Apparently we get tons and tons of material dumped yearly onto our planet from space. Just wondering how much would be necessary to affect earths gravity so we can see a measurable change and how long that could take? How would you go about figuring/calculating this? Would it be millions of years or longer? So say a 50 kilometer object were to pound into the earth, although we would surely all perish would something like this effect earths gravity to the point of being measurable?