The Largest Known Star, UY Scuti, Discovered By German Astronomers In 1860, Is In The Milky Way Galaxy, ~9500 Ly From Earth. It’s 1700x The Radius Of Our Sun. Stars Like UY Scuti Are Rare Due To Their Shorter Lifespan (In Millions), Unlike Those That Last For Billions Of Years. The Smallest Star, EBLM J0555-57Ab, Is About Saturn’s Size.What is the largest known star in the universe? It's a red hypergiant.https://www.usatoday.com/story/tech/science/2023/02/16/largest-star-universe-red-hypergiant/11075755002/There are billions and trillions of stars in our universe.\u00a0But what is the biggest known star in the universe?