Light-years and the Milky Way Galaxy

Light-years and the Milky Way

Multiple Choice

What spiral galaxy do we live in?

• Andromeda Galaxy

• Dwarf Galaxy Saggitarius

• Milky Way Galaxy

• Snickers Galaxy

Multiple Choice

What force keeps the arms of the Milky Way spinning around its center?

• The Force

• Friction

• Gravity

• Magnetism

Multiple Choice

Is the Milky Way the only galaxy in the universe?

• Yes

• No

Watch How Tiny We Are!

https://www.youtube.com/watch?v=0La58bUNNzQ

What is a Light-Year?

For most space objects, we use light-years to describe their DISTANCE. A light-year is the distance light travels in one Earth year. One light-year is about 6 trillion miles (9 trillion km).

Looking Back in Time

• When we use powerful telescopes to look at distant objects in space, we are actually looking back in time!

• Light travels at a speed of 186,000 miles (or 300,000 km) per second. This seems really fast, but objects in space are so far away that it takes a lot of time for their light to reach us. The farther an object is, the farther in the past we see it

The Andromeda Galaxy

The nearest large galaxy to us, Andromeda, is 2.5 million light-years away. So, we see Andromeda as it was 2.5 million years in the past. The universe is filled with billions of galaxies, all farther away than this. Some of these galaxies are much farther away.

Multiple Choice

The distance light can travel in one year is ______________

• 15,000 kilometers

• 1 light-year

• 15 Astronomical Units

• 6,000 miles

Multiple Choice

A light-year is a measure of

• time

• speed

• distance

• brightness

Multiple Choice

What travels the FASTEST?

• Light

• Sound

• You

Multiple Choice

How long does it take light from the Sun to reach us?

• 8 minutes

• 1 light year

• 5 milllion years

• 17 days