At the edge of the solar system, there is a beautiful blue giant spinning alone in the darkness. As of the time of this writing, Neptune is the last official planet in our little corner of the galaxy, with everything beyond it classified as dwarf planets. What makes Neptune, the beautiful blue gas giant, so special? Learning some facts about Neptune will help us find out.
10 Interesting Facts About Neptune
Neptune might be the furthest planet from the sun, now that Pluto is a dwarf planet, but we’ve still learned plenty about our most distant celestial neighbor. Here are 10 interesting facts about Neptune you should know:
1. Neptune Has a Shorter Day Than We Have Here on Earth
If you feel like there aren’t enough hours in the day on Earth, you’d be hard-pressed to get anything done on Neptune. One day on the gas giant is a little over 16 hours long, a full one-third shorter than our rotational cycle.
2. Methane Turns the Planet Blue
The methane in Neptune’s atmosphere absorbs red light and reflects blue, giving the planet its beautiful and iconic blue color.
3. Neptune Is Prone to Massive Storms
Since its discovery, we’ve seen two massive storms form on the planet’s surface. These storms, dubbed Dark Spots, can last for years. While they aren’t as long-lived as the Great Red Spot on Jupiter, Neptune’s Dark Spots frequently appear in the planet’s atmosphere.
4. Neptune Also Has Rings
They might not be as elaborate as the ones you see in orbit around Saturn, but Neptune has a series of faint rings. The three major ones are named for some of the astronomers credited with the planet’s discovery, including Adams, Le Verrier and Galle.
5. Only One Human Spacecraft Has Performed a Flyby of Neptune
We don’t have many pictures of the planets at the edge of the solar system. Voyager II is the only human-made probe to complete a flyby of the blue gas giant. It sent back pictures in 1989 as it flew by. We can see Neptune with the Hubble Space Telescope, but we don’t have any plans to send more probes as of right now.
6. Neptune Has the Longest Orbital Period in the Solar System
If we lived on Neptune, no one alive today would have reached their first birthday. Neptune’s orbital period is the longest in the solar system, with the planet taking 164.8 years to make its way around the sun.
7. Neptune Is Named for the Roman God of the Ocean
Neptune is the Roman god of the ocean and sea, which is an appropriate moniker for the bright blue gas giant. Neptune is one of the three primary gods in the Roman pantheon. He’s the brother of Jupiter. In Greek mythology, Neptune’s name is Poseidon, brother of Zeus.
8. Neptune Has 14 Moons, Including the Coldest Celestial Body in the Solar System
As of this writing, we’ve spotted 14 moons in orbit around Neptune. The largest satellite, Triton, continually spews nitrogen ice into the space around it. At minus 235 degrees C, Triton currently holds the title of the coldest place in the solar system.
9. Neptune Has an Axial Tilt Similar to Earth
On Earth, we have seasons because of the planet’s axial tilt of 23.5 degrees. Despite its vast distance from the sun, an axial tilt of 28.5 degrees also gives Neptune some pretty dramatic seasons.
10. Neptune Has Only Experienced One Year Since We Discovered It
We discovered Neptune in 1846. Since then, Neptune has only completed one orbit of the sun. It finally returned to the part of the sky where we first spotted it in 2011.
Neptune Properties & Information
Now that you’ve learned some planet Neptune facts, check out its properties and even more technical information:
- Location in solar system: 8th planet from the sun.
- Distance from Sun: 30.10 astronomical units (AU) or 4,498,396,441 kilometers (km).
- Composition: Gas giant.
- Size: 49,528 km (30,771 mi).
- Surface: No discernible surface.
- Structure: Atmosphere merges into vast oceans above solid core.
- Color: Blue.
- Atmosphere: Hydrogen, helium and methane.
- Moons: 14 moons, as of 2019.
- Temperature: Minus 201 degrees C (or minus 329.8 degrees F).
- Orbital period: 164.8 years.
- Rotation period: 16 hours, 6 minutes.
Who Discovered Neptune?
Neptune is currently the only planet you can’t see with the naked eye. There’s also a bit of a controversy surrounding the blue gas giant’s discovery. For one thing, Galileo marked it on a map of the sky hundreds of years before its official discovery. However, he had it down as a star rather than a planet. A pair of mathematicians — Urbain Le Verrier of France and John Couch Adams — predicted that a new planet dubbed Planet X would soon be spotted in a specific part of the sky.
The French astronomer Alexis Bouvard and a German one named Johann Galle officially found the planet on September 23, 1846. They didn’t spot it directly, instead predicting its location by observing irregularities in Uranus’ orbit. This information, paired with Galle’s calculations, helped them pinpoint Neptune in the sky. Of course, both sets of mathematicians took credit for the discovery, and astronomers have been arguing about this point for over 150 years.
What Is Neptune Known For?
Neptune is known for being the only planet in the solar system you can’t see with the naked eye. You can spot it with powerful ground-based telescopes if you’re skilled, but you’ll never see it just by looking up at the night sky. Once you do see it, you’ll understand why ancient astronomers named it for the Roman god of the seas. Its brilliant blue color is reminiscent of the depths of the Earth’s oceans.
It’s also known for the controversy surrounding its discovery, but beyond that, most observations have been from ground-based and orbital telescopes.
What Makes Neptune Unique?
There are many facts about Neptune that make it unique. For one thing, it’s home to some of the strongest winds in the solar system. At upper altitudes, these winds can exceed speeds of 1,100 miles per hour (mph). Also, despite its massive size, the planet’s gravity is similar to what you would find on Earth. Its gravity is only 17% stronger than Earth’s.
The History of Neptune
We still have so much to learn about the most distant planet in our solar system. Yet, as of the beginning of 2020, there are no plans to explore the blue gas giant. That might change as we start exploring further into the solar system, but everyone’s current focus is on the Moon and Mars.
We’ve reached the end of the solar system. Where will we go next? There is still much for us to explore — more than we can even imagine. We’re not done yet.
Featured Image Credit: NASA/JPL