How Did Astronomers Determine That Elliptical Galaxies Are Composed Mostly

question 98

Multiple Choice

How did astronomers determine that elliptical galaxies are composed mostly of dark matter?

• A) They measured the velocities of stars in the inner regions of the galaxies.
• B) They measured the rotation rates of gas as a function of distance from the centers of the galaxies.
• C) They measured the amount of gravitational pull elliptical galaxies have on companion galaxies.
• D) They assumed that the proportion of dark matter was roughly the same as in spiral galaxies.
• E) They measured the X-ray emission from hot gas gravitationally bound to the galaxies.

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Definitions:

Marginal Cost Curve

A graphical representation showing how the cost of producing one additional unit of a good or service changes as production volume varies.

Shutdown Point

The level of output and price where a firm's total revenue exactly covers its variable costs, below which the firm will cease production in the short run.

Marginal Revenue

The additional income generated from selling one more unit of a good or service, crucial for understanding profit maximization strategies in firms.

Average Total Cost

The total cost of production (fixed and variable costs combined) divided by the number of units produced.