Star Trek has now been an important and inspiring part of our culture over a span of fifty years. But it’s done. It is now time to let the shambling corpse have its rest. (more…)
September 9, 2016
August 17, 2016
We constantly hear about new or exotic materials which are stronger than steel, but for many uses it turns out that steel is still the best stuff available to use. When is one of these new materials actually going to be able to replace steel?
Quite possibly never. Fancy materials like kevlar and carbon-fiber and even titanium alloy are only stronger than steel by weight. Their sole advantage over steel is lightness. If you compare strength by volume, they do much more poorly. This means that if you were to, for instance, try to make a sword out of titanium, it would have a much fatter blade than a steel one, in order to have the same strength and heft. And it would be inferior at holding an edge. You’d have to, like, insert a separate bit of tungsten carbide or something along the edges, and have a way to replace parts of that when they get chipped.
(Such a design might be a pretty good way to make a sword, actually. A Japanese katana is a bit like this: whereas a western sword is hardened and then tempered, so the whole blade is springy and tough but not as hard as it could be, a katana is glass-hard at the edge but soft along the spine. If it’s damaged, the edge will chip, but the back part won’t even spring back into shape if bent. It has to be hammered straight again. Then the edge has to be ground down where it chipped. A titanium-plus-tungsten-carbide design would make the middle of the sword about as tough as tempered steel, but give it an edge able to cut notches into any metal. While it lasted.)
Any materials that really are stronger than steel are generally not hard or tough, and materials harder than steel, such as diamond, are generally brittle and easily shattered. It’s entirely possible that there’s no such thing as an exotic material that can outdo steel, even for such a mundane application as making nuts and bolts — that no possible combination of atoms can get there.
Which, to a science fiction reader like me, begs the question of whether you could make something that is not based on atoms. Is there some kind of exotic substance or field in the far reaches of physics that could replace ordinary chemical elements as building materials? Old-timey SF is full of improbable superstrong materials invented by advanced technology. Could any of them ever exist?
As far as we can currently tell, the answer is no. We might have small incremental improvements, such as putting alloys into a glasslike state instead of a crystalline one, but that’s probably all.
I did once see a physics paper which described a theoretical solid state far stronger than ordinary matter. All you need to do to create it is subject ordinary hydrogen to a magnetic field of a billion gauss (100,000 tesla) or more. The paper speculated that this substance might exist on the surfaces of neutron stars. In such a field, the electron clouds around the hydrogen nuclei elongate and finally merge with each other, so the atoms form a kind of polymer. The resulting substance is very dense — far heavier than any metal, though far lighter than neutronium — and very strong. As best I can recall without being able to access the text of the paper, sideways to the magnetic field the strength was calculated to be somewhat proportional to the density, but lengthwise along the field lines, it would be way stronger than that.
There are three problems with this idea. First is that it’s impossible to make a magnetic field like that to order, or to shape it for the convenience of the objects you want to create. Second is that the effects of such a field on all the other stuff around the superstrong material would make it impossible to fit in amongst anything else made of ordinary matter. It would, for instance, be lethal to any living thing in the area. And the third is that this paper has not received much followup as far as I have been able to find, and what I’ve been able to track down in later work often criticizes the assumptions of earlier authors, and says their calculated numbers may have substantial errors. It appears that “linear molecules” in intense magnetic fields are an accepted concept, but whether it would be superstrong in proportion to its density, or only in proportion to normal matter, is not clear to me. The key value is probably the binding energy per atom, and I’m seeing estimates of that all over the map, from a few times that of common materials to around a hundred thousand times. In newer calculations the smaller numbers seem to be predominating.
I mentioned neutronium. What about that? Unfortunately for our dream, it’s not a solid, it’s a superfluid. Not to mention that it can only exist under extreme pressure, and would otherwise first explode, then undergo rapid beta-decay. Unlike “linear molecules”, it has no resistance to flying apart.
Perhaps someday we might meet an advanced alien civilization — possibly one so advanced that they don’t even regard us as intelligent life, and can’t even remember what it was like to ever not know the answer to a question about science. We might expect that their stuff would be made of magically wondrous materials, but then end up finding that like us, they still have to make things out of steel.
August 6, 2016
In my occupation as a coder, I have to read a lot of technical documentation in order to use existing software components. And sometimes that documentation can be frustratingly incomplete or unavailable, but to me the worst situation to encounter is what I call pseudo-documentation. It’s abundant out there.
