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The International Astronomical Union (IAU) is the official naming body in astronomy, and they also set the terms used to describe planetary features. For example, you may have heard of "Mons" (Olympus Mons on Mars, for instance) – that term "Mons" means "mountain" and is an official term from the IAU. The IAU does not have any ...


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The French version of the Wikipedia article has a "nomenclature" section, absent from the English version. It says: Lorsque l'énergie cinétique de l'impacteur est suffisante pour atteindre le manteau à travers la croûte et provoquer des épanchements magmatiques, on parle de bassin d'impact et non plus de cratère d'impact. Which roughly translates ...


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The wasn't originally in our solar system, so when it came here it came into earth's orbit it's orbit was large and lopsided. Over time it got into a more even orbit.


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Unlike the sun, which follows exactly the ecliptic and so is directly on the zenith on the date of the equinoxes, the moon is tilted by 5 degrees relative to the eclipic. And the direction of this tilt changes over 18 years. Moreover the motion of the moon is quite fast so even if it is rising due East, by the time it culminates it will have moved and so ...


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Yes, the are angles in radians. With "i=0.5" to make things clearer: $p=0$ is the right half illuminated $p=\pi/2=1.57$ is top half illuminated (rotated anticlockwise by 90 degrees) $p=\pi=3.14$ is left half illuminated (rotated 180 degrees) and so on. The r parameter is the rotation of the moon, so $r=0$ is "lunar north up" $r=pi/2$ ...


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What you need, as Aristarchus, is a frame of reference in which the Earth's shadow is stationary. Otherwise you are trying to deal with a moving thing (the Moon) relative to another moving thing (the shadow cast by the light of the Sun as it orbits the Earth). In a stationary-shadow frame of reference, the period you need is the time it takes the Moon to ...


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Is there a problem here though? For any given month won't the full Moon oscillate between low and high above the horizon at midnight on an 18.6 year cycle? No. The full moon is always opposite to the sun (within 5.2 degrees, the angle between the moon's orbit and the ecliptic). So, when in summer the sun is high in the sky, the full moon will be low, ...


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No the energy required to do this would cause the moon to melt. However the story of the spitting of the moon supposes a supernatural cause, and one which is not bound by the physical laws. God could split the moon and put it back together by his word. And God could arrange so that only some people saw it and others looked away. When you bring God into your ...


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The minimum energy change to the moon's orbit to cause it to impact the earth is 3.2998e28 Joules. After the asteroid hits the moon, it would take 6.2 more days for the moon to hit earth. We can calculate orbital velocity $v$ of the moon at apogee using the Vis-Viva equation: $v^2=\mu(2/r-1/a)$ , where $r=4.046e8$ meters is the distance between the bodies, $...


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