Is the solar system full of interstellar vagrants, passing unseen? For decades, it was all conjecture, interrupted only by the brief glimpses of objects such as 1I/’Oumuamua and 2I/Borisov. But with ...

Our solar system may have a ninth planet after all, researchers say. The possibility that an additional planet may be hidden far into the solar system was touted more than a century ago.

NARRATOR: Our solar system is home to eight planets, near-perfect spheres spinning through the darkness of space. But the more we explore, the more weird and wonderful worlds we discover.

Snapped on March 9, the orbiter was 77 million kilometers (48 million miles) from the Sun. It snapped 200 individual images that were put together in this extraordinary view, 12,544 by 12,544 ...

All seven of the other planets in our solar system are about to become visible at once in a great planetary alignment – here’s how to spot the celestial show. Close. Advertisement.

The discovery challenges findings made by Voyager 2, which collected data suggesting Uranus, unlike other giant planets in the solar system, didn’t have an internal heat source.

Though Pluto has formally been considered a dwarf planet for almost two decades, it still has many lessons left for planetary scientists — including hints about how the solar system formed.