The great unknowns

One of my granddaughters, just turning 14, is fascinated with the big questions in astronomy and cosmology, and admitted recently that she desperately hopes that the nature of dark matter won’t be determined before she gets old enough to work on the problem herself.

That led me to reassure her that there were lots of big problems still to work on, and if dark matter has been understood by the time she finishes graduate school (unlikely), there will be lots of other interesting problems to work. And that conversation in turn led me to think for while about what some of the other remaining “big unknowns” were.

• We know a great deal about the neuroanatomy of the brain, and even a good bit about the molecular processes going on in and between brain cells, but we still have no idea how all of these mechanical and chemical processes result in a self-aware, thinking mind.

• We understand in great detail the working of gravitational fields, and can predict with high accuracy the effect of gravity of satellites and spacecraft and planets, yet at a fundamental level we still really have no idea how mass distorts spacetime in its vicinity to cause a gravitational field.

• We understand in great detail how to create and control electromagnetic fields, and routinely use this knowledge to build such sophisticated things as directional radio antennas and containment fields for plasma jets, yet at a fundamental level we still have no idea why an ordinary magnet draws some materials to it and not others.

• We now understand that black holes exist (a wild, off-the-wall idea only a few decades ago), and even that black holes seem to be essential to the formation of galaxies, and seem to exist in the center of most if not all galaxies, including our own. Yet we understand almost nothing about what goes on in a black hole. Calculations based on standard physics go awry (give indeterminate answers or go to infinity) in the center of a black hole.

• We know life exists, because it exists here on this planet, but we as yet have no idea if life is common or rare in the universe, and if the basic structure of earth life (DNA-RNA based) is the only form it can take. Neither do we know if, where conditions allow enough time for it to evolve, intelligence is rare or common in the universe.

• We understand the pace at which radioactive materials decay, according to the half-life rule, but we have no idea what causes a particular radioactive atom to decide to decay at one moment rather than another. Nor do we understand the recently-discovered fact that the rate of decay of radioactive elements all across the earth apparently fluctuates minutely but synchronously.


It’s worth remembering that just because we have equations that can accurately describe and predict an effect does not mean that we truly understand the effect, just as fire was used practically for tens of thousands of years before anyone had the slightest idea what was going on in a fire.

Rest assured, dear granddaughter, that there will be plenty of big problems left to work on when you grow up.