太空飞行器反常加速的问题，也是与日冕反常加热等一起被列为困扰人类的几个未解的反常问题（未解之谜）之一，在今年（2012）被认为已经解决了。这里涉及的飞行器，包括从1970s以来的一大批，如先驱者号（Pioneer）、伽利略号（Galileo）、NEAR、卡西尼号（Cassini）、 罗塞塔号（ Rosetta）及信使号（MESSENGER），等。反常加速的大小极小，10^-9 m/s^2量级，但是却真实存在，且可以很准确的测量到（插一句：中国的技术好像还做不到这一点，几年前我问了一位天文台的，大概可测到10^-7量级，还需努力）。 对相关情况不熟悉者，建议先阅读以下几个链接再读本文。 先驱者号探测器： http://home.51.com/mxfjiayuan/diary/item/10038547.html 先驱者号异常(Pioneer anomaly)： http://www.fyjs.cn/viewarticle.php?id=253958 解决先驱者号的反常现象： http://www.shao.ac.cn/kpyd/ywkd/201104/t20110412_3110584.html 先驱者号反常之谜已解开？ http://www.astron.ac.cn/bencandy-3-2298-1.htm 对于该问题，曾长期困扰这研究者，引起过大量的研究，尤其由于其可能包含新物理发现且问题看起来并不难（比如，不太需要量子力学之类的计算），激起了许多非主流科学家（俗称民科、民间科学家）的热情。 wiki中所列的未解物理问题（ http://en.wikipedia.org/wiki/List_of_unsolved_problems_in_physics ），其中已经解决的一栏 Problems solved in recent decades Pioneer anomaly (2012) There was a deviation in the predicted accelerations of the Pioneer spacecraft as they left the Solar System. It is believed that this is a result of previously unaccounted-for thermal recoil force . 基本认定是辐射压力引起的。详细的wiki介绍， http://en.wikipedia.org/wiki/Pioneer_anomaly ，其中给出了论文的链接。 ^ a b Slava G. Turyshev, Viktor T. Toth, Gary Kinsella, Siu-Chun Lee, Shing M. Lok, Jordan Ellis (11 April 2012). "Support for the thermal origin of the Pioneer anomaly". arXiv : 1204.2507 . Published in: Turyshev, S.; Toth, V.; Kinsella, G.; Lee, S. C.; Lok, S.; Ellis, J. (2012). "Support for the Thermal Origin of the Pioneer Anomaly". Physical Review Letters 108 (24). arXiv : 1204.2507 . doi : 10.1103/PhysRevLett.108.241101 . 可到PRL网站（ http://prl.aps.org/abstract/PRL/v108/i24/e241101 ）中找到，三个月前发布的，或arXiv（ http://arxiv.org/abs/1204.2507 ）。摘要： We investigate the possibility that the anomalous acceleration of the Pioneer 10 and 11 spacecraft is due to the recoil force associated with an anisotropic emission of thermal radiation off the vehicles. To this end, relying on the project and spacecraft design documentation, we constructed a comprehensive finite-element thermal model of the two spacecraft. Then, we numerically solve thermal conduction and radiation equations using the actual flight telemetry as boundary conditions. We use the results of this model to evaluate the effect of the thermal recoil force on the Pioneer 10 spacecraft at various heliocentric distances. We found that the magnitude, temporal behavior, and direction of the resulting thermal acceleration are all similar to the properties of the observed anomaly. As a novel element of our investigation, we develop a parameterized model for the thermal recoil force and estimate the coefficients of this model independently from navigational Doppler data. We find no statistically significant difference between the two estimates and conclude that once the thermal recoil force is properly accounted for, no anomalous acceleration remains. 不翻译了，有google翻译等各种机器翻译在，我想感兴趣者读懂这段文字不会太难。大意是，经过几年的反复验证，2012年（几年前有迹象，但未肯定）这篇文章，基本肯定了是热辐射反弹力导致的反常加速，把这个因素考虑进来，不再出现任何反常加速。附一张该论文的图。 文章中有详细的计算和对比。这个结局似乎有点好玩，不清楚会否还有争论。如果被确信，那么民科们要失望了，又少了一个反相对论、提出新力学的支撑了。 附注：鉴于Slava G. Turyshev的文章已经发表几个月了，wiki中的词条也早已更新，但是国内还没有提及这件事的。因此我（2008年时曾用一个简单的模型研究过这个问题，当然，除了部分可吻合观测外，没能真正解决问题）粗略的写下这篇文字。有做天文的，不妨写点更详细的中文资料。 xiehuasheng 2012-09-18 23:19
声 音 / 音 乐感知中的一个未解之谜 An Unsolved Puzzle in Sound / Music Perception 吴全丰 (Charles Q. Wu) Physically, the frequency of air vibration is one-dimensional; perceptually, however, the quality of pitch is like a two-dimensional helix: it goes from low to high, but it is circular as well in that two pitches an octave apart sound similar to each other (see the attached picture). Pitch circularity is a perceptual phenomenon -- it must be due to something in the human brain while perceiving or feeling sound or music. Why so? Although recently there has been some research on this phenomenon, it largely remains as an unsolved puzzle in perceptual psychology and neuroscience. A familiar yet still fascinating phenomenon indeed. Interested? Read a good review paper on pitch circularity by Diana Deutsch listed at: http://en.wikipedia.org/wiki/Pitch_circularity An illustration of pitch circularity
