There are a couple of ways that scientists can date planets, so which planets formed first in our solar system?

Learn how many suns exist in the Milky Way and how to understand how many sun-like stars are out there could help us understand how many Earth-like planets there are, too.

Is there a massive undiscovered planet on the outer reaches of the solar system? The idea has been around since before the discovery of Pluto in the 1930s. Labeled as planet X, prominent astronomers had put it forward as an explanation for Uranus’s orbit ...

Mercury reaches its greatest eastern elongation on October 29, appearing farthest from the Sun in the southwestern sky, offering a brief window for observation after sunset.