How Far is Uranus from Earth?

In the grand scheme of the universe our little solar system is not considered huge. To ourselves however the magnitude of distances between our planets is impressive. In this article we are going to look at one of the planets of our solar system to find out more about it as well as try to answer the question: how far is Uranus from Earth?

What Is Uranus?

Uranus is a gaseous cyan ice giant planet which is the seventh from the Sun in our solar system. It is the third largest planet in the solar system and has a unique 90-degree rotation angle which makes it appear to be spinning sideways. This gives the effect of it rolling like a ball as it orbits the Sun.

What Is an Ice Giant Planet?

Ice giants are massive planets composed mainly of elements heavier than hydrogen and helium. These might include oxygen, carbon, nitrogen and sulfur. Our solar system is home to two ice giants, Uranus and Neptune.

Ice giants form when gravity pulls together swirling gas and dust. They may form closer to a star but migrate further away over time becoming colder as they go. They usually have a smaller rocky core with most of their mass being made up of materials such as water, methane and ammonia.

Uranus’s Structure

With a mass roughly 14.5 times that of Earth’s, Uranus’ exact mass of ice in its interior is not known. Unlike standard gas giants Uranus’s composition consists of only a small amount of hydrogen and helium. Its mantle is mainly water, ammonia and methane in ice form while the atmosphere consists of the gases hydrogen, helium and methane. The Core of the plant is thought to be a dense rock which may be a nickel-iron silicate.

The extreme pressures and heat deep in the planet are believed to break up methane molecules with carbon atoms leading to condensation into crystals that rain down through the mantle as hailstones. Experiments at the Lawrence Livermore National Laboratory suggest that the mantle may comprise an ocean of metallic liquid carbon.

Does Uranus Have Moons?

The planet Uranus has at present 27 known moons most of which are named for characters from the works of William Shakespeare and Alexander Pope. This goes against the tradition of other planets’ moons which are usually named based on Greek and Roman mythological characters.

It was Sir William Herschel who discovered the first two moons of Uranus, Titania and Oberon, which he spotted on January 11, 1787, roughly six years after he had discovered the planet itself. It would be half a century before telescope technology improved enough to start seeing some of the planet’s other moons.

The Rings of Uranus

Saturn is probably the most famous planet with rings but Uranus also has some of its own. It in fact has two sets. The inner system consists of nine rings that are mostly narrow and dark grey in color. The outer two rings are different with the innermost being a reddish color and the outermost appearing blue.

The rings in order of distance from the planet are named Zeta, 6, 5, 4, Alpha, Beta, Eta, Gamma, Delta, Lambda, Epsilon, Nu, and Mu. Several of the larger rings are also surrounded by belts of fine dust. It was again William Hershel who in his continued observations of Uranus determined there may be rings around Uranus. In his journal he noted on February 22, 1789 “A ring was suspected.” He accompanied this with a sketch and noted that it appeared reddish in color.

History of the Observation of Uranus

Despite being visible from Earth with the naked eye Uranus was visible to the astronomers of the ancient world. Unlike some closer planets to Earth however these astronomers did not realize it was a planet because of its dimness and slow orbit. The assumption was that it was a star.

It was Sir William Herschel who first used a telescope to get a better look at Uranus in 1781 although initially he thought it may still be a star or perhaps a comet. Two years later it was the further observations of astronomer Johann Elert Bode that confirmed Uranus as a planet.

Herschel wrote of his observations after making them in his home garden. He wrote in his notes “In the quartile near Tauri … either [a] Nebulous star or perhaps a comet.” Just four days later he updated his observations by noting “I looked for the comet or nebulous star and found that it is a comet, for it has changed its place.”

His findings were submitted to the Royal Society with the assertion that he had found a new comet although there was implicit indication that it may be a planet. Hershel was convinced his find was a comet but other astronomers were already working to the assumption it was more likely a planet.

Space Exploration of Uranus

In 1977 the United States launched Voyager 2 with the intention of reaching Neptune. On the 24th of January 1986 it passed by Uranus within 81,500 kilometers of the cloud tops. In its past it made studies of the structure and chemical composition of the planet’s atmosphere. Special interest was focused on its weather conditions due to the planet’s unique rotation.

Voyager 2 also made in depth studies of its five largest moons and discovered a further 10 new ones. It also studied the planet’s nine known rings and discovered two more that were not previously observed. This so far has been the only flyby of Uranus by terrestrial spacecraft. Several other missions have been suggested but have not made it beyond early planning stages.

How Far Is Uranus from Earth?

The 1977 launch of Voyager 2 took around 9 years to reach its close pass with Uranus which should give you an indication of how far away the planet is from Earth. Uranus is roughly 1.8169 billion miles away from Earth.

This is obviously a vast difference and in fact it is so far that it takes almost 3 hours for light reflected off of the planet’s surface to reach us on earth. If we had a ship capable of traveling at the speed of light it would take about 2 hrs. and 45 minutes to arrive at Uranus. However with modern technology it takes almost a decade.

Final Thoughts

The ice giant planet Uranus is separated from Earth by Mars, Jupiter and Saturn as well as a vast asteroid belt. It would take the best part of a decade to send a probe to the planet traversing a distance over 1.8 billion miles.