1. EVIDENCE SUPPORTING THE EXPANDING UNIVERSE The Electromagnetic Spectrum and The Doppler Effect

2. The Electro-magnetic Spectrum The electromagnetic spectrum consists of waves with both electric and magnetic properties. All electromagnetic waves travel at the speed of light.

3. Spectrum of Light Dark lines within the specific spectrum of colors are characteristics of light given off by stars. The dark lines (missing wavelengths) within the light replace colors absorbed by elements in the cooler outer layers of the star. Each element in stars adds its own unique signature of dark lines.

7. Redshift Edwin Hubble discovered that light that reached Earth from distant galaxies shows spectral lines that are shifted toward the red end of the spectrum. Remember, each element in stars adds its own unique signature of dark lines.

8. Signature of Dark Lines

9. The Doppler Effect

10. Led to two significant discoveries: All distant galaxies are moving away from us; the only way that this can be explained is that the universe is expanding. The further away an object is from us, the faster it is moving. Putting these two pieces of information together, implies that not only is the Universe expanding, but it is exploding!