Electromagnetic Waves
H How do we know what we know about the beginning of the universe and it's subsequent evolution?

On Intelligence, and Blakeslee
The Big Bang
Wilkingson Microwave Anisotrophy Probe

Cosmic Microwave Background Radiation

    The 2.7 K Background Sky

The Wilkinson Microwave Anisotropy Probe (WMAP) is a NASA satellite whose mission was to survey the sky to measure the temperature of the radiant heat left over from the Big Bang.

    The goal of WMAP is to map out minute differences in the Cosmic Microwave Background (CMB) radiation in order to help test theories of the nature of the universe.

These spectra are examples of what an astronomer would obtain when aiming a spectrometer-equipped telescope to some galaxy far far away. . .

The middle spectrum would be the spectrum seen in the laboratory when the source and observer are not moving with respect to each other.

The top spectrum suggests that the source and the earth are moving toward each other because the lines are shifted to the blue part of the spectrum.

The bottom spectrum suggests that the source and the earth are moving away from one another because the lines are shifted to the red part of the spectrum.

The Doppler Redshift suggests that
the universe is Expanding.

The Doppler Redshift

Does light travel in waves?
Thomas Young's double slit experiment demonstrates that light is a wave phenomenon.

As the waves pass throught the slits they fan out and interfere with each other to produce the pattern on the screen.

This patterns reveals constructive and destructive intereference.
Propagation of Electromagnetic Waves.

The Electric and Magnetic Fields move perpendicular to the propagation of the wave.
How fast is light?
   Maxwell's Equations 1, 2

Electromagnetic Spectrum
Looking at the world through different 'eyes'.

Chandra X-Ray Observatory

a larger image
How are Electromagnetic Waves Generated?
Electrons moving from one orbit to another release photons of light. (electromagnetic radiation)
Accelerating Charges


Interaction of Electromagnetic Radiation and Matter
This is what the universe is all about.

Reflection and Refraction
White Light is composed of many different frequencies.
When passed through a prism, these frequencies are diffracted at different angles.