50 Fun Facts About Uranus

Where does Uranus rank in distance from the Sun?

It sits between Saturn and Neptune, roughly twice as far out as Saturn.

Who discovered Uranus in 1781?

He spotted it from his garden in Bath with a homemade 6.2-inch reflector, and first thought it was a comet.

What did Herschel first report his new object to be?

Anders Lexell computed its nearly circular orbit and showed it had to be a planet.

What name did Herschel want to give the planet, in honour of his royal patron?

King George III liked it; astronomers outside Britain did not, and 'the Georgian Planet' never caught on.

Who proposed the name Uranus, in 1782?

Lalande wanted to call it Herschel; Bode argued the new planet should be the father of Saturn, as Saturn was father of Jupiter.

Uranus is the only planet whose English name comes from which mythology?

The Roman equivalent of Ouranos would have been Caelus, but Bode apparently did not realise that.

In Greek myth, Uranus (Ouranos) was the god of what?

He was the father of Cronus (Saturn) and grandfather of Zeus (Jupiter).

Which chemical element was named in 1789 in support of the name Uranus?

Martin Klaproth, Bode's colleague at the Royal Academy, named his new element after the new planet.

How long did it take for astronomers to agree on the name Uranus?

Britain clung to Georgium Sidus well into the 19th century.

Uranus's rotation axis is tilted so far that the planet essentially does what?

Its axis lies almost in the plane of its orbit, at about 98 degrees, so each pole gets 42 years of daylight then 42 of night.

How long is a year on Uranus?

Since its discovery it has passed its discovery position only twice, in 1865 and 1949, and will again in 2033.

Each pole of Uranus gets roughly how many years of continuous sunlight, then the same in darkness?

Voyager 2 arrived during southern summer and could not see the northern hemisphere at all.

Roughly how long is Uranus's rotation period?

It rotates retrograde by the IAU definition, and the interior period was pinned down by tracking its aurorae.

Uranus and its outer neighbour are classified as what type of planet?

Water, ammonia and methane 'ices' dominate their bulk, unlike hydrogen-and-helium Jupiter and Saturn.

Which planet has the lowest recorded minimum temperature in the Solar System?

Its tropopause has dropped to 49 K, or −224 °C, colder even than more distant Neptune.

What is odd about Uranus's energy budget compared with the other giant planets?

Neptune, its near twin, radiates 2.6 times what it absorbs; Uranus barely breaks even, and nobody knows why.

What theory is offered for both Uranus's tilt and its low internal heat?

The impactor may have knocked the planet over and let it vent most of its primordial heat.

Uranus's mass is about how many times Earth's, making it the least massive giant planet?

Its diameter is roughly four times Earth's, slightly bigger than Neptune's.

Deep inside Uranus, extreme pressure may turn methane's carbon into what?

Lab experiments even suggest a sea of liquid metallic carbon with floating 'diamond-bergs' at the base of the mantle.

How many rings does Uranus have, according to the article?

They are extremely dark, reflecting only about 2% of the light that hits them; the brightest is the epsilon ring.

How were Uranus's rings definitively discovered in 1977?

James Elliot's team aboard the Kuiper Airborne Observatory had only meant to study the atmosphere during the occultation.

Uranus's rings reflect roughly what fraction of the light that hits them?

They are among the darkest objects in the Solar System, possibly blackened by radiation.

The moons of Uranus are named after characters from which two writers?

Titania, Oberon, Miranda and Ariel are Shakespeare's; Umbriel and Belinda come from Pope's The Rape of the Lock.

Which are the five major moons of Uranus?

Together they weigh less than half of Neptune's Triton alone.

What is the largest moon of Uranus?

With a radius under 790 km it is only the eighth-largest moon in the Solar System, less than half the size of our Moon.

Which small moon of Uranus has fault canyons 20 km deep and a chaotic patchwork surface?

Its cliff Verona Rupes may be the tallest in the Solar System; the chaos likely came from tidal heating during a past resonance with Umbriel.

How many known moons does Uranus have, according to the article?

Nineteen are regular moons and ten are distant irregular ones.

Which is the only spacecraft to have visited Uranus?

It flew past on 24 January 1986, found 10 new moons and two new rings, and carried on to Neptune.

In what year did the only spacecraft flyby of Uranus take place?

It came within 81,500 km of the cloud tops.

What did the 1986 flyby find peculiar about Uranus's magnetic field?

The dipole is shifted a third of the way to the south pole, giving a lopsided, corkscrewing magnetotail.

What is Uranus's peak wind speed, according to the article?

Winds of 820 km/h were clocked during a burst of storms in 2004.

What did John Flamsteed catalogue Uranus as, seeing it at least six times in 1690 without knowing it was a planet?

Hipparchus may even have logged it as a star in Virgo in 128 BC.

Irregularities in Uranus's orbit led to the prediction and discovery of which planet in 1846?

Adams and Le Verrier both did the maths; Galle found it near Le Verrier's predicted spot.

Which pronunciation of Uranus do astronomers prefer?

Both are considered acceptable, but the second sounds like something else in English.

Uranus's name translates as what in Chinese, Japanese, Korean and Vietnamese?

In Hawaiian it is Hele'ekela, a rendering of 'Herschel'.

The first proposed astronomical symbol for Uranus was borrowed from the symbol for which metal?

Köhler combined the signs for gold and iron because platinum, then newly described, is found mixed with iron.

Uranus can just be seen with the naked eye. What is its mean apparent magnitude?

That is right at the limit of naked-eye visibility in dark skies; binoculars make it easy.

Which sign of the zodiac has Uranus as its ruling planet in modern astrology?

Before 1781 the job belonged to Saturn.

Which composer's orchestral suite includes a movement for Uranus?

In The Planets (1914–16) Uranus is 'the Magician'.

Which poet's line 'When a new planet swims into his ken' refers to Herschel's discovery?

It comes from 'On First Looking into Chapman's Homer'.

What gives Uranus its cyan colour?

The planet's bulk is water, ammonia and methane 'ices', and methane absorbs red light.

Which mission did the 2023–2032 Planetary Science Decadal Survey rank as its top priority flagship?

Sending Cassini on from Saturn was considered in 2009 but would have taken twenty years.

What was Uranus's Thai alternative name, Dao Maruettayu, derived from?

Its official Thai name is simply Dao Yurenat, as in English.

Uranus is the second least dense planet, after which?

Its density of 1.27 g/cm3 points to a body made largely of ices rather than gas.

Which two large moons did Herschel himself discover in 1787, hinting at the planet's strange tilt?

Laplace worked out from their orbits in 1805 how far over the planet was tipped.

Uranus's rings are thought to be young and to be the remains of what?

Only a few surviving particles settled into stable zones where the rings now sit.

From the garden of his house in which English city did Herschel first observe Uranus on 13 March 1781?

The house at 19 New King Street is now the Herschel Museum of Astronomy; he used a homemade 6.2-inch reflector.

Which Finnish-Swedish astronomer working in Russia first computed the new object's orbit, showing it was a planet?

Its nearly circular path convinced him and Berlin's Johann Bode that Herschel had found a planet, not a comet.

What annual stipend did George III grant Herschel for the discovery, on condition he move to Windsor?

The condition was that the Royal Family could look through his telescopes; the sum equals roughly £26,000 today.

Which astronomer proposed naming the new planet 'Herschel' in honour of its discoverer?

Sweden's Erik Prosperin suggested Astraea, Cybele and Neptune, the last of which was eventually used for the next planet found.