Yarn

Coulombs law is F=kq1q2/r^2, where F is the force of repulsion between two charged objects, r is the distance between them, q1 and q2 are the objects' respective charges, and k is a constant whose value is dependent upon the medium between the 2 objects. The larger k is, the greater the force, and the smaller k is the smaller the force. k is at its greatest in a vacuum. In contrast, in water it is an eightyth as large. In the body it is about eighth as large. In rubber it is about half to a third. Etc etc. My question is why? I suspect it might have something to do with induction.

The 0.72 C effect was local, hence by comparing it to global temperatures you are comparing apples to oranges unless you are proposing that we put them everywhere.

I suppose storing blood in such a fashion as to prevent it from congealing would add to its cost, but given that we are able to store human blood in such a pristine form as to allow its functional reintegration into the circulatory system, in modern times the fact that blood normally congeals should offer no formidable barrier to it being drunken. However, preceding such technology, congealing would have provided a formidable barrier that would have required all blood to drunk "raw". I guess iron-overdose is also something to consider.

Water is a greenhouse gas, but it also frequently forms clouds. Clouds have very high albedos, and consequently cool the Earth. I once heard an environmentalist claim that for every amount CO2 increases global warming, the effect that this increase has on evaporation leads to it doubling. Is this true? How good an idea do we have of which effect predominates; clouds or water vapor's greenhouse effect?

When normal matter orbits a body, and when its orbit is crowded, it tends to eventually collide with the body it is orbiting due to friction slowing it down until the radius of its orbit transects the orbited object's radius (supposing the orbited object were a sphere, like all large continuous celestial objects comprised of normal matter are). Friction relies on the electrostatic force. Atom's are mostly empty space, and are interact less by direct contact between their actual physical parts than by the magnetic field produced by their charged subatomic particles. Some particles, e.g. neutrinos, lack a charge. This means they rarely interact with anything because charges do not effect them. In order for a neutrino to interact with normal matter, it must collide with that tiny portion of normal matter that is physical rather than a magnetic field. But neutrinos also have very little mass, so they don't, as far I as I have ever heard, get into orbits. Now, if dark matter exhibits a combination of the traits of normal and neutrino matter, both of which are kinds of matter that have been proven to exist, we have an explanation that fits the data regarding dark matter halos. If dark matter has large mass, that explains its orbit. If dark matter doesn't interact electrostatically, then that explains why its orbit apparently doesn't decay.

Slowing down air redistribution from one area to another will cause localized heating and localized cooling because if one place receives less hot air, another will retain more. We are talking about convection. Hot air flows not just poleward, but also up. To the extent that lateral movement is retarded one would expect an increase in vertical movement, so if the wind turbines were really obstructive to air flow to any significant degree, this would cause greater heat flow upward and out into space. However, I am skeptical of the idea that wind turbines are sufficiently obstructive to make a significant difference one way or another. Even supposing they made much of a difference at ground level, they are short enough that convection can simply continue apace by going above them. Cities have been mentioned in this discussion, however, i've never seen a set of wind turbines that came anywhere close to comparing to a city in size or blockage.

Obviously a lot of people are disgusted or titillated by the idea of drinking blood, but it seems like almost no one actually does it. The moral and practical barriers to drinking human blood are obvious, but animal blood is plentiful enough and probably plenty wasted. Do we avoid it just because of culturally taboo or are there medical reasons to avoid it? Presumably it would at least be a great source of iron. I've heard meat has hemoglobin in it, so we probably do ingest some blood, but why not drink it? In the Old Testament, blood drinking is explicity forbidden, which presumably means some people did drink it back then.

Gold is worth nearly as much as Platinum and therefore could also be worth extracting. However, all the other present metals aren't worth enough to justify extraction, and they make up the vast majority of the NEO. It would take a longtime to get to and from a typical NEO. You would frequently be dealing with trips of tens of millions of km.

The reason why we would need VASMRs, as opposed to traditional ion engines, is that NEOs are incredibly heavy. The $60 billion NEO I mentioned would weigh around 10 million metric tons. A traditional ion engine has a thrust measured in milinewtons. Even with VASMR, with its thrust being measured in whole newtons, the rate trajectory change would be small. Movie is about to start, gtg, more later

