Category: urano

Ten interesting facts about Uranus

Like the classical planets, Uranus is visible to the naked eye, but it was never recognised as a planet by ancient observers because of its dimness and slow orbit. Sir William Herschel announced its discovery on 13 March 1781, expanding the known boundaries of the Solar System for the first time in history and making Uranus the first planet discovered with a telescope.

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1° Uranus is the seventh planet from the Sun. 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 different bulk chemical composition from that of the larger gas giants Jupiter and Saturn.

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2° Like all of the giant planets, Uranus has its share of moons. At present, astronomers have confirmed the existence of 27 natural satellites. But for the most part, these moons are small and irregular.

3° Uranus’ moons are named after characters created by William Shakespeare and Alexander Pope. These include Oberon, Titania and Miranda.  All are frozen worlds with dark surfaces. Some are ice and rock mixtures.  The most interesting Uranian moon is Miranda; it has ice canyons, terraces, and other strange-looking surface areas.

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4° Only one spacecraft in the history of spaceflight has ever made a close approach to Uranus. NASA’s Voyager 2 conducted its closest approach to  Uranus on January 24th, 1986, passing within 81,000 km of the cloud tops of Uranus. It took thousands of photographs of the gas/ice giant and its moons before speeding off towards its next target: Neptune.

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5° Uranus has rings: 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.

6° Uranus makes one trip around the Sun every 84 Earth years. During some parts of its orbit one or the other of its poles point directly at the Sun and get about 42 years of direct sunlight. The rest of the time they are in darkness.

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7° 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.

But the axial tilt of Uranus is a staggering 98 degrees! In other words, the planet is rotating on its side.

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8° Uranus is approximately 4 times the sizes of Earth and 63 times its volume.

9° Uranus is blue-green in color, the result of methane in its mostly hydrogen-helium atmosphere. The planet is often dubbed an ice giant, since 80 percent or more of its mass is made up of a fluid mix of water, methane, and ammonia ices.

10° Uranus hits the coldest temperatures of any planet. With minimum atmospheric temperature of -224°C Uranus is nearly coldest planet in the solar system. While Neptune doesn’t get as cold as Uranus it is on average colder. The upper atmosphere of Uranus is covered by a methane haze which hides the storms that take place in the cloud decks.

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Images credit: NASA

What do you find most interesting about Uranus…

What do you find most interesting about Uranus? And some of its moons?

Uranus is a very incredible planet. Perhaps what draws the most attention is the fact that it spins “ lying down ”.

  • Uranus was officially discovered by Sir William Herschel in 1781. 
  • Uranus turns on its axis once every 17 hours, 14 minutes.

  • Uranus makes one trip around the Sun every 84 Earth years.

  • Only one spacecraft has flown by Uranus.

  • Uranus has an atmosphere which is mostly made up of hydrogen (H2) and helium (He), with a small amount of methane (CH4). 

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Uranus has 13 known rings. The inner rings are narrow and dark and the outer rings are brightly colored.

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Uranus has 27 moons. Uranus’ moons are named after characters from the works of William Shakespeare and Alexander Pope.

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The five largest satellites of Uranus are: Oberon, Titania, Umbriel, Ariel and Miranda.

An interesting thing is that some of the moons of Uranus are on a collision route, and could collide in a few million years. There may be a collision between Cressida and Desdemona, and also the collision between Cupid and Belinda, but these moons have irregular shapes and are very small compared to our moon.

Images: NASA/JPL/Keck Observatory

William Herschel Frederick William Hersch…

William Herschel

Frederick William Herschel, was a British astronomer and composer of German origin, and brother of fellow astronomer Caroline Herschel, with whom he worked. Born in the Electorate of Hanover, Herschel followed his father into the Military Band of Hanover, before migrating to Great Britain in 1757 at the age of nineteen.

Herschel constructed his first large telescope in 1774, after which he spent nine years carrying out sky surveys to investigate double stars. The resolving power of the Herschel telescopes revealed that the nebulae in the Messier catalogue were clusters of stars. Herschel published catalogues of nebulae in 1802 (2,500 objects) and in 1820 (5,000 objects). In the course of an observation on 13 March 1781, he realized that one celestial body he had observed was not a star, but a planet, Uranus. 

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This was the first planet to be discovered since antiquity and Herschel became famous overnight. As a result of this discovery, George III appointed him Court Astronomer. He was elected as a Fellow of the Royal Society and grants were provided for the construction of new telescopes.

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Herschel pioneered the use of astronomical spectrophotometry as a diagnostic tool, using prisms and temperature measuring equipment to measure the wavelength distribution of stellar spectra. Other work included an improved determination of the rotation period of Mars, the discovery that the Martian polar caps vary seasonally, the discovery of Titania and Oberon (moons of Uranus) and Enceladus and Mimas (moons of Saturn). In addition, Herschel discovered infrared radiation. Herschel was made a Knight of the Royal Guelphic Order in 1816. He was the first President of the Royal Astronomical Society when it was founded in 1820. He died in August 1822, and his work was continued by his only son, John Herschel. 

