Some news/promo/propaganda video out of Iran touting their Ra’ad-85 UAV/PGM drone aircraft, meant to crash into things and blow itself up (yes, a truly innovative idea to come out of the Middle East). As mentioned at length HERE, one amusing feature of the design is that it seems to be held together with tape.
[youtube 2mUhXWjIMmM]
I don’t believe I’ve mentioned Speedbump before. (EDIT: yes, I did, but before he was so named). After I came back from my trip and found that Marvin was no more, one of the outside farmcats (a son of One-Eye) made his presence known whenever I went outside: he turned himself into a hazard to navigation by constantly being underfoot whenever I went outside for anything. Perhaps unsurprisingly, he managed to work his way indoors a few weeks back, where he has been on probation, seeing how he interacts with the other cats. While he’s a bit of a knucklehead, he’s basically well behaved.
The last few days he’s been vocally complaining a *lot* and seemed to have an itchy ear, so today I took him to the vet to get his shots and a checkup. Turns out there was a reason for the itchy ear… down in it next to the eardrum he had a big ol’ tick chawin’ away on him.
gaaaaahhhhhhrhhhrrrhhhhaaaaaccchchhchchc.
In the several hours since it was removed, he has seemed less complainy, so I’m guessing that was the source of his discomfort.
Interestingly, when the vet went to poke the back of his neck with a needle, the needle wouldn’t actually penetrate. Damn thing bent. Had to give him his shots a little of-axis… seems he’s got a patch of bulletproof skin.
Huh. Now you know.
Seth Lloyd (MIT)
Merely by existing, all physical systems register information. And by evolving dynamically in time, they transform and process that information. The laws of physics determine the amount of information that a physical system can register (number of bits) and the number of elementary logic operations that a system can perform (number of ops). The universe is a physical system. This paper quantifies the amount of information that the universe can register and the number of elementary operations that it can have performed over its history. The universe can have performed no more than 10^120 ops on 10^90 bits.
Might take a little while for Moore’s Law to produce computers capable of competing with this, but once there a computer will be able to simulate the entire universe. within a few years after that, a universe-simulating computer will be as cheap as a laptop; a few years after that there’ll be an app for that.
Say what you will about his politics, Carl Sagan knew how to promote the wonder of the universe as revealed by science. And there are folks out there who know how to do proper mashups of Sagan with just the right music and video.
[youtube 923jxZY2NPI]
[youtube oY59wZdCDo0]
…Using this page as a starting point, since I’ll get a little bit of a commission: Cheap at twice the price!
———–
Two notional concept for “nuclear batteries were shown in a Defense Science Board report:
The upper concept shows something of a conventional radioistotope thermionic generator, but in small scale. Within it is a 1-cubic centimeter chunk of material infused with alpha and/or beta emitter; the radiation is emitted and absorbed within the chunk, raising the temperature to 1000 Kelvin. A “photonic crystal” captures the blackbody radiation (which in this case would be well into the visible at that temperature) and deposits it onto a thermophotovoltaic cell, where it is converted to electricity. The insulating shell keeps the exterior temperature to about 25 degrees C.
The lower design uses a “jelly roll” configuration with thin flat sheets of alpha and/or beta emitter sandwiched between a sheet of quantum dots, which directly converts the radiation to electricity.
Both designs seem to be made for the same requirements, would produce one to five watts for several years. The radioactive material would be americium or plutonium-238. Pu-238 is a strong alpha emitter, and produced about 0.39 of a watt per gram, so several dozen grams might be needed, depending on efficiency. The only real use for Pu-238 is radioisotope thermionic generators, used on spacecraft; these nuclear batteries would be quite similar. The sad thing is that the US stopped producing Pu-238 in 1988; we now buy it from Russia… but even they have stopped producing it. NASA and the DoE are trying to restore production at a rate of 1.5 kilos or so per year. Since these “nuclear D-cells” are specifically for military applications, restoring manufacturing capability would seem to be needed as a single D-cell would consume maybe 1% of the annual NASA/DoE production.
Americium-241 produces 0.12 watts/gram, substantially less than Pu-238. More importantly, it’s also a neutron emitter, which is obviously bad news for the guy carrying a dozen of these batteries on his belt to power his GPS system, radio and phased plasma rifle in the 40 Watt range.
OK, most of what was lost has been redrawn.
After spending a whole lot of time and effort the past couple days banging away on the computer to redraw the Dyna Soar stuff, I needed a break. So, what could be more relaxing than working out how to rebuild the universe?
If you want an idea for a really big place to live, science fiction can help you out. First, ya got yer Earth-like planets. But then you can have rocky planets that have low-density cores… instead of iron, lets say aluminum. This lets you build a terrestrial world with one-G of surface gravity, but perhaps one and a half to maybe twice the diameter. Then you go to supramundane worlds, where you build a “floor” over gas giant worlds like Saturn. Conceptually tricky, requiring tech beyond what we’ve got, but in principle it’ll let you build a 1-G world wit a surface area of perhaps 100 Earths.
