Headscratchers / Plan 9 from Outer Space

• Ignoring the numerous physics goofs in the movie, if the sunlight-exploding device is so easy for any old primitive species to create and is an unstoppable weapon, why hasn't another alien race in the universe built one and turned it on? How do they even know such a device would work without evidence?
  • And we call it the "Big Bang."
  • It is a lot safer if you detonate it in the dark.
  • Presumably, previous discoveries of the solaranite effect were made in enclosed areas with only artificial light to detonate.
• Why does the old man wear a Dracula cape? Why doesn't the airplane's cockpit have control wheels? Why does it switch back and forth from day to night within seconds?
  • As to the first of those, presumably the same old family tradition that requires him to be buried in the family crypt while his wife just gets the common graveyard.