Jump to content


  • Posts

  • Joined

  • Last visited


370 Excellent

Recent Profile Visitors

The recent visitors block is disabled and is not being shown to other users.

  1. Not in Finland. However, inches are commonly used in spoken language, especially in carpentry and other handcrafting. Nor example 100 mm nail is called "four inch nail" and 96x48 mm plank is "2x4 inch".
  2. Actually I would be happy if there were global compromise. Units could be imperial but one unit per quantity and decimal notations instead those very impractical rationals. For example an inch would be very practical unit in everyday needs. Most objects I handle have size of 1-10 inch. Kilometer would be 40 kiloinch. Megainch (25.4 km) would be quite practical for everyday traveling purposes. And I have already very used to mils (milli-inch), which is very common unit in electronic engineering.
  3. I understand. But in most case you buy some standard packet of meat. In my country that "normal" 4 person packet is 400 g. Next size is 600 or 700 g depending on meat company, which is practical for larger family. At least I buy very rarely arbitrary amount of food products except fruits and vegetables. Sometimes there are packets in imperial sizes but I count a pound as 500 g. It is also very common to have more complex values because companies have tendency to decrease packets for example 10 % instead of increasing price. After couple of silent decrease they can bring "new larger size" with advertisement campaign and increased price. Probably I could adapt quite easily. I am engineer and used to use and convert imperial units and also some other special unit systems used in certain physics areas in addition to metric units.
  4. If you could make anti-iron you could use ferromagnetism to handle it. It would be couple of orders of magnitude easier than handle plasma, but I would not like to live near antimatter storage. Unfortunately there is no stable configuration of permanent magnets able to levitate an object. A simple control system is needed. It may not be simple to make sure that it work after blackout, earthquake, military attack and all attempts to maximize the profit with simplification of system. Probably there is no need to store a ton of antimatter for any planetary use (except sterilize conquered planets from annoying semi-intelligent apes with nasty nuclear bombs). Large long term energy storage could use safer and more efficient methods (production of antimatter is very inefficient). Antimatter may still be allowed for small amounts if some technology needs very rapid release of energy.
  5. You can certainly buy disposable hypermagnets from the same shop from which you buy a ton of antimatter. There is a new year sale for magnetic monopoles going now. Take 3, pay 2. Please notice that shipping of antimatter may include longer delivery time and extra cost due to safety regulation.
  6. Biosphere makes the Earth clear winner, but if I think just planet without taking biosphere into account, maybe Jupiter. Those flow patterns are nice and it has also many different moons and interesting physical activity around. Neptunus has nice blue color but is little bit boring.
  7. It seem you also forgot how photosynthesis work. It takes water and carbon dioxide as ingredients. Photon energy is used to break bonds between hydrogen and oxygen in water molecule through complex biochemical reaction chain. Those molecules and radicals form glucose (through very complex reaction chain). Numbers of all kind of atoms is conserved and only changes in mass are very negligible relativistic effects. Photosynthesis do not make atoms from photons, it just uses photon energy to push chemical reactions. So, aluminated mylar foil would give much more push from sun than of all those fancy plants, blood generating zombie worms and waste recycling devices.
  8. All (practical) lunar orbit insertions for retrograde orbits needs braking burn behind the Moon. With modern tech it is easy but it was real problem during Apollo missions which had to also execute lunar orbit insertions and trans earth injections behind the Moon without communications to Houston.
  9. In Finland there was thick rain cloud layer, as always when something interesting happens in the sky. I wait impatiently when Sun grows to red giant and blows all atmosphere away. As a bonus, we will be liberated from terror of winters too. Then we can happily see all interesting things on night sky in comfort warm conditions. Unfortunately, I can see a mild problem. There will not be total solar eclipses anymore at those times because Sun's angular diameter will increase significantly but Moon's angular diameter will decrease.
  10. 301 is so called austenitic steel. It means it has face centered cubic lattice, in which iron is not ferromagnetic. It is ferromagnetic only if it is in body centered cubic lattice (ferritic iron). However, there may be small ferritic areas due to for example lattice defects and sometimes austenitic steels may have mild ferromagnetic properties. It is far too weak effect to hold anything but you can barely feel it with strong magnet. I also think that such defects are not wanted in rocket hull because they affect structural and chemical properties too.
  11. Good luck to apply license to use all those environmentally friendly and very safe fuels. Do not forget chlorine trifluoride. If it is too weak stuff for engines you can use it to ignite campfire on Moon or Mars. Maybe you could jump straight to the deep end of pool and build an Orion (that original version form 50's, not modern capsule).
  12. That green flame is spectacular. Maybe they should add little bit copper containing chemical in fuel in those missions do not need 100 % capacity. Do you know was that unexpected anomaly or did they some destructive or intentionally risky testing?
  13. Energy of normal ionization methods, like corona discharge or radioactive source, is negligible to energy of combustion. Ionized intake gas would give no benefits but corrode engine parts. Highly ionized gas is used for plasma cutting.
  14. Imaginary unit is usually written as j in electrical engineering. i(t) is instantaneous current (as a function of time) and I is usually RMS-value. You write that sinusoidal 50 Hz AC current I =10 A which means i(t) = 10A * sqrt(2) * exp(2*pi*50 Hz*t*j), where j is imaginary unit and t is time. Calculations use complex currents which arguments is phase in relative to some reference. Actual physical current is real value of complex current.
  15. At what price level? If passenger capacity is few people and trip takes thousands of tonnes of propellants and need special rocketports it need pretty scifi-ish assumptions about economy to be profitable. Environmental issues are also very severe and probably many companies avoid such trips due to reputational damage.
  • Create New...