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

All seven of the other planets in our solar system are about to become visible at once in a great planetary alignment – here’s how to spot the celestial show ...

and all lie on slightly different planes. NASA artist’s conception of a brown dwarf (main) and stock image of the planets in the solar system (inset). An object between 2 and 50 times the mass ...

The organic material found in a few areas on the surface of dwarf planet Ceres is probably of exogenic origin. Impacting asteroids from the outer asteroid belt may have brought it with them. In the ...