The overwhelming majority of the universe is:  who knows?

— Richard Panek, The 4 Percent Universe: Dark Matter, Dark Energy, and the Race to Discover the Rest of Reality

What is critical mass?
          The space between stars

Question Michelle Tennison,  Answer Paul Miller (2014)

What is the soul?
          A water bug skims over the surface
          perfectly balanced between
          here and there

Question and Answer Session with Mary Ellen Binkele and Michelle Tennison (1999)