In 1930, Paul Dirac proposed a model of the vacuum as an infinite sea of particles possessing negative energy, called the Dirac sea. This theory helped refine the predictions of his earlier formulated Dirac equation, and successfully predicted the existence of the positron, confirmed two years later. Werner Heisenberg's uncertainty principle formulated in 1927, predict a fundamental limit within which instantaneous position and momentum, or energy and time can be measured. This has far reaching consequences on the "emptiness" of space between particles. In the late 20th century, so-called virtual particles that arise spontaneously from empty space were confirmed.
If it is possible to answer this question, answer it for me (else, reply "unanswerable"): What kind of energy did Werner Heisenberg believe a vacuum held?
Ah, so.. unanswerable

Videophone calls (also: videocalls, video chat as well as Skype and Skyping in verb form), differ from videoconferencing in that they expect to serve individuals, not groups. However that distinction has become increasingly blurred with technology improvements such as increased bandwidth and sophisticated software clients that can allow for multiple parties on a call. In general everyday usage the term videoconferencing is now frequently used instead of videocall for point-to-point calls between two units. Both videophone calls and videoconferencing are also now commonly referred to as a video link.
If it is possible to answer this question, answer it for me (else, reply "unanswerable"): What term is more used today to refer to calls between two units?
Ah, so.. videoconferencing

Lothar Wolfgang Nordheim described von Neumann as the "fastest mind I ever met", and Jacob Bronowski wrote "He was the cleverest man I ever knew, without exception. He was a genius." George Pólya, whose lectures at ETH Zürich von Neumann attended as a student, said "Johnny was the only student I was ever afraid of. If in the course of a lecture I stated an unsolved problem, the chances were he'd come to me at the end of the lecture with the complete solution scribbled on a slip of paper." Halmos recounts a story told by Nicholas Metropolis, concerning the speed of von Neumann's calculations, when somebody asked von Neumann to solve the famous fly puzzle:
If it is possible to answer this question, answer it for me (else, reply "unanswerable"): What did Lecturer Polya think about von Nuemann?
Ah, so..
Johnny was the only student I was ever afraid of.