The Solar System and Earth Patterns
Planets in the Solar System
We now know that our sun is the center of our solar system.
Eight planets, some dwarf planets, many moons, dust, gas, and thousands of asteroids and comets orbit around the sun.
Our solar system is made up of eight planets: Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, and Neptune.
The eight planets sorted by size from largest to smallest are: Jupiter, Saturn, Uranus, Neptune, Earth, Venus, Mars, and Mercury.
Terrestrial planets: Mercury, Venus, Earth, and Mars
Made up mostly of rock or metal
Gas giants: Jupiter, Saturn, Uranus, and Neptune
Made up mostly of gases
Sun
Average-sized yellow star
Approximately 4.6 billion years old
The planets revolve around the Sun
Mercury
Closest to the sun
Small, heavily cratered planet
Smallest planet in our solar system
Venus
Second from the sun
Similar to Earth in size and mass
Has a permanent blanket of clouds that trap so much heat that the temperatures on Venus are very hot
Earth
Third from the sun
About 150 million kilometers from the sun
Large amounts of water and an oxygen-rich atmosphere
Earth’s protective atmosphere blocks out most of the sun’s damaging rays
Mars
Fourth from the sun
Thin atmosphere
The surface of Mars has an orange-reddish color because its soil has rust
Jupiter
Fifth from the sun
Largest planet in the solar system
No solid surface
Saturn
Sixth from the sun
Has prominent rings
Uranus
Seventh from the sun
Spins on its side; the tilt of its axis is more than 90°
Neptune
Eighth from the sun
Appears blue through telescopes
Pluto
Dwarf planet
Is no longer considered a planet due to its small size and irregular orbit
Earth's Seasons
Rotation: the Earth spins on its axis and completes a full rotation every 24 hours
Revolution: the Earth moves around the sun and completes a full revolution every 365 ¼ days
Earth’s axis is tilted 23.5°, and because of this, we get seasons. As the Earth revolves around the Sun, during different times of the year, sometimes the Northern Hemisphere is tilted towards the sun and sometimes the Southern Hemisphere is tilted towards the sun.
Summer occurs in a hemisphere when that hemisphere is tilted towards the sun.
Winter occurs in a hemisphere when that hemisphere is tilted away from the sun.
Phases of the Moon
The moon doesn’t produce its own light; it reflects the Sun’s light. As the moon revolves around Earth, as it does so about once every month, the Sun lights up different parts of it, creating the phases of the moon.
Waxing: the moon appears to be getting bigger
Waning: the moon appears to be getting smaller
New moon: the moon is between the Earth and the Sun, so the lit up side of the moon is facing away from us
Crescent: we can see a small sliver of the moon’s lit up side
First/third quarter: the moon, Earth, and Sun form a right angle, and we can see half of the moon’s lit up side
Gibbous: we can see the majority of the moon’s lit up side
Full moon: the Earth is between the moon and the Sun, and the moon is completely lit up
Historical Models of the Solar System
Earth-centered model
The Earth is the center of the universe and all other heavenly bodies orbit around Earth
Believed by early astronomers such as Aristotle and Ptolemy
Sun-centered model
Current model
The planets in our solar system orbit the Sun
Proposed by Copernicus and Galileo