In Photographs,the Pleiades Open Star Cluster Is Surrounded by a Bluish

question 203

Multiple Choice

In photographs,the Pleiades open star cluster is surrounded by a bluish haze (see Figure 11-2,Comins,Discovering the Essential Universe,6th ed.) .What causes this blue light?

• A) starlight scattered from interstellar dust in the star cluster
• B) starlight scattered by the light-sensitive grains in the photographic plate when the picture was taken
• C) shock waves losing energy to interstellar gas in the star cluster, causing the atoms to emit light
• D) starlight absorbed and reemitted by interstellar gas in the star cluster

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Definitions:

Ventricles

Cavities within the brain that produce and contain cerebrospinal fluid, playing a crucial role in cushioning the brain and maintaining intracranial pressure.

First Heart Sound

The sound produced by the closure of the AV (mitral and tricuspid) valves at the beginning of ventricular contraction or systole.

Second Heart Sound

The second heart sound is produced by the closing of the aortic and pulmonary valves at the beginning of ventricular diastole.

Ventricular Systole

The phase of the cardiac cycle in which the ventricles contract, pumping blood out of the heart into the arterial system.