1. How Far is Far?

2. Distances in space are so large that well-known units such as kilometres are almost meaningless.
Using kilometres to measure the distance between Earth and Jupiter would be as silly as using millimetres to measure the distance between Victoria and St. John’s. The units just aren’t suitable.
Distances within the solar system are usually measured by astronomical units (AU).
Distances involving galaxies use a unit called the light-year.

3. About 7400 km
( mm)

4. Earth to Moon Distance
Average of 384,400 km

5. 1 Astronomical Unit (AU)
Sun to Earth Distance
1 Astronomical Unit (AU)
93,000,000 Miles
1 AU = 149, 599, 000 km
Astronomical units video

6. Body AU
Mercury
Venus
Earth
Mars
Jupiter
Saturn
Uranus
Neptune
Pluto

7. The Light-Year 300,000 kilometres/second X 60 seconds/minute
X 60 minutes/hour
X 24 hours/day
X 365 days/year
9, 460, 800, 000, 000 kilometres
(~ 9.5 trillion kilometres)
Light years video

8. Our Nearest Neighbors Alpha Centauri A & B Proxima Centauri
5 Light-Years
4.2 Light-Years
about 40, 000, 000, 000, 000 km

9. The Solar Neighborhood
Galactic Center
~ 40,000 Light-Years

10. The Size of Galaxies
100,000 Light-Years

11. The Galactic Neighborhood
2 Million Light-Years

12. Hubble Deep Field Image