The solar system has many more moons than the one we can see in the sky. But how many do we actually know about? And how many ...

The workings of our solar system are roughly the same now as they have been for millions of years. Moons circle their planets, the planets circle the sun, the sun’s magnetic fields and sunspots wax ...

Astronomers are closing in on one of the most tantalizing possibilities in planetary science, evidence that a previously unknown world may be lurking in the outer reaches of the solar system. The ...

It was almost 100 years ago that Clyde W. Tombaugh discovered Pluto. That was the last planet found until 1992, when humans found another one. But this new planet wasn't in our solar system—it was ...

Far beyond Neptune, in the frozen depths of the Kuiper Belt, many ancient objects oddly resemble giant snowmen made of ice and rock. For years, scientists wondered how these delicate two-lobed shapes ...