Biosignatures, as the name implies, are purported to be markers of life. Chemical biosignatures are compounds either rarely or never produced without the assistance of life on Earth. Finding biosignatures thus implies a material conception of life, likely in the form of biochemistry, metabolism, or thermodynamics. There have been many attempts to detect biosignatures, primarily on Mars. These approaches include experiments done on planetary surfaces, observations from Earth or low-earth orbit, and study of meteors and other debris from nearby planetary bodies.