Because of the Period-Luminosity Relation for Cepheids and RR Lyrae

question 29

Multiple Choice

Because of the period-luminosity relation for Cepheids and RR Lyrae variable stars, astronomers are able to _____

• A) determine the relationship between the period of pulses and luminosity
• B) measure the mass of a star
• C) calculate a star's diameter
• D) determine the chemical composition of a Type I Cepheid
• E) narrow their study to eclipsing binary stars only

---

Definitions:

Nixon's Visit

Nixon's Visit refers to President Richard Nixon's historic trip to China in 1972, a pivotal moment in U.S.-China relations that marked the beginning of normalization between the two countries after years of estrangement.

China

A country in East Asia, the world's most populous nation, known for its rich history, culture, and as a major global economic power.

UN

The United Nations, an international organization founded in 1945, aimed at promoting peace, security, and cooperation among the world's countries.

Camp David Accords

Peace agreement between the leaders of Israel and Egypt, brokered by President Jimmy Carter in 1978.