Planetary Radio Q and A: What's Jupiter made of?

This week's Planetary Radio features astronomer Heidi Hammel on the recent impact on Jupiter, so go check it out! Each week on Planetary Radio, I do a "Questions and Answers" segment, and I've recently decided to start posting the text of my Q and As, in part so I can give proper credit to the people from whom I crib material.

This week's Q: "I've heard Jupiter called a 'failed star' because it's made mostly of hydrogen. What is it made of, other than hydrogen?"

My answer is taken in large part from a fine astronomy textbook, The Cosmic Perspective, by Bennett, Donahue, Schneider, and Voit:

If you'd like to submit questions for Q and A, just send an email to planetaryradio at planetary.org, or blog at planetary.org.