回复 1# inter06
暗流这个东西我也不是太了解,我翻译了维基上的词条,供参考吧.
Dark flow
暗流
Dark flow is a term from astrophysics describing a peculiar velocity of galaxy clusters. The actual measured velocity is the sum of the velocity predicted by Hubble's Law plus a small and unexplained (or dark) velocity flowing in a common direction.
暗流是来自天体物理的一个术语,用于描述星系团的一种本动速度.人们实际上测到的速度是哈勃定律预言的速度叠加上一个小并且无法解释(或说暗的)速度,指向一个共同的方向.
Contents
目录
1 Overview
概述
2 Criticisms
评论
3 See also
另见
4 References
参考文献
5 External links
外部链接
Overview
概述
According to standard cosmological models, the motion of galaxy clusters with respect to the cosmic microwave background should be randomly distributed in all directions. However, analyzing the three-year WMAP data using the kinematic Sunyaev-Zel'dovich effect, the authors of the study found evidence of a common motion of at least 600 km/s toward a 20-degree patch of sky between the constellations of Centaurus and Vela.
根据标准的宇宙学模型,星系团相对于宇宙微波背景(cosmic microwave background)的运动应该是随机分布在各个方向上的.然而,通过使用运动苏尼阿耶夫---泽尔多维奇效应来分析WMAP三年的数据,该项研究的作者发现了一个至少为600公里每秒的共同的运动方向的证据,该运动朝向人马座与船帆座之间的一个20度的天区.
The authors (Alexander Kashlinsky, F. Atrio-Barandela, D. Kocevski, and H. Ebeling) suggest that the motion may be a remnant of the influence of no-longer-visible regions of the universe prior to inflation. Telescopes cannot see events earlier than about 380,000 years after the big bang, when the universe became transparent (the Cosmic Microwave Background); this corresponds to the particle horizon at a distance of about 46 billion (4.6×1010) light years. Since the matter causing the net motion in this proposal is outside this range, it would in a certain sense be outside our visible universe; however, it would still be in our past light cone.
作者(Alexander Kashlinsky, F. Atrio-Barandela, D. Kocevski, and H. Ebeling)认为这种运动可能是宇宙在暴涨前的已经不可见的一块区域的影响的残迹.望远镜只能看见大爆炸三十八万年后的事物,那也是宇宙变为透明的时刻(参见宇宙微波背景),这对应着距离约为四百六十亿光年的粒子视界.既然引起这种运动的物质在此范围之外,在一定意义上它也在我们的可见宇宙之外,然而依然在我们的过去光锥之内.
The results appear in the October 20, 2008, issue of Astrophysical Journal Letters. The authors state that they plan to extend their analysis to additional clusters and the recently released WMAP five-year data.[1][2][3]
这个结果刊登在2008年10月20号的天体物理学报通信(Astrophysical Journal Letters)上.作者声称其计划分析更多的星系团已及最近刚释放的WMAP五年的数据(参考文献1,2,3).
Criticisms
评论
Astrophysicist Ned Wright posted an online response to the study arguing that its methods are flawed.[4] The authors of the "dark flow" study released a statement in return, refuting three of Wright's five arguments and identifying the remaining two as a typo and a technicality that do not affect the measurements and their interpretation.[5]
天体物理学家Ned Wright在线提交了对此项研究的回复,他认为这个方法是有问题的(参考文献4).研究”暗流”的作者进行了回复, 反驳了Wright的三个观点,并确认另外两个中的一个是印刷错误,另一个则是一个技术细节,并不影响测量的结果和解释(参考文献5).
A more recent statistical work done by Ryan Keisler [6] claims to rule out the possibility that the dark flow is a physical phenomenon because Kashlinsky et al. do not consider primary CMB anisotropies as important as they are.
更近的一项由Ryan Keisler完成的统计工作声称排除了暗流是一个物理现象的可能性,因为Kashlinsky等人低估了原初CMB的各向异性的重要性.
In March of 2010 it was reported by Discovery News that NASA's Goddard Space Center confirmed this could be the effects of a sibling universe or a region of space-time fundamentally different from the observable universe. Data on more than 1,000 galaxy clusters have been measured, including some as distant as 3 billion light-years. Alexander Kashlinksy claims these measurements show the universe's steady flow is clearly not a statistical fluke. Said Kashlinsky: "At this point we don't have enough information to see what it is, or to constrain it. We can only say with certainty that somewhere very far away the world is very different than what we see locally. Whether it's 'another universe' or a different fabric of space-time we don't know."[7]
2010年3月,发现新闻报导了NASA的戈达德航天中心证实了这可能是一个兄弟宇宙(sibling universe)或者是一块时空跟我们的可观测宇宙根本不同的区域的效应.人们测量了超过1000个星系团的数据,有些远至三十亿光年.Alexander Kashlinksy声称这些测量表明宇宙中稳定的流动显然不是一个统计上的例外.他说:”此时此刻我们还没有足够的信息来看清它到底是什么,或者来限制它.我们可以肯定的只是世界非常远处的某些地方跟我们在本地看到的非常不一样.我们不知道它到底是’另外一个宇宙’还是不同的时空构造.”(参考文献7)
另见,参考文献,外部链接 (略) |