The ball will weigh 2.5 grams. This fact may become important later on. By neglecting atmosphere, one can prove that the escape velocity of an item, such as a fence, is reached just before it is demolished by the cruel ground. Given that you dropped it from semi-infinite hight, at least. This is probably due to a lack of oxygen to the brain.
Atmosphere makes one's thinking much cloudier, and hence makes the problem more complex.
But since the atmosphere is arguably a part of the Earth, I will neglect it. I will neglect any other facts I choose to as well. Our money would not be as valuable to them as the garbage, or else they would rob a bank instead. So they wouldn't mind paying us for giving them our trash. We would be wise to produce as much garbage as we can before aliens come.