“赝能隙”和超导状态之间的关系 高温铜氧化物超导体一个长久未解之谜是“赝能隙”（pseudogap）的存在。所谓“赝能隙”，是指一个与超导状态的特征能隙相似、但也在非超导状态中出现的能隙。Kohsaka等人对与超导现象和“赝能隙”状态相关的电子激发进行了详细研究，发现了两个非常不同的行为类型： 一个类型为在动量空间的状态，它们相应于对超导现象负责的、预期存在的离位电子对；另一个类型为局限于真实空间的一些异常状态，它们相应于“赝能隙”。这两种激发类型之间的关系，为“赝能隙”和超导状态之间仍然神秘的关系提供了一个新视角，强化了与绝缘母化合物性能的概念联系（在绝缘母化合物中，真实空间的电子局域化是它们行为的关键）。 How Cooper pairs vanish approaching the Mott insulator in Bi2Sr2CaCu2O8+ δ Y. Kohsaka 1 , 2 , C. Taylor 1 , P. Wahl 1 , A. Schmidt 1 , Jhinhwan Lee 1 , K. Fujita 1 , 3 , J. W. Alldredge 1 , 4 , K. McElroy 4 , Jinho Lee 1 , 5 , 6 , H. Eisaki 7 , S. Uchida 3 , D.-H. Lee 8 J. C. Davis 1 , 6 LASSP, Department of Physics, Cornell University, Ithaca, New York 14853, USA RIKEN, Wako, Saitama 351-0198, Japan Department of Physics, University of Tokyo, Bunkyo-ku, Tokyo 113-0033, Japan Department of Physics, University of Colorado, Boulder, Colorado 80309, USA School of Physics and Astronomy, University of St Andrews, North Haugh, St Andrews, Fife KY16 9SS, UK CMPMS Department, Brookhaven National Laboratory, Upton, New York 11973, USA Institute of Advanced Industrial Science and Technology, Tsukuba, Ibaraki 305-8568, Japan Department of Physics, University of California, Berkeley, California 94720, USA Correspondence to: J. C. Davis 1 , 6 Correspondence and requests for materials should be addressed to J.C.D. (Email: jcdavis@ccmr.cornell.edu ). Top of page Abstract The antiferromagnetic ground state of copper oxide Mott insulators is achieved by localizing an electron at each copper atom in real space ( r -space). Removing a small fraction of these electrons (hole doping) transforms this system into a superconducting fluid of delocalized Cooper pairs in momentum space ( k -space). During this transformation, two distinctive classes of electronic excitations appear. At high energies, the mysterious ‘pseudogap’ excitations are found, whereas, at lower energies, Bogoliubov quasi-particles—the excitations resulting from the breaking of Cooper pairs—should exist. To explore this transformation, and to identify the two excitation types, we have imaged the electronic structure of Bi2Sr2CaCu2O8+ δ in r -space and k -space simultaneously. We find that although the low-energy excitations are indeed Bogoliubov quasi-particles, they occupy only a restricted region of k -space that shrinks rapidly with diminishing hole density. Concomitantly, spectral weight is transferred to higher energy r -space states that lack the characteristics of excitations from delocalized Cooper pairs. Instead, these states break translational and rotational symmetries locally at the atomic scale in an energy-independent way. We demonstrate that these unusual r -space excitations are, in fact, the pseudogap states. Thus, as the Mott insulating state is approached by decreasing the hole density, the delocalized Cooper pairs vanish from k -space, to be replaced by locally translational- and rotational-symmetry-breaking pseudogap states in r -space. LASSP, Department of Physics, Cornell University, Ithaca, New York 14853, USA RIKEN, Wako, Saitama 351-0198, Japan Department of Physics, University of Tokyo, Bunkyo-ku, Tokyo 113-0033, Japan Department of Physics, University of Colorado, Boulder, Colorado 80309, USA School of Physics and Astronomy, University of St Andrews, North Haugh, St Andrews, Fife KY16 9SS, UK CMPMS Department, Brookhaven National Laboratory, Upton, New York 11973, USA Institute of Advanced Industrial Science and Technology, Tsukuba, Ibaraki 305-8568, Japan Department of Physics, University of California, Berkeley, California 94720, USA
标签: 未解之谜
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