Neptune, the ice giant of our solar system, lies more than 30 times further from the Sun than Earth.

This distant planet, shrouded in darkness and frigid temperatures, has fascinated astronomers and space enthusiasts for centuries.

Neptune is the only planet in our solar system that cannot be seen with the unaided eye. Even though it was discovered in 1846, it wasn't until 2011 that Neptune completed its first 165-year orbit since its discovery.

1. A Name That Echoes the Sea

Neptune is named after the Roman deity of the sea, a fitting moniker for a planet that, despite being far from Earth's oceans, exudes mystery and intrigue. The planet was the first to be located through mathematical predictions. Thanks to the calculations made by Urbain Le Verrier, Johann Galle discovered Neptune in 1846, and the name was chosen to tribute the deity of the seas.

2. Not Suitable for Life as We Know It

Neptune's environment makes it an unlikely candidate for life as we understand it. Its extreme temperatures, high pressures, and volatile materials create conditions too harsh for organisms to survive. The icy planet is a world of extremes, where conditions are simply not conducive to the life we recognize here on Earth.

3. Size and Distance from the Sun

Neptune is enormous, with an equatorial diameter of 30,775 miles (49,528 kilometers)—about four times the width of Earth. To put this into perspective, if Earth were the size of a nickel, Neptune would be the size of a baseball. The planet is located about 2.8 billion miles (4.5 billion kilometers) away from the Sun, or 30 astronomical units (AU).

4. The Long Orbit and Rotation

A single day on Neptune lasts only about 16 hours, as that's how long it takes for the planet to complete one full rotation. However, Neptune's year is vastly longer—it takes around 165 Earth years for Neptune to make one orbit around the Sun. Neptune's orbit is sometimes even farther from the Sun than that of the dwarf planet Pluto.

5. The Moons of Neptune

Neptune is home to 16 known moons, with its largest moon, Triton, discovered just 17 days after Neptune itself. Triton is unique because it orbits Neptune in the opposite direction of the planet's rotation, indicating it might have once been an independent object that was later captured by Neptune's gravity.

6. The Rings of Neptune

Neptune has at least five main rings and several arc-like structures within those rings. These rings are relatively young and short-lived. The main rings are named Galle, Leverrier, Lassell, Arago, and Adams, while four prominent arcs within the outermost ring are named after French revolutionary ideals: Liberté, Egalité, Fraternité, and Courage.

7. Formation of Neptune

Like its neighbor Uranus, Neptune likely formed closer to the Sun before migrating to its current position in the outer solar system. The planet took shape about 4.5 billion years ago, when gravity pulled together swirling gas and dust to form this ice giant.

8. The Structure of Neptune

Neptune's structure is primarily composed of a hot, dense mixture of icy materials, including water, methane, and ammonia, surrounding a small rocky core. This dense composition gives Neptune the distinction of being the densest of the giant planets.

9. The Atmosphere and Winds

Neptune's atmosphere is predominantly made up of hydrogen and helium, with a small amount of methane. This composition gives the planet its distinct blue hue, as methane absorbs other colors of light but reflects blue wavelengths. The planet experiences incredibly strong winds, which can reach speeds of more than 1,200 miles per hour (2,000 kilometers per hour)—nearly nine times stronger than winds on Earth.

10. Magnetosphere and Magnetic Field

Neptune's magnetic field is one of the most peculiar in the solar system. Unlike most planets, its magnetic field is tilted by about 47 degrees compared to the planet's rotational axis. This tilt causes Neptune's magnetosphere to vary wildly during each rotation. The planet's magnetic field is approximately 27 times stronger than Earth's.

Neptune remains one of the most enigmatic and fascinating planets in our solar system. Its extreme conditions, powerful storms, and strange moons make it a subject of continuous scientific exploration, offering new discoveries with every mission that reaches its distant orbit.

Neptune 101 | National Geographic

Video by National Geographic