The number of planets that orbit the sun depends on what you mean by “planet,” and that’s not so easy to define ...

Does our Solar System have 9 planets or only 8? Astronomers have gone back and forth on that a lot, with Pluto now being classified as a dwarf planet. However, out beyond Neptune there could be ...

The Planet Nine theory was based on several trans-Neptunian ... This seemed odd and illogical as when the Solar system formed, it would be expected that objects that developed in the circumstellar ...

Scientists believe that two asteroids might be fragments of long-lost "planetary embryos" from the early solar system.

Timing: Dusk after sunset, but before 9 p.m. local time There are eight planets in our solar system and one dwarf planet (Pluto). Because we live on Earth, the most we could see is a maximum of ...

To better understand why the planets have variable compositions ... to the formation of the gas and ice giants in the outer solar system. This first-order model of planetary growth in the solar ...

one which can offer superb views of the other bodies in the solar system. But which one to choose? We've got you covered with our guide to the best telescopes for seeing planets. Now's a great ...

Timing: Dusk after sunset, but before 9 p.m. local time There are eight planets in our solar system and one dwarf planet (Pluto). Because we live on Earth, the most we could see is a maximum of seven ...