We Observe a Glowing Cloud of Gas in Space with a Spectroscope

question 42

Multiple Choice

We observe a glowing cloud of gas in space with a spectroscope. We note that many of the familiar lines of hydrogen that we know on Earth seem to be in a different place. They are shifted toward the blue or violet end of the spectrum compared to their positions in the spectrum of glowing hydrogen gas on Earth. From this we can conclude that:

• A) the cloud is much hotter than hydrogen on Earth
• B) the cloud is much cooler than hydrogen on Earth
• C) the cloud is moving toward us
• D) the cloud is moving away from us
• E) none of the above can be concluded from this observation.

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Definitions:

Spiral

A curve which emanates from a center point, getting progressively farther away as it revolves around the point.

Transverse

Positioned or lying across; situated crosswise.

Arthrography

A diagnostic imaging technique used to visualize the inside of a joint using X-ray after injecting a contrast medium.

Arthroscopy

A minimally invasive surgical procedure used to diagnose and treat issues within a joint, using a type of endoscope inserted through a small incision.