The 10,000 megatonne SUNDIAL bomb if detonated 53 KM above the earth surface, create a flash 300 times hotter and brighter than the sun at midday. instantly igniting or melting everything in a 1200km diameter circle on the surface of the earth.

pictured: Scientists from Laurence Livermore National Laboratory fuel the SUNDIAL secondary case with L6 Deuteride prior to launch.