K^2

Within proximity of the station, sure. But again, things that move fast enough to present danger need to be tracked long before they are in proximity. Hence the softball size limit on what we can track. Things larger than softball, for the most part, we know where they are all the time. But even if we know about them in advance, not much we can do about it. Smaller things we could do something about, but we can't track them.

If the softer of the two was also less dense, geology would be very, very different. Also, geography.

Oceanic one is soft. That's why it's bending down and diving under the continental plate. But it still generates enough force on the continental plate as it does so to cause the later to bulge.

Any pentaquark will have an anti-quark. That's required by color-neutrality rule. The fact that it's a cc-bar makes it a little less stable than one expects with a mismatched anti-quark, that's true. But even the best case, which is probably a p + K (uddds-bar) pentaquark (totally guessing here), the life time will be extremely short. Even À+, which is ud-bar, which is as good as it gets for a meson, has a half-life of only 29ns. And that thing is almost 10 times lighter than a proton. The resonances that have been detected are more than 4 times heavier.

Ah, so you mean just for the larger debris? Yeah, that could work, then.

They are all excited states which decay via strong interaction, so yeah, extremely unstable.

Again, you don't know where that junk is. How are you going to go and pick it up?

That would take quite a few subs. ICBMs are, as the name implies, ballistic. In other words, they follow Kepler's Laws. Mid-range ones tend to have pretty high apogees, because that reduces dV requirement. So they spend all their time in the slow part of their sub-orbital trajectory. Fifteen minutes just doesn't give you a lot of range with ICBM. Typical inter-continental times are closer to 30m, and that's the sort of thing you need to have for global coverage with a "few" subs.

How are you going to do that if the objects aren't being tracked? Keep in mind that debris that presents danger is the kind of stuff that's traveling at several km/s. Even if you manage to pick it up with some sort of radar shortly before impact, you won't have time to maneuver to try and catch it. Now, you might be able to shoot it down. Modern supercarriers do have weapons designed to track and shoot down re-entering warheads. The relative velocity is in the ballpark. Given the emptiness of space, id est, lack of false targets, you might be able to lock onto something the size of a pebble. Of course, it's going to create even MORE debris, unless you find a powerful enough laser to use in place of an auto-cannon. By this point, we're basically talking about a second station.

Well, there appears to be, what, five people on the board who know what pentaquarks are? Not really surprising that this news went under radar. And to be fair, it's not a shattering sort of news. People have been looking for them because everything says they should exist and contribute to certain decay modes. But that's about the extent of their impact. Just another entry into the long list of experimental facts that confirm standard model.

Haven't heard about that. Excellent news. They've been predicted, and pretty well studied in theory, but have not been formally observed until now. Met a few people looking for them at conferences, I bet they're having a party. Physics works, people!

Imagine if they hear about virtually all screw/bolt threads being right-handed. Although, this might be a great business opportunity. Sell left-handed screws for left-handed people. But yeah. The only sensible definition for a planet is rotation based. I suppose, a planet with zero rotation can exist, but the odds are overwhelmingly against it. On the other hand, not all planets have magnetic poles, and some objects (planets among them?) can have large number of magnetic poles. Which makes any compass-based definition useless. On that note, I wonder how feasible a Foucault compass would be. Naturally, it wouldn't be mechanical, but with optical gyros, you should be able to detect rotation precisely enough to tell which way the rotational north pole is.

For that, you use Horizons, as LordFerret recommended. Here are the settings you want for Saturn. Ephemeris Type [change] : ELEMENTS Target Body [change] : Saturn [699] Center [change] : Sun (body center) [500@10] Time Span [change] : Start=2015-07-17, Stop=2015-08-16, Step=1 d Table Settings [change] : defaults Display/Output [change] : default (formatted HTML) Set the time span to whatever makes sense. Note that this will show you the osculating elements, because perturbations. They should drift by much in any sensible time window, so feel free to just average everything but the true/mean anomalies. Alternatively, you can take the time of periapsis and compute mean anomaly for any moment of time. Ignoring perturbations, of course. That's probably what you should do for on-the-rails simulation. Then you can check true anomalies you get against the table. P.S. Almost forgot. Horizons can also generate actual locations of bodies at specified times in polar or Cartesian coordinates. That's absolutely fantastic for debugging. You can run your code and compare your output to Horizons.

Yes to both. Soyuz has been designed with spacewalks in mind, so the orbital module can act as an airlock and allows entry with inflated space suit. I'm not sure if they keep door to the descent module closed. If so, then it wouldn't even need to be re-pressurized, since there is an airlock. In either case, it can be. Even if we imagined that descent module's air system was incapable of it, you can just leave the door to orbital module open and let airlock's system re-pressurize the entire vessel.

