Sun and Other Stars

A star is a sphere of hot gases that gives off light and heat. The only
star you can see during the day is the sun. Stars are found in large
groups called galaxies.

•
The sun is about 93 million miles from Earth.

•
The next closest star to us is 24.8 trillion miles (or 4.2 light-years)
away.

•
Astronomers use light-years to measure large distances in
space. A light-year is the distance that light travels in one year.

•
The temperature of a star determines its color

•
A star with a warmer surface temperature is blue or white

•
A star with a cooler surface temperature is red or orange

Stars go through different cycles between their beginning and
ending. Different kinds of stars go through different cycles. The

diagram below shows the stages that a medium- sized star will go

through. Can you guess which stage our sun is in?

•Huge cloud of dust
and gases - mostly

hydrogen and

helium

•Gravity pulls

hydrogen atoms

closer together and
as they collide, they

produce heat

•Can also be called

a protostar

•Our sun is a

main-sequence star

•For a few billion years,

hydrogen atoms

continue combining

to form helium

•The star gradually

increases in
temperature

•Eventually, the heat
forces the hydrogen
on the edge of the
star to expand into

space

•It cools and turns red

•A red giant may

expand to 100 times

its former size

•The star will begin to
collapse under the
pressure of gravity

•It will shed its outer
layers after it has run

out of energy and

leave behind a
cloud of gas and

dust

•The star begins to

cool and shrink

•It becomes a small
and dense star that
shines with a cooler

white light

•Eventually a white
dwarf cools and
becomes a Black

Dwarf

Reorder

Put the life cycle of a star in order.

• Stellar Nursery

• Main-Sequence Star

• Red Giant

• Planetary Nebula

• White Dwarf

1

2

3

4

5

• 1
• 2
• 3
• 4
• 5

• The sun is the closest star to Earth and our primary source of

energy

• The sun is made of gases – hydrogen and helium

• It is about 1.3 million times larger than Earth

• The sun is made of

layers

• In the core, hydrogen

is turned into helium
through nuclear fusion

• Energy moves

outward from the
core

• These reactions

produce light and
heat

Labeling

Label the layers of the sun.

Drag labels to their correct position on the image

chromosphere

core

convection zone

radiative zone

corona

photosphere

Sunspots are areas with strong
magnetic fields. They are cooler

darker areas in the

photosphere.

Solar flares are sudden flash of
increased brightness from the
Sun’s atmosphere. They usually

occur near a sunspot group.

Categorize

Options (5)

The sun is made of gases.

The sun provides energy here on earth.

The sun is currently in its main-sequence phase.

The sun is a planet.

The sun's light reaches the Earth in about one minute.

Identify if these statements are true or false.

True

False

Dropdown

A

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is a sphere of hot gases that gives off light and heat. The only star you can see during the day is the ​

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. The next closest star to us is 24.8 trillion miles away. Because the distance is so great, astronomers use ​ ​

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to measure large distances in space. Stars are different colors. A star with a cooler surface temperature is ​

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. A star with a warmer surface temperature is ​

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.