I wonder since there is carbon based poop from life, is there silicon based poop too? http://www.sciforums.com/showthread.php?t=59376
Huh? I don't understand the thread you refer to. Silicon-based life is a cliche in sci-fi. Silicon is directly beneath carbon in the periodic table and therefore can be expected to have many of its same properties. It's easy to postulate the chemistry of life based on silicon because it would be vaguely recognizable. Life based on gas bubbles or photon clouds or electronic waves would not be so easy for us to even know it was there.