The nukes are for gross adjustment, VASIMR ion engines could be used for fine adjustment. Once the trajectory of the object is set into the ball park of the Earth-Moon system, over the course of years, if I am not mistaken, VASIMRs could adjust the trajectory to wherever we wanted it therein. A nuclear-powered VASIMR ion engine, though one has yet to be tested because VASIMR's are a very new technology and so far we are still working on and succeeding at weaker nonnuclear prototypes for near Earth use, could supposedly get humans to Mars in 39 days. That is a distance of more than 54 million km in a duration of 5 and a half weeks. However, NEOs are much more massive than spaceships. Still, for fine adjustment, we are looking at much smaller distances over far longer periods of time. Several carefully placed multimegaton nuclear warheads could also be placed on the object to vaporize it in the event we messed up and it intersected with Earth. An asteroid of of 10^10 kg, though perhaps containing tens of billions in mineral wealth, would only be around a 100 meters across. Nuclear adjustment is the most sketchy part of the capture scheme because the nukes used would have to be weak enough to not obliterate the object, aka somewhere in the kiloton range if even that would work. This would mean we would to have use quite a few of them, perhaps a prohibitive number. I am not sure whether VASIMR engines by themselves, perhaps by manipulating interaction with gravitational effects, could capture an object within 50 years. If they could, they would probably be the better choice.

Regarding the price of platinum, the vast majority of all platinum is used in a diverse assortment of industrial applications. Most of it, by a small majority, is used in making engines burn gas more completely. So it is as scalable as these applications are, and initially platinum from space will, as far as jewelry is concerned, be more valuable than that from Earth. No doubt the price will go down, but if space supply is the limiting factor on total supply then it could not go down far enough to make existing levels of space extraction unprofitable. Regarding the safety issues, that would be why you would put it in lunar orbit rather than in Earth orbit. Trajectory calculations are reliable things, meaning so long as we lined up the object's trajectory well in advance there would be no risk of it colliding with the Earth when you have a practical margin of error of more than 380,000 km.

In another forum, I was engaged in a sizable conversation with an aerodynamics student specializing in propulsion about the feasibility of capturing NEOs with vast amounts of mineral wealth into the Earth-Moon System and then mining them for profit through import of precious metals to Earth's surface so as to establish large amounts of self-sustaining space infrastructure that would bring us substantially closer to being able to construct and maintain space colonies. It has come to my attention that some nickel-iron asteroids, such as 1986 DA, possess in excess of $6 trillion worth of Platinum embedded in, in this instance, dimensions of a 2km rock composed primarily of other heavy elements. Platinum, once refined, is worth more than $21,000 a pound. Although it is possible fusable elements like helium-3 could someday rake in more money per mass if fusion technology ever took off, as of today platinum is probably the most instrinsically valuable material we could hope to find in space and the one with the best chance of justifying capital investments towards its acquisition from therein. It is thought in turn that several of the major mining sites from which we extract this resource on Earth gained their high concentration of it from long ago nickel-iron asteroid impacts. A problem with these impacts is that their intense violence ensured that a large portion of the mineral wealth contained in the colliding asteroids became diffused by them, thereby making mining less attractive than if the asteroids had magically landed intact and compact on the Earth's surface. The Moon of course has its own challenges for extraction, but it is thought asteroid impacts on the moon would've caused less diffusion because the moons lower gravity ensures a less violent collision. Also, since the moon doesn't geologically resurface, the minerals would not have the same tendency to sink over the course of many millions of years like heavy minerals do on the Earth. Mining the moon may be the most economically feasible method of mining space at present, and indeed one of the three main competitors for the lunar X-Prize has mining platinum group metals off the moon as one of its longterm objectives. However, one thing a captured NEO would have that the moon would not have is an extremely low extremely cheap escape velocity. With NEOs, for instance, we could propel mining operations with VASMIR ion engines (200 kw thrust of 5 newtons) alone. The moon requires more thrust to escape than any ion engine could provide, so it would require a chemical rocket of some sort. It has water (i.e. potential sources of H2 and O2) in polar craters that could be used to synthesize rocket fuel, but anyways, this thread is to be about NEOs. There are several challenges then that we face towards mining NEOs. First we have to get them here, second we have to adjust their velocity finely enough to get them into orbit (probably lunar orbit for safety reasons), and third we would have to come up with an economically feasible way to mine them. I have some things to say about how we might do these things, but I don't have sufficient background to have confidence in them. So i'll layout a couple questions, as well as invite everyone to give their own ideas and skepticism regarding the feasibility and potential methods for fulfilling these 3 elements. Is it feasible, within a time frame of 50 or so years, to influence the course of a 10^10 Kg sized NEO (which could be worth $60 billion supposing same ratio of mass to platinum as 1986 DA) into an orbit with the moon via use of ion engines? We did calculations in the other forum to the effect that nuclear explosions are powerful enough that they can easily and extremely manipulate the velocity and trajectory of an object of that size, but would the object be able to survive nuclear explosions intact enough to remain useful?