Intro to Planetary Astronomy Quest #4

Saturn's Shepherd Moons

- Pan (Encke gap) - Daphnis (Keeler gap) - Atlas (A Ring) - Prometheus (F Ring) - Pandora (F Ring)

Spacecrafts that have flown by Jupiter

- Pioneer 10 & 11 (had a plaque attached to look for ET) - Galileo Spacecraft - Juno Spacecraft

Dwarf planets w/ moons

- Pluto: 5 - Eris: 1 - Haumea: 2

Saturn's disappearing rings

- a phenomenon caused by the planet's rotation on an axis (Its rings are oriented edge on as viewed from Earth every 15 years) - makes rings look "invisible" in all but the very largest telescopes

Saturn's Magnetic Field

- almost perfectly aligned with the planet's rotation - far weaker than Jupiter's

Giant Red Spot on Jupiter

- an upwelling of material from Jupiter's interior that is a long-lived enormous storm system - 20,000 km in diameter - Smaller & less red than it used to be - appearing consistently the last 300 years

Besides discovering Uranus, William Hershel also....

- built telescopes - discovered 4 moons - discovered infrared radiation

Composition of Ice Giants

- contain larger amounts of water and other ices than the gas giants - lesser amounts of H and He than gas giants

Clouds on Saturn

- less activity than Jupiter - less color than Jupiter

Atmosphere of Jupiter

- mostly hydrogen and helium - lots of molecular hydrogen in outer atmosphere (goes from gas to liquid to liquid metallic hydrogen to ice to rock the deeper you go)

Atmospheric Gases/Clouds by Elevation (Jupiter)

-100 km: H2O -50 km: NH4HS -25 km: NH3 150 km: N2H4

Average Temperature on Uranus

-195 degrees C

Average Temperature on Neptune

-200 degrees C

Atmospheric Gases/Clouds by Elevation (Saturn)

-275 km: H2O -175 km: NH4HS -100 km: NH3 150 km: P2H4

Saturn's Average Density

0.7 g/cm^3

The three giant planets than can be seen w/ the unaided eye

1. Jupiter 2. Saturn 3. Uranus (difficult to see)

Zones of Jupiter

light-colored bands in Jupiter's cloud cover

Neptune has clouds in its atmosphere made up of.....

methane ice crystals

Uranus color

pale green

Jupiter's Magnetic Field

- 10 times stronger than earth due to the liquid metallic region - leads to aurora like earth

Galileo and Saturn's Rings

- 1610: observed 2 objects near Saturn - Thought to be "moons" but these "moons" didn't orbit Saturn - 1612: the "moons" disappeared

Jupiter's Rings

- Discovered by Voyager 1 - they are very dim, but still exist - Likely formed from debris of a broken moon

Giant planets in general are made up of....

- Gases (Hydrogen, Helium) - Ices (Nitrogen, Carbon, Oxygen, etc.) - Rocks (Iron, Magnesium, Silicates, etc.)

Jupiter's Galilean moons

- IO - Europa - Ganymede - Callisto

Moons of the outer solar system

- Jupiter: 95 - Saturn: 146 - Uranus: 27 - Neptune: 14

Moons in the inner solar system

- Mercury: 0 - Venus: 0 - Earth: 1 - Mars: 2

Composition of Saturn's Interior

- Molecular hydrogen - Liquid hydrogen - Metallic liquid hydrogen - Ice - Rock

Orbit of Saturn's ring particles

- Obey Kepler's laws - Closer particles orbit faster - Motions of particles in opposite directions cancel out

Diameter of Neptune

49,500 km

Clouds in Jupiter's Atmosphere

- Lots of different colors (tan, yellow, red, white, etc.) - Differ based on elevation

Mass of Neptune

1.024 × 10^26 kg

Uranus's Average Density

1.3 g/cm^3

Jupiter's Average Density

1.33 g/cm^3

Neptune's Average Density

1.6 g/cm^3

Mass of Jupiter

1.9 x10^27 kg

Saturn's Rotation Period

10.7 Hours

Jupiter's Period of Orbit

11.86 Years

Diameter of Saturn

120,540 km

Neptune's Number of Moons

14

Diameter of Jupiter

143,000 km

Saturn's Number of Moons

146 (82 known?)

