Which solar system model is best? For as long as humans could look up at the night sky, we’ve been fascinated with the stars. How far away are they? Where did they come from? What secrets do they hide ...

Beyond the edge of Neptune, a distant realm of icy debris known as the Kuiper Belt stretches deep into space. This frozen frontier holds the scattered remains of the early solar system, offering ...

If our solar system seems stable, it's because our short lifespans make it seem that way. Earth revolves, night follows day, the moon moves through light and shadow, and the sun hangs in the sky. But ...

Their strange movements don’t match the predictions of current solar system models. This odd behavior has sparked new theories, including the bold idea that a yet-undiscovered Earth-sized planet may ...