Excellent presentation. This was just what I was looking for -- an overview of the chemical processes in deep space. I actually have a question ... the word "dust" is frequently mentioned when talking about "stuff" in space, how do we go from atoms, to molecules (the subject of this talk) to dust. What are the likely dominant compositions of this dust? I follow and agree with P.M. Robitaille (KZbin Sky Scholar) that a gas cannot collapse upon itself to form a star because the hydrogen molecules are too light and have too much kinetic energy relative to each other to self-compress. However, if the atoms can grow by chemistry into dust grains, then the relative kinetic energy is reduced and gravitational attraction can collapse the larger molecules. So a good discussion about dust formation is my next learning goal.