compare the rings systems of saturn and uranus. why were uranus rings unnoticed until the 1970's?
It's possible, if you do it often enough, and the drain pipes are steel. But that's unlikely in a newer house. Most of the drain pipes are PVC - a plastic - that won't rust. If you can go in a basement and see the plumbing under the bathroom, look for the larger lines that are say 3-4 inches thick. If they're plastic, you have no worries. But it could damage the metal fixtures in the tub. After the bath, give everything a good rinse, to wash the salt off of them, and that will help keep them in good shape.
No. It does not pass through much. Plastic bags, Balloons. But not glass, or plastic. However, it can appear to pass through, because if you have a heat source behind the metal, the heat will pass through, and cause the outside of the metal to glow in IR. IR light like a heat signature for the most part.
