Project Sundial wasn’t just theoretical. We had the ability, the materials, and the technical knowledge to build it. You know how you can absolutely verify that? We built it in thousands of different bombs rather than just one big one. If we had made a 10 gigaton device where it was supposed to be located in eastern California, or western Nevada, blowing that up would have created a massive crater that probably would have measured at least 30 miles in diameter, and all of the US would die in the first blast. The shockwave would circle the globe multiple dozens of times. This is a world ending bomb. Half the planet’s crust would be molten for decades if not centuries. 10 gigatons is about 1/4-1/5 the amount of energy that Theia imparted to Proto-Earth which created two moons for a very short period of time, and made the entire planet molten for another 1/4 billion years.