Edward Ashton's Blog, page 18
September 15, 2015
Publication day: like a birthday, but with more judgment, and...
Publication day: like a birthday, but with more judgment, and less cash.
September 12, 2015
Perihelion Science Fiction
A nice review of Three Days in April in this month’s PerihelionSF
September 7, 2015
Want to look at your insides and/or destroy the world? Antimatter may be right for you.
In science fiction and the popular press, antimatter often gets a bad rap. If it’s not breaching a warp core somewhere and destroying a spaceship, it’s being used by a supervillain to power a death ray. In actual fact, though, antimatter can be very useful stuff.
Antimatter, of course, is just normal matter with the electrical charges reversed. Normal protons are positively charged, and normal electrons are negatively charged. Anti-protons are negatively charged, and anti-electrons (or positrons) are positively charged. This is interesting, but the fun (and useful) thing abut antimatter is what happens when it encounters regular matter. Turns out, the bit about the warp core breach blowing up the spaceship is pretty accurate. Matter and antimatter, like pasta and antipasta, do not get along.
To see how this works at the smallest scale, consider what happens when a positron runs into an electron. This reaction is the basis for positron emission tomography (PET), a medical imaging technique that provides the best method we have for detecting small, distant metastases in cancer patients. When positrons and electrons collide, the mass of both is converted into a neutrino, which we don’t worry too much about, and two high-energy photons (gamma rays) that shoot off in exactly opposite directions. If this reaction occurs inside a cancer patient, and the patient happens to be inside a gamma camera, those photons will strike elements of the camera on opposite sides of the patient’s body more or less simultaneously. This tells us that the positron was somewhere on a straight line between the two detector elements. With enough of these simultaneous detections, we can build up a picture of how the positrons (which are coming from a tracer with an affinity for tumors, like fluorodeoxyglucose) are distributed in the body. This, in turn, tells us where the tumors are.
This is all well and good, but what if you’re interested in doing something more energetic? The problem with positrons is that they have very little mass, so their annihilation produces very little energy. To drive a spaceship, for example, we need to start generating (and destroying) anti-protons. Anti-proton annihilation produces both charged and un-charged pions (sub-atomic particles consisting of a quark and an anti-quark) as well as neutrinos (again, not particularly useful) and a shit-ton of gamma rays.
Depending on what, exactly, you’re trying to do, this reaction can be very helpful from a propulsion standpoint. The charged pions, in particular, are moving at very close to the speed of light, and because they are charged, a magnetic field can be used to funnel them out the back of your ship. One of the main limiting factors in how fast a rocket can go is the speed at which its propellant material shoots out the back. An antimatter rocket provides the greatest specific impulse (a measure of the efficiency of a rocket or jet engine) that is possible using known physics. Because of this, a spacecraft using an antimatter rocket may be able to achieve speeds as great as a bit less than a third of the speed of light. As a point of comparison, this would allow you to travel from Earth to Pluto in about sixteen hours (compare that to the nine and a half years it took the New Horizons probe to get there), and to the nearest star in about fifteen years.
So, why aren’t we building these things right now? Well, the issue is that, like the hydrogen that’s supposed to running all those fuel-cell cars, antimatter isn’t an energy source. It’s an energy storage medium. The energy required to create one anti-proton is just a bit greater than the energy released by its annihilation. So, how much energy would be required to generate the fuel for an Alpha Centauri probe?
Start with an assumption about the mass of the probe. The New Horizons is a hair under 500kg. This one will be exploring an entire new star system, so let’s give it a bit more heft (and also make our math easier) by calling it 1000kg. How much energy will we need to get this guy up to speed? Well, the kinetic energy of the probe at 0.3c will be about 4.5x10^18 joules. For perspective, that’s roughly the output of 100 large nuclear power plants over a full year. Remember, though, that we’ll need to decelerate the probe at the other end–so, better get another hundred plants on-line. Remember also that only a fraction of the annihilation energy of our antimatter fuel will actually go toward propulsion. The uncharged pions can’t be funneled, and we don’t really have a good way to make use of the gamma rays either. Probably need to multiply our fuel requirements by another factor of five.
So, in order to generate the fuel to get one smallish robotic probe to Alpha Centauri in about 15 years (meaning we’ll hear back from it in 19 or so) we’ll need to make use of the entire output of 1000 nuclear power stations for a full year. That’s assuming a completely lossless production process, of course, so you might want to have a few hundred extra plants running just in case.
While we’re thinking about how much energy we’re blowing, we might also want to consider that when our little probe is sitting on the launch pad at Cape Canaveral, it will be carrying all that juice with it in highly concentrated form. We’ve been talking about this energy in terms of electrical output. Here’s another comparison: In 1961, the Soviets detonated the Tsar Bomba, which is to this day the most powerful nuclear weapon ever devised. It’s explosive yield was 50 megatons. The fireball when it went off was visible from 1000 kilometers away, and the mushroom cloud pierced the stratosphere. If something goes wrong during the launch of our probe–if we suffer a “core breach”–the explosion will be roughly 200 times as powerful. This wouldn’t destroy the world or anything, but I don’t think I’d want to be in Jacksonville when it happened.
