How Do We Know That AGN Have Sizes on the Order

question 8

Multiple Choice

How do we know that AGN have sizes on the order of our Solar System?

• A) Quasars and Seyfert galaxies are stellar-like sources.
• B) Their brightness varies by factors of a few.
• C) The emission lines in their spectra show gas rotating at speeds of thousands of km/s.
• D) Their brightness varies on timescales of hours to a day.

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Definitions:

Activation-Synthesis Theory

A theory suggesting that dreams are the result of the brain trying to make sense of neural activity that occurs during sleep by synthesizing this activity with stored memories.

Cognitive Development Theory

A theory, often associated with Piaget, that outlines how children's thinking abilities evolve in stages as they mature.

Memory Consolidation Theory

The Memory Consolidation Theory postulates that stable, long-term memories are formed from the transfer and reorganization of short-term memories during specific brain states.

Wish-Fulfillment Theory

A psychological concept proposed by Sigmund Freud suggesting that dreams represent the fulfillment of unconscious desires or wishes.