The Solar System and Planets

Slide 1: The Solar System and Planets

Exploring Our Cosmic Neighborhood - Understanding the Sun, Inner Terrestrial Planets, and Outer Gas Giants

Slide 2: Contents

1. The Sun: Our central star that contains 99.8% of solar system mass and powers all life through nuclear fusion.
2. Inner Terrestrial Planets: Rocky worlds close to the Sun including Mercury, Venus, Earth, and Mars with solid surfaces.
3. Outer Gas Giants: Massive planets Jupiter, Saturn, Uranus, and Neptune composed primarily of hydrogen and helium gases.
4. Key Comparisons: Understanding fundamental differences between inner terrestrial planets and outer gas giants in our solar system.

Slide 3: Our Solar System: A Gravitationally Bound System

1. Formation: Formed 4.6 billion years ago from a spinning cloud of gas and dust called the solar nebula
2. Composition: Contains 8 planets, 5 dwarf planets, and countless asteroids, comets, and other smaller objects
3. Sun Dominance: The Sun contains 99.8% of the entire solar system's mass, holding everything together with gravity
4. Orbital Motion: Planets orbit the Sun in elliptical paths, with the Sun slightly off-center of each ellipse
5. Two Regions: Divided into inner rocky planets and outer gas giants, separated by the asteroid belt

Slide 4: Sun Characteristics

1. Composition & Size: 70.6% hydrogen, 24% helium, 5% other elements. Radius: 432,000 miles - 109 times Earth's radius. Mass: 333,000 times Earth's mass
2. Temperature Extremes: Core: 27 million°F (15 million°C). Surface: 10,000°F (5,500°C). Corona: 3.5 million°F (2 million°C)
3. Energy Source: Nuclear fusion converts hydrogen to helium, releasing enormous energy that powers all life in the solar system
4. Distance & Rotation: 93 million miles from Earth (1 AU). Rotates 25 days at equator, 36 days at poles

Slide 5: Inner Planets: Four Small, Rocky Worlds

1. Composition: Solid surfaces made of silicate rocks and metal cores. Also called terrestrial or rocky planets
2. Size & Location: Much smaller than outer planets. Located within 1.5 AU from Sun, inside the frost line
3. Atmospheres & Moons: Thin to moderate atmospheres. Few or no moons: Mercury (0), Venus (0), Earth (1), Mars (2)
4. Surface Features: Impact craters, mountains, valleys, volcanoes shaped by impacts, tectonics, and volcanism

Slide 6: Mercury & Venus: Extreme Temperatures

Smallest planet, closest to Sun (0.39 AU)

No atmosphere to retain heat, so temperatures vary widely

Temperature extremes: 840°F day to -290°F night on the surface

Day length: 176 Earth days, Year length: 88 Earth days

Heavily cratered surface with appearance similar to the Moon

Similar size to Earth, second planet from the Sun (0.72 AU)

Hottest planet: about 900°F at the surface due to greenhouse effect

Atmosphere is about 96% CO2 with dense sulfuric acid cloud layers

Surface pressure roughly 92 times that of Earth at ground level

Rotates backwards very slowly, with a rotation period of 243 Earth days

1. Smallest planet, closest to Sun (0.39 AU)
2. No atmosphere to retain heat, so temperatures vary widely
3. Temperature extremes: 840°F day to -290°F night on the surface
4. Day length: 176 Earth days, Year length: 88 Earth days
5. Heavily cratered surface with appearance similar to the Moon
6. Similar size to Earth, second planet from the Sun (0.72 AU)
7. Hottest planet: about 900°F at the surface due to greenhouse effect
8. Atmosphere is about 96% CO2 with dense sulfuric acid cloud layers
9. Surface pressure roughly 92 times that of Earth at ground level
10. Rotates backwards very slowly, with a rotation period of 243 Earth days

Slide 7: Earth & Mars: Our Home and The Red Planet

Third planet and only known world with life. Liquid water covers 70% of surface.

Atmosphere: Nitrogen and oxygen, protects from radiation and supports life

Average temperature: 14°C (57°F) on global average

Active plate tectonics reshaping the planet's surface over time

One large moon (natural satellite) orbiting the planet

Fourth planet, the Red Planet with rusty iron oxide surface.

