The moon's rotational speed at the equator is 10.3 miles per hour (4.627 m/s), a fact that is often overlooked in discussions about lunar characteristics. This speed is derived from the formula v=d/t, where d is the moon's circumference and t is its rotational period of approximately 27.32 days. At the poles, the moon's velocity is 0, and to calculate the speed at any latitude, one must multiply the equatorial speed by the cosine of the latitude. The discussion highlights the importance of contextualizing the moon's rotation in relation to its orbital period rather than relying solely on arbitrary units of measurement.
PREREQUISITESAstronomy enthusiasts, educators teaching lunar science, and students studying celestial mechanics will benefit from this discussion on the moon's rotational speed and its implications.
mgb_phys said:It's a conspriracy!
ps. Wiki gives it as 4.627 m/s
russ_watters said:I guess people just don't consider that factoid to be very important.
LURCH said:Generally, I think people find it more useful to measure the moon's rotation in comparison with its orbital period. "Miles" and "meters" are strictly man-made units of measure, so measuring the rotation of the moon in miles per hour or meters per second might seem (to some people) rather arbitrary. Referring to the time it takes the moon to complete one revolution on its axis as "one lunar orbit" is a much more relevant bit of information, for most applications.
tony873004 said:That's the Moon's rotational speed at the equator.
It's easy to compute: v=d/t = Moon's circumference / period = 2*pi*1737km/(27.32*24) = 16.645 km/hr, same as 10.3 mi/hr or 4.6 m/s.
But at the poles its velocity is 0. To get the speed for any latitude inbetween, multiply the equatorial speed by cos(latitude).