Here's a thought: vinyl. While I haven't done intensive research on this, it occurs to me that plastic lasts a long time. Vinyl records are a format that seems

Here's a thought: vinyl. While I haven't done intensive research on this, it occurs to me that plastic lasts a long time. Vinyl records are a format that seems fit for long-term archiving. The format is so obvious that it could be reverse engineered by any future civilization. So at least they'll know something about our taste in music.