Hubble_Redshift_prelab_04-05-10

Hubble_Redshift_prelab_04-05-10 - Expansion of the Universe...

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Expansion of the Universe pre-lab Answer the questions at the end of this text by typing them into the submission box on Blackboard. In 1914, V. M. Slipher began taking spectra of what were called “spiral nebulae.” At the time astronomers thought these were located within our galaxy, but Slipher noticed that the spectral lines in 11 out of 15 of these nebulae were shifted towards redder wavelengths, indicating they were moving away from Earth. This implied that most of them were moving away from us. In the 1920 Edwin Hubble and Milton Humason observed the periods of Cepheid variables within the “nebulae” and calculated their distances from us, establishing that that these spiral nebulae were not withint the Milky Way, but were farther away, vast galaxies similar to our own. They also showed that the closer the galaxy the smaller the red shift of its spectra lines, the farther the greater. Hubble and Humason demonstrated that the radial velocities were proportional to their distance D from the Milky Way, as
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This note was uploaded on 02/06/2011 for the course ASTR 114 taught by Professor Staff during the Spring '08 term at George Mason.

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Hubble_Redshift_prelab_04-05-10 - Expansion of the Universe...

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