Uranus, Nine Planets in Universe
Uranus is the seventh planet discovered in the Solar System that also led to the discovery of the last planet, Neptune they are both referred to as ice giants. Officially recognized in 1781 after many observations in the past, it is the third-largest planet of the Solar System.
- Since ancient times it was not recognized due to its dimness and slow orbit. However, in 1781 Sir William Herschel announced its discovery being the first planet discovered with the help of a telescope.
- It was given the name Uranus, after the Greek god of the sky Ouranos.
- It is the only planet whose name is derived directly from a figure of Greek mythology.
- The mean apparent magnitude of Uranus is 5.68 with a standard deviation of 0.17, making it near the limit of naked-eye visibility.
- Uranus is the seventh planet from the Sun, around 1.8 billion miles or 2.9 billion kilometers distance away.
- It has the third-largest planetary radius and fourth-largest mass in the Solar System.
- It has a radius of 25.362 kilometers or 15.759 miles and has about 14.5 times the mass of Earth and four times its diameter – about 51.118 kilometers or 31.763 miles.
- It is on an average distance of 19.2 AU away from the Sun and currently 18.8 AU away from Earth. Its actual distance can be checked online as Uranus is constantly tracked.
- Its volume is about 63 times greater than Earth’s, which means that 63 Earths can fit inside it.
Though it is visible to the naked eye, Uranus escaped clear classification for decades. Generally mistaken for a star, it is speculated that Hipparchos might have recorded it first in 128 BC in his star catalog. Later it was incorporated into Ptolemy’s Almagest.
Through simulations after the Nice model, it has been suggested that both Uranus and Neptune formed closer to the sun and later drifted away. It is hypothesized that the Solar System formed from a giant rotating ball of gas and dust known as the pre-solar nebula. Much of it formed the Sun while more of its dust went on and merged to create the first proto-planets. As they grew, some accreted enough matter for their gravity to hold unto the nebula’s leftover gas. Estimates suggest the creation to have taken place about 4.5 billion years ago, and the drifting about 4 billion.
Distance, Size and Mass
Since its discovery, the planet has shifted it 1° west every 72 years however, its average distance from the sun still remains about 20 AU or 2 billion kilometers – 2 billion miles. The difference between its furthest and closest point from the sun is about 1.8 AU, larger than that of any other planet with the exception of the dwarf planet Pluto.
Though its mass is roughly 14.5 times that of Earth, it is the least massive compared to the other giant planets, having a mass of 8.681 × 10^25 kg. However, its diameter is slightly larger than that of Neptune, and it’s about four times that of Earth: about 51.118 kilometers or 31.763 miles.
The density of Uranus 1.27 g/cm3 makes it the second least dense planet, after Saturn. This value indicates that it is made primarily of various ices such as water, ammonia, and methane. The mass of its interior is however debatable, it is speculated to be around 9.3 and 13.5 Earth masses.
It has the third-largest planetary radius: 25.362 kilometers or 15.759 miles, and its volume is about 63 times greater than Earth’s, which means that 63 Earths can fit inside it.
Orbit and Rotation
It takes Uranus about 7 years to pass through each zodiac constellation, and a total of 84 years to make a complete trip around the sun. It’s interesting orbing caught the attention of astronomers because the planet escaped its predicted location, and thus it led to the discovery of the last planet in 1846 that would later be called Neptune.
The interior rotation of Uranus is completed in about 17 hours, 14 minutes, and as in the case of all the gas giants, its upper atmosphere experiences strong winds in the direction of rotation thus making a full rotation faster, in about 14 hours.