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kerbiloid

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Everything posted by kerbiloid

  1. Due to relativistic time dilation. Does the relativistic time dilation affect salary?
  2. Pagination is cheating. Misspelling Jim diGriz's name is cheating.
  3. Lexx's laughing at all your planet killaz. https://lexx.fandom.com/wiki/The_Lexx It's blowing up planets almost every episode, in two Universes. Do you say "Planetocalypse"? Lexx says it's just Tuesday.
  4. The longer the wine is aged the better.
  5. Telemetry is tested. Scientific tools are tested and have delivered scientific measurements. https://www.interfax.ru/russia/916003
  6. The high walls were making sense in the epoch of archery, with aiming range 30..50 m and maximum ~200 m, so the archer on ground (especially separated by the moat) could not aim the top of the wall effectively, while the archer on top had much greater shooting range. The thickness was not essential, as the trebuchets had the same problem, and wooden rams could penetrate the gate, but unlikely the wall. Also, it was possible to make them out of stone and/or "concrete", as they could hardly be damaged with those tools. Artillery made it possible to cause severe damage to the stone walls, and it's a problem to repair a 20 m wall made of stone blocks. Also it made the top of the wall easily shootable. So, they tended to drive the enemy artillery away from the walls, by surrounding the fortress external embankments with artillery positions. Their great height would mean cross-section and thus vulnerability to the horizontal fire (while the mortars and others had puny range and hardly could be placed close to the walls). So, these embankments (then turned into bastions) had minimum possible height, just to prevent them from being captured by a lance-long hand-held ladder, so about 6 m. At the same time the embankment worked as a trap for the enemy soldiers having climbed on top, and becoming aims for the internal guns and artillery. Also, even a meter-deep water in the moat made it hard to hold a ladder.
  7. The gaseous uranium would anyway be exponentially-radially distributed, just statistically. And as it's 238/2 times heavier than H2, it would concentrate at the CoM.
  8. First correction is done at 16:00 Moscow Time, burn duration 46 s. One more correction is left. https://www.interfax.ru/russia/915958
  9. Machinery and equipment can last for decades, sometimes a century+ (something is working since XIX). So, the flight time should not exceed 100..200 years. Relevant stars (alpha Cen , epsilon Eri, Sirius, etc,) are at 4...11 ly from here. So, the minimum delta-V to get there before the ship gets out of order = 4..11 / 100..200 = 0.05 c. The engine characteristic power, W ~= thrust, N * exhaust speed (i.e. ISP * g), m/s. Its energy conversion efficiency is (much) less than 1, so comparable power is produced as waste heat. The waste heat is produced as energy of electrons, heavy particles, and photons, so in any case mostly as electromagnetic radiation (primary or secondary). It weakens proportionally to 1/r2, while the established equilibrium temperature is proportional to 1/sqrt(r). This means that the combustion chamber size is limited from below by heat, and from above by mass. This means that realistic size of the chamber/nozzle is ~tens to hundreds meters, and the power (i.e. F*ISP) is very limited from above. You can have either high thrust but inefficient low ISP, or high ISP but weak thrust and slow acceleration (which in turn leads to flight duration beyond the equipment stability). Two ways can increase the limit of power. Both are based on the idea that you drop the energy of photons, and use the energy of plasma. Lattice-like magnetic nozzles, made of ribs, flat in cross-section, oriented with edges to the hot spot. Most of photons pass between the ribs and fly away. Those ones who hit the ribs, heat them, but as the ribs are wide in radial direction and thus massive, it allows to cool them with active cooling system down to appropriate temperature. The plasma inside is held and pushed back by magnetic field, produced by the rib lattice. The appropriate size is greater than for solid chamber/nozzle, but still very limited. Another way is to place the hot spot far behind the ship, focus the plasma beam towards the ship, and let photons (and neutrons) just fly away without any structure around. It's the Orion way. In this case you can place the reaction zone at several kilometers to tens kilometers behind away from the ship. All waste heat stays behind. So, you virtually have an immaterial chamber of many kilometer size, and just have to reflect the plasma beam with a magnetic trap. This type engine combines exhaust speed of 1 000 up to 10 000 km/s (ISP 100 000 ... 