The Hubble Space Telescope (HST) is a space telescope that was launched into low Earth orbit in 1990 and remains in operation. It is named after the astronomer Edwin Hubble and is one of the largest and most versatile telescopes ever built. The HST has been used to observe distant galaxies, measure distances between galaxies, study stars, and observe the formation of new stars. It has also been used to study dark matter, dark energy, and other aspects of the universe. The telescope has helped scientists to better understand the structure and evolution of our universe.