Why Is 21-Cm Radiation the Best Way to Map the Spiral

question 58

Multiple Choice

Why is 21-cm radiation the best way to map the spiral arms in the Milky Way?

• A) The molecular hydrogen gas that produces this emission is concentrated in the spiral arms.
• B) These photons,which are produced by neutral hydrogen,penetrate the dense clouds of gas and dust in the disk.
• C) This synchrotron emission is produced by supernovae,which are concentrated in the spiral arms.
• D) Radio telescopes are easier to operate than optical telescopes and observations can be made even during the daytime.

Graph inequalities and interpret graphs representing inequalities.

Apply knowledge of percentages and ratios in real-life situations.

Conceptualize and solve problems involving mixtures and solutions.

Understand and manipulate formulas to isolate a variable.

---

Definitions:

Stereotype

Oversimplified and generalized beliefs about a particular group of people or things, often leading to prejudiced attitudes and actions.

Internal

Pertaining to or situated within something; intrinsic, coming from the inside.

Stable

Constant and unchanging; not prone to fluctuations or sudden changes.

External

Pertaining to or located on the outside of something; often refers to influences or factors coming from the environment around an individual or system.