【 以下文字转载自 Joke 讨论区 】 发信人: Albacore (LongFin), 信区: Joke 标 题: Re: 三体是很棒的科幻小说,虽然其基本思想不科学 (转载) 发信站: BBS 未名空间站 (Mon Apr 21 13:23:15 2014, 美东) Also the effective gravitating mass at the center of gravity is not the total mass of the system. It depends on the explicit spatial mass distribution and changes over time in a 3-body system. I can give a simple example that illustrates the point. Consider a empty sphere S^2 (empty both in and out of the sphere, like a Ping-Pang ball) that has static, homogeneous mass distribution. A test body in the inner space of this sphere do not experience any gravity (since the contribution from different part of the sphere perfectly cancels) . It is either static or moves with a constant velocity until it hits the inner wall of the sphere. But according to lz it will orbit the center of the sphere, which is not what it does.
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Reprogrammed Stem Cells Hit a Roadblock: Reprogramming Cells Leads to Ge nomic Aberrations ScienceDaily (Feb. 21, 2011) It's a discordant note in the symphony of good news that usually accompanies stem cell research announcements. St em cells hold enormous promise in regenerative medicine, thanks to their ability to regenerate diseased or damaged tissues. They have made it po ssible to markedly improve the effectiveness of many medical treatments