by John Carswell » Thu Mar 30, 2006 2:22 pm
I think I might have figured it out. The shadow would move east if the whole earth travels through the shadow faster than it's rotation carries any given place on its surface in the opposite direction. Also, the moon is moving so if the earth were stopped in it's orbital path and not rotating, the shadow would move east. Three motions, the earth in it's orbit, the earth on it's axis, and the moon in it's orbit determine the point at which a projection of a line from the center of the sun through the center of the moon ( the eclipse shadow) falls on the surface of the earth. It seems like I should be able to understand this if people have been calculating eclipse time and place for 3000 years.
I think I might have figured it out. The shadow would move east if the whole earth travels through the shadow faster than it's rotation carries any given place on its surface in the opposite direction. Also, the moon is moving so if the earth were stopped in it's orbital path and not rotating, the shadow would move east. Three motions, the earth in it's orbit, the earth on it's axis, and the moon in it's orbit determine the point at which a projection of a line from the center of the sun through the center of the moon ( the eclipse shadow) falls on the surface of the earth. It seems like I should be able to understand this if people have been calculating eclipse time and place for 3000 years.