K^2

Not at all. "Dark Matter" merely states that majority of matter in the observable universe is non-luminous. What you are referring is the WIMP hypothesis. That drives things like search for heavy photons. Problem is, we don't have any good candidates at the moment. One of the alternatives is the MACHO hypotehsis. That just says that it's ordinary matter, but it's compact, and there is a lot of it. Comets and comet-like objects are one of the potential contributers to MACHO. The problem there is that it doesn't quite align with our modesl of star system formations and the age of the universe. Either way, albedo of the comet has nothing to do with it. The "dark" in "Dark Matter" simply means non-luminous.

Anything you'd like, in the bizarre universe where hydrogen turns superconductive at low temperatures. The conditions under which hydrogen is expected to be metallic and is predicted by some analysis to be superconductive are yet to be produced in the lab. Although, I'm sure it won't stop you from claiming that MSMH is the main component of dark matter.

Or you can charge it non-uniformly, and have some variable potential inside. But that potential still cannot have a maximum or minimum in empty space. So you cannot suspend something in the middle with any fixed arrangement of charges. Active system is the key word here. OP suggested keeping it in place by mere fact of charging the container.

What do you know? So it is. Well, there goes everything I believed in. Thank you for correcting me.

(Edit: Warning. Everything in this post is wrong.) I've specifically stated,"barring inclination change". In a 2d circular transfer, Hohmann is most efficient. In 3d, you add a 3rd parameter, requiring a 3rd burn. Most general elliptic to elliptic transfer is a 4 parameter change, requiring 4 burns. All of this is because each constant of motion has its own optimization. (There are actually 6 constants, but the assumption is that we do not care about final time and anomaly.) Energy with Obereth effect being only one of these constant - optimization pairs. Angular momentum is another one that is easy to understand. From there, things get complicated. Edit: Pardon me. That's 5 parameters/burns total for a most general 3d transfer. Anomaly is completely defined by the other orbital elements. It's only the time of periapsis that we don't care about. The reason it's 3 in circular to circular is because both argument of periapsis and longitude of ascending node become irrelevant. So bi-elliptic can get away with a 3-burn optimization. The most general problem is a 5-burn monstrocity, and I have no idea if a closed form expression for it even exists or if it has a name.

If you want to raise your AP, you should always burn at PE, but lowering PE intentionally just to raise AP is a waste of fuel. Unless, of course, you have an opportunity to lower your PE for free using a flyby. Rosetta's Earth flyby, for example, was angular momentum trade, rather than energy trade. It lowered its PE and raised its AP without major energy change. If you have opportunity to do this, then yeah, Obereth effect will consequently make it easier to leave the system. But that's because you get free angular momentum. This is something to keep in mind in general. When you adjust your orbit, you need to change your energy and your angular momentum. Obereth effect makes it most efficient to get energy low, but it's also the worst place to burn for angular momentum. This is part of the reason why Hohmann transfer is most efficient way to change orbits (barring inclination change). At lowest point, you get most of the energy change you need, and at highest point, you get most of the angular momentum change.

Modern supercarrier missile defense system consists of a dozen or more anti-aircraft autocannons linked to a central control system and set to automatically track and fire on anything moving towards it. They are actually designed to be capable to take out a maneuvering ICBM warhead on reentry. It's not 100% reliable against these, of course, but one nuke isn't going to cut it. You need multiple ICBM strikes. There is no such thing as a vicinity, either. You'll need a hit well within 1km to bring something like this down, so you basically have to aim for the target, and not some abstract "vicinity". You have a minor advantage that you con't have to score a direct hit with a nuke, unlike kinetic ICBMs, but you still have to be firing well within range of the defense systems. As for overwhelming it with cruise missiles, you have to keep in mind that the system won't need more than a few seconds to deal with each missile, and it can track and target a number of them independently. Yeah, you'll probably score some hits with a volley of 100 or so, but unless these are all tactical nukes, one hit won't bring it down. Nor will a few hits. You will need dozens of hits on critical systems, potentially into hundreds in all, and only a few percent of your missiles will be getting through. You do the math. If you do go with tactical nukes on your missiles, a lucky hit might bring it down right away. More realistically you'll need a couple to a few. And again, we are talking about something on the order of hundred tactical strikes attempted to achieve it. All of these are options. All of these are achievable, and way cheaper than it was to build the thing in the first place. But it is still an enormous effort that very few countries are actually capable of. Like I said before, I don't think something like this would ever be cost effective. You can lead multiple wars in multiple countries for a fraction of a cost. But it is viable, in principle.

