, albeit a very lucky one? One could posit that it is indeed accidental. How does this postulate contend with the others on the battlefield of scientific thought? In some regards it may triumph over its opponents, because it relies on any contrary observation to disprove it, while both the multiverse theory and intelligent design can be valid even in the face of one or the other being true. So really, the Random Chance theory is more falsifiable, and thus more scientific.

But of course the Random Chance theory is completely unpleasing to the philosophical human mind. A much more palatable theory is the multiverse theory, which, like a wolf in sheep’s clothing, slips in among the legitimate scientific advancements and completes a scientist’s world view satisfactorily. But is a scientist’s world view scientific? No. Science is a tool for developing a physically accurate view of the world, and we employ it because the human mind is not built to obey scientific rules. Our capacity for cognitive dissonance is astounding. Thus a scientist can in good conscience accept a non-scientific belief to assuage his existential conflicts by slathering the belief in the manner of other physics theories.
Another such unfalsifiable belief system is string theory. String theory is a self-consistent way of interpreting physical data using notions that fall out of mathematical equations but have no basis in experimental science. Indeed, string theory exists only as a way for some physicists and mathematicians to unify all of reality under some Platonic mode. But it is only that; a way to think about the universe, to help explain the Great Unexplainable, as Sax Russell calls it. String theory cannot produce hypotheses that can be tested to confirm the mode of thought. It can explain the observed, but only as well as previous existing theories. While it is nice that it can bring physical laws under a single wing, niceness is not a necessary quality of scientific theory. It is a subjective human measurement applied in the realm of philosophy.

Philosophy is not useless. It is a tool, like science, for examining the world. However, instead of measuring and describing physical phenomenon objectively, it takes human concepts or unimaginable realities (such as that beyond the realm of science) and compresses them down and creates a set of rules for the human mind to follow. It generates modes of thought that allow us to function and think about that which might otherwise turn us into quivering lumps of existential dread.

But assembling a philosophical system of thought only to pass it off as a product of science is dangerous. Besides preying on those incapable of evaluating the modes of thought on their own, it tricks the creator as well. Thus we can see the inevitable and unending conflict between the “rational” scientist and the “faithful” man of religion. Neither of them realizes that they are jousting with philosophical ideas, and as a result keeps hitting his opponent not at the weak spots, but at the bastions of his belief. The scientist calls his mode of thought “scientific truth” (a misleading term in and of itself), and the religious man calls his mode of thought “religion”.

Unfortunately for the world, nobody (certainly not the loud ones) seems to realize that science and religion are not diametrically opposed. Religion is not taken entirely on faith; while it does depend on some unfalsifiable core, it builds up a philosophical belief system around that which, beyond the basic axioms, is self-consistent and pretty damn useful. The scientist, used to tackling scientific theories, thinks that by attacking the core tenets of religion, he can bring down the entire system. But the core is unfalsifiable, so the methods of science are useless. Science and religion shouldn’t even overlap in their realms of explanation. In truth, they don’t. But unfalsifiable philosophy is given the title of science, and physical explanations are given the title of religion, so two incompatible systems are faced against each other. It would be better for everyone if both sides retreated to their realm of the human experience, but since they won’t, we get tripe like Lightman’s essay.

Does Space Exploration have an ROI?

It’s easy to dismiss the current space program as a giant waste of money. Collectively, the world spends billions upon billions of dollars launching tiny pieces of metal into the sky. How could that possibly be better than, say, building a school in India or providing clean water to poor African countries, or even spending it domestically to improve our country? In the face of recent budget crises, this cry gains even more clout.

And indeed, a lot of space programs are very wasteful, especially NASA and the Roscosmos. However, this is generally due to the fact that politicians treat space as a football — another barrel of pork for their constituents. When politics and space exploration mix, you get bloated programs like the Space Shuttle and the new SLS. It’s much better when the politicians set broad goals (AKA land on the moon), fork over the money, and let the engineers work their magic. Otherwise you get a twisted maze of bureaucracy and general management which ends with wasted money and subpar designs.

But let us not forget that NASA has produced a number of very tangible technological advancements, which is summarized here better than I could. In addition, satellites are a cornerstone of the global communications network, not to mention the Global Positioning System, which is satellites. Although communications satellites are now built and launched by commercial ventures, NASA was the first and only customer for a while, and allowed companies to get some expertise in designing and building rockets. Furthermore, the space industry employs tens of thousands of people, all possible because of initial government funding.

