What Is the Best Evidence That Sagittarius A* Is a Black

question 45

Multiple Choice

What is the best evidence that Sagittarius A* is a black hole at the centre of the Milky Way galaxy?

• A)Orbits of stars indicate a mass several million times that of the Sun within a very small volume.
• B)Sagittarius A* is a powerful radio source.
• C)No visible light from Sagittarius A* reaches the Earth.
• D)Radio maps of the region around Sagittarius A* show complicated gas structures believed to be related to massive star formation.

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Definitions:

Optimum Interstimulus Interval

The ideal time gap between the presentation of a conditioned stimulus and an unconditioned stimulus for effective associative learning to occur.

Knee-Jerk Reflex

A reflexive action produced by a sharp tap on the tendons just below the kneecap, demonstrating the patellar reflex.

CS

Stands for Conditioned Stimulus, which is a previously neutral stimulus that, after becoming associated with an unconditioned stimulus, eventually comes to trigger a conditioned response.

UCS

Unconditioned Stimulus, an aspect of classical conditioning; a stimulus that naturally triggers a reflexive or unconditioned response without prior learning.