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.
The IAU accepted Eris as a dwarf planet because it is more massive than Pluto. They subsequently decided that unnamed trans-Neptunian objects with an absolute magnitude brighter than +1 (and hence a diameter of â¥838 km assuming a geometric albedo of â¤1) are to be named under the assumption that they are dwarf planets.1) A planet 1 is a celestial body that (a) is in orbit around the Sun, (b) has sufficient mass for its self-gravity to overcome rigid body forces so that it assumes a hydrostatic equilibrium (nearly round) shape, and (c) has cleared the neighbourhood around its orbit.