Have you tried Wikipedia? Articles on celestial bodies have their orbital elements listed in a neat little pannel on the right. Along with whole bunch of other useful data. If you want an on-rails simulation of our Solar System, you should have everything you need there.

You can use helicopter recovery for your lower stage.

I haven't looked at the full article, but from the abstract it follows that these are numerical solutions based on desired topology. Therefore, a formula for period does not exist. It has to be numerically evaluated for a particular trajectory. That said, once you have the trajectory, it's a trivial thing to compute. Given the DoF, if you know positions of all 3 bodies, you know their velocities from relevant conservation laws. I also wouldn't jump to conclusions about stability, unless article specifically states that they have found this configuration to be stable. P.S. Actually, if I was solving this, I'd make period fixed, and let it expand/contract during optimization. So it'd be a way of computing distances from masses and period instead. But the point stands, there isn't a formula. It's a numerical problem.

Keep in mind that kinetic energy is quadratic in velocity. The faster you're moving the less of a change in velocity you need to experience for heatting to occur. And as someone pointed out, gravity is in that equation too. It's entirely possible to be generating increadible amounts of heat and still be speeding up if you're going down. We're catching up, though.

There are different kinds of reactors, some more dangerous than others. In particular, there is a class of nuclear reactors called breeder reactors which can generate weapons grade plutonium, among other things. While there are legitimate reasons for wanting to build breeder reactors, especially if country's supplies of nuclear fuel are low, building a breeder reactor is also one of the steps in developing a nuclear arsenal. So naturally, it makes everyone worried when a country decides to build one.

Hm. That's strange. Maybe TD gas produces more neutrons for the fission. I'll look into it.

Modern boosted fission devices also use lithium deuteride for all the same reasons explained above. So a modern thermonuclear warhead contains no tritium.

Why would liquid "atmosphere" prevent a probe from landing? What you don't want is a sharp boundary between gas and liquid. That can cause all sorts of problems to the probe during landing. Even that isn't an automatic disqualifier. But all you are really dealing with here are extreme pressure and density that's approaching that of a liquid.

Surely, you're a traveler of both time and space, to be where you have been.

Ayup. A neutron bomb is just a low yield nuke designed to make sure that all of its products, both from fuel and irradiation of the casing, are very short-lived isotopes. The idea is that these isotopes will burn through in a few weeks, making area safe to enter, rather that leaving an irradiated wasteland for decades to come. Low yield also ensures that it doesn't lift quite as much of a dust cloud, hopefully, reducing any chance of irradiating anything downwind. It's the combination of density and confinement time that are important. If your confinement is very short, such as during a nuclear explosion, density needs to be very high. Tokamak achieves fusion by having very long confinement times instead.

The atmosphere will be a supercritical fluid. Which means, there is no longer a difference between it being a gas or a liquid. It also means that, unfortunately, most formulae you could have used for scale height are going to be useless. This sort of fluid is very far from ideal gas. The relationship between pressure, volume, and temperature is dominated by molecular interactions rather than ballistic movement of particles in an ideal gas. Fortunately, the goal isn't to get exact numbers, but rather something plausible. I would assume, for sake of calculations, that density isn't going to change much once your atmo hits critical pressure. You can't really model that in KSP, but we'll pretend for sake of temperature calculations. I also am not sure what the critical pressure of this mix would be, but critical pressure of hydrogen is 12.96 bar, so lets use that. Next, you need pressure at the upper cloud layer, because that's where radiation equilibrium with the star will establish. Do you know how to compute radiation equilibrium, by the way? Wikipedia's article on Black-Body Radiation has a section called "Temperature of Earth" that runs through an example. Use that to compute your T0. You also need pressure at cloud layer, P0. I have no idea what that should be, but I'd use pressure of upper cloud layer on smaller gas giants as a guess. From here, I would assume Adiabatic compression to your P1, which is your critical pressure of 12.96 bar. Use that to get T1, which you'll use as surface temperature. Now, this is technically wrong. Atmospheric compression isn't Adiabatic, but correct model depends on so many factors... And you need an estimate, which this will give you. Finally, we get back to the question of scale height. Now, KSP actually has support for non-exponential atmosphere in its source code, but I don't know how to enable it for modded planets, or if it's even possible, so even though it's technically isn't right for supercritical atmo, you'll still need an H value. As I've explained above, anything you'd get from scale height formula is technically wrong. But what I'd do is get scale heights at T0 and T1, and use something in between. Real planet probably wouldn't be anything like that in terms of your ability to escape it, but it should, at least, give you something semi-plausible for landing probes. And that's probably all you'll be able to do with this world, so maybe that's good enough? For atmospheric height, just see at what pressure they cut it off in KSP, and use your scale height formula to find the correct cutoff altitude. Again, it's not really correct, seeing how so many standard assumptions are incompatible with this world, but at least this value will be self-consistent with all the assumptions KSP makes.