1972年白日大火球
外观
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1972年白日大火球(或编号 US19720810)是一个于UTC 1972年8月10日20:29 掠过地球57公里高空的掠地流星体。该天体在当时是白昼的美国犹他州(当地时间 14:30)直到北方的加拿大亚伯达省都有人目击。该火球被许多人录下影像[2]。
描述
[编辑]当时分析该火球的影像和路径后认为该流星体的大小是在3米(如果是碳质球粒陨石)到14米(如果是从彗星剥落的含冰物质)[3][4]的地球轨道穿越小行星中的阿波罗型小行星,并认为下次接近地球时间是1997年8月[2]。1994年捷克天文学家兹德内克·赛普尔查(Zdeněk Ceplecha)重新分析相关资料,该物体质量估计降为先前的二分之一到三分之一,其体积估计则为 2 至 10 米[3]。
该流星体掠过地球大气层 100 秒之中的速度则降为 800 m/s,因此其轨道倾角也自角度 15 度改为 8 度[4]。
US19720810 流星体在亚瑟·查理斯·克拉克的小说《上帝之锤》第一章前言中被提及。
如果该天体撞击地球?
[编辑]如果该天体的擦地角有所改变,该天体可能在高空失速,可能结果就是在空中爆炸,并有部分碎片以终端速度掉落。流星体进入大气层后的运动相当复杂,并且需要完整的模拟才能计算;但在网络上也有加雷思·柯林斯(Gareth Collins)等人[5]开发的大幅简化的计算模式可供估计撞击能量[6]。下表显示在不同进入大气层角度和成分下的不同结果:
直径(m) | 密度(cm3) | 进入大气层角度(°) | 丧失能量(kt) | 爆炸高度(km) | 爆炸能量(kt) |
---|---|---|---|---|---|
3 | 3.4 | 1 degree | 1.3 kiloton | 43 km | 0.7 kiloton |
3 | 3.4 | 45 degrees | 1.3 kiloton | 39 km | 0.4 kiloton |
8 | 0.9 | 1 degree | 6 kiloton | 80 km | 0.4 kiloton |
8 | 0.9 | 45 degrees | 6 kiloton | 45 km | 2 kiloton |
参见
[编辑]参考资料
[编辑]- ^ Astronomy Picture of the Day. 2009 March 2.
- ^ 2.0 2.1 Observation of Meteoroid Impacts by Space-Based Sensors (页面存档备份,存于互联网档案馆) Astronomical Society of the Pacific, Edward Tagliaferri, 2003, 'It was first detected by satellite at an altitude of about 73 km, tracked as it descended to about 53 km, and then tracked as it climbed back out of the atmosphere', 'object is still in an Earth-crossing orbit around the Sun and passed close to the Earth again in August 1997'
- ^ 3.0 3.1 Daylight Fireball of August 10, 1972. [2024-08-18]. (原始内容存档于2005-01-20).
3 meters, if a carbonaceous chondrite, or as large as 14 meters, if composed of cometary materials', 'post-encounter ... 2 or 10 meters
- ^ 4.0 4.1 US19720810 (Daylight Earth grazer) (页面存档备份,存于互联网档案馆) Global Superbolic Network Archive, 2000, 'Size: 5 to 10 m'
- ^ Collins, Gareth S.; Melosh, H. Jay; Marcus, Robert A. Earth Impact Effects Program: A Web-based computer program for calculating the regional environmental consequences of a meteoroid impact on Earth. Meteoritics & Planetary Science. 2005-06, 40 (6). doi:10.1111/j.1945-5100.2005.tb00157.x (英语).
- ^ Robert Marcus, H. Jay Melosh, and Gareth Collins. Computing Effects of an Impact on Earth (页面存档备份,存于互联网档案馆)
- Abe, S. et al. (abstract) Earth-grazing fireball on March 29, 2006(页面存档备份,存于互联网档案馆) European Planetary Science Congress 2006. Berlin, Germany, 18 - 22 September 2006., p.486. code:2006epsc.conf..486A, 'the first and second Earth-grazing fireballs observed on August 10, 1972(Jacchia, 1974; Ceplecha, 1979) and on October 13, 1990(Borovicka and Ceplecha, 1992)'
- Abe, Shinsuke; et al. 2006. (PDF). Earth-grazing fireball on March 29, 2006(页面存档备份,存于互联网档案馆) (full details: orbit, charts, spectra, composition) Retrieved 2008-07-07
外部链接
[编辑]- Youtube上怀俄明州目击者录影(页面存档备份,存于互联网档案馆)
- Youtube上亚伯达省目击者录影(页面存档备份,存于互联网档案馆)
- US19720810 (Daylight Earth grazer) orbital characteristics from Global Superbolide Network Archive, 2000
- fireball, meteorite, bolide, meteor, video and photo(页面存档备份,存于互联网档案馆) link to photos and cine film by Linda Baker
- Earthgrazer: The Great Daylight Fireball of 1972(页面存档备份,存于互联网档案馆) overview of the event including photo by NASA's Astronomy Picture of the Day
- Astronomical Society of the Pacific: Observation of Meteoroid Impacts by Space-Based Sensors - one of several similar events; includes ground track
- 每日一天文图 (成大物理分站) 2009年3月2日
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