I will give you a little example of what that’s like. Let’s say you just encountered a line of code like this:
You have no idea what this does, so you look it up, and this is what you find:
Frabnicates a Zinxer for an instance of Thingy. If successful, the Zinxer will become frabnicated for this Thingy. If the Zinxer was already frabnicated for another Thingy, the new Thingy will be placed first in the frabnication order of the Zinxer. If it is already frabnicated for this Thingy, no change takes place.
public void FrabnicateZinxer(Zinxer zinxerToFrabnicate);
zinxerToFrabnicate – the Zinxer which is to be frabnicated for this Thingy.
NullParameterException – a null value was passed as zinxerToFrabnicate.
InvalidOperationException – the Zinxer passed as zinxerToFrabnicate is in a nonfrabnicable state.
Thingy thingy = new Thingy();
Zinxer zinxer = Zinxer.Load("brb");
. . . You see what the problem is? The documentation covers all aspects of what needs to be available in reference material, but you learn nothing by reading it. It labels the parts but says nothing about what they actually do. All it tells you is what you had already assumed just from seeing the name — that some unknown thing undergoes some unknown process. The only new knowledge you come away with is maddening hints of ways it might go wrong, none of which have any explanatory context.
There are many outfits which produce crap like this, but Microsoft may be the worst. Their tech writers don’t seem to have any supervision by anyone who checks the quality of the work. Even when they’re writing at length in tutorial or instructional form, the result is often full of gaps and omissions where crucial pieces of context are missing, not to mention inconsistencies which undermine your chances of piecing together anything definite.
July 6, 2016
The Erdős-Bacon number is defined as the sum of the number of onscreen filmmaking collaborations it takes to connect a person to actor Kevin Bacon, and the number of academic publishing collaborations it takes to reach mathematician Paul Erdős. The number has no value except for the small set of people who are both academics and film performers. Natalie Portman has a Erdős-Bacon number of seven, as does Colin Firth, and Danica McKellar’s number is six. The actor with the lowest number is apparently Albert M. Chan, who appeared with Bacon in Patriots Day. His number is four. Coming from the other direction, Carl Sagan’s number was four. Stephen Hawking’s is seven. The lowest number that anyone is known to have is three, held by Professor Daniel Kleitman of MIT, who was a math advisor for Good Will Hunting (which is one step from Kevin Bacon via Minnie Driver’s appearance in Sleepers) and appeared in the film as an extra.
Can this number be beaten? Lots of mathematicians are still alive who have collaborated with Erdős, and if any of them ever appears in a Kevin Bacon film, they will achieve a value of two. The other way this could be achieved is if Mr. Bacon himself goes into academia and collaborates with one of this group. Since Paul Erdős left us twenty years ago, a value of one is not achievable.
For an even more exclusive club, there are people who have an Erdős-Bacon-Sabbath number, in which the third component is the number of musical collaborations which separate the subject from the members of Black Sabbath. Some famous people for whom low Erdős-Bacon-Sabbath numbers have been claimed include Lisa Kudrow (15), Adam Savage (13), Albert Einstein (11), Richard Feynman (10), Mayim Bialik (10), Tom Lehrer (9), Terry Pratchett (9), Ray Kurzweil (8), and Brian May (8). I don’t think any values lower than eight are known.
Some of these collaborations are a stretch — it’s easy to question whether they count. Among those mentioned earlier, Natalie Portman has a pretty solid 10 via a joke rap track she recorded with some people from Saturday Night Live, Danica McKellar has a dubious 10 by singing in an ad jingle, and Carl Sagan has an even more dubious 10 by being sampled in an autotuned remix of bits of narration from Cosmos. Mayim Bialik’s case might be the poorest of all: Michael Jackson put his celebrity friends into a crowd scene in a music video, and I don’t think she even sings in it. In Brian May’s case, it’s the Erdős side which is very dubious, via some book called Bang! The Complete History of the Universe, which does not exactly seem to be a peer-reviewed publication. For Kurzweil, it’s the Bacon number which is shaky, as they’re counting an appearance on a nonfiction TV show. But some are much more legitimate: for instance, by singing in Mamma Mia!, Colin Firth has given himself a value of 11 which should be beyond dispute.
June 21, 2016
People have been trained to be scared of the word “radiation”. But all it means is that something spreads outwards from a source. Sound counts as radiation. So do ripples on a pond, or earthquake waves in solid rock. If you use the term broadly enough, the shrapnel that blasts outward from a grenade can be considered as a form of radiation. And, of course, light is a form of radiation.
What people need to be legitimately scared of is the narrower category of ionizing radiation. That’s the nasty stuff that comes out of radioisotopes, nuclear reactions, and x-ray machines. It’s bad for ya because it destroys protein and DNA molecules inside your cells. Anything that’s capable of ionizing an atom is also capable of breaking apart an organic molecule in the process, and if that molecule is inside you, damaging enough of them in this way will give you radiation sickness, cancer, three-headed children, and so on.
