Solar System and Universe

Solar System and Universe

Middle School

​

Learning Objectives

• Define the parts of our solar system and the role of the Sun's gravity.

• Differentiate between planets, moons, and smaller objects like asteroids and comets.

• Compare the key features of the inner and outer planets.

• Explain how the solar system formed about 4.6 billion years ago.

Key Vocabulary

​

Solar System

The solar system includes the sun, planets, their moons, and other smaller objects orbiting the sun.

​

Astronomical Unit (AU)

An astronomical unit is the average distance from the center of our Earth to the sun.

​

Planet

A planet is a large, round body that orbits the sun and has cleared its orbital path.

​

Dwarf Planet

A dwarf planet orbits the sun and is spherical, but has not cleared its orbital path.

​

Natural Satellite

A natural satellite, also known as a moon, is a celestial body in a stable orbit around a planet.

​

Asteroids

Asteroids are small, rocky bodies that orbit the sun, often in a belt between Mars and Jupiter.

Key Vocabulary

​

Meteoroid

A chunk of rock or dust in space that is smaller than an asteroid and orbits the sun.

​

Meteorite

A meteoroid that survives its journey through the atmosphere and successfully lands on the Earth's surface.

​

Comet

A loose ball of ice and rock that has a very long, narrow orbit around the sun.

​

​

Our Solar System

• The solar system includes the Sun, planets, moons, asteroids, and comets.

• The Sun is at the center, and its gravity keeps everything in orbit.

• Gravitational pull is stronger with more mass and weaker with more distance.

• An astronomical unit (AU) is used to measure vast distances in space.

Multiple Choice

What is the primary force responsible for keeping planets, moons, and asteroids in orbit around the Sun?

• The planets' speed

• The Sun's light

• The vacuum of space

• The Sun's gravity

Multiple Choice

Which of the following changes would cause the Sun's gravitational pull on a planet to become stronger?

• The planet begins to spin faster.

• The planet moves farther away from the Sun.

• The planet's mass increases.

• The planet develops more moons.

Multiple Choice

Why is it important to use both astronomical units (AU) and include objects like comets and asteroids when describing the solar system?

• To make the solar system seem smaller and simpler.

• To focus only on the objects that have moons.

• To accurately represent the system's vast scale and all its components.

• To show that only planets are affected by gravity.

​

​

The Sun and the Planets

• The Sun is a star containing 99.85% of our solar system’s total mass.

• A planet is a round object that orbits the Sun in a clear path.

• The four inner planets are small and are made mostly of rock and metal.

• The four outer planets are very large and made mostly of gas and liquid.

Multiple Choice

What is the main characteristic used to classify planets as either inner or outer planets?

• The color of their surface

• The materials they are made of

• Their size and mass

• Their distance from the Sun

Multiple Choice

Which statement accurately compares the general characteristics of inner and outer planets?

• Both inner and outer planets are small and rocky.

• Inner planets are large and gaseous, while outer planets are small and rocky.

• Inner planets are small and rocky, while outer planets are large and gaseous.

• Both inner and outer planets are large and gaseous.

Multiple Choice

A scientist discovers a new planet that is very large and composed mostly of hydrogen gas. Where is this planet most likely to be located?

• It could be anywhere, as size and composition do not relate to location.

• In a region far from the Sun, with the other gas giants.

• In a position closest to the Sun, with the other rocky planets.

• In an orbit between Earth and the Sun.

​

​

Dwarf Planets, Moons, and More

Dwarf Planets and Moons

• A dwarf planet orbits the Sun and is spherical, but has not cleared its orbit.

• There are five known dwarf planets: Pluto, Eris, Ceres, Makemake, and Haumea.

• A moon is a natural satellite that orbits a planet, held by the planet's gravity.

Asteroids and Comets

• Asteroids are small, rocky bodies found in the asteroid belt between Mars and Jupiter.

• Comets are loose balls of ice and rock with very long, narrow orbits.

• They develop tails of gas and dust when they get closer to the Sun.

Multiple Choice

What is the key characteristic that defines a dwarf planet?

• It is a natural satellite that orbits a planet.

• It is a small, rocky body found between Mars and Jupiter.

• It is a loose ball of ice and rock with a long orbit.

• It has not cleared other objects from its orbit.

Multiple Choice

What is the primary difference between a moon and an asteroid as described in the text?

• A moon is made of rock, while an asteroid is made of ice.

• A moon is always spherical, while an asteroid has a long, narrow orbit.

• A moon orbits a planet, while an asteroid is found in a belt between planets.

• A moon develops a tail near the Sun, while an asteroid does not.

Multiple Choice

A celestial body made of ice and rock is tracked moving from the outer solar system. What would you predict will happen as it gets closer to the Sun?

• It will become spherical and be classified as a dwarf planet.

• It will be pulled into orbit around the nearest planet.

• It will begin to develop a tail of gas and dust.

• It will break apart into many smaller asteroids.

​

​

Meteoroids

• ​Meteoroids are small chunks of rock or dust traveling through space, often smaller than asteroids.

• ​​When a meteoroid enters Earth's atmosphere, it burns up, creating a streak of light called a meteor.

• ​If a piece of the meteoroid survives and lands on the ground, it is then called a meteorite.

​

​

​1. The solar system formed about 4.6 billion years ago from a cloud of gas, dust, rock, and ice.

​​2. Gravity pulled this material into a spinning disk, and the hot, dense center eventually formed the Sun.

​3. The remaining particles of rock and ice slowly clumped together over time to form the planets.

​Solar System Formation

Multiple Choice

If a small chunk of rock from space survives its journey through the atmosphere and lands on Earth's surface, what is it called?

• An asteroid

• A meteor

• A meteoroid

• A meteorite

Multiple Choice

According to the description of how the solar system formed, what caused the initial cloud of gas, dust, and rock to form a spinning disk?

• The pull of gravity

• The heat from the newly formed Sun

• The speed of the moving particles

• The clumping of rocks and ice

Multiple Choice

What does the existence of meteoroids, which are small chunks of rock and dust, suggest about the formation of the solar system?

• That they are leftover materials from when the planets formed

• That the solar system is still expanding outward

• That planets are slowly breaking apart into dust

• That they are pieces that have broken off from the Sun

​

Common Misconceptions

Misconception	Correction
The Sun is a solid, burning ball of fire.	The Sun is hot gas that makes energy through nuclear fusion.
Pluto was 'demoted' because it is too small.	Pluto is a dwarf planet because it has not cleared its orbital path.
Meteors are 'shooting stars'.	Meteors are space rocks burning up in Earth’s atmosphere.

​

Summary

• Our solar system is a sun-centered system held together by gravity.

• Inner planets are rocky and small, while outer planets are large and gaseous.

• Planets are defined by being spherical and having a clear orbital path.

• Dwarf planets, asteroids, comets, and meteoroids are other objects orbiting the Sun.

Poll

On a scale of 1-4, how confident are you about the concepts covered in today's review?

• 1

• 2

• 3

• 4