Farthest Planet From the Sun
Neptune is recognized as the planet farthest from the Sun, positioned eighth in order of distance. It is approximately 4.5 billion kilometers away from the Sun, which is over 30 times the distance from Earth to the Sun. Consequently, Neptune receives only about 9% of the solar energy that Earth does. This limited exposure results in Neptune being categorized as a dark and extremely cold planet. Due to its vast distance from Earth, Neptune cannot be seen with the naked eye; it appears as a tiny bluish-green disk through small telescopes. It is worth noting that Pluto was initially classified as the ninth planet in the solar system upon its discovery in 1930, regarded as the farthest planet from the Sun. However, this classification was later disputed following the discovery of similar worlds near the Kuiper Belt, which led to Pluto being redefined as a dwarf planet.
Overview of Neptune
Neptune completes its orbit around the Sun every 165 years. The depth of its atmosphere extends significantly, blending gradually with water and melting ices above its massive, solid core, which has a mass equivalent to that of Earth. The presence of methane in Neptune’s atmosphere is the reason behind the planet’s blue color, similar to that of Uranus. However, Neptune exhibits a more vibrant and bright blue hue, leading scientists to suspect there is another unidentified component contributing to this increased intensity of blue color. Below are additional facts related to the planet:
- The Voyager 2 spacecraft was the first to fly by Neptune.
- Neptune rotates fully on its axis approximately every 16.11 hours.
- The average orbital speed of Neptune around the Sun is about 5.43 km/s.
- Neptune has a diameter of approximately 49,528 kilometers, which is about four times larger than Earth’s diameter.
- When comparing the two planets, Neptune’s mass is approximately 17.14 times that of Earth, and its density is about 0.31 times that of Earth. In terms of distance from the Sun, Neptune is about 30.06 times farther from the Sun compared to Earth.
To learn more about Neptune, you can read the article titled “Facts About Neptune.”
Exploration of Neptune
Neptune was the first planet whose existence was predicted by scientists through mathematical calculations after discrepancies were found in the expected position of Uranus. French mathematician Urbain Le Verrier proposed that another planet might be influencing Uranus’s orbit. His predictions were sent to the astronomer Johann Galle at the Berlin Observatory, who discovered Neptune on the very first night of his search in 1846. Seventeen days later, Galle identified Neptune’s largest moon, Triton. While astronomer Galileo Galilei had previously observed Neptune with his small telescope in 1612, he mistook it for a fixed star.
The Pioneer 10 spacecraft successfully passed beyond Neptune’s orbit in 1983, marking it as the first human-made object to traverse all the planetary orbits in the solar system. Pioneer 10 continues on a trajectory towards the red star Aldebaran located in the Taurus constellation, expected to make a close encounter in approximately two million years. In 2016, scientists detected a dark spot on Neptune, recognized as the first atmospheric vortex observed on the planet in the 21st century.
- The Taurus constellation is the second zodiac sign and can be observed from April 21 to May 22, symbolized by the bull.
- Aldebaran is the brightest star in the Taurus constellation, also known as the “Eye of the Bull.” The name “Aldebaran” means “the follower,” as it appears to follow the cluster of stars that form the bull’s head.
For more information about the distance between planets and the Sun, you can read the article “Ranking the Planets by Their Distance from the Sun.”
To further explore the planets of the solar system, consider reading the article “What is the Solar System?”