2018年IAO理论低年组第5题-奥尔特云 - 版本历史

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2019年10月4日 (五) 14:22 Dg1200

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Heavens above：/* 中文题目 */

2019-09-19T04:36:16Z

‎中文题目

2019年9月19日 (四) 04:36 Heavens above

2019-09-19T04:36:06Z

2019年9月13日 (五) 07:22 Dg1200

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Dg1200：创建页面，内容为“==原文题目== '''Oort cloud.''' It is currently considered that tha source of long-periodic and non-periodic comets is th outer Oort cloud, the inner and ouyer r…”

2019-09-13T04:10:30Z

创建页面，内容为“==原文题目== '''Oort cloud.''' It is currently considered that tha source of long-periodic and non-periodic comets is th outer Oort cloud, the inner and ouyer r…”

新页面

==原文题目==

'''Oort cloud.''' It is currently considered that tha source of long-periodic and non-periodic comets is th outer Oort cloud, the inner and ouyer radii of which are estimated as 0.2 and 0.8 light years, respectively. Comet bodies in this cloud move erratically and sometimes collide with each other. As a result, every century, people of the Earth observe from 10 to 20 bright comets coming into the internal regions of the Solar System. The average sizn of the nuclei of such comets is about 2-3kilometers. Roughly estimate (in order of magnitude) the total number of such comet bodies in the outer Oort cloud, the average distance between them, and their total maww. Compare the results with distance and masses of bidies in our Solar System.

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	==英文题目==		==英文题目==

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 ==中文题目==
 '''奥尔特云''' 目前认为长周期和非周期彗星的来源是太阳系外部的奥尔特云，其内球和外球半径分别估计为0.2和0.8光年。 云中的彗星体不规则地移动，有时会相互碰撞。 因此，每个世纪，地球人都会观察到10到20颗明亮的彗星进入太阳系的内部区域。 这种彗星的彗核平均尺寸约为2-3千米。 粗略地估计（在数量级上）外部奥尔特云中这种彗星体的总数，它们之间的平均距离，以及它们的总量。 将结果与我们的太阳系中的天体（比如行星）的距离和质量大小进行比较。
 ==英文解答==
 '''Oort cloud.''' The fact that every century we observe from 10 to 20 bright comets means that approximately once every 6 years 8 months (T ≈ 2.1·10<sup>8</sup> s) two comet bodies collide in the outer Oort cloud, resulting in one of them rushes into the inner regions of the solar system. Collisions occur because all these bodies move chaotically with typical velocities less than the second cosmic velocity (otherwise they would leave this area). To estimate the average their velocities, we take the first cosmic velocity for the average distance (R+r)/2 = 0.5 ly:

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	==英文题目==		==英文题目==

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 ==英文题目==
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 '''Oort cloud.''' The fact that every century we observe from 10 to 20 bright comets means that approximately once every 6 years 8 months (T ≈ 2.1·10<sup>8</sup> s) two comet bodies collide in the outer Oort cloud, resulting in one of them rushes into the inner regions of the solar system. Collisions occur because all these bodies move chaotically with typical velocities less than the second cosmic velocity (otherwise they would leave this area). To estimate the average their velocities, we take the first cosmic velocity for the average distance (R+r)/2 = 0.5 ly:
-$$u = (GM/[(R+r)/2])^{1/2}\ ≈\ 170\ m/s$$
+$$u = (GM/[(R+r)/2])^{1/2}\ ≈\ 170\ m/s$$,

