Why Do Stars in the Disk of a Spiral Galaxy

question 38

Multiple Choice

Why do stars in the disk of a spiral galaxy orbit in roughly the same direction, in the same plane in space?

• A) It is pure coincidence; the stars just happen to be going in the same direction.
• B) The gas that formed the stars was shaped as a giant, rotating disk.
• C) Collisions between the stars caused their motions to organize into a general, spinning disk direction.
• D) After the stars formed, gravity pulled the stars down into a plane in space, all orbiting a supermassive black hole.

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Definitions:

Estimator

A statistic used to estimate the value of a population parameter.

Simple Linear Regression

A statistical method that models the relationship between a dependent variable and one independent variable by fitting a linear equation to observed data.

Confidence Interval

A range of values derived from sample data that is likely to contain the true value of an unknown population parameter, expressed at a given confidence level.

Total Winnings

The aggregate or combined amount of gains or earnings, often used in the context of gambling or competitions.