Neptune is the fourth largest planet in the solar system, with a radius of 15,599.4 miles (24,622 kilometers) — the distance between its core and the surface.

New Horizons flew past Neptune and its moon Triton in 2014 from a distance of about 2.45 billion miles (3.96 billion kilometers), but also just zoomed past the planet.

Since then, the planet has only been visited once by spacecraft when, in 1989, Voyager 2 completed its 'Grand Tour' of our solar system's outermost planets. It took this image of Neptune and its moon ...

Neptune, long believed to be dark blue, is actually very pale like Uranus, scientists say. They used modern telescopes to re-assess artificially enhanced images taken by NASA's Voyager 2 probe.

Additionally, Neptune storms rising from the deep atmosphere do influence the planet’s cloud cover — but aren’t related to clouds formed in the upper atmosphere.

With its vanishing clouds and now a large dark spot, the planet Neptune appears to be going through some things. Here’s a bit about why the eighth planet in our solar system is causing all this ...

New images from the space-based observatory offer a novel view of the planet in infrared. By Jonathan O’Callaghan No spacecraft has visited Neptune since 1989, when the NASA probe Voyager 2 flew ...

The images of Uranus, the seventh planet from the sun, and Neptune, the eighth planet, were collected in 1986 and 1989, respectively, as NASA's Voyager 2 spacecraft headed out of the solar system.

In 1989, Voyager 2 became the first and only spacecraft to ever fly by Neptune, and images from that mission famously show a planet that's a deep azure color. But in reality, Neptune is far more ...