Tuesday, October 28, 2014

Progress comes of looking in the dusty corners

Climate-change assertions notwithstanding, there is no such thing as "settled science."

No, this isn't a post about climate change, neither for or against, convinced or skeptical. But I'm not above -- before I move on to today's main topic -- a crack against those (not typically scientists) who believe anything in science is ever proven. What science can do is:

(a) propose theories (read: models, aka simplified representations) of reality useful for solving problems and making predictions in particular circumstances and

(b) refine -- or refute -- theories as their shortcomings and limitations become clear, or as conflicting data show up.

(A favorite Einstein quote, after which I promise to come to the point: “Everything should be made as simple as possible, but no simpler.”)

A brief history of time and space
Thus Newton's simple and elegant seventeenth-century theory of gravity sufficed until astronomers and physicists began theorizing about extreme conditions (e.g., in the vicinity of black holes) and were able to make increasingly precise observations (e.g., to discern in nineteenth-century observations the deviations between Mercury's actual orbital motion and the predictions of same from Newtonian theory).

These and other difficulties were resolved a century ago with Einsteinian gravity theory -- aka General Relativity. A century later, after many tests have been performed to poke and prod GR theory for limits to its accuracy and applicability, theorists look for alternative models (see Alternatives to General Relativity) and experimentalists continue to test GR's predictions and implications (see "Tests of general relativity").

And with all that by way of stage setting, let's have a look at some recent peering into the dusty corners of our physical understanding of the universe ...

Humans weren't around to observe the Big Bang, and yet physicists have through their model of the universe's earliest moments accurately described many of the overall features of the universe. The observed prevalence of hydrogen and helium, for example, can be explained in this way. (Heavier elements are -- the process still ongoing -- largely cooked up much later, inside stars.) Most of the universe's lithium, it has long been believed, was also produced in the immediate aftermath of the Big Bang. So it's interesting to see, on physicsworld.com, that "Big Bang ruled out as origin of lithium-6."

Part of a fusion reactor
A mere two weeks ago I posted (see "Nanotech and starships and fusion, oh my!") on -- among other topics -- the state of research in fusion-based power generation. In that post I quoted a senior DOE official predicting that we are decades from commercial power generation via fusion. So imagine my surprise when, days later, the (nonscientific) general press was breathless with news about Lockheed Martin planning to have practical fusion within ten years. I dearly hope LockMart succeeds -- that they discovered opportunity in one of those dark and dusty metaphorical corners -- but I'm betting otherwise. See (from Yahoo Finance) "Scientists Are Bashing Lockheed Martin's Nuclear Fusion 'Breakthrough' ".

(Note that I'm not criticising LockMart. Indeed, the article states:

While headlines touted Lockheed's results as a "breakthrough" that could "change the world forever," the corporation used no such language in its press release. 

Dust gets in your eyes (er, experiment)
Last March I posted (see "Physics with a Bang") about the BICEP2 experiment attributing particular observations to gravitational waves from the "inflationary era" in the immediate aftermath of the Big Bang. Gravitational waves were a prediction of GR -- that had yet to be detected. The inflationary phase of the early cosmos is a critical element of modern Big Bang theory (no TV reference intended). Inflation was reverse engineered to plug holes in early Big Bang models, and was without independent corroboration. Discovery of gravitational waves attributable to the Big Bang -- firmer foundations for two pillars of modern physics -- would be A Certified Big Deal.

With a hat tip to Carl Sagan, "extraordinary claims require extraordinary evidence." Just maybe, the observations attributed to faint and ancient ripples in space-time itself were, instead, the result of cosmic dust. See (from the the Washington Post) "Cosmic smash-up: BICEP2′s big bang discovery getting dusted by new satellite data" and (from Scientific American) "Betting Against Gravitational Waves: Q&A with Cosmologist Neil Turok."

That's how real science is done -- checking, and rechecking everything.

For some final food for thought, see (again from physicsworld.com) "Is desperation for new physics clouding our vision for new colliders?" In this opinion piece, Nobel laureate Burton Richter wonders:

“In this discussion I see too much theoretical desperation caused by the so-far unsuccessful hunt for what is beyond the Standard Model" (of particle physics) "and too little of the necessary interaction of the accelerator, experimenter and theory communities necessary for a scientific and engineering success.”

Let's hear it for people with the curiosity, skill, and stubbornness to not accept science as "settled," to search in the dusty corners, and in so doing (on occasion) to revise, refine, or utterly alter what we -- thought we -- understood.

1 comment:

Anonymous said...

It strikes me that Western culture in general has come to (and wishes to) believe that we are closing in on all that can be known. Settled science is required if we are ever to be confident that we know anything. Otherwise the list of unknowns accelerates ahead of discoveries. Must scientists continually disturb our blissful benightedness.