1 000 000 s), normal acceleration, limited ship size, and limited requirements for the cooling system. At the same time the developed magnetic trap, equipped with expandable structure, can serve as a magnetic chute to slow down from interstellar speed to interplanetary without spending of fuel (catching the protons of solar wind of the destination star, using them to generate electricity in the trap, produce magnetic field, and reflect other protons of that solar wind to produce deceleration thrust), and then as electric chute to slow down from interplanetary speed to planetary, using the planetary magnetosphere. Also, the magnetic nozzle can be used as a front shield, reflecting incoming protons and clouds of ionized dust, produced by X-ray beams, destroying meteoroids on the way. As currently the fusion Orion design is the only known such design, with high thrust, high ISP, and listed advantages, it could be said that at the current state of physics, 1 000 ... 10 000 km/s is the top limit of available exhaust speed. Mass ratio = exp(0.05 * 300 000 / 10 000) = 4.5 If ISP*g = 1 000 km/s, ln(4.5) * 1000 / 300 000 ~= 0.005 c. This means that 0.05 c is the minimum what can let the ship reach the closest stars, staying intact; and at the same time it's the maximum of what can be achieved without unknown future-tech technologies (like hyperjumps, teleportation of hydrogen from Jupiter or energy from Sun to the ship, a pocket universe for the combustion chamber, etc.).
  10. The howitzer grenades fall from above, and the fortress shape doesn't play role for them, only vertical projection total area does. The horizontal fire is done with more lightweight and mostly penetrating shells. They will bury inside, blow up, and the ground will just fall down. The thick embankment will need a repair, but it will anyway need it after battle, and the ground means that the repair is easy, unlike granite walls. The front stone is also usually an artificial trash stone (lime + sand, or clay, or gypsum, or tuff → artificial sandstone, limestone, Roman concrete, etc.), which is as easy to deliver, mix, and shape in bags, as ground. So, the greatest advantage of the early bastions is their easy repairability, and at the same they allow to keep the enemy artillery far from the internal part of the fortress when the cannon fire is limited with 600 m distance. They are by origin not angular towers , but additional external elements of field fortification around the fortress itself, at the same time having made the fortress inside excessive. So, the increased distance of the artillery fire allowed to shoot farther than from the bastionish 200..500 meters distance, so the angular shape became excessive and obsolete. The bastions were making sense only for close combat.
  11. These ones look so (though, the top looks unprotected and asking for sandbags or so). But most of them look like leaf-like flat hills with no structures on top. Often placed in the middle of nowhere, far from strategic points. Sometimes cut by a sea coast or another landscape detail. And it's funny to compare in Google Earth the mentioned fort Lippe near Elvas and Elvas itself (two nearby star forts). The tricky geometry of the former contrasts with proper bastion-like geometry of the city.
  12. Still flying. https://www.interfax.ru/russia/915781
  13. Mentioning the D-word in vanilla thread is cheating.
  14. No problem, sir, but we must inform police. Waiter! Jinn with tonic, please.
  15. Every donkey is in its donlock. Where was King Kong gathering huge bananas?
  16. Most of them don't have walls, they are solid flat hills. So, it's nothing to penetrate, except the hill 200 m in diameter, like we have here. Also, in those who are wall-based, the wall can be 10..20 m thick, made of ground. So, I still prefer the cryptocivilisation hypothesis, lol. Btw, two more good examples are in N'York, the basement of the Statue of Liberty, and the Hovernor's island aside. (What again, in its turn, makes to think that it's made by cryptoatlants.)
  17. Yes, I have one right a mile from here, and two more in me-related cities, But they are older than 1812,
  18. Not specifying the number of faces of the die is cheating.
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