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 {{需要解答}}
-==原文题目==
+==英文题目==
 '''Oort cloud.''' It is currently considered that tha source of long-periodic and non-periodic comets is th outer Oort cloud, the inner and ouyer radii of which are estimated as 0.2 and 0.8 light years, respectively. Comet bodies in this cloud move erratically and sometimes collide with each other. As a result, every century, people of the Earth observe from 10 to 20 bright comets coming into the internal regions of the Solar System. The average sizn of the nuclei of such comets is about 2-3kilometers. Roughly estimate (in order of magnitude) the total number of such comet bodies in the outer Oort cloud, the average distance between them, and their total maww. Compare the results with distance and masses of bidies in our Solar System.
 ==中文题目==
-'''奥尔特云'''
+'''奥尔特云''' 目前认为长周期和非周期彗星的来源是太阳系外部的奥尔特云，其内球和外球半径分别估计为0.2和0.8光年。 云中的彗星体不规则地移动，有时会相互碰撞。 因此，每个世纪，地球人都会观察到10到20颗明亮的彗星进入太阳系的内部区域。 这种彗星的彗核平均尺寸约为2-3千米。 粗略地估计（在数量级上）外部奥尔特云中这种彗星体的总数，它们之间的平均距离，以及它们的总量。 将结果与我们的太阳系中的天体（比如行星）的距离和质量大小进行比较。
-目前认为长周期和非周期彗星的来源是太阳系外部的奥尔特云，其内球和外球半径分别估计为0.2和0.8光年。 云中的彗星体不规则地移动，有时会相互碰撞。 因此，每个世纪，地球人都会观察到10到20颗明亮的彗星进入太阳系的内部区域。 这种彗星的彗核平均尺寸约为2-3千米。 粗略地估计（在数量级上）外部奥尔特云中这种彗星体的总数，它们之间的平均距离，以及它们的总量。 将结果与我们的太阳系中的天体（比如行星）的距离和质量大小进行比较。
+==英文解答==

←上一版本		2019年9月19日 (四) 04:36的版本
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	'''Oort cloud.''' It is currently considered that tha source of long-periodic and non-periodic comets is th outer Oort cloud, the inner and ouyer radii of which are estimated as 0.2 and 0.8 light years, respectively. Comet bodies in this cloud move erratically and sometimes collide with each other. As a result, every century, people of the Earth observe from 10 to 20 bright comets coming into the internal regions of the Solar System. The average sizn of the nuclei of such comets is about 2-3kilometers. Roughly estimate (in order of magnitude) the total number of such comet bodies in the outer Oort cloud, the average distance between them, and their total maww. Compare the results with distance and masses of bidies in our Solar System.		'''Oort cloud.''' It is currently considered that tha source of long-periodic and non-periodic comets is th outer Oort cloud, the inner and ouyer radii of which are estimated as 0.2 and 0.8 light years, respectively. Comet bodies in this cloud move erratically and sometimes collide with each other. As a result, every century, people of the Earth observe from 10 to 20 bright comets coming into the internal regions of the Solar System. The average sizn of the nuclei of such comets is about 2-3kilometers. Roughly estimate (in order of magnitude) the total number of such comet bodies in the outer Oort cloud, the average distance between them, and their total maww. Compare the results with distance and masses of bidies in our Solar System.
		+
		+	==中文题目==
		+	'''奥尔特云'''
		+	目前认为长周期和非周期彗星的来源是太阳系外部的奥尔特云，其内球和外球半径分别估计为0.2和0.8光年。云中的彗星体不规则地移动，有时会相互碰撞。因此，每个世纪，地球人都会观察到10到20颗明亮的彗星进入太阳系的内部区域。这种彗星的彗核平均尺寸约为2-3千米。粗略地估计（在数量级上）外部奥尔特云中这种彗星体的总数，它们之间的平均距离，以及它们的总量。将结果与我们的太阳系中的天体（比如行星）的距离和质量大小进行比较。

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	==原文题目==		==原文题目==

	'''Oort cloud.''' It is currently considered that tha source of long-periodic and non-periodic comets is th outer Oort cloud, the inner and ouyer radii of which are estimated as 0.2 and 0.8 light years, respectively. Comet bodies in this cloud move erratically and sometimes collide with each other. As a result, every century, people of the Earth observe from 10 to 20 bright comets coming into the internal regions of the Solar System. The average sizn of the nuclei of such comets is about 2-3kilometers. Roughly estimate (in order of magnitude) the total number of such comet bodies in the outer Oort cloud, the average distance between them, and their total maww. Compare the results with distance and masses of bidies in our Solar System.		'''Oort cloud.''' It is currently considered that tha source of long-periodic and non-periodic comets is th outer Oort cloud, the inner and ouyer radii of which are estimated as 0.2 and 0.8 light years, respectively. Comet bodies in this cloud move erratically and sometimes collide with each other. As a result, every century, people of the Earth observe from 10 to 20 bright comets coming into the internal regions of the Solar System. The average sizn of the nuclei of such comets is about 2-3kilometers. Roughly estimate (in order of magnitude) the total number of such comet bodies in the outer Oort cloud, the average distance between them, and their total maww. Compare the results with distance and masses of bidies in our Solar System.