The Proper Motions of Stars Are

question 107

Multiple Choice

The proper motions of stars are:

• A) easy to measure for most stars on photographs taken six months apart.
• B) noticeable to the unaided eye as a gradual shift of the constellations westward over the course of a month or two.
• C) easy to observe with the unaided eye over the course of an hour or two.
• D) difficult to measure, even on photographs taken several years apart for any but the nearest stars.

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Definitions:

Adult Population

The segment of the population that comprises individuals who are considered adults, typically measured by age, and which can participate in activities such as voting and working.

Labor-force Participation Rate

The percentage of the working-age population that is either employed or actively looking for employment.

Population Participation

Often referred to as the labor force participation rate, it measures the proportion of the working-age population that is employed or actively looking for employment.

Labor Force

The total number of people who are available to work, including those who are employed and those who are unemployed but seeking work.