Quote Originally Posted by Youngblood View Post
Things are quiet in here, so a bit off history/geo.

What is the speed of Earth's rotation?

The moons orbital speed of earth?

The Earth around the Sun?

roughly.
ok, not a lot happening at my place, so here goes on the other two questions.

OK, I seem to recall froom my Rick Hansen post that the circumference of the earth is about 45,000, can't remember if it was miles or kilometeres, so I'll say kilometers. Seeing as how the earth completes a rotation in 24 hours, that makes the rotational velocity of the earth 45,000/24 = 1,875 km/h no wonder it's so fucking windy all the time.

Also I seem to recall that the distance fom the moon to the earth is about 140,000 miles, multiply by 1.6 to get 224,000 km. add to that the radius of the earth, which is circumference / (2* pi) = 7,162 km. So the distance from the moon to the center of the erth is 231,162 km.

Therefore, the circumference of the moon's orbit around the earth 2 * pi * 231,162 = 1,452,437 km. Now I think that one revolution of the moon around the earth is marked by a cycle of moon phases, which is 28 days, therefore...

the orbital velocity of the moon around the earth is approximately

1,452,437 / (28*24) = 2,161 km/h approximately.