The hot particles which spit out of radioisotopes, and which are generated in tremendous floods by nuclear reactors and bombs, are ionizing radiation. They aren’t waves, like sound or light (at least, no more than any solid object is wavelike) — they’re the subatomic equivalent of grenade shrapnel, consisting of solid pieces flung through the air. But the way that they shine straight out in all directions is such that the word “radiation” has never gone out of fashion for describing them.
X-rays and gamma rays are also ionizing radiation — especially the latter, which tend to be produced in nuclear reactions and accompany the other emissions of radioisotopes. But unlike the alpha and beta and other hot particles, these are electromagnetic waves. They are, essentially, light.
The heat on your skin from standing in front of a fire is also a form of light (infrared), but it is not ionizing. The only way it’ll ever disrupt organic molecules is by cooking them, and it’s far less effective for that purpose than, say, contact with hot water. But how can light be both ionizing and non-ionizing?
June 16, 2016
In a recent post, I mentioned in passing that “the close relationship between energy, gravity, and inertia is still a mystery, despite apparent confirmation of the Higgs boson.” But wow, I may have just stumbled on an outsider theory that can resolve that whole mystery, and more. It’s from a laser specialist and entrepreneur named John A. Macken, and his work can be found at onlyspacetime.com.
Where Macken begins is with the idea that “mass” is just energy confined to a particular frame of reference. This sounds like it might be just an obvious truism based on special relativity, but once one looks at the details, it covers more ground than you might think.
His start on this came, naturally enough, when thinking about lasers. The light inside a laser has energy, which means it has an equivalent mass, which means it has inertia. Now inertia seems very mysterious as a property for particles, but for light, he realized, there’s nothing mysterious about it. (more…)
June 5, 2016
So if you had an electric car, would it be worthwhile to put a solar panel on the roof?
At first blush, it wouldn’t seem so. A decent electric car ought to have something like 100 kilowatt-hours in its battery pack, and it sure would be nice if it could hold 200 or more. (The total energy in a moderately sized tank of gasoline is about 500 kwh, but at least two thirds of that just goes into waste heat.) The biggest solar panel area you could fit on top of a car, disregarding all competing design criteria, would be about two square meters, and a more typical car would probably make room for about one square meter. Over a whole day in blazing sun, that’s only going to produce about one kwh, and in most circumstances you’ll get quite a bit less. So it’ll probably only extend your daily driving range by three miles at most, and if you park it indoors you’ll never get even one mile out of it.
But range extension isn’t the only benefit of having a bit of free power available when not driving. You’d never have to worry about running things down with the fan or the stereo or mobile-device chargers. On a hot day you could even use the air conditioner. The car could even cool itself automatically while left in a parking lot, with no fear that this would affect your ability to get home. Cars left unattended for months might still be fully ready to drive away in. And if you run out of juice in a lonely desert, the next day you might be able to drive a few crucial miles to get to a spot where help is reachable.
I think this is starting to sound like a good idea even on gasoline cars. Or on hybrids, at the very least.
June 2, 2016
Nowadays the popular media report on the latest gadgets almost as eagerly as they report on celebrity gossip. Since my smartphone is now three models out of date, I’ve been reading more than my share of this stuff. And this is inspiring me to try adding a little noise of my own to that topic. So:
Five Things Premium Phones Will Need in Order to Stay Premium
May 30, 2016
Just clearing up a little thing that’s always bugged me…
“Torque” is rotational force: the measure of how hard you’re twisting something. We don’t measure it directly; we can only take a measurement of it by gauging the amount of linear force that it exerts at a given distance from the axis of rotation. Because of how levers work, this force is high if you’re close to the axis and low if you’re a long ways off. The linear force times the length of the lever-arm from the center equals the torque. So we measure it in foot-pounds or newton-meters. If you double the length, you halve the force, and the product is the same, so the particular force and length numbers don’t matter — only the combined value does.
But wait — force times length equals work. Is torque in some sense the same thing as energy? Hell no. Torque is static; you aren’t doing work until you make it move. If you exert force at the end of the lever through some distance, thereby rotating something while exerting that torque, that’s work. If you continue to do so over more distance, that’s more work. Now doubling the lever length halves the force at the end, but doubles the distance it has to travel for a given angle of turn, meaning that the particular lengths don’t matter — the work is the same for a given angle of turn.
Work equals torque times amount of rotation. The correct SI unit of torque is not newton-meters, but newton-meters per radian.
