How Can Astronomers Determine the Size of an Emission Region

question 350

Multiple Choice

How can astronomers determine the size of an emission region in a very distant and unresolvable source?

• A) by measuring the object's mass and using a reasonable value for the average density for matter to calculate its volume and hence its diameter
• B) by using radio interferometry since this technique can resolve far greater detail than optical imaging
• C) by measuring brightness variability since an object cannot vary more rapidly than the time taken for light to cross the source
• D) by measuring the redshift of its spectrum since the redshift will depend on the source size

---

Definitions:

U.S. Government

The federal system of political organization in the United States, comprising the executive, legislative, and judicial branches, established by the Constitution.

Naturalization Act

A U.S. law enacted to establish the process for immigrants to become American citizens, subject to changes and revisions over time.

Citizenship

The status of being a legal member of a particular country or nation-state, encompassing both rights provided by the state and duties expected from the individual.

Slaves

Individuals forced into servitude, denied personal freedom and rights, and compelled to work without pay.