Thin atmosphere: 95% CO2, about 1% of Earth's surface pressure

Temperature range: -87°F to -5°F across different regions

Evidence of ancient water and subsurface ice detected by missions

Olympus Mons: Largest volcano in the solar system by height

Two small moons: Phobos and Deimos orbiting close to Mars

1. Atmosphere: Nitrogen and oxygen, protects from radiation and supports life
2. Average temperature: 14°C (57°F) on global average
3. Active plate tectonics reshaping the planet's surface over time
4. One large moon (natural satellite) orbiting the planet
5. Thin atmosphere: 95% CO2, about 1% of Earth's surface pressure
6. Temperature range: -87°F to -5°F across different regions
7. Evidence of ancient water and subsurface ice detected by missions
8. Olympus Mons: Largest volcano in the solar system by height
9. Two small moons: Phobos and Deimos orbiting close to Mars

Slide 8: Outer Planets: Four Massive Gas and Ice Giants

1. Composition: Primarily hydrogen and helium gas with possible small rocky cores. They lack solid surfaces, so spacecraft cannot land on them and must remain in orbit or perform flybys.
2. Mass & Size: Jupiter alone contains about 71% of all planetary mass in the solar system. Together the four outer planets hold the majority of planetary mass and are vastly larger than Earth in both mass and volume.
3. Rings & Moons: Each has extensive ring systems composed of dust and ice particles. They also host numerous moons, with Jupiter boasting 63+ known moons and Saturn more than 60 confirmed satellites.
4. Features: Located beyond roughly 5 AU from the Sun, these planets have strong magnetic fields, very thick atmospheres, and extreme weather systems including powerful storms and high-speed winds.

Slide 9: Jupiter & Saturn: The True Gas Giants

Largest planet: 1,300× Earth's volume, 318× mass

Distance: 5.2 AU, Orbit: 11.8 Earth years

Composition: 71% hydrogen, 24% helium

Great Red Spot: Giant storm larger than 3 Earths

Fast rotation: Under 10 hours per day

Four Galilean moons: Io, Europa, Ganymede, Callisto

Second largest, famous ring system of ice crystals

Distance: 9.5 AU, Orbit: 29.5 Earth years

Less than 1/3 of Jupiter's mass, lower density

Beautiful extensive ring structure

Titan: Largest moon with thick atmosphere

Over 60 known moons

1. Largest planet: 1,300× Earth's volume, 318× mass
2. Distance: 5.2 AU, Orbit: 11.8 Earth years
3. Composition: 71% hydrogen, 24% helium
4. Great Red Spot: Giant storm larger than 3 Earths
5. Fast rotation: Under 10 hours per day
6. Four Galilean moons: Io, Europa, Ganymede, Callisto
7. Second largest, famous ring system of ice crystals
8. Distance: 9.5 AU, Orbit: 29.5 Earth years
9. Less than 1/3 of Jupiter's mass, lower density
10. Beautiful extensive ring structure
11. Titan: Largest moon with thick atmosphere
12. Over 60 known moons

Slide 10: Uranus & Neptune: Ice Giants in Deep Space

Third largest planet with pale blue-green color from methane in its atmosphere

Distance: 19.2 AU, Orbit: 84.1 Earth years

Unique 98° axial tilt - rotates on its side

Cold temperatures: -357°F (-216°C)

Faint ring system discovered in 1977

27 known moons

Fourth largest with deep blue color from atmospheric methane

Distance: 30.1 AU, Orbit: 164.8 Earth years

Internal heat source despite distance from Sun

Fastest winds: over 1,200 mph

Great Dark Spot: Storm like Jupiter's Red Spot

14 known moons, largest is Triton

1. Distance: 19.2 AU, Orbit: 84.1 Earth years
2. Unique 98° axial tilt - rotates on its side
3. Cold temperatures: -357°F (-216°C)
4. Faint ring system discovered in 1977
5. 27 known moons
6. Distance: 30.1 AU, Orbit: 164.8 Earth years
7. Internal heat source despite distance from Sun
8. Fastest winds: over 1,200 mph
9. Great Dark Spot: Storm like Jupiter's Red Spot
10. 14 known moons, largest is Triton

Slide 11: Key Differences: Inner vs Outer Planets

1. Composition & Density: Terrestrial: Solid rocky surfaces with metal cores, high density (Earth 5.5g/cm³). Jovian: Hydrogen/helium gas, no solid surface, low density (Saturn 0.69g/cm³).
2. Size & Location: Terrestrial: Small (Earth 7,926 miles diameter), within 1.5 AU inside frost line. Jovian: Massive (Jupiter 88,846 miles), beyond 5 AU outside frost line.
3. Atmospheres & Temperature: Terrestrial: Thin/moderate atmospheres, warmer (closer to Sun). Jovian: Extremely thick hydrogen/helium atmospheres, extremely cold despite internal heat sources.
4. Moons & Rings: Terrestrial: 0-2 moons, no ring systems. Jovian: Dozens to hundreds of moons, all have extensive ring systems of dust and ice.

Slide 12: Thank You For Exploring

Thank You For Exploring Continue discovering the wonders of our Solar System. Visit NASA Science at science.nasa.gov for more information.