One last note on antimatter–there is no reason we know of that the Big Bang shouldn’t have produced it and regular matter in equal amounts. If that had happened, of course, all those protons and anti-protons and electrons and positrons would have annihilated one another, and we’d have been left with a matter-free, life-free universe. For some reason, however, there was a slight excess of our sort of matter, and that excess now makes up all the matter we have left. Chalk this up as another item on the long list of things that had to go exactly right in order for you to exist, and if you can, take just a moment to wonder how many cosmos had to be born and die before all of those things fell perfectly into place.
September 6, 2015
AT APOCALYPSE’S EDGE • by Rebecca Birch | Every Day Fiction - The once a day flash fiction magazine.
I’m a sucker for a good end-of-the-world story.
September 3, 2015
The Science Fiction and Fantasy Books You Can’t Afford to Miss in September!
Skip over Atwood and Rushdee. The good stuff is all the way at the bottom.
August 29, 2015
Gluten Intolerance or Chemical Sensitivity: An Unethical Experiment on an Innocent Child
1.0 Background
For roughly ten thousand years, the human species has very much enjoyed eating gluten, a chewy and delicious mixture of two proteins found in wheat and other cereal grains. A small number of humans (roughly 0.7% of the population) suffer from a condition known as celiac disease, which makes them unable to digest gluten, and causes a number of unpleasant symptoms when gluten is consumed. A much larger portion of the population believe themselves to be “gluten intolerant.” This condition is generally characterized by gastric distress when wheat and wheat by-products are eaten, but not by diagnosable celiac disease.
Gluten intolerance is a relatively recent phenomenon, appearing mostly in the United States in the past ten years. This raises the inevitable question: what has changed?
2.0 Materials and Methods
2.1 Study Population
This study was carried out on a population consisting of one unsuspecting and innocent child.
2.2 Experimental Procedure
Commencing around age 17, subject began experiencing severe and unremitting gastric distress, characterized primarily by extended bouts of what appeared to be her pureed internal organs pouring out through her rectum. Medical advice was sought. Tests were run, including those for celiac disease. All were negative.
In the absence of helpful medical advice, subject began eliminating items from her diet. Dairy. No effect. Caffeine. No effect. When wheat and wheat by-products were eliminated, however, all symptoms resolved within a matter of days.
Over the course of the next few months, subject periodically unknowingly consumed items containing wheat by-products. Examples included Twizzlers, soy sauce, and butter containing toast crumbs. Each incident induced hours of colonic blowout. These natural experiments seem to eliminate the placebo effect as a possible cause for subject’s improvement.
After some six months of consuming grainy and flavorless corn and rice based baked goods, subject obtained five pounds of imported Italian wheat flour, having heard that others with similar issues were able to safely eat wheat when traveling in Europe. Subject cleared her calendar for the next 48 hours, then commenced to bake and eat a batch of chocolate chip cookies made with the aforementioned flour. Result? Nothing. No distress whatsoever.
3.0 Discussion
Three observations can be made from this experiment:
Subject’s initial distress resulted from eating wheat and wheat by-products.
Subject’s distress was not psychological in origin.
Subject’s distress appears to be specific to American wheat and wheat by-products.
Based on these observations, we can conclude that subject’s distress was not in fact related to gluten per se, since Italian wheat contains gluten just as American wheat does. Some have hypothesized that European wheat may have lower gluten concentrations. However, it is difficult to argue that more gluten is contained in a splash of American soy sauce than in an entire batch of Italian cookies.
It is true that American farmers in some cases may be using different strains of wheat than European farmers. Another explanation put forward for these observations (which are not unique to this experiment) has been that hybridization of the American strains may have introduced a new protein or compound into the wheat kernel that was not there previously, and that is not present in European wheat. It could be this unknown substance which is inducing the symptoms of so-called gluten intolerance.
A more likely explanation, however, lies in the harvest practices of the majority of American wheat farmers. It has become common in recent years to douse wheat fields with glyphosate, a broad-spectrum herbicide, just prior to harvest. This serves two purposes: it kills the wheat stalks, bringing the entire field to harvest readiness, and desiccates the kernels, making them ready for processing. It also, of course, introduces a certain amount of glyphosate into the kernel, from whence it makes its way into all that nice, fluffy American flour.
Glyphosate has been used as an herbicide both in agriculture and in yard care for more than forty years. It is generally considered to be safe. Lots of things that are safe to spray around the yard, however, are not entirely so in your cookies.
