simplicity is prerequisite for reliability

科学家发现trappist - 1比我们的太阳系还要古老

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当涉及到可栖身性研究时,要推敲的关键身分之一是恒星体系的年纪。从根本上说年青的恒星有一种趋势,即在行星环绕老恒星的轨道上长时光受到辐射时,会忽然爆发并释放出有害的辐射。多亏了一对天文学家的一项新研究如今已知的trappist - 1体系的汗青是太阳系的两倍。

【博科园-科学科普】在2017年2月一组欧洲天文学家宣布发清楚明了一颗环绕邻近恒星trappist-1的七行星体系。除了这七颗行星都是岩石的事实之外,还有三颗行星在特拉普斯- 1的宜居带内的轨道运行。是以已经进行了多项研究,以肯定体系中的任何行星是否合适栖身。

这项研究将揭橥在《天体物理学杂志》上,标题为"在trappist - 1体系的时代\

What is the origin of the term 'UFO'?"UFO"一词到底是怎么来的?


The word UFO is an abbreviation which comes from the initial letters of the words 'unidentified flying object'. A UFO is a mysterious object in the sky which can't be explained by current scientific theories. UFOs are often associated with extraterrestrial beings: they're believed to be the spaceships of the 'little green men' of science-fiction movies and stories.

"UFO"一词其实是由"unidentified flying object"的首字母缩略而成。"飞碟"(UFO)是空中的神秘飞翔物,今朝的科学理论尚无法解释它的存在。飞碟往往让人联想到外星人:它们被认为是科幻片子或故事中的"绿色小矮人"的宇宙飞船。

根据《牛津英语词典》的记录,"unidentified flying object"一词可以追溯到二十世纪五十年代:在1953年,美国的飞翔员和作家Donald Keyhoe在他的书中应用了该词。《牛津英语词典》也引用了美国空军军官Edward Ruppelt于1956年所说的话,他如许说道:他创造了这个UFO这个含义更为笼统的词语,来代替之前的flying saucer一词。

According to the Oxford English Dictionary, the term 'unidentified flying object' goes back at least to the 1950s: it is recorded in 1953, in a book by the US aviator and writer Donald Keyhoe. The OED also gives a citation in 1956 by Edward Ruppelt, an officer in the USAF, stating that he'd invented the term as a more general one to WordStr the earlier description for such objects, flying saucer.

Strange objects in the sky were first named flying saucers in the 1940s: the first OED citation is from The Times, in 1947. They were so called because of an account by a US pilot, Kenneth Arnold, who stated in various newspaper and radio interviews of that year that he'd seen 'saucer-like' objects in the sky while he was flying past Mount Rainier. The media seemed to have quickly changed this to the snappier 'flying saucer' and so the term was born. By the time Ruppelt and his USAF colleagues were investigating reports of these sightings in the 1950s, it was clear that 'saucer' was too limited a description, since the objects in question were said to be of many different shapes: hence Ruppelt's invention of 'UFO'.

早在二十世纪四十年代,人们起先用的是"飞碟"(flying saucer)一词来指代空中的不明飞翔物,而《牛津英语词典》最早对该词的引用,源于1947年《泰晤士报》。这些不明飞翔物之所以被叫做飞碟,是源于当初美国一个叫做Kenneth Arnold的飞翔员的话,他在各个报纸和电台的受访中,声称本身昔时在飞越雷尼尔山时,看到了空中的碟状物体。而媒体似乎很快就把这个"碟状物体"的说法改为了更为时髦的词语"飞碟(flying saucer)\

科学家发现trappist - 1比我们的太阳系还要古老