Uranus is the seventh planet from the Sun and is a gaseous cyan ice giant. Most of the planet is made of water, ammonia, and methane in a supercritical phase of matter, which in astronomy is called 'ice' or volatiles. The planet's atmosphere has a complex layered cloud structure and has the lowest minimum temperature of 49 K (−224 °C; −371 °F) out of all Solar System's planets. Uranus has the third-largest diameter and fourth-largest mass among the Solar System's planets. Based on current models, inside its volatile mantle layer is a rocky core, and surrounding it is a thick hydrogen and helium atmosphere. Unique Tilt: Uranus is often referred to as the "sideways planet" because it has a tilt of approximately 98 degrees. This extreme axial tilt means that Uranus essentially rotates on its side as it orbits the Sun. This unique feature is thought to be the result of a massive collision with another celestial object in its distant past. Discovery: Uranus was the first planet to be discovered with a telescope. It was observed by German-born British astronomer Sir William Herschel on March 13, 1781. Herschel initially thought he had discovered a comet but later realized it was a new planet. Composition: Uranus is classified as an ice giant. It is composed mainly of hydrogen and helium, like Jupiter and Saturn, but it also contains a significant amount of water, ammonia, and methane ices. These gases give Uranus its distinctive blue-green color. Magnetosphere: Uranus has a unique and highly irregular magnetosphere, unlike the relatively simple and symmetrical ones found on other planets. Its magnetic field is tilted at a sharp angle relative to its rotational axis, and it is lopsided, likely due to its unusual axial tilt. Ring System: Uranus has a system of rings, though they are not as prominent or well-known as Saturn's. The rings of Uranus were discovered in 1977 when astronomers observed the planet passing in front of a distant star, causing the star's light to temporarily dim. These rings are made up of small particles, mostly composed of water ice. Moons: Uranus has a diverse array of moons, with the planet currently known to have 27 natural satellites. Some of the largest and most well-known moons of Uranus include Miranda, Ariel, Umbriel, Titania, and Oberon. Each of these moons has unique characteristics and geological features. Extreme Cold: Uranus is an extremely cold planet, with temperatures dropping as low as -224 degrees Celsius (-371 degrees Fahrenheit) in its upper atmosphere. Its frigid conditions are primarily due to its considerable distance from the Sun, averaging about 2.8 billion kilometers (1.7 billion miles). Limited Exploration: Unlike some of the other planets in our solar system, Uranus has been relatively unexplored by spacecraft. The only spacecraft to have visited Uranus is Voyager 2, which conducted a flyby in 1986. There are currently no concrete plans for future missions to this distant ice giant. Seasonal Changes: Because of its extreme axial tilt, Uranus experiences extreme seasonal changes. Each pole alternately faces the Sun during its 17.24-hour day, leading to long periods of daylight and darkness. A single season on Uranus can last for over 20 Earth years. Mysterious Interior: Despite what we've learned from remote observations, many mysteries about Uranus's interior remain. Scientists believe it has a small rocky core surrounded by a layer of icy materials, but the exact composition and structure are still subjects of research.