This is written by two guys who teach physics (Wiggins) and chemistry (Wynn) at the college level in a reader-friendly manner in which each of the five unsolved problems is presented, explained, and critiqued. Each section is then concluded with indications of how these problems might be solved. There are some nice cartoons by Sidney Harris to augment the text.
The five "biggest" problems are (from different disciplines and not without controversy):
1. The nature and origin of mass. (Why do some particles have mass while others do not?)
It is obvious that we really do not understand the nature of mass from our inability to form a unified theory involving gravity, a theory that would unify quantum mechanics and relativity. Indeed I think physicists are just whistling in the dark when they talk about particles and fields. It's clear to even this casual observer that the real nature of particles/waves, particles/fields is not really understood, and perhaps cannot be understood in anything other than a once or twice removed mathematical sense. We can write equations that describe what we observe, but the intrinsic nature of all phenomena remains veiled. We avoid infinities in the mathematics of physics as a long-observed and much beloved rule (something like Occam's Razor) with the result that we (necessarily) "construct" limits on the physical world like those named after Max Planck. Beyond (or "below," or "under" or "smaller than," etc.) those limits is potentially a whole universe of physics much like what might be beyond the Big Bang in cosmology.
Authors Wiggins and Wynn acknowledge that the Standard Model of physics has a "dark side" (p. 30) and that the long-sought Higgs field particle may be a "mathematic convenience." (p. 31) From my point of view everything in physics (and this includes all of string theory) that has not met with experimental proof is possibly a "mathematical convenience." This is not to denigrate physics or physicists. On the contrary. What physicists have accomplished toward an understanding of the world in which we live stands as one of humankind's most glorious achievements. The problem is that (as quoted from J.B.S. Haldane on page 159) "the universe is not only queerer than we suppose, but queerer than we can suppose." In other words don't hold your breath for the dreamed-of "Theory of Everything." And if it arrives, don't imagine that "everything" really is "everything."
2. How did lifeless chemical reactions become life?
The authors present some of the history (Stanley Miller's primordial soup experiment; panspermia, etc.), outline the problems, tell us a little about DNA and RNA, and finish with how the puzzle might be solved and by whom. I would observe that imbedded within this question is a theoretical bugaboo that first needs to be resolved. We have to agreeably define what "life" is before we can hope to make a distinction between very complex but "lifeless" self-replicating molecules and molecules forming living organisms. As such, the problem is one of definition as much as anything else. Clearly if we left out our notion of things living as opposed to things not living, we might discover a step-by-step continuum without a clear demarcation point.
3. How do proteins control cells and tissues? ("What is the complete structure and function of the proteome?")
The authors note that since the genome has been mapped and sequenced, "the unsolved problem" in biology "has shifted" to "How do protein molecules built from directions provided by [the]...genomes contribute to the structure and function of organisms?" (p. 71) A very complex problem indeed, but at least it is a practical problem and not a theoretical one, and as such (unlike some others in this book) is one that conceivably can be solved through a whole lot of hard work.
This is about cells and how they function. The authors reprise the genome mapping and sequencing story, and then point to "Protemics: The Next Frontier."
4. Can we predict the weather? (Or, how accurate can our weather predictions be?)
This of course is about complexity theory and why that famous butterfly in the Sahara continues to influence the formation of hurricanes in the Carribean.
Quick answer: accuracy will continue to fall off as the square of the distance in time. Just joking, but clearly the more lengthy the forecast, the more uncertain it will continue to be.
5. Why is the universe expanding faster and faster?
Ah, yes. What IS the nature of Einstein's fudge factor that has recently returned? I love this one. The real question is what IS all that dark energy and dark matter out there? As the authors point out only 4%(!) (see page 129) of all the matter in the universe is accounted for in terms of things seen. Seventy-three percent is in the form of dark energy and another 23% in the form of dark matter. It is amazing to realize that 96% of what exists is stuff we know next to nothing about!
A nice part of the book are the "folders" at the back in which many other interesting issues are briefly presented. The problems in the "Problem Folder" are organized according to disciplines, "Physics Problems," Chemistry Problems," etc. There are sixteen ideas in the "Ideas Folder," including such things as anti-matter, protein folding, chaos theory, global warming, and so on.
Bottom line: Wiggings and Wynn do a good job of introducing the general reader to what scientists at the horizon are working on. It's really amazing to realize how far we've come as knowledge-seeking creatures, and then to get a glimpse of how incredibly much there is we don't know.
--Dennis Littrell, author of 鈥淭he World Is Not as We Think It Is鈥