The universe is about 13.8 billion years old. Venus is the hottest planet due to a runaway greenhouse effect. Elliptical galaxies are the most common type. Stars produce energy through nuclear fusion.

Beginning Nov. 25, 2025, Mercury will be far enough west to peek above the horizon just before sunrise. Venus will also be naked-eye-visible as a bright point of light but you’ll want a telescope or a ...

A new explanation for the solar system's radioactive elements suggests Earth-like planets might be found orbiting up to 50 ...

Ian Whittaker does not work for, consult, own shares in or receive funding from any company or organization that would benefit from this article, and has disclosed no relevant affiliations beyond ...