图说毕宿五毕星团昴星团(二)

金牛座是冬季星空的代表星座,大约11月的傍晚之后,它便出现于东方天空,1月到2月它横越过头顶方向,直到4月的傍晚才降到西方天空.由于金牛座出现的时间长,升空的位置又相当高,因此,很利于大家观赏.在金牛座的"牛眼"附近有一颗闪耀着橙色光的亮星,中名毕宿五,学名金牛座α星,是全天21颗最亮恒星之一,在<中国大百科全书·天文学卷·最亮星表>中排名第13位.在毕宿五附近有7颗小星,与毕宿五一起排列成Y字形,这是著名的毕星团.由毕星团向西北方向寻去,可以找到6～7小星,这是金牛座的另一个著名星团--昴星团.毕宿五、毕星团和昴星团这三个天体就是本文的主角.     

UFO研究在苏联——冰山之一角

随着苏联的解体,一些严密封锁的档案资料逐渐解密,铁幕慢慢拉开,越来越多鲜为人知的内幕在世人面前露出了真面目.对UFO研究爱好者而言,苏联作为一个先进的航天强国,在发展航天技术的过程中,获取了哪些有关UFO的绝密信息,又是怎样实施对各种异常现象的研究,在研究中投入了哪些力量,有什么研究结果,都是大家迫切想了解的.人们兴奋的心情难以言表,期待能得到出乎意料的信息.     

激战海天

星光碧影,海浪声声,一艘神秘的远望号船正快速航行在太平洋的深处,庞大的船体灯火通明,甲板上高高低低、形态各异的天线,正在高速运转,向太空发散着电波,船舱的机房内各类仪器仪表的指示灯跳跃闪动,一切繁忙有序。此刻距离天宫发射升空不到10分     

华尔兹的舞步

一夜微凉,窗栏轻湿,在风舞之下旋出华尔兹典雅的步调,映着皓明的月光,蹁跹于桂花飘香的气息之中,任思绪随舞步飞扬,划出一道道唯美的弧线,构成一个圆,恰似那轮明月华丽的身姿。     

帕斯卡格拉事件

事情发生于1973年10月11日夜的美国密西西比州东南部的帕斯卡格拉镇,它是面向墨西哥湾的渔港。事发那天,在流经这个小镇的帕斯卡格拉河的荒凉岸边,有两个在造船厂工作的男人正在垂钓,其中一个是45岁的主任,名叫查尔斯·希克松,另一个是18岁的青年帕卡·朱尼耶。晚上21时左右,希克松听到金属物体发出的"嗖嗖"声。他抬头仰望夜空,看见了一个像放大的青灰色蛋那样的椭圆形物体。物体转瞬间靠近二人,悬停在附近的岸上,离地面约60厘米。整个物体高约2.4米,长约3米。按照希克松的说法,那个物体看上去好像是宇宙飞船,尽     

火箭伴我成长——上海市报童小学开展航天科普活动记

报童小学,坐落在上海市最繁华的南京东路和最具有文化气息的福州路之间。提到报童小学,人们马上会联想到安娥作词、聂耳作曲的那首脍炙人口的歌曲:"啦啦啦,啦啦啦,我是卖报的小行家,不等天明去等派报,一边走,一边叫,今天的新闻真正好,七个铜板就买两份报……"这支歌,唱的就是上海解放前夕报童小学的爱国师生,不畏国民党反动派的阻拦和迫害,毅然走上街头,唱响了迎接解放和光明的歌声,同时将一份份进步报刊,或是红色传单,分发到广大市民的手中。     

追踪宇宙第一道光"新一代太空望远镜"

□□研究宇宙的起源与演化是天文学的重要任务之一。20世纪中叶,一些著名的天文学家认为,宇宙起源于(137±2)亿年前的一次大爆炸,大爆炸后,整个宇宙不断地膨胀,星系整体退行。各个方向上的星系都在飞快地离地球远去。 由于多普勒效应,地球上接收到离其远去的星系发射的电磁波,频率会降低,也就是发射光谱向长波(红光)方向移动,天文学上称之为“红移”。离地球越远的星系,退行速度越大,产生的红移越大。遥远的、退行中的恒星、星系和类星体等天体发射的光本是可见光和紫外辐射,由于红移,地球上探测接收到的大多是红外辐射。所以,利用红外探测,…     

孩子们的乐园

无边无际的宇宙,神秘、神奇、神妙,令人无限神往,对儿童和青少年来说,更是充满巨大的诱惑力。这个时期,如果孩子们得到良好的引导和教育,将来很有可能成为航天领域的有用人才。为此,美国几十年来始终致力于孩子们的航天科普教育,精心为他们营造喜闻乐见的航天乐园。教育从孩子开始儿童和青少年大多活泼、好动,     

两弹一星秘史

1960年11月5日,凝聚着中国人民自力更生精神和顽强意志的争气弹"1059"竖立在酒泉发射场.发射现场,从设计师、指挥员到操作手,清一色的"中国牌".上午9时2分,我国自己仿制的第一枚近程导弹点火起飞,直上蓝天,8分钟后,导弹击中目标,试验圆满成功.聂荣臻亲赴发射试验场,指挥了这次试验,并在发射场举行的庆祝宴会上说:"在祖国的地平线上,飞起了我国自己制造的第一枚导弹,这是我国军事装备史上一个重要的转折点."从苏联专家全部撤走之日算起,到11月15日导弹发射成功,这是第83天.     

