The Age of the Milky Way Galaxy Has Been Estimated

question 61

Multiple Choice

The age of the Milky Way galaxy has been estimated to be at least 13 billion years based on

• A)observations of globular clusters.
• B)observations of open clusters.
• C)21-cm radiation from H I regions.
• D)the rotation curve of the galaxy.
• E)the energy produced by Sagittarius A*.

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Definitions:

Timber Output

Refers to the production volume of timber, including both raw and processed wood materials.

Regional Rail

A passenger rail service that operates between different regions within a country, offering medium to long-distance travel options.

Annual

Occurring once every year.

Plains Droughts

Long periods of abnormally low rainfall, especially prevalent in the Great Plains of the United States, leading to severe water shortages and agricultural difficulties.