The Period-Luminosity Relationship for Cepheid Variable Stars,relating Variability to Absolute

question 177

Multiple Choice

The period-luminosity relationship for Cepheid variable stars,relating variability to absolute overall brightness,thereby providing identifiable beacons throughout our local space,was discovered by:

• A) Harlow Shapley.
• B) Henrietta Leavitt.
• C) Edwin Hubble.
• D) Sir Isaac Newton.

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Definitions:

Generalized Anxiety Disorder

A mental health disorder characterized by excessive, uncontrollable worry about everyday things, beyond normal stress or anxiety levels.

Chronic Dread

A persistent and overwhelming feeling of fear and anxiety about the future or unknown.

Pessimism

A predisposition towards observing the most negative aspects of situations or expecting the most unfavorable outcomes; an absence of optimism or trust in what lies ahead.

Agoraphobia

A type of anxiety disorder characterized by an intense fear of places or situations from which escape might be difficult or embarrassing, or in which help may not be available in the event of a panic attack.