Ast10: Lesson 11 - Uranus/neptune

Front 1

Can you see Uranus and Neptune?

Back 1

Discovered after the invention of the telescope, Uranus is barely visible to the unaided eye, and Neptune can be seen through a telescope

Front 2

What are the colors of Uranus and Neptune?

Back 2

The blue-green, turquoise color of Uranus and the blue, indigo color of Neptune come from methane in their clouds.

Front 3

What differentiates Uranus and Neptune from Jupiter and Saturn?

Back 3

Uranus and Neptune have a similar size, mass, and bulk composition and they are both much smaller, less massive, and denser than the other two giant planets, Jupiter and Saturn.

Front 4

Why does Uranus have extreme seasonal variations in its polar regions?

Back 4

In contrast to all the other planets in the solar system, Uranus is tipped sideways so its rotation axis lies nearly within the planet’s orbital plane, leading to extreme seasonal variations in solar heating of its polar regions.

Front 5

How much energy/heat does Uranus and Neptune radiate?

Back 5

- Uranus apparently has no strong internal source of heat

- Neptune radiates 2.7 times the energy it absorbs from the Sun. The source of Neptune’s excess energy is most likely heat leftover from the planet’s formation.

Front 6

What controls the cloud bands and winds on Uranus?

Back 6

As they blow parallel to the planet's equator, they are controlled by the planet's rapid spin, not by the direct heating from the Sun

Front 7

Why is Neptune's atmosphere still active although it is farthest from the Sun?

Back 7

Despite receiving a relatively small amount of sunlight, Neptune’s atmosphere is surprisingly active and dynamic, with large storm systems and high-speed winds that may be driven by internal heat.

Front 8

How does Neptune's southern hemisphere change in response to sun?

Back 8

As the southern hemisphere of Neptune turned slowly toward the Sun’s faint heat, the temperature increased by just 10 kelvin and methane storm clouds became more frequent

Front 9

What is the interior of Uranus and Neptune composed of?

Back 9

Unlike Jupiter and Saturn, there is no liquid metallic hydrogen inside Uranus and Neptune, but they both contain deep atmospheres of molecular hydrogen. The interior includes vast internal oceans of water, methane and ammonia “ices”, melted at the high temperatures inside.

Front 10

How are the magnetic fields of Uranus and Neptune formed?

Back 10

The magnetic fields of Uranus and Neptune are askew, tilted from their rotation axes; rotation-driven currents in internal shells of ionized water could generate these magnetic fields.

Front 11

What are the characteristics of Uranus's rings?

Back 11

The austere, skeletal rings of Uranus are very narrow and widely spaced from each other, and made of very dark material. Shepherd satellites are responsible for the narrowness of the rings of Uranus and Neptune. The rings around Uranus are not quite circular, do not lie exactly in Uranus’s equatorial plane, and vary in width

Front 12

What causes the rings of Uranus to be varying and irregular?

Back 12

gravitational interaction of ring particles with small nearby moons contributed to the irregularities. For example, the material in one narrow ring around Neptune has been concentrated into three clumps, probably by the gravity of a nearby moon or moons.The sparse rings around Neptune contain no more material than that found in a single small moon only a kilometer across.

Front 13

What is the future of the rings of Neptune?

Back 13

Most of Neptune’s rings will probably be ground into dust by collisions and meteoritic bombardment in a few hundred million years, eventually being consumed by their central planet and vanishing from sight. But the rings can easily be replaced by debris blasted off small moons already embedded in them.

Front 14

How many moons does Uranus have and what are they made of?

Back 14

The five major moons of Uranus are dark and dense, made up predominantly of rock and water ice.

Front 15

What are the surface features of Miranda (innermost moon of Uranus)?

Back 15

The surface exhibits a bizarre variety of surface features that suggest repeated violent impacts in the past. It may have been shattered by catastrophic collisions and reassembled, or it became frozen in an embryonic stage of differentiation.

Front 16

How do moons of Uranus move?

Back 16

Uranus’s large moons all revolve in the planet’s equatorial plane, almost perpendicular to the planet’s orbital plane, in circular synchronous satellite orbits with the same side always facing Uranus.

Front 17

How does Neptune's largest satellite Triton move?

Back 17

Neptune’s largest satellite, Triton, revolves about the planet in a direction opposite to that in which Neptune rotates.

Front 18

What are the characteristics of Triton?

Back 18

Triton has a very tenuous, nitrogen-rich atmosphere, bright polar caps of nitrogen and methane ice, frozen lakes of water flooded by past volcanoes of water ice, and towering geysers that may now be erupting on its surface.

Front 19

How did Triton become Neptune's satellite?

Back 19

Triton may have formed in orbit around the Sun and was subsequently captured by Neptune, whose tidal forces kept Triton molten for much of its early history. These tides are now pulling the satellite toward a future collision with the planet.