URANUS
Uranus is the seventh planet from the Sun. Its name is a reference to the Greek god of the sky, Uranus, who, according to Greek mythology, was the grandfather of Zeus (Jupiter) and father of Cronus (Saturn). It has the third-largest planetary radius and fourth-largest planetary mass in the Solar System. Uranus is similar in composition to Neptune, and both have bulk chemical compositions which differ from that of the larger gas giants Jupiter and Saturn. For this reason, scientists often classify Uranus and Neptune as "ice giants" to distinguish them from the other gas giants. Uranus' atmosphere is similar to Jupiter's and Saturn's in its primary composition of hydrogen and helium, but it contains more "ices" such as water, ammonia, and methane, along with traces of other hydrocarbons.[16] It has the coldest planetary atmosphere in the Solar System, with a minimum temperature of 49 K (−224 °C; −371 °F), and has a complex, layered cloud structure with water thought to make up the lowest clouds and methane the uppermost layer of clouds. The interior of Uranus is mainly composed of ices and rock.
Like the other giant planets, Uranus has a ring system, a magnetosphere, and numerous moons. The Uranian system has a unique configuration because its axis of rotation is tilted sideways, nearly into the plane of its solar orbit. Its north and south poles, therefore, lie where most other planets have their equators. In 1986, images from Voyager 2 showed Uranus as an almost featureless planet in visible light, without the cloud bands or storms associated with the other giant planets. Voyager 2 remains the only spacecraft to visit the planet. Observations from Earth have shown seasonal change and increased weather activity as Uranus approached its equinox in 2007. Wind speeds can reach 250 metres per second (900 km/h; 560 mph).
Interesting Facts:
- Uranus is the coldest planet in the Solar System:
Uranus is the seventh planet from the Sun, orbiting at a distance of 2.88 billion km. But it’s still much closer than Neptune, which averages a distance of 4.5 billion km from the Sun. However, this does not prevent Uranus from being colder than Neptune. Whereas the former experiences an average temperature of 72 K (-201 °C/-330 °F), reaching a low of 55 K (-218 °C/-360 °F).
- Uranus orbits the Sun on its side:
All of the planets in the Solar System rotate on their axis, with a tilt that’s similar to the Sun. In many cases, planet’s have an axial tilt, where one of their poles will be inclined slightly towards the Sun. For example, the axis of the Earth’s rotation is tilted 23.5-degrees away from the Sun’s plane. Mars is similar, with a tilt of about 24 degrees, which results in seasonal changes on both planets.
But the axial tilt of Uranus is a staggering 99 degrees! In other words, the planet is rotating on its side. All the planets look a bit like spinning top as they go around the Sun, but Uranus looks more like a ball rolling in a circular pattern. And this leads to another strange fact about Uranus…
- A Season on Uranus lasts one long day – 42 years:
A sidereal day on Uranus (that is, the time it takes for the planet to complete a single oration on its axis) is only about 17 hours long. But the tilt of Uranus is so pronounced that one pole or the other is usually pointed towards the Sun. This means that a day at the north pole of Uranus lasts half of a Uranian year – 84 Earth years.
So, if you could stand on the north pole of Uranus, you would see the Sun rise in the sky and circle around for 42 years. By the end of this long, drawn-out “summer”, the Sun would finally dip down below the horizon. This would be followed by 42 years of darkness, otherwise known as a single “winter” season on Uranus.
- Uranus is the second-least dense planet:
The least dense planet in the Solar System is Saturn. In fact, with a mean density of 0.687 g/cm3, Saturn’s body is actually less dense than water (1 g/cm³). This means that the planet would float in a pool, provided it were roughly 60,000 km wide. With a mean density of 1.27 g/cm3, Uranus has the second-lowest density of any planet in the Solar System.
- Uranus has rings:
When it comes to ring systems, Saturn’s are the most famous. In addition to be colorful and far-reaching, they are also highly visible. One could spot them using nothing more than a backyard telescope. But in truth, all the gas and ice giants have their own ring systems, and Uranus’ is the second most dramatic set of rings in the Solar System.
However, these rings are composed of extremely dark particles which vary in size from micrometers to a fraction of a meter – hence why they are not nearly as discernible as Saturn’s. Thirteen distinct rings are presently known, the brightest being the epsilon ring. And with the exception of two very narrow ones, these rings usually measure a few kilometers in width.
- The atmosphere of Uranus contains “ices”:
Compared to Jupiter and Uranus, Neptune seems quite… normal. When one looks at the swirling clouds and eddies that stream across the surface of Jupiter and Saturn, the violent and turbulent nature of their atmospheres is made clear. Uranus, by contrast, appears as a light and uniform blue. But thanks to improved instruments that can examine planets through other wavelengths (i.e. infrared) and the flyby conducted by the Voyager 2 spacecraft, some significant things become apparent.
For example, Uranus has powerful zonal winds within its atmosphere that can reach up to 250 m/s (900 km/h, 560 mph), and can generate anticyclonic storms like Jupiter’s Great Red Spot (known as the “Dark Spot“). It also has cloud patterns that differ between hemispheres, some of which last for mere hours while others can persist for years or decades.