There’s an interesting article in New Scientist that purports to describe “seven questions that keep physicists up at night”. The list is very heavy on the “deep questions” that tend to percolate around the more esoteric quarters of the high-energy physics world, and not so much on the vast bulk of physicists who (ad Chad and I like to harp on) do physics that’s much more directly connected to the real (i.e., observable) world. For instance, it’s the question of high-temperature superconductivity probably dominates the dreams of lots of solid state physicists, but it’s not on the list. So let’s look at the questions and rate them on Matt’s AMO Physicist Insomnia Index:
Why this universe?
In other words, “why these laws of physics and not others?”. I can’t say I worry about this much. The laws are what they are. I hold out zero hope for the idea that only one set of laws will turn out to be mathematically possible.
What is everything made of?
Electrons and photons – wait, you mean there’s more? Seriously, it would be nice to know what’s what in the world of fundamental particles and fields. But it doesn’t keep AMO physicists up at night, since as far as we’re concerned atoms are pretty much as small as we need to worry about.
How does complexity happen?
Ah, now this is an interesting question and has lots of bearing everywhere in physics. The trivial answer is “because the mathematics puts it there”, but nonlinearity and all the rest of that difficult math is not completely understood despite its vast importance. This one actually registers at a modest level on the insomnia scale for me. (Not literally of course.)
Will string theory ever be proved correct?
Nope. But I wouldn’t be at all shocked if it’s proved incorrect. In any case I worry about it exactly none, as it affects experimental physics exactly none.
What is the singularity?
What is a singularity, not what is The Singularity. I don’t really worry about this, but it’s an interesting and important question. We have great mathematical descriptions of gravity and quantum mechanics, but they don’t mesh well in the domains where both effects are of similar scale. How to resolve this? Beats me, but I’d say this one at least registers at a small level on the insomnia scale.
What is reality really?
Ok, this is just ridiculous.
How far can physics take us?
The article is a little vague and airily philosophical about this, but I think it’s asking how close physics is to being “finished”. This isn’t a purely hypothetical question. As in chemistry, large pieces of the subject are – if not finished – then at least only in need of some work around the periphery. But I’d say even if the Theory of Everything were found tomorrow, we’d have many decades of work left both exploring its consequences and continuing work in non-fundamental physics. In any case, not worth worrying about.
So of the seven questions, I think two are actually relevant to most physics. Well, it’s a start.