If an extraterrestrial civilization can cross interstellar distances and actually reach Earth, then the materials they use for their ship’s hull are probably far beyond anything we classify as “spacecraft materials” today. A craft like that would need to survive: extreme cosmic radiation high‑velocity micrometeoroid impacts long‑term thermal and mechanical stress and possibly the effects of whatever propulsion method they use, especially if it involves manipulating spacetime So what *kinds* of materials make sense at that level? Some broad categories people often speculate about: advanced metamaterials self‑healing or adaptive composites bio‑tech hybrid structures or something completely outside our current physics models I’m curious what do you thinks: Which material categories seem most plausible for a genuinely extraterrestrial, interstellar craft? submitted by /u/Time_Yesterday_2058 [link] [comments]