The So-Called Water Hole, a Region of the Radio Spectrum

question 49

Multiple Choice

The so-called water hole, a region of the radio spectrum chosen for searches for signals from intelligent life because galactic and Earth-based noise and atmospheric absorption are at a minimum, is so named because

• A) water vapor (H₂O) has an intense laserlike emission line at this wavelength that extraterrestrials might use to communicate with Earth.
• B) two astronomically important wavelengths, the 21-cm line of H and a line from the hydroxyl radical OH, are in this region, the letters H and OH signifying water.
• C) water vapor emissions from planets at this wavelength will be a good indicator of life on other planets because water is essential for life as known.
• D) water vapor absorption in Earth's atmosphere reaches a sharp minimum at this wavelength.

---

Definitions:

Financing Activity

Transactions and events where cash is raised for business purposes, including issuing equity, borrowing, and repaying loans.

Fixed Asset Acquisition

The process of purchasing fixed assets, like property, plant, and equipment, that are used over a long period in the operation of a business.

Times Interest Earned Ratio

A financial ratio that measures a company's ability to meet its debt obligations by comparing its income before interest and taxes to its interest expenses.

Earnings Before Interest and Taxes

A measure of a firm's profit that includes all expenses except interest and income tax expenses.