If you want to visit (and not live in) the United States you must first obtain a visitor visa. Travelers from certain countries may be exempt. If you want to travel to the United States for reasons other than business or pleasure, such as study or work, you must apply for a visa in the appropriate category. DHS provides a full range of online resources to help you plan your trip, manage your arrival and if needed extend your stay.
Some astronomers called Eris our Solar System's tenth planet when it was first discovered. After a lot of discussion, astronomers decided to make up a new category for objects like Eris. That is where the idea of dwarf planets came from.
After 1992, its planethood was questioned following the discovery of several objects of similar size in the Kuiper belt. In 2005, Eris, which is 27% more massive than Pluto, was discovered, which led the International Astronomical Union (IAU) to define the term planet formally for the first time the following year. This definition excluded Pluto and reclassified it as a member of the new dwarf planet category.