Radio Wave Interaction with Interstellar Matter

Directions: Answer the following questions in complete sentences. Where appropriate, a diagram may be used.

1) Explain how molecular hydrogen is different from H II.

2) What is meant by the term “flips its spin” and what role does this action

play in emission?

3) Why is the 21cm line a useful tool?

4) Name two things that can change the frequency of the 21 cm radiation.

5) What could cause the polarization of radiation to rotate?