2. Red Orange Yellow Green Blue Indigo Violet
Visible Light
Humans divide visible Light into “colours”
Red Orange Yellow Green Blue Indigo Violet
ROY-G-BIV

3. The Production of Light
Light is produced by three main ways:
Incandescence
Hot things glow 3

4. The Production of Light
Luminescence
Electrons jump around

5. The Production of Light
Chemoluminescence
Chemical reactions
Video – Bioluminescence

6. Speed of light The speed of light in a vacuum is a universal constant.
300,000,000 m/s
The speed of light in a medium is always slower than the speed of light in a vacuum.

7. Speed of Light
Earth
Moon
384,000,000 m
About 1 Sec.

8. Looking Into The Past
By looking at objects in the universe (stars and galaxies), you are looking into the past.

9. Looking Into The Past Time for the light to reach us Object The Moon
1.3 seconds
The Sun
8 minutes
Jupiter
35 to 52 minutes
Pluto
5.5 hours
Alpha Centauri (nearest star)
4.3 years
Sirius (Brightest star in our sky)
9 years
Betelgeuse (Another bright star)
430 years
Orion Nebula
1500 years
Andromeda Galaxy
2.5 million years

10. Hubble Ultra Deep Field
HUDF captures over 10,000 galaxies
This picture represents a piece of the sky you would see by looking through a straw