Animation taken from the video ‘‘The Discovery of Uranus’

To know more about the history of William Herschel, click here.

The Faint Rings of Uranus

The Faint Rings of Uranus

Taken in January, 1986 by Voyager 2. Uranus assembled using orange, simulated green, and violet light. The rings were taken in clear (white) light, but colored red here.

Image Credit: NASA/JPL/Kevin M. Gill

Two moons of Uranus: Titania and Oberon. Both …

Two moons of Uranus: Titania and Oberon. Both moons were discovered by William Herschel in 1787.

Credit: NASA/JPL

Comparison of the planets of the solar system,…

Comparison of the planets of the solar system, Pluto and Sun in relation to the earth.

Images: commons.wikimedia (Sun: Alan Friedman)

Uranus and Its 5 Largest Moons 1° TitaniaTitania is the…

Uranus and Its 5 Largest Moons

1° Titania

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Titania is the biggest moon of Uranus. It was discovered in 1787 by William Herschel. It carries the name of Titania, the queen of Fairies in “ The Dream of a summer night ” of William Shakespeare. Titania consists about 50 % of ice, 30 % of silicates and 20 % of organic compounds close to some methane. 

One of its main physical characteristics is the presence of an immense canyon, widely bigger than a Big canyon on Earth, the same order of height as Valles Marineris on Mars or Ithaca Chasma on Tethys, the moon of Saturn.

2° Oberon 

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Oberon is the most remote from the big satellites of Uranus and the second in size. It was discovered in 1787 by Herschel.
Obéron consists about 50 % of ice of water, 30 % of silicates, and 20 % of compounds of methane, carbon and nitrogen.
Its surface is covered with craters, and indicates a very weak internal activity if we except a not identified dark material which fills the floors of numerous craters.

3° Umbriel

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Umbriel is the third biggest satellite of Uranus. It was discovered in 1851 by William Lassell.
Umbriel is the most somber satellite of Uranus and also the least active geologically, consisted mainly of ice of water, the rest being constituted by silicates and to 20 % of ice of methane ( CH4). One of the characteristics of the surface of Umbriel is the crater Wunda, a wide brilliant ring 140 km in diameter of materials close to the equator.
The nature of this ring is not known, but he could involve a deposit of ice, maybe following an impact.

4° Ariel

Ariel is the fourth biggest satellite of Uranus. It was discovered in 1851 by William Lassell.
Ariel would consist in 50 % of ice of water, in 30 % of silicates and in 20 % of ice of methane ( CH4) and it seems that certain regions of its surface are recently frozen. Widely deprived by craters of impact, Ariel seems to have undergone a period of intense geologic activity which produced a complex network of canyons and drainage of liquid water on its surface.

5° Miranda

The weak density of Miranda indicates that it contains silicates and organic compounds derived of some methane, the quite surrounded of ice of water.
This surface is crossed everywhere by faults and canyons gigantic, sometimes 20 km deep, with mountains reaching 24 km in height and valleys 16 km deep. This chaotic geography indicates that Miranda knew an intense geologic activity.
This activity could result from strengths of tide of Uranus either Miranda was maybe broken by a massive object then would have been reconstituted.

Source: astronoo.com | Images: NASA/JPL (x, x, x)

The faint rings of Uranus, shot in 1986, are made of countless…

The faint rings of Uranus, shot in 1986, are made of countless fragments of water ice containing radiation-altered organic material.

Credit: NASA/JPL/Michael Benson, Kinetikon Pictures

Venus, Earth, Jupiter, Saturn, Uranus and Neptune as seen by…

Venus, Earth, Jupiter, Saturn, Uranus and Neptune as seen by Voyager 1 in 1990. Mercury is too close to the sun to be seen. Mars was not detectable by the Voyager cameras due to scattered sunlight in the optics, and Pluto was not included in the mosaic because of its small size and distance from the sun.

Credit: NASA

NASA Completes Study of Future ‘Ice Giant’ Mission…

NASA Completes Study of Future ‘Ice Giant’ Mission Concepts

A NASA-led and NASA-sponsored study of potential future missions to the mysterious “ice giant” planets Uranus and Neptune has been released—the first in a series of mission studies NASA will conduct in support of the next Planetary Science Decadal Survey. The results of this and future studies will be used as the Decadal Survey deliberates on NASA’s planetary science priorities from 2022-2032. The study identifies the scientific questions an ice giant mission should address, and discusses various instruments, spacecraft, flight-paths and technologies that could be used.

“This study argues the importance of exploring at least one of these planets and its entire environment, which includes surprisingly dynamic icy moons, rings, and bizarre magnetic fields,” said Mark Hofstadter of NASA’s Jet Propulsion Laboratory in Pasadena, California, one of the two co-chairs of the science team that produced the report. The European Space Agency (ESA) also participated in the study.

Read more at: NASA