Our Solar System
A Journey to Our Planetary Neighbors
1. Ideas about the night sky have changed over time…
l ______-centered model – early Greeks thought planets, Sun, Moon and stars rotated around the Earth
l Modern view –
u The sun is the ______ of our solar system
u All other objects in the solar system ______ around the sun in elliptical orbits at different speeds.
2. How did our solar system form?
l A ______ of gas, ice, and dust slowly formed in space, and rotated in space.
l The cloud began to ______ and the matter was squeezed into less space.
l The cloud became dense, heated up and triggered a nuclear ______ reaction that created the sun.
3. What happened next?
l All leftover ______ became the planets and asteroids
l The four inner planets – (Mercury, Venus, Earth, and Mars) are small and rocky with iron cores
l The four outer planets – (Jupiter, Saturn, Uranus, and Neptune) are large, lightweight, and composed of gases.
4. Inner Planets
l ______ - closest to the Sun, smallest planet
u Many craters and high cliffs
u No true ______ so temperatures can range from -292 to 806° F.
u It orbits the sun once every 88 days and is an average of 36 million miles from the sun.
5. Inner Planets
l ______ – second from the sun and similar to the Earth in size and mass
u Mostly smooth volcanic plains
u Extremely dense atmosphere of clouds
u Carbon dioxide gas traps solar energy resulting in temperatures between 842 to 887° F.
u It is an average distance of 67 million miles from the sun and orbits every 225 days
6. Inner Planets
l ______ – third planet from the Sun
u More than 70 percent of surface is covered with water
u Atmosphere consists of several layers, is mostly composed of nitrogen and oxygen, and protects the surface from meteors and Sun’s radiation
u It is an average of 93 million miles away from the sun, and completes its orbit in 365.5 days
7. Inner Planets
l ______ – fourth planet from the Sun
u Called red planet because of iron oxide in rocks
u Polar ice caps made of frozen carbon dioxide and water
u Surface contains gullies, mountains and canyons, plains and the largest volcano in the solar system
u The thin atmosphere mostly contains carbon dioxide
u It is an average of 141 million miles from the Sun, and completes its orbit in 1.9 years
8. Asteroids and Other Objects in Our Solar System
l Asteroids – rocks similar to that which formed the planets
l Asteroid Belt – group of asteroids that orbit the Sun between the planets Mars and Jupiter
9. Comets
l ______ - dust and rock particles combined with frozen water, methane, and ammonia
u Halley’s comet (occurs every 76 years), Hale-Bopp (1995)
l Look similar to a dirty snowball
l The ice and dust vaporize as it approaches the sun
u This forms a comets tail
10. Meteoroid, Meteor, and Meteorite
l ______ – small pieces of debris in space
l ______ – small meteoroid that burns up in Earth’s atmosphere (falling or shooting star)
l ______ – meteoroid that strikes Earth
11. Outer Planets
l ______ – Fifth planet from the sun and the largest in our solar system
u Atmosphere mainly consists of hydrogen and helium
u Surface is suspected to be composed of liquid hydrogen and helium, and may have solid core at the center
u It is an average of 484 million miles from the sun and 11.8 years to complete one orbit
u Has 16 moons
12. Outer Planets
l ______ – sixth planet from the Sun
u Thick outer atmosphere of hydrogen, helium, ammonia, methane, and water vapor
u Might have rocky core
u Rings that circle around planet are composed of ice and rock particles
u It is an average of 887 million miles from the Sun, and completes one orbit in 29.5 years
13. Outer Planets
l ______ – seventh planet from the sun
u Atmosphere of hydrogen, helium, and methane
u Rotates on its side
u Contains thin, dark rings
u It is an average of 1.8 billion miles from the sun, and completes one orbit in 84 years
14. Outer Planets
l ______ – eighth planet from the Sun
u Atmosphere is similar to that of Uranus
u Storms on Neptune reveal an active and rapidly changing atmosphere
u It is an average of 2.8 billion miles from the sun, and completes its orbit every 165 years