What major 20th-century discovery by Edwin Hubble also went unrecognized by the Nobel Committee?

Answer

The expansion of the universe and the existence of galaxies outside our own

Edwin Hubble's foundational work demonstrating that the universe is expanding and that numerous galaxies exist beyond the Milky Way never received a Nobel Prize, as astronomy lacks a dedicated category.

What major 20th-century discovery by Edwin Hubble also went unrecognized by the Nobel Committee?
Nobel PrizeAwardWinnerAstronomerscience