HMH Unit 5.4 Day Four

HMH Unit 5.4 Day Four

Pgs 342-344

Light Years

• Distances between stars are enormous. If we used units, such as kilometers, we would end up with very big numbers. 

• To measure the huge distances in space, scientists use a unit of measurement called a light-year. 

• A light-year is how far light travels in one Earth year. The distance traveled is about 9,500,000,000,000 kilometers (9.5 trillion km).

Multiple Choice

Why are distances to stars measured in light-years instead of a familiar unit of distance, such as kilometers or miles? Choose the correct answer.

• Stars are very far from Earth, so large units are used to measure their distances.

• Stars give off light, so light units are used to measure their distances.

• It takes a long time to travel to stars, so time units are needed to measure distances to stars.

How Far is that Star?

All the stars in a constellation may appear to be the same distance from Earth, but they are not.The following picture is of the constellation Leo, and how far they are from Earth. On your paper you will be listing out where the stars are really located to each other.

How Far is That Star?

• As you can see from the chart, stars vary greatly in their distance from Earth.

• It would take over a million years to travel to Denebola, which is the closest star shown here!

Multiple Choice

Which statement about stars is true?

• They are all the same distance from Earth

• They are closer to Earth than the sun.

• They vary greatly in their distance from Earth

Multiple Choice

Use the distance in the diagram. Which pair of stars below are the greatest distance apart?

• Rasalas and Regulus

• Algenubi and Adhafera

• Zosma and Regulus

• Denebola and Zosma

Open Ended

You've learned that your view of an object depends on your perspective, or your location compared to the object. Explain how distance can affect your view stars. Answer in complete sentences.