Each time you look up to the sky and see a star you are looking at a sun in another galaxy. If you were on another planet looking back at our solar system, you would see our sun as a star. It’s believed that every sun has planets orbiting it. Our Milky Way galaxy has more planets than it has stars. In our solar system we have eight planets: Mercury, Venus, Earth, and Mars are the inner rocky planets.
Jupiter and Saturn are the outer gas giants. Uranus and Neptune are the outer ice giants. In recent years, astronomers have designed a new class called the “dwarf planets.” These are smaller worlds, not quite big enough to be considered a standard planet, and include Pluto. Uranus is the seventh planet from the sun.
- Distance from Sun: 1.784 billion mi
- Rings: 13
- Radius: 15,759 mi
- Polar Diameter: 49,946 km
- Orbital period: 84 years
- Mass: 8.68 × 10^25 kg (15 Earths)
- Effective Temperature: -216 °C
- Moons: (27, including Miranda, Titania, Ariel, Umbriel & Oberon)
- Date of Discovery: March 13, 1781 by William Herschel
How did Uranus get its name:
The planet Uranus is one of the gas giants and in our solar system, it’s huge diameter makes it the third largest and the fourth in mass. Uranus got its name from the father of the Roman god, Saturn. When the astronomer, William Herschel, was trying to chart the stars, he thought he found a disk-like object that was a comet. In reality, he discovered Uranus and his discovery is therefore considered to be the first in what is called “modern history.”
Our solar system didn’t always look the way it does now. Early on, planets were bouncing around, moving in location and it’s thought that there once was actually a lot more that got tossed out our crashed into each other.
Around 4 billion years ago Uranus settled into its current position and it wasn’t until 4.5 billion years ago that the planets settled into where they are now. Gravity, pulling at dust and swirling gas created the ice giant, Uranus. It’s thought that both Neptune and Uranus were originally closer to the sun.
Structure and Surface:
Uranus and Neptune are the two ice giants located in the outer solar system. Around 80% of the mass of Uranus is made up of dense, hot fluid of “icy” materials including water, methane, and ammonia. These are above a rocky core and near the core are temperatures of 9,000 degrees F/4,892 degrees C.
The inside of Uranus is believed to contain two layers which are the core and a mantle. Scientists think that the core is mostly made up of rock and ice and the mantle is around 13.3 times the mass of the Earth and made up of water, ammonia, and other elements.
The difference between Uranus and other gas giants also relates to the mantle as it may be “icy” but it’s also hot and thick. Unlike other gas giants, Uranus doesn’t emit more energy than it gets from the Sun and scientists are interested in finding out why Uranus generates so little heat.
Although slightly larger in diameter than its neighbor, Neptune, Uranus has a smaller mass. It’s the second least dense planet in the solar system, with Saturn being the least dense of all of the planets.
Uranus has a rather strange rotation when compared to other planets in our solar system. All other planets, with the exception of Uranus, have a rotation axis that is almost perpendicular to the orbital plane. Uranus has a tilt that is around 98 degrees and this makes it rotate on its side. The situation of the tilt creates a condition so that its northern pole and southern pole only face the sun half of the year each. Day and night measurements are 42 Earth years at a time.
Uranus is an ice giant made up of mostly swirling fluids so it doesn’t really have a true surface. If we tried to send a spacecraft to Uranus there wouldn’t be anywhere to land, and besides, the extreme temperatures and pressures would destroy the spacecraft.
Atmosphere. Magnetosphere, and Moon Status:
Uranus has a blue-green color from all of the methane gas in its atmosphere. When sunlight passes through the atmosphere it reflects light back through the top of the clouds. Methane gas absorbs the red factors in light, leaving the blue-green shade
During the 1986 Voyage 2 spacecraft trip, scientists saw a few clouds on Uranus, along with a Great Dark Spot, and a small dark spot. Recent discoveries have shown that Uranus has dynamic cloud activity near the equinox that include fast-changing bright features.
The atmosphere of Uranus can get as low as 49K(-224.2 degrees C), and this makes the planet colder than the other ice giant, Neptune. The wind speeds on Uranus are another extreme, reaching up to 560 mph/900 kph. At the equator the winds are retrograde and blow in the opposite direction of the rotation of the planet. However, the closer you get to the poles, the winds shift to the direction of prograde, rotating to match the planet’s rotation.
Magnetic fields are usually aligned with the rotation of the planet, but not so on Uranus. It has an irregular magnetosphere which is tipped over on an axis of almost 60 degrees from the axis of rotation of the planet. Due to the lopsided magnetic field, the auroras are also not lined up with the poles, like they are on Earth, Jupiter, and Saturn. The tail of Uranus’ magnetosphere extends into space for millions of miles and its magnetic field lines are twisted due to Uranus’ sideways rotation so that it’s shaped like a corkscrew.
