A newly studied solar system breaks the usual planet pattern, raising fresh questions about how rocky and gas planets form.

Earth and Mars were formed from material that largely originated in the inner solar system; only a few percent of the building blocks of these two planets originated beyond Jupiter's orbit. A group of ...

Trans-Neptunian objects (TNO) are some of our solar system's lesser-known objects. They number in the thousands, and they get their name from their orbits. These dwarf planets orbit the sun at a ...