How Was Edwin Hubble Able to Use His Discovery of a Cepheid

question 8

Multiple Choice

How was Edwin Hubble able to use his discovery of a Cepheid in Andromeda to prove that the "spiral nebulae" were actually entire galaxies?

• A)There are no Cepheids in the Milky Way,so his discovery proved that it had to be in another galaxy.
• B)He measured the stellar parallax of the Cepheid in Andromeda,was able to determine the distance to it,and showed that it was far outside the Milky Way Galaxy.
• C)From the period-luminosity relation for Cepheids,he was able to determine the distance to Andromeda and show that it was far outside the Milky Way Galaxy.
• D)Since a Cepheid is a type of luminous galaxy,when he found it in Andromeda he was able to prove that Andromeda was a separate galaxy from the Milky Way.

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Definitions:

Membrane Potential

The electrical potential difference across a cell's plasma membrane, crucial for transmission of nerve impulses and muscle contraction.

Neurotransmitter-Response

The reaction of a cell to the binding of neurotransmitters, which can alter the cell's activity or provoke a series of cellular events.

Skeletal Muscle Contraction

The process by which skeletal muscles, attached to bones, produce movement through the shortening of muscle fibers, using ATP as energy.

Dopamine

A neurotransmitter involved in many functions including mood, sleep, learning, and the regulation of body movements, often associated with the pleasure and reward system of the brain.