So why don’t people mention the radians? Because radians are defined as arc-length over radius: a distance divided by a distance. This cancels out to a pure number, a dimensionless ratio. Or so it is traditionally argued.
But we’ve clearly lost something there. The rotation is a very real physical thing, and its presence or absence makes all the difference, as we’ve seen, when relating torque to work. For that matter, just trying to solve for how far a projectile will fly, given its speed and angle, falls apart dimensionally if you say the angle is just a number. I think it’s time to acknowledge that when we divide a curved distance by a straight distance, what’s left is the curvature, and this should be treated as an independent dimension in its own right.
Traditional analysis regards mass, distance, and time as the only fundamental dimensions; since then we’ve added quantities such as electric charge, and (when in a generous mood) various arcane quantum properties for which the universe seems to have conservation laws, such as quark type and “color”, and whatever it is that is shared by electrons and electron-neutrinos, but distinguishes them from muons and muon-neutrinos. But these “material” values, as we might call them, don’t cover everything we need.
Some dimensional analysis enthusiasts have been saying that angles may not be the only neglected metric. A minority even argue that inertial mass, gravitational mass, and “substantial” mass (whatever that is) are at least two and maybe three subtly distinct dimensions which just happen to always coincide in value. (And indeed, the close relationship between energy, gravity, and inertia is still a mystery, despite apparent confirmation of the Higgs boson.) But even without that, we all too easily forget that length is not a single dimension when dealing with vectors in space — each axis is separate, just as you’d think from hearing the word “dimension” in the first place.
Donald Siano has shown that if you get sophisticated enough with vector dimensions, it can express the concept of a measure of angle or rotation as a derived quantity. He even shows that mathematical functions that we think of as pure numbers are incommensurable: for instance, sine and cosine are dimensionally distinct, and it makes no sense to add a cosine value to a sine, or (in further extensions by others) a logarithm to anything not logarithmic. Such mathematical expressions cannot correspond to anything physical, and indeed, you should not normally ever see them when doing even the most abstract math. So if we go for the full potato on using his “orientational” analysis, we don’t need a separate dimension just for angles. But that’s quite cumbersome for everyday use — if we don’t want to be constantly doing 4×4 matrix arithmetic to keep our dimensions straight, we can just treat angularity as a dimension.
On the opposite side from those who want to nitpick subtly distinct properties of mass, some argue that the universe’s fundamental constants mean that quantities such as time and distance and mass and charge really are all commensurable, and at bottom there’s only one fundamental dimension (probably best expressed in our terms as energy), and all natural laws are dimensionless. If so, so what, I say — that approach makes dimensional analysis less useful rather than more so. And if you think about vectors, space and time are still incommensurable, especially since in relativistic geometry, lengths on a timelike axis are imaginary numbers.
May 21, 2016
Senator Lois Wolk, Assemblymember Bill Dodd, Senate candidate Mariko Yamada, Assembly candidate Dan Wolk, and Assembly candidate Don Saylor,
Are you tired of dealing with pennies? I sure am. They take time and effort out of one’s day even if all you want to do is get rid of them. I don’t think any other economy keeps such a worthless coin in circulation — in Mexico, for instance, you never see anything smaller than a half peso. The US Treasury has been considering eliminating the penny from our coinage for twenty years, but hasn’t been able to move forward due to pointless obstructionism from assorted directions.
But fortunately, we don’t have to wait for the federal government to act. We can solve the problem right here in California. We can make it so people can use pennies if they want to, but nobody will need to. How can we do this? With a minor adjustment of the sales tax code.
All we have to do is make a rule that when buying retail at a location which accepts cash, the tax amount is rounded up or down by a cent or two, so that the total purchase price including tax is always a multiple of five cents. Note that this applies to noncash purchases as well, as long as they’re made at cash registers, so the amount remains consistent. But it would not apply to mail order purchases as they don’t offer a cash option. This means that we would not burden merchants in other states with adjusting to any new complexity.
The result would be that nobody who pays cash would need to either bring pennies, or receive them as change. People would become accustomed to nickel prices and before long, merchants might get into the habit of advertising nickel prices also. The other states would envy our penniless lifestyle and start copying us, and eventually the Treasury will stop minting pennies. And California will once again be seen as taking a leadership role.
But before that, we need someone to lead this idea in Sacramento. I’m hoping that among you, the legislators and candidates to represent me in Napa County, are the ones to do so.
I hope that this change can be accomplished by simple legislation, without requiring a ballot measure. If one is needed, I am confident that would pass, without requiring any substantial campaign effort.
Thank you for your attention, and I hope this idea appeals to you.