Astronomers Aim a Radio Telescope at a Distant Region of the Milky

question 42

Multiple Choice

Astronomers aim a radio telescope at a distant region of the Milky Way Galaxy and detect 21-cm radio waves with no Doppler shift. Which one of these possible explanations is NOT correct?

• A) The neutral hydrogen in this region is not moving relative to Earth.
• B) The neutral hydrogen in this region is moving perpendicularly across the line of sight.
• C) The neutral hydrogen in this region is in a circular orbit around the galactic center at the same radius as the solar system.
• D) The neutral hydrogen in this region is moving away from Earth instead of toward Earth.

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Definitions:

Marginal Cost

The additional cost resulting from the production of one more unit of a product or service.

Public Goods

Goods that are non-excludable and non-rivalrous, meaning they are available for everyone to consume, regardless of who pays for them.

Production

The process of creating goods and services from various inputs like labor, land, and capital.

Public Goods

Goods that are non-excludable and non-rivalrous, meaning they are available for everyone to use without preventing others from using them as well.