What are the three new planets in our solar system?
In our solar system, Uranus and Neptune are the most recent planets discovered (although I don’t think anyone would consider these “new” discoveries anymore). Pluto does not fit the current definition of planet, as determined my the International Astronomical Union. So really, we “lost” a planet. Dwarf Planets and Plutiods are the terms currently used to define Spherical bodies that do not “dominate” their own orbit, and don’t qualify as satellites. Ceres is the largest dwarf planet (it resides in the asteroid belt). Pluto, very cleverly, fits the definition of Plutiod, being out in the Kuiper Belt. If you are referring to extra-solar planets, these are discovered every couple of months these days, and the AIU has no plans to begin giving them casual names. Osiris is probably the one you’ve heard about the most.
