system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5 Asteroids mining will begin eventually, what will be the consequence if earth quickly gains weight?
gpt
You have to realize how *large* earth actually is. The statistic that gets this across the most clearly is that if earth were a billiard ball, then Mt. Everest would not be large enough to disqualify the ball for competitive play. Mt. Everest is not big enough, when compared to the overall size of earth, to make a noticeable difference on its size. Earth's diameter: 12,756,200 meters. Mt. Everest: 8,848 meters. 

The point of all that is that it would probably take millennia of constant work to mine enough materials to ever make a difference in earth's size or weight.