写在前面的话

正我国第一颗X射线天文望远镜——硬X射线调制望远镜(HXMT)——预计于2016年年底发射升空。HXMT的成功研制表明我国在空间X射线天文探测器设计、制造以及配套的性能测试(标定)以及地面科学应用系统等方面取得了全面突破,跻身国际上少数能够自主研制一颗X射线天文卫星的全部科学仪器的国家。为介绍X射线天文科学研究和HXMT的基本情     

科学家问答

正他是最受媒体欢迎的科学家,也是会写诗的天文学家,尽管工作任务极为繁重,仍坚持以极大的热情投身科学传播,他就是张双南研究员。我们特别收集整理了张双南研究员对部分科学爱好者提问的回答,在《现代物理知识》杂志上连续刊登。问:太阳变成黑洞,世界将会怎样?答:首先,根据广义相对论理论和恒星演化理论,太阳在耗尽了它内部的核燃料之后不会变成黑洞,也不会发生超新星爆发,最后只会安静地变成一颗白矮星。白     

高辐射宇宙射线来袭

 今晚12：30-3：30请务必关机：电视已经宣布了这一消息。请仔细阅读一下和照顾好自己。告诉你其他的亲爱的亲人和朋友：今天晚上从12：30-凌晨3：30，极度危险的、高辐射的宇宙射线将会贴近地球而通过。所以，请关掉你的手机，不要让你的手机靠近你的身体，可能会造成伤亡或者损坏。请告知这条消息给你关心的人，晚上记得关机，记得群发给你的朋友，关爱身边的每一个人。群发，电视播报中央13台新闻。     

电影《星际穿越》中的科学问题——黑洞、白洞和虫洞

 《星际穿越》是一部科幻电影, 讲述的故事发生在很多年之后, 那时地球环境已经不再适合人类生存。一位宇航员库波为了拯救人类去探索新的宜居星球, 期间历经艰险, 最后和自己的女儿墨菲重逢。电影引人入胜, 科学概念层出不穷, 被评为2014 年“年度最烧脑电影”, 豆瓣网给出了9.1 的高分。     

A Two-Field Dilaton Model of Dark Energy

We investigate the cosmological evolution of a two-field model of dark energy, where one is a dilaton field with canonical kinetic energy and the other is a phantom field with a negative kinetic energy term. Phase-plane analysis shows that the ＂phantom＂-dominated scaling solution is the stable late-time attractor of this type of model. We find that during the evolution of the universe, the equation of state w changes from w 〉 -1 to w 〈 -1, which is consistent with recent observations.     

Exact solutions for spherical gravitational collapse around a black hole:the effect of tangential pressure

Spherical gravitational collapse towards a black hole with non-zero tangential pressure is studied.Exact solutions corresponding to different equations of state are given.We find that when taking the tangential pressure into account,the exact solutions have three qualitatively different outcomes.For positive tangential pressure,the shell around a black hole may eventually collapse onto the black hole,or expand to infinity,or have a static but unstable solution,depending on the combination of black hole mass,mass of the shell and the pressure parameter.For vanishing or negative pressure,the shell will collapse onto the black hole.For all eventually collapsing solutions,the shell will cross the event horizon,instead of accumulating outside theeventhorizon,even if clocked by a distant stationary observer.     

A study of the pointed observation methods and sensitivity of HXMT

The Hard X-ray Modulation Telescope （HXMT） is an X-ray astronomy satellite consisting of three slat-collimated instruments, the High Energy X-ray Instrument （HE）, the Medium Energy X-ray Instrument （ME）, and the Low Energy X-ray Instrument （LE）. HXMT will carry out an all sky survey and make pointed observations in the 1-250 keV energy band. In order to get the source and background fluxes simultaneously in the pointed observations, two methods, i.e., the combined field of view （FOV） method and the off-axis pointing method are proposed in this paper. Comprehensive analyses of the sensitivities of the three instruments by using these two methods are presented, respectively. It is found that the off-axis pointing method has a higher sensitivity for HE and ME but a lower sensitivity for LE. Since the axes of the three instruments are aligned along the same direction, the off-axis pointing method is recommended as the main method in the pointed observation for HXMT; the combined FOV method can be used when LE is the most relevant instrument in order to satisfy the scientific objective of the observation.     

科学家问答

正问:因为宇宙在膨胀,所以我们每个人也都在变大吗?答:如果宇宙正在膨胀中,那么宇宙中各个天体,乃至我们人类自己,是不是也在不断变大?这是一个非常严肃的科学问题,我和我的一个研究生曾经认真地研究过。对这个问题的标准和主流的回答是:膨胀的是空间,不是空间中的物体,包括所有的天体和人类。比如,我曾在回答其他宇宙相关的问题时用过图1这张图片:假设我们的宇宙是一个二维的球面,     

2017年诺贝尔物理学奖解读

 2017年10月3日,我提前结束了远在河南家乡的“十一”长假,匆匆看望了父母和众多亲友,难分难舍地告别了几十位参加初中毕业40周年聚会的同学们,坐高铁到了北京西站,我把自己几乎变成液体挤进了地铁,准时赶到了“果壳”的2017年诺贝尔奖点评直播间,和主持人吴欧女士、另外两位大牛嘉宾一起点评2017年的诺贝尔物理学奖。