What Makes up the Solar System?

Notes for Chapter 3:

What Makes Up the Solar System?

I. Stars and Galaxies

A. Stars - A star is a ______of hot gases that gives off ______and other types of energy

1. New stars are born as old stars ______

a. new stars are formed in a cloud of dust and gas called a ______

b. when stars form, they can grow to many sizes

1. the smallest ones are the ______

2. the sun is an average size star – but if it were hollow, a million Earths would fit inside!

3. the ______stars are many times bigger than our sun

4. because they were so far away, even the largest stars look like ______of light

2. An average star, such as our sun, will live for ______of years

3. The ______is the nearest star to Earth

4. Stars look close together, but they are actually very far apart!

a. most stars are trillions of ______apart

b. between the stars is some gas and dust, but mostly empty space

c. all stars, gas, dust, planets, moons, other objects, and empty space make up the ______(which contains everything that exists)

B. Galaxies – a system of stars, gas, and dust held together in space by ______

1. Many stars have ______moving around, or orbiting them

2. gravity holds these objects in orbit

3. the universe contains billions of galaxies in different shapes and sizes

a. when you look up in the sky, some of the points of ______that you see are galaxies that are very ______

b. there are three basic shapes of galaxies

1. ______– looks like a pinwheel with thousands of stars in the middle and moving away from the center are “arms” that contain many more stars. Earth is located in a spiral galaxy called the Milky Way.

2. ______– round or oval with no arms. They contain little or no gas or dust, only stars

3. ______– have no regular shape. They contain many clouds of dust and gas in which new stars are forming

II. Constellations

A. Constellations are groups of stars in our galaxy (______) that form a recognizable pattern

1. People used to rely on star patterns to mark the changes of the seasons, before there were ______

a. ______would decide when to plant and harvest crops

b. constellations used to be used to explain natural events or religious beliefs

c. travelers would use the familiar star patterns to find their way around (______)

d. different ancient civilizations saw different “pictures as they looked into the sky

e. whatever shape was seen, the constellation appears to be ______because you are standing on Earth. If you were in space, the stars that make up the constellation would be very far apart, and look ______

f. there are ______recognized constellations

g. the constellations seen in the ______hemisphere are different than the constellations seen in the ______hemisphere

III. The Solar System

A. A galaxy is a ______system that has millions of stars

1. some star systems have only one star – like our solar system. It has only one star (the ______)

2. Our solar system involves the Sun and all the objects that ______around it

3. ______are the largest space object that orbits a star

a. our solar system has ______planets

b. some planets are closer together than other planets

c. each planet is shaped generally like a ______, but not a perfect sphere

d. the eight planets are separated into two groups – the ______planets and the ______planets

e. Inner planets are the 4 planets closest to the sun – Mercury, Venus, Earth, Mars

1. all made mostly of ______

f. outer planets are the 4 planets farthest from the sun – Jupiter, ______, Uranus, Neptune

1. made mostly of ______surrounding a small rocky core

2. the largest planets

3. called the gas giants

B. The Planets – see chart

IV. Other objects in the solar system

A. Asteroids

1. ______objects that orbit the sun

2. smaller than ______planets

3. can be as large as ______miles across to as small as a grain of sand

4. mostly found between Mars and Jupiter in the ______

5. some scientists think that asteroids are small pieces from a planet that have ______off. Others think that they formed when two or more large objects crashed into one another. Some scientists think that they are just left-over material from when the solar system was formed

B. Dwarf planets

1. an object that orbits the sun, is ______than an asteroid, but smaller than a planet

2. Pluto used to be classified as a planet, but now scientists have decided it is a ______planet because it has an unusual orbit

C. Comets

1. an object in space made of ______and ______

2. when they pass close to the sun, the sun’s energy changes some of the ice to a gas, which makes the comet “______”

a. the “glowing” part is called the ______

b. a trail of gas and dust streams out behind it – called the tail and it can extend for millions of ______!

c. eventually it gets far away from the sun and it ______, until it gets close again

d. as planets pass through a comet’s ______(made of rocky dust), a meteor shower is created (called shooting stars). A meteor ______are thousands of bits of solid material hitting Earth’s atmosphere and burning up

e. bits of solid material that enter Earth’s atmosphere are called ______(smaller than asteroids or comets). When these hit the atmosphere, there first is ______and then light

f. a comet, asteroid, or meteoroid that does ______completely burn up in the atmosphere can land on Earth’s surface. These are called meteorites