2012:如果气候灾难来了,你要留下什么?

<正>在2012年12月21日,美国黄石公园的火山洞熔岩爆炸,加州发生10.5级强烈大地震,一瞬间地层下陷,陆地应声崩裂,洛杉矶的大楼被震得拦腰断裂倒向地面,高架公路折断,行驶中的汽车、建筑物跟着掉进地底……不只美国,欧洲的梵蒂冈教堂因为地震而整个坍塌;西斯汀教堂屋顶的创世纪壁画龟裂了;里约热内卢的耶稣像也倒下,震得粉碎;大海啸紧随而来,全世界的沿海城市因为板块推挤,全都掉     

宽带取样示波器一种新校准方法研究

用一种新校准方法即“Nose to Nose”校准法可以校准带宽50GHz以上的宽带取样示波器。“Nose toNose”校准法通过宽带取样示波器相互对接,产生“Kick-out”脉冲,然后利用“Kick-out”脉冲求出取样示波器的幅频响应和上升时间。通过仿真和实验验证了“Nose to Nose”校准宽带取样示波器的可行性。     

Near-infrared study of open clusters Teutsch 10 and Teutsch 25

The astrophysical parameters have been estimated for two unstudied open star clusters Teutsch 10 and Teutsch 25 using the Two Micron All Sky Survey ($2\mathit{MASS}$) database. Radius is estimated as 4.5 arcmin for both clusters using radial density profiles. We have estimated proper motion values in both RA and DEC directions as $2.28\pm 0.3$ and $-0.38\pm 0.11$?mas?yr^?1 for Teutsch 10 and $0.48\pm 0.3$ and $3.35\pm 0.16$?mas?yr^?1 for Teutsch 25 using $\mathit{PPMXL}$¹ catalog. By estimating the stellar membership probabilities, we have identified 30 and 28 most likely members for Teutsch 10 and Teutsch 25 respectively. We have estimated the reddening as $E(B-V)=0.96\pm 0.3$?mag for Teutsch 10 and $0.58\pm 0.2$?mag for Teutsch 25, while the corresponding distances are $2.4\pm 0.2$ and $1.9\pm 0.1$?kpc. Ages of $70\pm 10$?Myr for Teutsch 10 and $900\pm 100$?Myr for Teutsch 25 are estimated using the theoretical isochrones of metallicity Z?=?0.019. The mass function slopes are derived as $1.23\pm 0.30$ and $1.09\pm 0.35$ for Teutsch 10 and Teutsch 25 respectively. Estimated mass function slope for both the clusters are close to the Salpeter value ($x=1.35$) within the errors. Estimated values of dynamical relaxation time are found to be less than cluster’s age for these objects. This concludes that both objects are dynamically relaxed. The possible reason for relaxation may be due to dynamical evolution or imprint of star formation or both.     

Simulation-based evaluation of a cold atom interferometry gradiometer concept for gravity field recovery

The prospects of future satellite gravimetry missions to sustain a continuous and improved observation of the gravitational field have stimulated studies of new concepts of space inertial sensors with potentially improved precision and stability. This is in particular the case for cold-atom interferometry (CAI) gradiometry which is the object of this paper. The performance of a specific CAI gradiometer design is studied here in terms of quality of the recovered gravity field through a closed-loop numerical simulation of the measurement and processing workflow. First we show that mapping the time-variable field on a monthly basis would require a noise level below $5\text{mE}/\sqrt{\text{Hz}}$. The mission scenarios are therefore focused on the static field, like GOCE. Second, the stringent requirement on the angular velocity of a one-arm gradiometer, which must not exceed ${10}^{-6}$?rad/s, leads to two possible modes of operation of the CAI gradiometer: the nadir and the quasi-inertial mode. In the nadir mode, which corresponds to the usual Earth-pointing satellite attitude, only the gradient $V_{\mathit{yy}}$, along the cross-track direction, is measured. In the quasi-inertial mode, the satellite attitude is approximately constant in the inertial reference frame and the 3 diagonal gradients $V_{\mathit{xx}}\text{,}{V}_{\mathit{yy}}$ and $V_{\mathit{zz}}$ are measured. Both modes are successively simulated for a 239?km altitude orbit and the error on the recovered gravity models eventually compared to GOCE solutions. We conclude that for the specific CAI gradiometer design assumed in this paper, only the quasi-inertial mode scenario would be able to significantly outperform GOCE results at the cost of technically challenging requirements on the orbit and attitude control.     

An analytical model of prominence dynamics

Solar prominences are magnetic structures incarcerating cool and dense gas in an otherwise hot solar corona. Prominences can be categorized as quiescent and active. Their origin and the presence of cool gas ($～{10}^4$?K) within the hot ($～{10}^6\text{K}$) solar corona remains poorly understood. The structure and dynamics of solar prominences was investigated in a large number of observational and theoretical (both analytical and numerical) studies. In this paper, an analytic model of quiescent solar prominence is developed and used to demonstrate that the prominence velocity increases exponentially, which means that some gas falls downward towards the solar surface, and that Alfvén waves are naturally present in the solar prominences. These theoretical predictions are consistent with the current observational data of solar quiescent prominences.