This episode explores Spectra, meteorites, spacecraft measurements and the limits of remote interpretation. The story keeps the mechanisms clear and the research grounded for a casual listener. Inside this episode: - Sunlight as a chemical clue - Brightness, color, and rotation - Mass and density - Radar and radio - Meteorites in the lab Sources include NASA Science, Asteroid Facts, NASA Dawn mission science, and NASA Johnson Space Center, meteorite collection. This episode is a researched narrative summary. Historical records may be incomplete, translated differently, or interpreted differently by scholars. We distinguish documented facts, estimates, disputed interpretations, and later stories where material. Corrections are logged and incorporated into future editions. Follow Solar System Field Notes for more researched stories about the evid ...