Uranus is the seventh planet from the Sun. The primary composition of Uranus atmosphere is of hydrogen and helium, containg as well water, ammonia, and methane, along with traces of other hydrocarbons. It is the coldest planetary atmosphere in the Solar System, with a minimum temperature of −224.2 degree C (-371.6 degree F). The uppermost layer of clouds is composed of methane, and the lowest clouds consist of water. The interior of Uranus is mainly composed of ices and rock. The Uranus consists of three layers: a rocky (silicate, iron, nickel) core in the centre, a mantle of a hot and dense fluid (water, ammonia and other volatiles) in the middle and an outer gaseous hydrogen-helium atmosphere. The Uranus rings, thirteen distinct presently known, consist of extremely dark particles, which size vary from micrometres to a fraction of a metre.
Its average distance from the Sun is roughly 3 billion km and orbits the Sun once every 84 Earth years. The Uranian axis of rotation is approximately parallel with the plane of the Solar System, with an axial tilt of 97.77 degrees. Each pole gets continuous sunlight or darkness around 42 Earth years. Nevertheless, Uranus is hotter at its equator than at its poles. The polar and equatorial radii are approximately 25 km (15.5 miles), so Uranus is almost a perfect sphere.
Uranus has 27 known natural satellites and the five main are Miranda, Ariel, Umbriel, Titania, and Oberon. Below thay are listed in order of increasing distance from Uranus.
Miranda is the smallest and innermost of Uranus five spherical satellites and is just 470 km (292 miles) in diameter. The surface of Miranda may be mostly water ice, also probably containing silicate rock and organic compounds in its interior.
Ariel, fourth largest satelite and is the second closest to the planet, orbits and rotates in the equatorial plane, which is almost vertical to the orbit of Uranus. Its mean radius is about 579 km (360 miles). It consists of roughly equal parts water ice, rock and carbonaceous materials.
Umbriel is the third farthest moon from Uranus among its five major moons. Its mean radius is approximately 585 km (364 miles) and orbit the equatorial plane of the planet. It mainly consists of water ice, with a dense non-ice component constituting around 40% of its mass.
Titania moon is the eighth largest in the Solar System and the largest of Uranus with a diameter of 1,578 kilometres (981 miles). Titania has an icy mantle and a rocky core with a layer of liquid water at the mantle-core boundary.
Oberon is the outermost major moon of the planet Uranus. It is the second-largest of the Uranian moons with mean radius of 762 km (473 miles). It consists of roughly equal proportions of water ice and a dense non-ice component.