Getting up to date again in physics

About 20 years ago when the chattering classes were chattering about black holes, string theory, antimatter and other totally mysterious ideas, I thought I ought to bring myself up to date, purely as a self-defensive survival strategy. I read books by Richard Feynman, Stephen Hawking, and scientific popularizers like John Gribben. Lately I've had a few conversations with Richard's very bright nephew Martin who is a first year student at Ottawa U, studying physics. I didn't feel as strongly motivated to get up to date all over again, but browsing in one of the neighbourhood book shops, I saw several remaindered book in a series called "The Big Questions" and on impulse, bought two of them, one on physics, the other on mathematics. It was an inspired impulse. A lot has been happening in physics in the last 20 years, and after a rapid run through The Big Questions in physics, I feel more confident that I can hold my own in conversations with young Martin. I've learned a great many new details and some new principles of physics - there has been a great deal of progress in the past 20-30 years. Some of the new ideas and information are disturbing, alarming even, and some are reassuring. One fact I didn't know before is the vital life-protecting role of the earth's magnetic field. I knew the earth's rotating/revolving molten metal core had something to do with creating the magnetic field and I did know that interaction of the magnetic field and cosmic radiation is responsible for the spectacular displays of the aurora borealis and aurora australis. But I didn't know that the magnetic field has a vitally important role in protecting all living organisms from exposure to lethal solar radiation. I knew that the magnetic field shifts, responding to turbulent movement in the earth's molten core. If it were to happen that even very briefly at such a time of shift, the earth's magnetic field failed to shield living body cells from lethal solar or cosmic radiation, all life on earth could be fried to crisp in a matter of moments. Now there's a thought to help you sleep more easily in your bed tonight.