I'm not sure what the alien Theory says or if there really is such a theory. If the theory says that aliens definitely exist and that they have visited Earth in the past then the theory is totally and completely without any kind of support. It's not scientific in any way because there is no evidence for such a claim. It may be thought to be probable but no solid evidence has ever been presented.
Momentum describes an object in motion and is determined by the product of two variables: mass and velocity. Mass -- the weight of an object -- is usually measured in kilograms or grams for momentum problems. Velocity is the measure of distance traveled over time and is normally reported in meters per second. Examining the possible changes in these two variables identifies the different effects momentum can have on an object in motion.
68 miles per hour 1.1333 miles per minute