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http://chouza.com.ar
They don't, see https://arxiv.org/abs/2309.07061 . The basic idea is to use "picosecond-level" synchronization to improve the signal-to-noise ratio. They mention that a truly phase-coherent swarm would perform much better but they consider that a longer term prospect (section 2.1.4).
Probably just converted from 1500 km.
I am quite confident all the current employees of OpenAI qualify as real people. They certainly have problems and probably a good share of those problems are "real" too.
Of course their priorities may be off and they could be open to be persuaded to work in a different direction. But I don't think that condescension would be very effective for that.
Many theoretical and experimental studies were done. One example from the early 70s is http://ipnpr.jpl.nasa.gov/progress_report2/II/IIO.PDF
That's true, but supersonic planes also travel higher (Concorde -> 18 km, XB-70 -> 22 km). The real problem is that L/D decreases at supersonic speeds. For example, the XB-70 had a L/D of about 7, while the 707 had a L/D over 18...
It's mostly a question of power. The 1987 design for the TAU probe communication system would have handled 20 kb/s from 1000 AU... by using between 100 and 260 watts for the transmitter (and relatively big antennas):
Photons are generally considered to be their own antiparticles: http://van.physics.illinois.edu/qa/listing.php?id=27107
Japan has more than 1000 kg of HEU: http://www.nti.org/analysis/articles/civilian-heu-japan/
He is the first author cited in their paper:
http://www.witricity.com/pdfs/highly-resonant-power-transfer...
It's already public: http://www.dawn.com/news/1077275/nsa-tapped-into-undersea-ca...
Oil can be produced synthetically: http://en.wikipedia.org/wiki/Fischer%E2%80%93Tropsch_process
Though the FT process is quite bad from a CO2 emissions POV.
No, the algorithm as described is very different from binary multiplication. It requires a number of stones proportional to the result, while the number of bits required when doing binary multiplication is polylogarithmic.
It's a big difference: 1000 * 1000 would require 1000000 stones if done with the "Ehiopian algorithm", but it can be done with less than 1000 stones by using normal binary multiplication.
You can launch from the ocean, though with more limitations: http://en.wikipedia.org/wiki/Sea_Launch
Maxwell didn't come up with anything himself [...]
Maxwell "invented" the displacement current:
In the short run:
- Ion thrusters are way simpler and they are trying to do something that is much easier.
- Ion thrusters are relatively mature, working "fusors" don't exist.
- Existing machines that are trying to get fusion breakeven are building-sized.
- Trying to start a fusion reaction is hard, it only makes sense if you get a commensurate result (energy gain).
In the long run, I'm very optimistic about fusion.
Yes, I agree. My point was that you cannot do substantially better than ion engines without having energy gain and, in fact, you are probably going to do much worse due to the weight of the "fusion hardware".
I'm quite optimistic about magnetized inertial fusion. But the idea of doing the job much better than the Z-machine, with something lightweight enough to carry into space and in less than 10 years seems to me... unlikely, to put it mildly.
Well, controlled fusion hasn't reached energy breakeven at all, even taking into account the kinetic energy of the reaction products. But the low thrust of current ion engines is mostly due to power restrictions (https://groups.google.com/group/sci.space.science/msg/0cb332...). If your spaceship has a mass of one ton and you want an acceleration of 1 centigee with an exhaust velocity of 30 km/s, you will need at least:
0.5 * thrust * velocity = 0.5 * (0.1 m/s^2 * 1000 kg) * 30 km/s = 0.5 * 100 N * 3E4 m/s = 150E4 W = 1.5 MW
of power.
If fusion doesn't provide a substantial energy gain, it's not worth the effort. Existing ion thrusters are quite efficient (60+%) at translating electrical power to exhaust kinetic energy.
Project Orion was much more than science fiction (http://www.scribd.com/doc/28668567/Nuclear-Pulse-Space-Vehic...) though it was much less than operational. Very big Orion spaceships would have used fusion explosions (http://galileo.phys.virginia.edu/classes/321.jvn.fall02/Dyso...), but not the relatively small ones that were subjected to detailed analysis.
Simulating explosions helps determine maintenance for nuclear warheads?
It's not completely unreasonable: they need to validate the computational models that are used to check if an aged nuclear weapon will explode.
A more skeptical analysis by Phil Plait: http://blogs.discovermagazine.com/badastronomy/2011/10/17/di...
The basic idea is to ablate the asteroid to deflect it: https://e-reports-ext.llnl.gov/pdf/343984.pdf http://permalink.lanl.gov/object/tr?what=info:lanl-repo/lare...
There are some places in the "natural universe" that are colder than the CMB. That's because they aren't in equilibrium:
http://en.wikipedia.org/wiki/Absolute_zero#Very_low_temperat...
It's not as stupid as it seems. Due to the cosmic microwave background, the equilibrium temperature far from other natural radiation sources is about 3K. But, as we don't know the temperatures in the whole universe and there are natural processes that can cool things below their equilibrium temperature, they should have said "... anywhere in the known natural universe".
The puzzle can be found at http://meshcapital.com/application.tar.gz
You can try posting your question in http://cstheory.stackexchange.com/
The paper can be found here:
http://www.eso.org/public/archives/releases/sciencepapers/es...
All plutonium isotopes can be used to make nuclear weapons [1], though Pu-238 would give big problems to weapon designers due to its intense decay heat.
Fast-moving people will also be Lorentz contracted, so there will be plenty of room... if there's enough energy.