8. UNANSWERED QUESTIONS
I conclude with a list of questions I think we need to address
before claiming to understand the nature of infrared emission from
- Is there a fundamental difference between normal and ``starburst''
- What is the best way to separate ``cirrus'' emission from emission
from star-forming regions?
- Do measurements of visible H II regions provide a reliable guide to
the current star formation rate?
- Is the far-infrared optical depth in spiral galaxy disks large
enough to produce self-absorption at high inclination?
- Does the radio emission come from supernova remnants or from cosmic
rays in the interstellar medium?
- What is going on in early-type barred galaxy nuclei?
- Is there star formation in S0 galaxies?
- Do star formation conditions in the central regions of spiral
galaxies resemble those in the disks?