Ardenau4, CC0Uranus
The ice giant that rolls around the Sun on its side
Overview
Uranus is the seventh planet from the Sun. It is a gaseous cyan-coloured ice giant. Most of the planet is made of water, ammonia, and methane in a supercritical phase of matter, which astronomers call "ice" or "volatiles". The planet's atmosphere has a complex layered cloud structure, and has the lowest minimum temperature of all of the Solar System's planets. It has a marked axial tilt of 82.23°, with a retrograde rotation period of 17 hours and 14 minutes. This means that in an 84-Earth-year orbital period around the Sun, its poles get around 42 years of continuous sunlight, followed by 42 years of continuous darkness.
Source: Wikipedia
Why it matters
- Axial tilt of about 98° means each pole gets 42 years of sunlight followed by 42 years of darkness.
- The coldest planetary atmosphere measured in the Solar System, down to about −224 °C.
- Visited only once, by Voyager 2 in 1986; a flagship orbiter mission is the top-ranked US planetary priority for the 2030s.
System
- Discovered
- known since antiquity
- Discoverers
- William Herschel
- Star
- Sun · G2 V · 5,772 K · 1 M☉
- System
- 8 known planets
Orbit in the Solar System
| World | Period | Distance | Radius | Mass | Temp. |
|---|---|---|---|---|---|
| Mercury | 88 d | 0.387 AU | 0.38 R⊕ | 0.055 M⊕ | 440 K |
| Venus | 224.7 d | 0.723 AU | 0.95 R⊕ | 0.82 M⊕ | 737 K |
| Earth | 365.2 d | 1 AU | 1 R⊕ | 1 M⊕ | 288 K |
| Mars | 687 d | 1.52 AU | 0.53 R⊕ | 0.11 M⊕ | 208 K |
| Ceres | 4.6 yr | 2.77 AU | 0.07 R⊕ | 0.94 ×10²¹ kg | — |
| Jupiter | 11.9 yr | 5.2 AU | 1 R♃ | 1 M♃ | 163 K |
| Saturn | 29.4 yr | 9.57 AU | 0.84 R♃ | 95.11 M⊕ | 133 K |
| Uranus | 83.7 yr | 19.16 AU | 0.36 R♃ | 14.53 M⊕ | 78 K |
| Neptune | 163.7 yr | 30.18 AU | 3.88 R⊕ | 17.08 M⊕ | 73 K |
| Pluto | 247.9 yr | 39.48 AU | 0.19 R⊕ | 13 ×10²¹ kg | 48 K |
| Haumea | 282 yr | 43.1 AU | 0.12 R⊕ | — | 50 K |
| Makemake | 306.6 yr | 45.6 AU | 0.11 R⊕ | 3.1 ×10²¹ kg | — |
| Eris | 561.3 yr | 67.9 AU | 0.18 R⊕ | 17 ×10²¹ kg | 43 K |
| Sedna | 12,676.2 yr | 544 AU | 0.08 R⊕ | — | 12 K |
By the numbers
- Radius
- 0.36 R♃4 R⊕
- Mass
- 14.53 M⊕86.8 ×10²⁴ kg
- Orbital period
- 83.7 yr
- Distance from Sun
- 19.16 AU2,867 million km
- Eccentricity
- 0.047nearly circular
- Mean temperature
- -195 °C78 K
- Gravity
- 8.7 m/s²0.89 g
- Day length
- 17.2 h0.7 Earth days
- Moons
- 28with a ring system
- Density
- 1.27 g/cm³
- Axial tilt
- 97.8°
Sources
Image: Ardenau4, CC0 · CC0 · image page
Text: Wikipedia (CC BY-SA 4.0). Taglines and highlights are editorial.