20/11/2025
🌌 Edwin Hubble was an American astronomer who changed the way we understand the universe. Born in 1889, Hubble made one of the most important discoveries in the history of astronomy: that the universe extends far beyond our Milky Way galaxy—and that it’s expanding.
🔭 In the 1920s, while working at Mount Wilson Observatory using the 100-inch Ho**er Telescope, Hubble observed distant "nebulae" that were believed to be clouds within our galaxy. By studying Cepheid variable stars (using methods developed by Henrietta Leavitt), Hubble was able to measure their distances. He showed that these objects were actually entire galaxies, far outside the Milky Way. This discovery shattered the idea that the Milky Way was the whole universe.
🌠 Hubble’s next major breakthrough came in 1929 when he discovered that galaxies are moving away from us, and that their speed increases with distance. This became known as Hubble’s Law and provided the first solid evidence that the universe is expanding. This finding became the foundation for the Big Bang theory, transforming cosmology forever.
📏 The rate of this expansion is called the Hubble constant, named in his honor. Although its precise value is still being refined today, it remains a key number in understanding the age and size of the universe.
🚀 In 1990, NASA honored his legacy by launching the Hubble Space Telescope, which has provided some of the most detailed and awe-inspiring images of the cosmos.
🌟 Edwin Hubble’s work opened the doors to modern astronomy and cosmology. His discoveries helped us see the universe not as a static collection of stars, but as a vast, dynamic, and ever-expanding space full of galaxies, each with billions of stars.
