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China Plans Moonbase

jfruhlinger writes: "According to this BBC news article, the Chinese government plans to put a human on the moon by 2010, with the long-term goal of 'set[ting] up a base on the moon and min[ing] its riches for the benefit of humanity.' The article seems to think that the program is more for the benefit of China's defense and aerospace industry. D'ya think they can pull it off?"

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  1. Discussions on Physics by virg_mattes · · Score: 5, Informative

    I'll take a swing at a few of your ideas, although I can't address much about the photographs as I've never studied them.

    > After watching the video of the moon rover driving around and kicking up dust as it went... and then seeing the video of the Lunar Lander rocketing off the moon's surface without stiring up any dust at all????? The only way I could see the smaller force of the rover kicking up more dust than the larger force of the rocking pod not able to moving ANY dust at all is if the laws of physics are not constant on the moon.

    Actually, the trap you're falling into is based on assumptions about how dust behaves on the Moon. Those assumptions almost always stem from observed behavior of dust and dirt on Earth. There are a few key differences, however, that make a HUGE difference in how small particles behave in these two very different environments. They are:

    Atmosphere: this is by far the most important, and the most confusing. This causes two things. First is that there's a lack of turbulence that is unfamiliar to those who don't work with vacuum. This is what causes your disparity of observation. You'll notice in the film that the return module of the lander did not fire a rocket directly at the moon, but instead it pushed on the top of the descent module. That means the main thrust of the engine went downward into the descent module and then straight out sideways. On Earth, this would cause a swirl of air all around the module, but on the Moon, there's no air to swirl, and the thrust never gets to the ground, so there's no dust movement. Second, dust on the Moon is not like dust or dirt or sand on Earth. On Earth, these things get worn smooth by air and water. On the Moon, they don't so dust is very hard-edged, and its behavior more closely mimics wet snow than sand.

    Gravity: this tends to cause things to behave differently than expected, and it goes hand in hand with the lack of atmosphere. Just as Mr. Armstrong did not descend quickly to the surface, we'd expect dust to fall slowly. However, what the mind fails to suss out is that the lack of air resistance more than makes up for the lesser gravity when small particles are concerned, so when dust falls quickly, it looks odd. However, the rub is that the only place dust can fall as quickly as a human being is in a low gravity vacuum, which would seem to prove that they were in fact on the Moon.

    > Not going to get into the issues of trying to pass through the Van Allen Belts wearing suits of 7 layers of 'glass like' material for protection.

    This stems from misunderstanding how radiation works on the human body. The method for determining exposure has two factors: intensity and duration. One can get a fairly high dose of radiation and not develop health problems if the the duration is short. Conversely, low exposure for long periods can cause difficulties, which is why x-ray technicians stand behind a wall when they use the machine (else they'd get small doses, but lots of small doses) while you get to stand in the beam (high exposure, but you only do it a few times in your lifetime). The Van Allen belt has (relatively) high radiation levels, but unless you're planning on living in it (and most space stations are positioned outside it (well, inside it, relative to Earth)) you're not going to get a lethal dose. All of the discussions about how much shielding is needed for the Van Allen belt are based on the amount of shielding necessary to block all of the radiation, but it's not necessary to do that if you limit the amount of time spent there. The balance is that the Apollo astronauts did get a dose of radiation, but it was in the area of 1 rem (radiation sickness doesn't normally appear until the levels get to about 20-25 rems), so it wouldn't be particularly dangerous (or at least no more so than the trip to space on the booster rocket was to begin with).

    Virg

  2. Actually... by virg_mattes · · Score: 5, Informative

    The space-based Hubble doesn't have the resolution to see such things, and even if it did, the very properties of light are such that you can't see something that small from that far out (the wavelength of the light itself limits resolution). However, there's a reflector on the Moon designed to bounce a laser back, which was put there by Apollo astronauts (I don't remember which mission) to measure distances to the Moon. It has since been used many times, and every time someone shoots a laser at the right coordinates, they get the beam back, which is impossible to do with regular Moon surface. It's odd that the conspiracy theorists are so quiet about this device.

    Virg