说是太阳系里有个叫做Oort云的东西,就是彗星的云存储,里面无数的潜在彗星,而且 基本是包着太阳系的(跟行星们共面的地方密度高一些),所以理论上任何方向看到彗 星都是有可能的 。 The Oort cloud is thought to occupy a vast space from somewhere between 2, 000 and 5,000 AU (0.03 and 0.08 ly)[90] to as far as 50,000 AU (0.79 ly)[71] from the Sun. Some estimates place the outer edge at between 100,000 and 200,000 AU (1.58 and 3.16 ly).[90] The region can be subdivided into a spherical outer Oort cloud of 20,000–50,000 AU (0.32–0.79 ly), and a doughnut-shaped inner Oort cloud of 2,000–20,000 AU (0.03–0.32 ly). The outer cloud is only weakly bound to the Sun and supplies the long-period ( and possibly Halley-type) comets to inside the orbit of Neptune.[71] The inner Oort cloud is also known as the Hills cloud, named after J. G. Hills, who proposed its existence in 1981.[91] Models predict that the inner cloud should have tens or hundreds of times as many cometary nuclei as the outer halo;[91][92][93] it is seen as a possible source of new comets to resupply the relatively tenuous outer cloud as the latter's numbers are gradually depleted. The Hills cloud explains the continued existence of the Oort cloud after billions of years.[94]
阳系里面的彗星有轨道面跟黄道面夹角很大的,所以从地球上看有些是可以接近北极星的 At the shorter extreme, Encke's Comet has an orbit that does not reach the orbit of Jupiter, and is known as an Encke-type comet. Short-period comets with orbital periods shorter than 20 years and low inclinations (up to 30 degrees) are called "Jupiter-family comets".[69][70] Those like Halley, with orbital periods of between 20 and 200 years and inclinations extending from zero to more than 90 degrees, are called "Halley-type comets".[71][72]
【在 H********g 的大作中提到】 : 阳系里面的彗星有轨道面跟黄道面夹角很大的,所以从地球上看有些是可以接近北极星的 : At the shorter extreme, Encke's Comet has an orbit that does not reach the : orbit of Jupiter, and is known as an Encke-type comet. Short-period comets : with orbital periods shorter than 20 years and low inclinations (up to 30 : degrees) are called "Jupiter-family comets".[69][70] Those like Halley, with : orbital periods of between 20 and 200 years and inclinations extending from : zero to more than 90 degrees, are called "Halley-type comets".[71][72]
c*3
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bless
z*n
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这个奥尔特云是太阳带着一起走的么?我咋觉得不那么靠谱。
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【在 H********g 的大作中提到】 : 说是太阳系里有个叫做Oort云的东西,就是彗星的云存储,里面无数的潜在彗星,而且 : 基本是包着太阳系的(跟行星们共面的地方密度高一些),所以理论上任何方向看到彗 : 星都是有可能的 。 : The Oort cloud is thought to occupy a vast space from somewhere between 2, : 000 and 5,000 AU (0.03 and 0.08 ly)[90] to as far as 50,000 AU (0.79 ly)[71] : from the Sun. Some estimates place the outer edge at between 100,000 and : 200,000 AU (1.58 and 3.16 ly).[90] The region can be subdivided into a : spherical outer Oort cloud of 20,000–50,000 AU (0.32–0.79 ly), and a : doughnut-shaped inner Oort cloud of 2,000–20,000 AU (0.03–0.32 ly). The : outer cloud is only weakly bound to the Sun and supplies the long-period (