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 ...

All of our solar system’s planets are lining up in the night sky at once this week. This extraordinary celestial event will see the sky scattered with seven visible planets in what is known as a great ...

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 ...