You are thinking of cube/square problem. Which would be a factor if you tried to build conventional lift by moving this thing through the air. But you don't. All you really need to do is move air over its top surface. Given the huge size, you get almost no drag. You can basically maintain a low pressure system above the craft, and using it to support the weight. There is seriously a break-even point to this, where it gets easier to fly if you are bigger. Well, vulnerability to subs is definitely out of the question here. And missiles really have to be coming in in huge numbers. Modern automated missile defense systems are absurdly good at protecting carriers. Again, I'm not saying it can't be brought down with enough fire power. Just that you are greatly underestimating the amount needed. There's a reason why US navy practically consists of carrier groups. With its inertia it won't maneuver well. It can still travel at airliner speeds. Even if it doesn't accelerate, hitting something going at Mach .8 isn't the same thing as hitting stationary ground targets. Offence is the best defense in this case. Besides armor, it has a considerable range advantage on your ground guns, which it will use to level anything that threatens it before getting into range. In most cases, you will be limited to missiles as the only thing that can hit it, and you'd need to overwhelm its defense systems with quantity and speed of incoming missiles. That means either a huge amount of conventional missiles, or a good number of ICBM warheads.

Erm... I'm not sure you understand. We aren't talking about bringing down an airplane, where you have to burn through a few mm of aluminum or plastic. We are talking about burning through naval armor from range of 100 miles or more. Not only do not lasers like that not exist, it'd cost more to build one than the carrier in question, because the only way to even do this would involve an enormous particle accelerator. Railguns are still way outgunned on large caliber by conventional artillery. Which this thing will carry. In spades. And it will have the altitude advantage + not being a stationary target. You are not bringing this thing down with dumb projectiles. It can and will level anything capable of harming it before getting into actual range. Yup. Now we are getting somewhere. You'd have to spam missiles at it. Except aircraft carriers are also vulnerable to such an attack. Do you know when the last aircraft carrier was sunk? WWII. And that was one of the smaller carriers. A nuke still remains the only reliable way to sink a supercarrier. You watch too much TV. Let me put this into perspective. The control systems would only be necessary to control reactors and the turbines. Basically, this is equivalent to nuclear power plant operation. Number of nuclear power plants hacked by terrorists: 0. Ditto. EMP sources like that do no exist. The only thing capable of producing enough EMP to disrupt a machine like this is a nuclear blast. Which makes question of whether it can stay afloat moot. So we're back to having to nuke it. Which means multiple ICBM launches against a moving target. This is not an easy thing to destroy. You're still much better off building multiple aircraft carriers with the same resources, but this is far from a useless thing. A country that has one of these would automatically be a major world power.

It's not too fast. But keep in mind that I'd need to take a good number of readings during a single revolution to estimate the rate of rotation and orientation of the axis. All on a processor that can push about 1M instructions per second. If attitude control was the only task, I'd say, the hell with it, lets go for 1k RPM. But if there is a delay of any kind while it's making adjustments at that rate, you can end up with an uncontrolled tumble, and that can definitely screw up the experiment. But that's why I'm suggesting we go incremental and only set firm goals for easily achievable rates. P.S. I reserve the right to change my opinion of this completely once the simulation is running.

The cool thing about flight of any kind is that the bigger you get, the more efficient flying gets. Proportionally speaking, that is. So there is nothing theoretically wrong with the principle of a flying aircraft carrier. It'd be basically be a series of nuclear reactors driving huge fans, all paved on top with an air strip, but that's basically what you're asking for. Would it be vulnerable? Not much more than an aircraft carrier. Between naval caliber cannons you'd be able to install on that thing, missile defense system, a full load of fighters and other support aircraft, it'd be hard to get close enough to attack it. And since a lot of its systems would be redundant, a few hits won't do it. So short of a nuclear ICBM hit, I can't imagine anyone bringing it down. What it comes down to is cost to benefit. A nation can own at least a few supercarriers, complete with support fleets, for the cost of one of these. And a single nuke that gets past defense systems would bring it down. It's just not really worth it.

