What Observations Convince Us That the Energy Source of a Quasar

question 80

Multiple Choice

What observations convince us that the energy source of a quasar is physically very small?

• A) rapid fluctuations in brightness since variations over 1 day mean that the source must be less than 1 light-day across
• B) instant disappearance of the quasar when occulted by the Moon's edge as the Moon moves in front of a quasar, indicating a very small source size
• C) sharpness of the emission lines in their optical spectra since motions within a large source would smear out the line shapes
• D) extremely small size of the image of a quasar, even from Hubble Space Telescope images and radio interferometry measurements

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Definitions:

Sigmund Freud

A neurologist from Austria who initiated the field of psychoanalysis, which employs conversation between a psychoanalyst and a patient as a therapy for mental disorders.

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The treatment of disease by the administration of drugs, as distinguished from surgery, radiation, etc., often specifically referring to the use of medication to treat mental health conditions.

ECT

Electroconvulsive Therapy is a psychiatric treatment in which seizures are electrically induced in patients to provide relief from severe mental disorders.

Insight Therapies

A range of psychotherapeutic techniques aimed at helping clients understand the root causes of their psychological issues.