John Mather: When I was a child, I was really interested in astronomy, and it was just one of those things that was full of mystery at that time.  I studied lenses and telescopes, and I saw the surface of the sun with a little telescope that I made with lenses in a cardboard tube.  So I was all enthusiastic about astronomy when I was in grade school.  And then I learned a little bit more in high school, and I took physics courses.  And finally, through graduate school, I was thinking I wanted to be a particle physicist, because that was the biggest mystery of that time.  Then I was looking for a thesis project, though, and I found an advisor who had this new idea to measure the cosmic microwave background radiation — the primordial heat of the universe. It had just been discovered five years before that, so it was time to go measure.  So okay. Well, I’ll try that.  So that was the beginning of my career as an astrophysicist. Most of my training is as a physicist rather than as an astronomer.