Astronomers have recently detected a rogue planet entering our solar system, marking a rare event that has sparked ...

Astronomers propose a new hypothetical planet, Planet Y, beyond Neptune, based on observed orbital anomalies in the Kuiper ...

New discoveries of objects in the Kuiper Belt have also presented challenges for the Planet Nine theory. The latest is known ...

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 ...

For years, astronomers have speculated about a mysterious ninth planet. Now new evidence suggests we may be closer than ever ...

Aliens may have been closer to Earth than first thought. New research from NASA reveals that Ceres, the dwarf planet in the ...

Since its fiery birth nearly 4.5 billion years ago, Mercury, the smallest planet in our solar system, has been slowly ...

The core of Jupiter, the largest planet in our solar system, has long been a source of mystery for astronomers. Conventional ...

The rusty world is full of mysteries—and some of the solar system's most extreme geology. Learn more about Earth's smaller, ...

Previous studies showed a roughly 1 percent chance of it dropping into the sun or being ejected from the solar system because of planetary dynamics in the next five billion years or so, but ...

Yet actually finding Planet Nine, sometimes called Planet X, has eluded scientists for nearly a decade. But the hunt for the solar system's potential ninth planet may soon be coming to a close.

"The solar system’s distant reaches exhibit a wealth of anomalous dynamical structure, hinting at the presence of a yet-undetected, massive trans-Neptunian body — Planet 9," the study abstract ...