Levitated Mass [SEP] material used
a much smaller, carved rock set on hidden supports, and does preserve this 'floating' effect.
Heizer rarely explains or comments on his work and has never offered a public explanation of "Levitated Mass"'s meaning or significance. He has however described the piece as being 'static art' and emphasized the importance of the boulder's size and of the work's longevity, saying that the work is meant to last 3,500 years. LACMA has published a preliminary sketch of the work by Heizer that contains a handwritten
insertion
Neither of these effects is likely with implosion weapons since there is normally insufficient fissile material to form a critical mass without the correct detonation of the lenses. However, the earliest implosion weapons had pits so close to criticality that accidental detonation with some nuclear yield was a concern.
On August 9, 1945, Fat Man was loaded onto its airplane fully assembled, but later, when levitated pits made a space between the pit and the tamper, it was feasible to use in-flight pit insertion. The bomber