Distance in Space

Why do we use light years and astronomical units to measure distances in space?

• Scientists want to sound smart.

• Hubble discovered these units and wanted to use them.

• Space is too small to use km, it wouldn't make sense.

• Space is too big, vast, enormous to use traditional units, like miles.

In the image , what does X represent?

• 1 light-year

• 1 meter

• 1 year

• 1 AU

Tags

NGSS.MS-ESS1-3

A light-year (ly) is the distance that light travels in one year. If a star is 3 ly from Earth, how long does it take light from that star to reach Earth?

• 3 min

• 3 hours

• 3 years

• 3 months

Astronomers use the light-year to describe the relationship between objects in space. For example, the Andromeda galaxy is 2.5 million ly from Earth. Which of the following units is most similar to the light-year?

• gram

• second

• kilometer

• degrees Celsius

Which two objects in space are located farthest apart?

• Earth and Mars

• Earth and the sun

• Earth and the moon

• the Milky Way galaxy and the Andromeda galaxy

Q1. What is the phenomenon where the moon passes between the Earth and the Sun?

• A) solar eclipse

• B) lunar eclipse

Tags

NGSS.MS-ESS1-1

light year is a measure of

• brightness

• time

• distance

• color

Tags

NGSS.MS-ESS1-3

How do we determine the distance of a star or galaxy?

• Parallax

• Luminosity (brightness)

• BOTH Parallax and Luminosity

When we measure how far light travels in a year, we are talking about _ of miles.

• hundred

• thousands

• millions

• billions

• trillions

What is the primary reason astronomers use light-years instead of kilometers to measure distances in space?

• Light-years are easier to calculate.

• Kilometers are too small for vast cosmic distances.

• Light-years are a more modern unit.

• Kilometers are not used in astronomy.