So I was curious about this explore planet feature. I understand that by exploring colonized planets I can sometimes find artifacts or "other features." I have found heavy glaciers exploring but I could not find any place telling me what those do. I've noticed other planet "features" like dense core that don't require exploring but I can't find what they do either. Has anyone compiled a list of all the different features a planet can have and what effect they have? I have not found an artifact yet. Are the artifacts really good? Do they offset the cost of having to explore (possibly) several planets to find one. Also, are you more likely to find something on a terran world than an asteroid, for example? And finally, how long do people usually wait before exploring? Does finding an artifact early help more then upgrading your planets infrastructure?