单词：Martens spectroscope
马腾斯分光镜
单词：Martens spectroscope 相关文章
By measuring how fast these stars were moving, he could prove if there really was a black hole at the center of an active galaxy. I picked a galaxy nearby which is called NGC 1068, an active galaxy, w
发表于:2018-12-07 / 阅读(349) / 评论(0)
超大质量黑洞
超大质量黑洞
Indian Prime Minister Manmohan Singh says he welcomes Pakistani steps to rein in extremists. But he says Pakistan must do everything it can to punish those who planned and carried out the Mumbai attacks last year. Ravi Khanna | Washington 25 Novembe
发表于:2019-01-14 / 阅读(72) / 评论(0)
VOA标准英语2009年(十一月)
VOA标准英语2009年(十一月)