Science 2.07 Fixed Points of Light

Science Module 7 Lesson 2.07

Fixed Points of Light

Fixed Points of Light

I will be able to

-recognize that stars are fixed points of light in the sky

-explain that stars are fixed points in the sky

Light, Stars, and Other Things

If you could see different stars close up, they would look quite similar. Stars are big balls of gas that light up the sky. Some stars are big, and some stars are small. All of the stars that we see in the sky are points of light because they are so far away from Earth. 

Not all points of light are stars though! What are they, then?

Light, Stars, and Other Things

This star appears to be moving. That can't be! Stars don't move, do they? Don't they just sit there and twinkle in the sky? 

The night sky is full of things other than stars. Some are part of our solar system, like planets. Others are man-made, like airplanes or satellites. Let's do some research to learn more. 

Meteors

A meteor is a big, glowing space rock. If a light is moving fast in a straight line and disappears quickly, it is probably a meteor. A meteor is not a fixed point of light because it is moving

Planets

Planets appear as points of light in the sky, but they do not give off their own light like stars do. They reflect the light of the sun in the way the moon does.

Satellites

The light from a satellite or a space station moves and follows a slow and steady path.

Airplanes

A slow-moving point of light is usually caused by the lights of a flying airplane or a landing space craft. They are not fixed points of light because they are moving.

Did you know: Meteors are not stars?

Meteors appear in the night sky and usually only last a few seconds. They are sometimes called "shooting stars" or "falling stars" because they leave bright streaks of light across the night sky. They are not stars at all! When one enters Earth's atmosphere at a high speed they get hot very quickly and create the bright streaks of light we see.

Multiple Choice

Which object appears as a point of light in the sky?

• cloud

• kite

• meteor

• bird

Multiple Choice

Which object is a fixed point of light in the sky?

• bats

• stars

• clouds

• trees

What Is That Thing in the Sky?

Astronomers can tell the difference between the stars and other points of light in the sky. Stars appear as fixed points of light. This means that we cannot see stars move. They appear to stay put in the same spot. Usually, we can see other points of light in the sky moving from one place to the next. If a point of light changes its location, it is not a fixed point and therefore, not a star.

Did you know: Some points of light are not moving?

The North Star, also known as Polaris, is a supergiant star that is found in a fixed point in the northern sky. The star lies straight above the Earth's north pole and can only be seen in the northern hemisphere. 

Objects in the Sky

Space not only has stars and planets. It also has pieces of rock floating around in it. Falling stars are actually tiny pieces of dust and rock called meteoroids. When a meteoroid hits the Earth's atmosphere, it burns up causing a brief, but beautiful trail of light to streak across the night sky!

Did you know: Stars Can Move Over a Long Period of Time?

It is not true that stars do not move. All stars move through space. Stars are so far away, we just can’t see them move in a short period of time. Over the course of a few days you may observe stars in different parts of the sky. 

Objects in the Sky

There are so many objects in the night sky! Some objects, such as stars, appear as fixed points of light, while other objects visibly move from one location to another. All of these objects light up the sky to make it bright. The sky at night is quite a sight!

Write Like a Scientist

In your Science Notebook, list the different objects that appear as points of light in the sky. Explain the difference between the stars and other points of light in the sky.  

Sailors and Stars

A long time ago, people did not know what stars were. When ancient people first looked up to the sky, the stars were just there as tiny pinpoints of light. People found that the stars seemed to stay fixed in the sky and never moved around. People learned how to use these fixed points of light to help them find their way across land and sea. 

North Star Navigation

Today, if we need directions somewhere, we just look it up on our smartphones. But long ago, before cell phones, GPS or even the internet, people relied on the stars for directions. Read the article below to learn more about how stars were the first GPS.

North Star Navigation

The North Star is a very important star because it appears to stay fixed in the same place in the northern hemisphere. Polaris, or the North Star, is located almost directly above the north pole. When you locate the North Star, you have located where north is. Some sailors use this star so that they know which direction they want to travel with their ships.

Multiple Choice

Stars help sailors navigate their ships at sea because they stay fixed in one spot.

• True

• False

Multiple Choice

Stars are fixed points of light and meteors are not.

• True

• False

Multiple Choice

Meteors do not move through the sky and so they are always in the north.

• True

• False

Lesson Summary

Stars have always been a part of our lives, in more ways than we realize. Stars are fixed points of light in the sky, and because they appear to stay in one location, they are useful when navigating over land or water. 

Multiple Choice

Stars appear as _____ points of light in the night sky.

• fixed

• moving

• traveling

Multiple Choice

This is because they are very _____ from.

• near

• shiny

• far

Multiple Choice

There are some objects in the sky that appear to be fixed points of light, but are actually _____.

• moving

• skipping

• jumping

Multiple Choice

Which of the following objects is a fixed point of light?

• airplane

• meteor

• satellite

• star

Multiple Choice

Which object appears as a point of light in the sky?

• bird

• cloud

• kite

• meteor

Multiple Choice

If you observe the stars in the same spot in the sky for three nights, will the stars move?

• The stars will move because they are fixed points of light.

• The stars will not move because stars are not able to move.

• The stars will appear to move slowly from one location to another.

• The stars will not appear to move because they are fixed points of light.

Multiple Choice

What is a meteor a good example of?

• a point of light

• a star

• a fixed point of light

• a planet

Multiple Choice

What is a falling star in the sky?

• meteor

• moon

• planet

• satellite

Multiple Choice

How can a star help sailors on the water at night?

• A star can help sailors see better in the night sky.

• A star moves in the sky so it directs sailors where to go.

• A star is too far away to be useful to sailors on the water.

• A star is a fixed point of light so it helps sailors know which direction they are going.

Multiple Choice

Why is a star a fixed point of light?

• It is close to Earth.

• It never stays in the same spot.

• It doesn't appear to move in the sky.

• It moves from one location to another.

Multiple Choice

How is a meteor different than a star?

• A meteor does not move but, a star does.

• A meteor makes its own light but, a star does not.

• A meteor is not a fixed point of light in the sky but, a star is.

• A meteor is a ball of gas that burns, but a star is made of rock.

Multiple Choice

Is the sun a fixed point of light?

• The sun is not a fixed point of light because it is not a true star.

• The sun is a fixed point of light because it is a star.

• The sun is not a fixed point of light because it appears to move in the sky.

• The sun is a fixed point of light because it moves from one location to another.

Multiple Choice

Which light in the sky is a fixed point of light?

• a blinking light

• a light moving slowly

• a bright light in one spot

• a streak of light going across the sky

Multiple Choice

Some examples are meteors, _____, and satellites.

• airplanes

• cars

• boats