Then you start getting into things like Ringworlds (millions of Earth equivalent area). But those aren’t “worlds” in the regular sense, spheres with actual 1-G of surface gravity. But let’s say you were a Kardashev Type III or Type IV civilization, and you wanted to build a planet to impress your neighbors. Let’s say not just big, but so big that it would kinda-sorta punch a hole in the universe. How big would it have to be?
Start off by assuming a surface gravity of 1 G, 9.81 m/sec^2. The equation g=(G*M)/(r^2) defines this… g=surface gravity (m/sec), G is the universal constant of gravitation (6.672E-11), M=mass (kg) and r=radius (meters). You have to adjust the mass and radius to get the “g” you want. But there’s another factor: escape velocity. There is of course a maximum escape velocity, the speed of light. If you have an item so massive that at some radius from it the escape velocity is equal to the speed of light, you have yourself a black hole. That radius is the Schwartzchild radius, and is given by: r = (2*G*M)/(c^2) where c=speed of light, 299,792,458 m/sec.
If you mash these equations together and solve for mass, you can determine how big of a world you need to be so that the surface gravity is 1 G and the escape velocity is the speed of light. And the answer? A sphere with a mass of 3.08E24 kilograms (about 1.55E11 suns) packed within a radius of 4.58E15 meters (about 0.484 light years) is the answer, giving you a “planet” with the surface area of 5.17E17 Earths.
Interestingly, the density of the massive sphere is only 7.66e-6 kilograms/cubic meter, numerous orders of magnitude less than air. How would you build such a thing? Damnfino. I’m just assuming that by the time you get to Type III, you’ll have that noodled out. My guess would be to have an ordered cluster of supermassive black holes orbiting each other, surrounded by a shell of… I dunno, foamed Unobtainium with a fine matrix of Bolognium fibers providing extra strength.
When you build your nearly lightyear-diameter ball containing something like one-tenth of the mass of the entire Milky Way galaxy, you have a black hole you can walk around on. Unless you have some sort of faster than light propulsion, if you land on it, you’ll never be able to get away from it. But even landing on it would be a neat trick… you’d need a starship capable of attaining nearly the speed of light to get close, and would have to rely on impressive aerobraking for terminal descent.
Another issue would be time dilation. Gravitational time dilation does for observers close to massive objects the same as relativistic velocity does for fast-moving observers: time slows down. The basic equation: dilation = square root of (1-Schwatzchild radius/radius). The end result is that right at the Schwartzchild radius, time *stops.* So for the people and critters wandering around on your giant world, the universe will fade away and the last elementary particle will evaporate into a cold fuzz of nothingness in the time it takes to sneeze. Another effect of this would be that all the light that would fall on this “planet” would, from the viewpoint of an observer on the surface, fall within a a fraction of a second. A billion years of starlight would blast the surface inhabitants like a phaser blast.
There would be some interesting philosophical implications. As designed, the escape velocity at the surface is exactly the speed of light. But what would happen if the contractors working on it made the interior mass ten percent heavier, so that the escape velocity on the surface was *faster* than the speed of light? The time dilation math suggests that time wouldn;t just go to zero, it’d go *imaginary,* being the square root of a negative number. Buh?
And of course, this would be a black hole with no singularity. Indeed, if the “planet” was made of some monolithic extremely low density and insanely strong foam, if you tunneled your way all the way to the center, the gravity field would seem to be flat. Assume something even better: the outer shell is the whole mass of the thing, so that there was the better part of a lightyear of empty space inside the thing. What’s the time dilation effect inside *that?* Shrug. My guess would be that if the shell was effectively vanishingly thin, then the time dilation at the surface of the shell would continue all the way in… so you’d have a sphere a lightyear in diameter that would “freeze” time till the structure decays away.
I’ve done my math in Excel. HERE is the spreadsheet if you want to check my numbers.
After the CAD screwup, I’ve been working on recovering what I lost. The image below shows status as of a few minutes ago. The TIII/156 is back. The TIII/early is back. The TIII/operational is mostly back. The Dyna Soar overview and DS/Transstage overview weren’t lost. The inboard profile lost much. Now lost are the Saturn, “Skylab,” 932-102 and 934-606. They’ll have to be redrawn from scratch. The other ones listed will need to be created more or less from scratch, but weren’t lost in the screwup. There will be others as well, to be created not via 2D AutoCAD but via 3D Rhino. That model, fortunately, was unaffected.
This has been a schedule-bomber. If you want to see me obsessed, see me after I lose something I didn’t want to lose; I tend to go “grrrr” and devote myself to getting it back, at the expense of whatever else I needed to be doing. It messes with my sense of the way the universe aught to be. Of course, sometimes what’s lost *can’t* be recovered (go ahead and *try* to bring back the dead, for example), and that can make a permanent mess of things. I get caught in sort of a neurological do-loop; “just get over it” not being a function built into my programming.
Worse by far than the werewolves of London, seeing as how they’re real and all…
Yeeeeesh.
