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

Mars is chilly, Earth moderate, while Venus scorches, and Mercury fluctuates With an average temperature of about -224°C (-371°F), Uranus takes the top spot as the coldest planet in the solar ...

Six of our cosmic neighbors are expected to line up across the night sky tonight, in what has been dubbed a "planetary parade ...