Lesson 05

COSMIC
SHIFT

How the Doppler Effect revealed the expansion of the universe.

Just like sound, light has a frequency that determines its color.

High Freq (Blue) Low Freq (Red)

Shorter wavelength = Blue | Longer wavelength = Red

Stars emit a specific "barcode" of light called an absorption spectrum.

Object is moving TOWARD us. Wavefronts bunch up. Wavelength decreases. Color shifts toward blue.

Approach

Object is moving AWAY from us. Wavefronts stretch out. Wavelength increases. Color shifts toward red.

Recession

Edwin Hubble noticed that almost EVERY distant galaxy showed a Redshift.

"The farther away a galaxy is, the faster it is moving away from us."

THE CONCLUSION:

THE UNIVERSE IS EXPANDING