Henry Slesar's "Reluctant Genius" (flash fiction, uplift, free): How aliens aided the beginning of modern physics!
Only, their bodies aren't physical - they're vaporish. They've selected a man worthy of imparting inspiration, but how do they communicate? Until inspiration strikes one of them...
Fact sheet.First published: Amazing Stories, January 1957.
Download full text from Project Gutenberg, or Manybooks. [via QuasarDragon]