Why Do Astronomers Search for Signals of Extraterrestrial Intelligence at a Wavelength

question 13

Multiple Choice

Why do astronomers search for signals of extraterrestrial intelligence at a wavelength of 21 centimeters?

• A) At 21 centimeters there is very little contamination from other material in the galaxy.
• B) Hydrogen emits radiation at 21 centimeters.
• C) Oxygen emits radiation at 21 centimeters.
• D) Greenhouse gases emit radiation at 21 centimeters.

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Definitions:

Peak-Period Requirements

The increased demand or resources needed during the busiest or most active times for a business or service.

Variable Cost

An expense that fluctuates in tandem with the levels of output or sales, such as raw materials and direct labor costs.

Trucking Department

A division within a company or organization responsible for managing the transportation and delivery of goods via trucks.

Peak-Period Requirements

The highest level of resources, such as labor or raw materials, required to manage production or service delivery during periods of maximum demand.