What are the most plausible explanations of Navy pilots seeing hypersonic objects at 30K feet, objects with no visible engine and sometimes described as a cube within a sphere? See link. – Quora

A few hours ago "Ibteesam Reaz, Staff Physicist at Lockheed Martin" answered this Quora question: "What are the most plausible explanations of Navy pilots seeing hypersonic objects at 30K feet, objects with no visible engine and sometimes described as a cube within a sphere?" - conspiracy