In every galaxy scientists looked at, they found evidence for a supermassive black hole. NGC 3115 NGC 3377 NGC 3379 In M31 and M32 In total there is probably 20-30 or so black holes that have been fou

发表于:2018-12-07 / 阅读(320) / 评论(0) 分类 超大质量黑洞

Of the many puzzles mathematicians ponder, one is new ways to tie knots. There are more than six billion different types of knots that have been tabulated by mathematicians. Six billion. David Leigh, a chemist at the University of Manchester in the U

发表于:2018-12-24 / 阅读(51) / 评论(0) 分类 2017年Scientific American(一)月

[00:00.52] 12.18 Holes in His Mind [00:06.29]Major James Nesmeth had a dream of improving his golf game and he developed a unique method of achieving his goal. [00:14.35]Until he devised this method, he was just your average weekend golfer, shooting

发表于:2018-12-26 / 阅读(44) / 评论(0) 分类 温馨夜读II

BARBARA KLEIN: Im Barbara Klein. STEVE EMBER: And Im Steve Ember with EXPLORATIONS in VOA Special English. A blue hole is a flooded sea cave with a hole that opens up at the lands surface. These cave systems form in carbonate rock, often on islands.

发表于:2019-01-12 / 阅读(70) / 评论(0) 分类 2010年VOA慢速英语(十一)月

New Data Adds to Understanding of 'Black Holes' WASHINGTON Scientists continue to learn more about black holes in space, places where the pull of gravity is so strong that not even light can escape. Black holes occur after supergiant stars explode in

发表于:2019-01-14 / 阅读(68) / 评论(0) 分类 VOA标准英语2016年(九月)

Larry和李华今天去给他们的朋友Jim买结婚礼物。Jim下个周末就要结婚。今天李华会学到两个常用语:to tie the knot和drop-dead gorgeous. LL: I can't believe Jim is goin

发表于:2019-02-01 / 阅读(56) / 评论(0) 分类 美国之音《流行美语》