I recall reading, years and years ago (maybe something posted back then here on HN?), about an idea: sending some big "sail" into space that'd block some of the

I recall reading, years and years ago (maybe something posted back then here on HN?), about an idea: sending some big "sail" into space that'd block some of the sun. Anybody remember that? It seems less crazy than blocking sun rays using aerosols put into our atmosphere like in TFA.