There are 27 known moons around Uranus and they hold the distinction of being named for characters from the works of Alexander Pope and William Shakespeare. All of the inner moons of Uranus seem to be around 50% water and 50% rock, however, scientists are unsure of the composition of the outer moons. It’s thought that the outer moons may be asteroids captured by the gravitational pull.
In 1977, the Voyager 2 spacecraft discovered that Uranus does have rings. They couldn’t be detected from earth because they are so far away and their reflection of light was also low. In 1986 the Voyager 2 spacecraft did a flyby to get more details on the rings and then in 2005 the Hubble Telescope located two more rings.
The rings around Uranus are different than those that we find around Saturn, which are mostly dust and ice and relatively small. Uranus has two sets of rings, with the inner ring being made of a set of dark grey, thinner 9 rings. The other set has some that are a reddish color and another that is blue.
Could Life Exist on Uranus?
Temperatures and pressures are too extreme on Uranus for us to consider that life could exist there. There wouldn’t be any way for an organism to adapt or thrive.
In 2018 a global research team discovered that the clouds of Uranus are made up of hydrogen sulfide. This is the stinky smell of rotten eggs that no one likes.
Uranus was first discovered in 1781 by astronomer William Herschel who thought at first that it was a star or comet. It took 2 years before astronomers accepted Uranus as an actual planet.
Herschel originally tried to name his discovery “Georgium Sidus” after King George III, but no one really liked the name.
In 1789 scientists named the radioactive element, uranium, eight years after the planet Uranus was discovered.
The size of Uranus is around four times wider than our Earth. To compare sizes, if earth was the size of an apple, Uranus would be the size of a basketball.
One Uranian day on Uranus is about 17 Earth hours. This is the amount of time it takes for Uranus to complete one rotation. However, it takes 84 Earth years for Uranus to complete its orbit around the sun, also known as a “Uranian year.”
The sideways rotation that Uranus has creates bizarre seasons. The north pole of Uranus has 21 years of nighttime during the winter, 21 years of daytime during the summer, and during the spring and fall it has 42 years of day and nighttime.
Space Missions to Uranus:
There has been only one spacecraft that visited near Uranus. NASA’s Voyager 2 took 9 years and traveled 1.8 billion mi/3 billion km, gathering important information about our solar system. It flew by Uranus, spending only six hours and collected much of the data that we know about the planet.
Almost everything else that we have learned about Uranus has been thanks to the Hubble Space Telescope observations.
- 1781: William Herschel, a British astronomer was searching for stars and discovers Uranus. It’s considered to be the first planet discovered in modern times.
- 1787-1851: There is a discovery of 4 moons around Uranus and they are given the names: Titania, Oberon, Ariel and Umbriel.
- 1948: The moon Miranda is discovered around Uranus.
- 1977: Scientists at the Kuiper Airborne Observatory and the Perth Observatory in Australia were observing the path of a distant star as Uranus passed in front of it and discovered that Uranus had rings.
- 1986: NASA’s Voyager 2 made the only visit so far to Uranus. As the craft came within 50,600 mi/81,500 km of the tops of the clouds it discovered 10 new moons, 2 new rings, and that Uranus had a stronger magnetic field than Saturn.
- 2005: Using images taken by the Hubble Space Telescope of Uranus, NASA was able to release the new discover of a new pair rings, and 2 new moons (named Cupid and Mab).
- 2006: Results of study from both the Hubble Space Telescope and the Keck Observatory, scientists were able to show that the outer ring of Uranus is blue n color and the inner ring has a reddish color.
- 2011: The New Horizons spacecraft passes Uranus as it heads to Pluto. New Horizons is the first spacecraft to go beyond the orbit of Uranus since Voyager 2. Unfortunately, Uranus wasn’t close to the crossing point.
Facts about Uranus for Kids:
- Uranus has the coldest temperatures of all of the planets, hitting as low as -224 degrees C.
- Uranus has a tilted axis and it’s thought that a collision with another large celestial object was the cause of it.
- The color of Uranus is blue due to the fact that it has an atmosphere made up of water, ammonia, and methane.
- Uranus may be one of the “gas giants” but it is also the lightest in mass.
- The year that Uranus was discovered they also discovered a new element and named it Uranium after the planet.
- The moons of Uranus are named after characters created by William Shakespeare and Alexander Pope.
- All of the moons around Uranus have dark surfaces and are frozen.
- The moon Miranda, around Uranus has terraces, ice canyons, and many odd looking areas on its surface.
- Part of the atmosphere of Uranus contains ices.
- Uranus has a total of 27 moons.
- Uranus is so bright that at times it can be seen by the human eye, without the help of a telescope.
There is no getting around the “butt” of so many jokes about this planet, however, it’s also been the focus of quite a few science fiction stores, television shows, and games, including “Doctor Who” and the video game “Mass Effect.”