All solar system planets circle our sun with slightly tilted orbits — and a new study shows even distant planetary systems in quiet neighborhoods have orbital tilts, too.

But once upon a time, billions of years ago, a massive object could have passed closely enough to gravitationally stir up the orbits of objects in the outer Solar System, causing the peculiar orbits.

A massive interstellar object passing through our solar system during its formative years likely altered the orbits of planets into trajectories observed today, a new study says.

The enormous visitor to our solar system may have been about 8 times the mass of Jupiter, and come nearly as close to the sun as the orbit of Mars.

Astronomers recently made an important discovery when they found a rare "in-sync" solar system with six planets all moving in one big grand harmony.

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

Even though the solar system’s organization is more often the exception than the rule, this study shows that the high degree of alignement of our system might well be the norm.

Scientists have been trying to find a hypothetical Planet 9 that may exist outside our known solar system based on the unusual orbits of certain dwarf planets. But those orbits might not require a ...

The solar system's main asteroid belt may have taken its shape when three gas giant planets were flung into more distant orbits, scattering the remote, icy objects that were lurking at the solar ...

The solar system currently contains a population of asteroids that follow essentially the same orbit as Jupiter, but lead or trail that planet by an angular distance of roughly 60 degrees.