It was supposed to be 50mm. I really need to proof-read even short posts. 10E/plant isn't that bad, even for some basic experimentation. I'm assuming that someone who knows what they are doing wouldn't need more than one to get going. (Ah, +30E/order. Well, that's still reasonable.) And 90E/plant for the actual selected species is cheap. Scientific equipment/supplies tend to be absurdly expensive. So yeah, that's a good find. We just need someone who wouldn't need to go through 20 of these before figuring out how to keep them alive. (That totally excludes me, by the way.)

You are doing this wrong. Mass doesn't play a role in it. Also, we won't have anything more than 50mm from center.

GregroxMun, PM me your e-mail. I'll write a conversion tool for you.

Theory predicts identical bulk behavior of matter and antimatter, including with respect to gravity. Granted, there is very little, almost none, direct experimental data, but there are a whole bunch of indirect results that would have been different if there was a reason for bulk properties to be different. So while it might be nice, at some point, to confirm all of this with actual measurements, we can pretty much carry on with assumption that matter and antimatter behave the same way.

And women live longer than men. We should outlaw men.

If you are switching from FAT32 to exFAT, you definitely need to do a full format. NTFS is tree-based, so it doesn't care if you have random junk floating on your drive. FAT's table-based, as the name suggests, so it needs at least the table to be completely cleared when switching formats.

Take Mars, drop it on Mercury's orbit. Put Moon on orbit around Mars. Drop periapsis to 30k km. Apoapsis at 1M km, just within Hill Sphere. The Moon would go around Mars in 130 days, during which the barycenter will spend a couple of days inside Mars' radius. A year at Mercury's orbit is 88 days. So there will be a lot of "years" where barycenter stays completely out, and a lot of years where it would cross into planet's radius. This arrangement would require interior star system to be pretty barren to be stable, but there is no reason why it can't exist. I was actually referencing a 90's movie. But with that title, 50's might be a better decade for it.

That's a very artificial solution. And if planet severely loses tug-of-war, the mutual orbit can take much longer than a year to complete. So your definition would still change from year to year. The convexity is a very elegant mathematical principle, and it simply either holds or it does not. Nah. US will claim right away that they've already put a man on the planet. It's not like something about the Moon changed, just the definition. Edit: Though, if there is an ongoing mission when new definition is adopted, "The men who went to a moon, but came back from a planet," has a nice ring to it.

You should read this post by Mazon Del. Tl;dr is that Physcomitrella patens moss seems like the best candidate. They are specifically engineered/selected to have certain kinds of gravitometric response. But for basic pre-flight testing, the garden variety should be fine. Unfortunately, I only see species specifically bred for testing for sale, and these might not be as cheap as we'd like to start with. I know bugger all about botany, though. This might be something you can just go into forest and find, for all I know.

You have to get creative to find something you can't build a rocket engine out of.

Yes. It is called a traversable wormhole. Unfortunately, all known configurations require negative energy. Same stuff you need for warp drive, basically. It has been suggested that Casimir Effect can be used for this, but it's all very hypothetical. Even on paper, there are some uncertainties. Naturally, experimental evidence is non-existent. That isn't actually true. A supermassive black hole has fairly gentle gravitational field at the event horizon. Unless you try to stop yourself from falling in, in which case it gets stronger. Gravity gets a bit weird when you have things like black holes and wormholes involved. Heh, that's a neat idea. Though, I'm not sure if it's necessary. If you just want to go through, gravity on one side will accelerate you, and on the other side slow you down. So as long as the wormhole is traversable, you'll just shoot through.

Antimatter is the only stuff that gives you ISP of c/g. Hopefully, we'll find a workaround for that, but otherwise, might be the only way to go for interstellar.

Nope. Doesn't work. There is a theorem in classical electrodynamics that says that you cannot trap a charge with electrostatic forces in free space. Edit: Just to add a bit of detail. The key here is that you cannot have a maximum/minimum in electrostatic potential that is not located on a source.

Sorry. Brain-fried. 1m/s². I'll fix it in the post. Just trying to keep RPM reasonable.