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

All of our solar system’s planets are lining up to parade through the night sky at once. This extraordinary celestial event will see the sky scattered with seven visible planets in what is known ...

If everything in our solar ... outer solar system. This first-order model of planetary growth in the solar nebula is mainly driven by temperature and density variation, but there are many other ...

This may explain the strange properties of the orbits of our solar system's planets, which are not quite ... sun-like stars in the Galaxy is on the order of 10 10 and that stars are commonly ...