1. Why is the sky blue?
Ibn al-Haytham
© 2008 FAU 1

2. Why is the sky blue?
The most important word in Physics …
Why?
© 2008 FAU 2

3. Why is the sky blue?
Physics Biology Chemistry
© 2008 FAU 3

4. Why is the sky blue?
You Are Here
You Are Here
You Are Here
© 2008 FAU 4

5. Why is the sky blue?
You Are Here
You Are Here
You Are Here
© 2008 FAU 5

6. Why is the sky blue?
Newton.
What makes an apple fall is the same thing that makes the planets circle the sun.
1600’s Early work in Greece, China, India.
Physics through History.
Einstein.
Nothing can ever move faster than the speed of light.
1900’s
Name a famous female Physicist.
© 2008 FAU 6

7. Why is the sky blue?
Small.
Atoms, electrons – Quantum Physics.
Today
Two theories.
Both right.
They don’t fit together.
Big.
Space/Time bend and twist – Relativity.
© 2008 FAU 7

8. Why is the sky blue?
String Theory.
Ten dimensions, maybe eleven, maybe twenty-six.
Strings vibrate; things happen.
Could this be the answer?
(Calabi-Yau Space)
© 2008 FAU 8

9. Why is the sky blue?
Who uses Physics?
© 2008 FAU 9

10. Why is the sky blue?
So … Why is the sky blue?
© 2008 FAU 10

11. Why is the sky blue?
Guesses …
The sky reflects the color of the ocean?
Space is dark – maybe dark blue?
Who cares?
© 2008 FAU 11

12. Why is the sky blue?
Blue light is scattered more than red.
When the sun is rising/setting, mostly red light reaches us.
At noon, bluer light is scattered to earth, red light not so much.
© 2008 FAU 12

13. Why is the sky blue?
And here is what that looks like …
Midday Sunrise/Sunset
© 2008 FAU 13

14. Why is the sky blue?
Thank you.
© 2008 FAU 14