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

NASA’s Hubble Space Telescope captured a cameo appearance of the tiny moon Phobos on its trek around the Red Planet. This composite image, from NASA Galileo and Mars Global Survey orbiters, of Earth ...

Between the orbits of the terrestrial planets and the gas giants, there are millions of asteroids – rocky objects that orbit the Sun and vary in size from 1km to around 1000km. Like planets ...