1. What is a Light Year?

2. If you could travel to the closest star from the sun in a car traveling 60 mph, how long would it take you to get there?

3. 48 million years

4. If you could travel to the closest star from the Earth in a space shuttle at 18,000 mph, how long would it take you to get there?
Like any other object in low-Earth orbit, a Space Shuttle must reach speeds of about 17,500 miles per hour (28,000 kilometers per hour) to remain in orbit.

5. 160,000 years

6. If you ride on a beam of light, how long would it take you to get there? It travels 300,000,000 m/s

7. 4.29 years

8. Why do we use Light Years?
Because distances in space are too vast (big), miles and kilometers are too small to be used.
Scientists measure the distances in space outside our solar system in light years (ly)

9. The Milky Way is the galaxy in which the Solar System is located.
The Milky Way Galaxy is about 100,000 light years across
Older one

10. One light-year is the DISTANCE that light travels in one year
What is a Light Year?
One light-year is the DISTANCE that light travels in one year

11. HOW FAR a Light Year is, If we are going to find out
we need to know two things…
The speed of light, measured in meters per second and
The number of seconds in a year

12. What’s the fastest speed in the universe?
- The Speed of Light
What is the speed of light? (abbreviated “c”)
300,000,000 meters per second or 3 X 108 m/s

13. How Many Seconds in a Year?
60 seconds per minute
X minutes per hour
X hours per day
X days per year
= the number of seconds per year
31.55 million

14. So How Far is a Light Year?
9,500,000,000,000,000 meters.
This said out loud is..
That’s Nine Quadrillion, Five Hundred Trillion Meters

15. What is this in scientific notation?
9,500,000,000,000,000 meters.
In scientific notation, this is
9.5 x 1015 m

16. Distance from the Earth
Practice!
Location
Distance from the Earth
Standard Form
Scientific Notation
Proxima Centauri
4.29 ly
Center of the Milky Way
2.99 x 104 ly
Andromeda
2,490,000 ly
Coma Cluster of Galaxies
3.34 x108 ly
Edge of the observable Universe
14,900,000,000 ly

17. More Practice! Location Distance from the Sun Standard Form
Scientific Notation
Mercury
57,910,000 km
Earth
1.496 x 108 km
Mars
2.279 x 108 km
Saturn
1,426,730,000 km
Pluto
5,906,380,000 km