A so-called "planetary nebula" is a confusing misnomer because these clouds have nothing to do with planets. As a medium-size star nears the end, it puffs out into a red giant — about 100 to 1,000 times its original size — eventually engulfing the space around it, including any nearby worlds.
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But agar’s superior qualities come with complex chemistry. “To speak of agar as a single substance of certain (if known) chemical structure is probably a mistake,” wrote phycologist Harold Humm in a 1947 article. According to the Food and Agriculture Organization of the United Nations, agar is merely recognized as “a hydrophilic colloid extracted from certain seaweeds of the Rhodophyceae class.” In terms of its actual composition, agar is mostly a combination of two polysaccharides, agaropectin and agarose, which themselves are complex and poorly-characterized polysaccharides made mostly (but not exclusively) from the simple sugar galactose.8