However, those examples involve geostationary orbit at the most. What is the practical value of going out and scanning the other bodies in our solar system. Why should we launch space telescopes and space probes? If you don’t believe in the inherent value of knowledge, here is a very down-to-earth example (so to speak): the Solar and Heliospheric Observatory (SOHO) watches the sun 24/7 from L1. It gives us an advance warning for solar flares, allowing satellite operators enough time to turn their expensive pieces of equipment away from the sun, shielding the most delicate electronics from the impending wave of radiation. It is estimated that SOHO has paid for itself 10 times over in this fashion.

Finally, part of space exploration is the attempt to answer some of the big questions. Deep space telescopes answer some part of “Where did we come from?”, and probes to the surfaces of other planets and moon are often trying to answer “Are we alone?”. If you think this is far too sentimental an appeal, I urge you to imagine the ramifications if a future mission to Europa found microorganisms living in the oceans under the ice, or a mission to Mars found lithophiles buried under the Martian regolith. How would world philosophies change?

Regardless, we may be spending too much money and spending it in the wrong places. I submit to you the Indian space program, which designed and launched a mission to Mars for about 75 million dollars. I think the US should follow India’s example and lean towards frugality and very specific, directed goals. Accomplishing a single mission for a small amount of money is better, in my opinion, than developing several high-profile, high-cost programs simultaneously.

While my language and previous post may make it seem like I am opposed to any sort of space exploration, I am merely of the opinion that our society views space exploration in the wrong way. Space exploration should not be about sending humans to other bodies, at least not right now. It should be about trying to find out more about the rest of our solar system, so we can extrapolate and make predictions about the other systems and exoplanets we are discovering. And if all else fails, it can be a platform for many kinds of materials and electronics research.

Say “No” to Manned Spaceflight

I like the idea of people walking around on other planets as much as the next guy, but at the end of the day I can’t go away with a clear conscience without making this point. There is no reason for a manned space program, either now or in the immediate future. In fact, it would be quite irresponsible of us to go mucking around on other balls of dirt.

Much like the archaeologists of the past who used ancient scrolls to keep their fires going, any serious presence or in-situ resource utilization could be inadvertently destroying priceless research subjects. Imagine if we started harvesting ice from asteroids, and then discovered that very old ice tends can contain detailed records of proto-stellar conditions in the Solar System. Even things like rolling robots across Mars or slamming probes into the Moon are calculated risks. We’re pretty sure we won’t mess up anything important, but we aren’t sure. Paradoxically, we can’t be sure what we’re missing without taking some of these risks.

Nonetheless, sending advanced primates to do the job of fast, clean, accurate robots is as irresponsible as it is stupid. Animals are hosts to trillions of bacteria, and if even one strain gets onto the surface of Mars, say, and adapts to the not-so-inhospitable conditions, it’s all over. We rely on the hard vacuum of space to kill off any potential infection vectors on robotic spacecraft, but we can’t do the same for humans. If we’re going to be sending humans to any place remotely capable of developing life, we need to be almost 100% sure there is no life there to begin with, or that the presence of invasive species of bacteria won’t eliminate it.

Even if we make sure to within reasonable doubt that there is no longer or never was life on Mars, we might be screwing ourselves in the long run by sending humans to colonize. If a mutant strain of bacteria spreads to cover the planet like the stromatolites of ancient Earth, and starts eating up what little oxygen is left, then any terraforming efforts could be foiled before they begin. Imagine if our engineered bacteria produces oxygen as a byproduct, and a rogue strain works in the other way. We’d have created a widespread stable ecosystem that leaves us asphyxiating out in the cold.

The two arguments in favor of long-range manned spaceflight have never held much water for me, even if I wanted them to. First, the “putting our eggs in one basket”. Now, current manned spaceflight has nothing to do with the colonization of space. If we were serious about spreading a permanent, self-sustaining presence to another planet, we would have to completely reorganize the existing attitude and institutions surrounding manned spaceflight. Currently, the world’s collective manned spaceflights are a road to nowhere. The ISS is a good sandbox for learning about long-term missions, but we don’t really use it like that.

The second argument is economic. I’ve gone over this is previous posts, but the short of it is that it will be a long time before its profitable to go off-world for resources — unless, that is, there is an exterior source of funding. It’s conceivable that a mild industry might build up around mining space ice for fuel and 3D-printing components. However, at some point funding has to be provided by someone interested in scientific exploration or the intrinsic value of space exploration. A self-contained space economy with Earth as the main buyer is not viable. Perhaps there exists a chicken-egg dilemma: a permanent off-world colony needs industry to survive, and industry needs off-world colonies to thrive.

That’s the cold, hard reality of the matter. I don’t want to have this opinion, but avoiding the truth about manned space exploration isn’t doing anybody any good.

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