Uranus and Neptune

Question 1

What are the basics of Uranus?

Answer 1

1. At an average distance of just over 19 AU,
   Uranus takes over 84 years to orbit the Sun
2. Uranus rotates more slowly than Jupiter in just over 17 hours
3. Uranus is smaller than Jupiter (4x the Earth) but much less massive (14.5x Earth)
4. Even though Uranus is small its high density
   suggests that its core takes up a larger of the
   planet than the cores of Jupiter and Saturn
5. Uranus receives roughly 1/400th of the radiation the Earth receives
6. The cloud top temperature is only 55K

Question 2

What are the basics of Neptune?

Answer 2

1. At an average distance of just over 30 AU,
   Neptune takes over 164 years to orbit the Sun
2. Neptune rotates at a similar rate to Uranus in just over 16 hours
3. Neptune is similar in size and mass to Uranus
   (size 3.8x the Earth, mass 17.2x Earth).
4. Neptune also has a high density for its small size
   indicating that it also has a significant core
5. Neptune receives roughly 1/900th of the radiation the Earth receives
6. The temperature of Neptune is the same as
   Uranus even though it is further from the Sun

Question 3

What is Uranus axis tilt?

Answer 3

98 degree

Due to its large axis tilt Uranus has very extreme seasons lasting more than 20 Earth-years

Question 4

Which mission studied Uranus and Neptune?

Answer 4

Voyager 2 Flybys

Question 5

Atmospheric Composition?

Answer 5

Mostly hydrogen and helium like Jupiter and Saturn
Atmospheres rich in methane
Neptune has more methane than Uranus
No ammonia gas present
Reason: too cold

Question 6

The Rings of Uranus

Answer 6

Nine rings
Named with letters of Greek alphabet
Rings are narrow and widely spaced
Ring particles very dark

Question 7

The Rings of Neptune

Answer 7

Five rings
Named after scientists who studied planet
Three narrow, two broad
Ring particles very dark

Question 8

Why are the rings so dark?

Answer 8

In outer solar system ring particles contain methane
Radiation and solar wind particles from Sun
break down the methane and turn it into a
dark complex material with low reflectivity

Question 9

How does Miranda’s surface look like?

Answer 9

Smallest of the medium-sized moons
Chaotic surface: shattered by a collision?
Verona Rupes: An ice cliff more than 3 miles (5 km) high

Question 10

What’s interesting about Triton, Neptune’s largest moon?

Answer 10

Triton is in a retrograde orbit which is tilted by 23° to Neptune’s equator
Few craters indicating high levels of geological activity
The Mysterious “Cantaloupe Terrain”