The Presence of a Very Large Amount of Unseen Matter

question 102

Multiple Choice

The presence of a very large amount of unseen matter ("dark matter") in the halo of the Milky Way Galaxy is deduced from

• A) the rotation curve of the Galaxy, in which orbital speeds of stars appear to obey Kepler's law.
• B) the rotation curve of the Galaxy, in which orbital speeds of stars in the outer regions of the Galaxy are significantly higher than is predicted by Kepler's law in which the value for the observed mass in the Galaxy is used.
• C) the unexpected absence of luminous matter (stars, and so on) beyond a certain distance from the galactic center.
• D) the high amount of interstellar absorption in certain directions.

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Definitions:

Note Receivable

A written promise for amounts to be received by a debtor, where the debtor agrees to pay back the amount, often with interest, by a specified date.

Accounts Receivable Turnover

A financial ratio that measures how efficiently a company collects revenue from its credit sales, calculated as sales divided by average accounts receivable.

Net Sales

The total revenue from sales transactions after deducting returns, allowances, and discounts.

Average Accounts Receivables

The average amount of money owed to a company by its customers for goods or services provided on credit over a specific period.