Astronomers using the Vera C. Rubin Observatory have discovered 2026 ED138, a large object beyond Neptune that could become the solar system's sixth recognized dwarf planet if further observations confirm it is massive enough to be round. Located about 46 times farther from the Sun than Earth, the object is estimated to be 600 to 1,500 kilometers wide and had remained hidden because it lies against a particularly crowded field of Milky Way stars. Scientific American reports: The discovery was made by running billions of pieces of data collected by the Rubin Observatory through a search code developed by Center for Astrophysics | Harvard & Smithsonian astronomers Matthew Holman and Kevin Napier. "My first reaction was one of excited disbelief," Holman said in a statement .…