4.0 Conclusions
This study has an n of 1. As such, all conclusions must be taken with a grain of glyphosate. However, it seems clear that in this particular case, something in American wheat which is not present in Italian wheat is wreaking havoc on an otherwise healthy subject’s digestive system. The two possibilities for what exactly that is are a tasty treat that has been a part of our diet since antiquity, and an herbicide that I refuse to use on my yard because I’m concerned it might sicken my dog. The selection of the most likely explanation is left as an exercise for the reader.
August 27, 2015
August 22, 2015
Fun Science Fact #25: We’re all going to die.
Immortality has always been a popular topic of discussion for we humans. One of the major downsides of our big-ass brains, aside from what they do to our mothers during the birthing process, is that they allow us to imagine the future—and while this is useful when it helps us to anticipate and avoid a visit from the in-laws, it is much less so when it allows us to anticipate our own deaths. Consequently, despite the sound advice of moral philosophers like Socrates and Blue Oyster Cult, we’ve spent a great deal of time and effort trying to imagine ways to cheat the reaper.
Some of these efforts have been dumber than others. Qin Shi Huang, the first emperor of a united China, was so terrified of death that he turned the efforts of all of his court scholars toward developing elixirs of immortality, executing those who failed to come up with anything useful. He eventually died after ingesting mercury pills. These were supposedly intended to make him live forever, but after all the executions, it’s hard not to wonder whether the alchemist who provided them to him might not have known exactly what he was doing.
Later, less amusing efforts at extending the human lifespan included those of Elizabeth Bathory, who spent the early years of the seventeenth century bathing in the blood of virgins, eventually torturing and killing as many as 600 peasant women. This didn’t actually make her immortal, though it did result in her spending the last three and a half years of her life walled up in a lightless room—which, come to think of it, probably seemed to her like an eternity. On a positive note, her story reputedly helped to inspire Bram Stoker, later leading to one decent book, several crappy movies, and one awesome Sesame Street character.
Modern efforts toward immortality tend less toward elixirs and virgins and more toward robotics and nanotech. Ray Kurzweil, for example, has argued that we are rapidly approaching the point at which it will be possible to replicate our minds in software, which he believes will provide a form of immortality. He has apparently gone to Qin Shi Huang - like lengths to try to keep himself alive until we actually get there, ingesting alkaline water, red wine, and hundreds of pills daily in order to “reprogram his biochemistry.” Kurzweil is undoubtedly a brilliant man, and I guess we don’t know for sure yet that he hasn’t found the key to eternal life. Based on history, however, I wouldn’t hold my breath.
So, is immortality even theoretically possible? Could some combination of new medical technology, robotics, mercury pills and virgin blood lead to a world free from death? Anything is possible, right?
No, this particular thing is not possible.
To understand why, we need to remember that, while most of our body essentially regenerates itself over and over again throughout our lives—your skeleton, for example, is completely replaced on a cellular level every ten years or so—our neural system does not. Unfortunately, it’s our neural system that we’re really concerned with preserving, since that’s where the part of us that we actually think of as “us” resides. Even if we figured out a way to prevent our body cells from senescing without becoming cancerous, our brains would eventually rot away.
But wait, we could still figure out a way to keep our neurons from dying, right? Maybe the blood of really slutty people is good for that? No, even if we could figure out a way to completely shut down the aging process on a cellular level, the constant bombardment of cosmic rays and other background radiation would kill off our neurons one by one, dooming us to a slow mental decline, and ultimately to death. How fast this would occur would depend on a number of factors, including how often you fly and how high above sea level you live, but the outside limit is probably around 300 years. That’s a big bump over what we get now, of course, but it’s hardly immortality.
Okay, so the bodies and brains we’re in now are irreducibly impermanent. What about Kurzweil’s big idea? Will we eventually be able to upload ourselves onto a server somewhere? Here, we get into a bit of a philosophical discussion. What does it mean to be you? Imagine that we eventually develop hardware and software sophisticated enough to completely contain a human mind, and that we figure out a way to upload you. Your brain goes through the magical scanner, and your laptop starts speaking in your voice. Are you immortal now? Is that really you?
Here’s the affirmative argument: Imagine that when you go to sleep tonight, you don’t just go to sleep. You die. You die, and someone else wakes up in your body tomorrow. He has all your memories, all your hopes and dreams, and he thinks he’s you—but he’s not. He goes through his day, then lays down in your bed and dies in his turn, only to be replaced the next morning by the next soul in line. Question: would this make any difference at all in your life? Is there any way you’d even be able to tell? Go ahead and upload yourself into the computer system, then go outside and stick your head in a wood chipper. You’re immortal.
Here’s the negative argument: I don’t care how much my laptop thinks it’s me. I’m not sticking my head in a wood chipper. I guess you can see where I stand.
So, what would my advice be to seekers of immortality? Your father produced roughly four hundred billion sperm cells during the course of his lifespan, and you were the one out of that near-infinite multitude that didn’t wind up in a gym sock or a condom or someone’s digestive system. Every day you have on this earth is a near-miraculous gift, and it’s churlish to complain if you don’t get to have quite as many of them as you think you deserve.
