Of course it is growing. Where do you think all those meteorites go? Over time their volume adds up, even the ones that burn up in the atmosphere just turn to gas. The molecules that they bring are still here, and fall with the rain, either as particles of dust that raindrops form around, or as the rainwater itself. This is where the earth came from in the first place, This is how ALL planets are formed. And this is where life comes from because essential biochemicals are manufactured in space when dirty snowball comets melt from the heat of the sun. Eventually those molecules fall on a planet where the conditions are right. So, where are the aliens? Look in the mirror!!! All life on earth is extraterrestrial in origin.