Neptune's Rotation Period

16.1 Hours

Neptune's Period of Orbit

164.8 Years

Uranus's Rotation Period

17.2 Hours

Uranus discovery

1781 by William Hershel - first unknown planet to be discovered - called the "Georgian Star" because of King George III

Neptune discovery

1846 by Jean-Joseph Le Verrier - after its discovery the position of Uranus didn't match positions predicted by Newton's laws

Uranus's Average Distance from the Sun

19.2 AU

Winds on Neptune

2,000 km/hr winds (strongest in the solar system!!)

Neptune's magnetic field

24x stronger than Earths and stays pretty typical

Uranus's Number of Moons

27

Saturn's Axial Tilt

27 degrees

Neptune's Axial Tilt

28.3 degrees (Similar to Earth, meaning there's well defined seasons)

Saturn's Period of Orbit

29.5 Years

Jupiter's Axial Tilt

3.13 degrees

Distance of the Asteroid Belt from the Sun

3.2-4.2 AU

Neptune's Average Distance from the Sun

30 AU

At each pole, Uranus has.....

42 years of darkness and 42 years of sunlight due to the axial tilt at the poles (Period of orbit = 84 years)

Jupiter's Average Distance from the Sun

5.2 AU

Mass of Saturn

5.683 × 10^26 kg (95 Earths)

Diameter of Uranus

51,200 km

Chemical Composition of the Gas Giants (Jupiter & Saturn)

75% hydrogen, 25% helium

Mass of Uranus

8.681 × 10^25 kg (15 Earth's)

Uranus's Period of Orbit

84.1 Years

Saturn's Average Distance from the Sun

9.5 AU

Jupiter's Rotation Period

9.8 Hours

Chemical Composition of the Sun

92.1% hydrogen, 7.9% helium

Jupiter's Number of Moons

95

Uranus's Axial Tilt

97.8 degrees (Extreme seasons) - this unique tilt makes the planet look like its spinning sideways

How Clouds form on Jupiter

A process called convection - Hot material deeper in Jupiter's interior rises while cooler material sinks. As the hot gases rise, they cool and condense into liquid droplets or ice crystals to form clouds.

Belts of Jupiter

Dark, reddish bands in Jupiter's cloud cover.

Winds on Saturn

Equatorial ones reach almost half a km/sec

Types of Giant planets

Gas & Ice

Atmospheres of Ice Giants

Hydrogen and Helium with some methane

Composition of Jupiter's Interior

Ice, Rock, Metal

Gas Giants

Jupiter and Saturn

Uranus rings

Kept in place by shepherd moons (has 13 of them)

Ices examples

Nitrogen, Carbon, Oxygen, Hydrogen

Storms on Jupiter

No friction to slow storms so some last decades or centuries

Dwarf planet examples

Pluto, Eris, Ceres, Makemake, Haumea

Christian Huygens, 1655

Realized Galileo's "moons" of Saturn are actually rings (believed rings were a solid disk)

James Clerk Maxwell (19th Century)

Realized rings would break apart if they were a solid disk

Why are moons studied?

The similarities and differences between moons is an important part of understanding the way the Solar System formed and continues to evolve

Ice Giants

Uranus and Neptune

"Shepherd" moons definition

a small natural satellite that clears a gap in planetary-ring material or keeps particles within a ring contained

As a result of the pressures and temperatures on Saturn...

ammonia can condense and freeze

Cassini Division

an apparent gap between Saturn's A and B rings (about 4,700 km in width)

Neptune color

dark blue

Jean-Dominique Cassini, 1675

discovered a gap in the "solid" ring system

Neptune's rings

faint and dark, made of clumps of dust (has 6 of them)

Winds on Uranus

far less extreme than Neptune

Uranus's atmosphere is largely _________

featureless

Liquid metallic hydrogen

form of hydrogen with both liquid and metallic properties that exists as a layer in the Jovian atmosphere.

The compositions of Uranus and Neptune are significantly more ________ elements than Jupiter and Saturn

heavy (any material beyond H and He)

Saturn's ring's composition

ice that forms a flat disk & small amounts of silicates

Winds on Jupiter

in opposite direction based on bands (550km/hr at the equator)

Neptune is further from the sun than Uranus but it is warmer by 5 degrees due to....

internal heating

Saturn's ring formation

pieces of comets, asteroids, or shattered moons that broke up before they reached the planet, torn apart by Saturn's powerful gravity

Dwarf planet

planetary object not a planet or moon and is in direct orbit around the sun

The Asteroid Belt

the region of the solar system between the orbits of Mars and Jupiter, where many asteroids are found

Uranus's magnetic field

varies haphazardly (atypical)