Joel Primack and Nancy Abrams: Shared Cosmology
Gravity Is the Ultimate Scrooge Principle, Part I
Gravity in the cosmos presents a provocative metaphor for the large-scale behavior of the economy and the distribution of wealth. In astronomy, a “rich” region of the universe is defined as one that has more matter than average; a “poor” region has less matter than average. Gravity magnifies differences in the expanding universe: denser regions expand more slowly, and less dense regions more rapidly, than average. Gravity is the Ultimate Scrooge Principle because it always makes the rich regions of the universe comparatively richer and the poor regions poorer. Eventually galaxies form in denser places, and low-density regions become cosmic voids. Wealth left to its own devices can work like gravity: the rich tend to get richer and more powerful.
The important thing about gravity for this metaphor is that it concentrates matter just enough for the universe to become interesting, but not so much that everything falls into black holes. If the universe had started out perfectly uniform and gravity didn’t concentrate matter in the rich regions, matter would have evenly thinned out as the universe expanded, and galaxies like our own Milky Way could not have formed. Similarly, if wealth were so evenly distributed that everyone in the world had the same amount, there might be little progress since only concentrated wealth can undertake ambitious projects. But if wealth is concentrated in very few hands, most people are too poor to buy much—and this situation often leads to political as well as economic instability.
In the universe the inexorable force of gravity always gets counterbalanced—except at black holes. If we think cosmically, the natural tendency of wealth to concentrate must also be counterbalanced if we want to achieve an economic stability comparable to the gravitational stability of our solar system and our galaxy. What is it that counterbalances gravity? Motion. Everything is in motion. The earth and other planets are orbiting the sun, and the sun with its planetary entourage is orbiting the center of our galaxy. The balance between gravity and motion maintains our universe. It is worth understanding how this works, because it can perhaps tell us something important about money.
There is a quantity in physics that measures all such curving motion, and that quantity, called “angular momentum,” is constant—or, as physicists like to say, it is conserved. Common sense often misleads people to assume that motion runs down, that friction eventually slows it down; but in fact angular momentum is lasting and unchangeable and thus a permanent counterbalance to gravity. Conservation of angular momentum is what makes an ice skater spin faster if she pulls in her arms. Angular momentum is simply mass times radius times rotational speed. When the skater pulls in her arms, her mass stays the same but her radius decreases, so conservation of angular momentum dictates that her speed of rotation must increase. Similarly, when a galaxy forms, ordinary matter falls toward the center, and as it gets closer it rotates faster and faster about the center until its angular momentum shapes it into a disk and prevents it from falling any farther. Gravity is then counterbalanced by stable circular motion, stars like our sun form in the galactic disk, and the result is a spiral galaxy like our own Milky Way. Circular motion in the sense of angular momentum is as real and measurable as energy, and like energy it can be transferred but not lost. In the formation of our galaxy, a balance was quickly achieved between gravity and motion, and the galaxy has been stable for billions of years, during which it evolved life and intelligence on at least one planet.
Does wealth behave like gravity? The present trend in some countries including our own certainly looks that way. For most of the world’s wealth to end up in just a few hands would be the economic equivalent of a black hole. From the 1930′s to the early 1970′s, the distribution of income in the United States was stable. More recently, however, that has changed. Although the United States has the highest average income of any large industrial country, it also has the greatest income inequality, the largest fraction of its population in poverty, and the largest fraction incarcerated. Most of the past decade’s economic growth has gone to the upper five percent of families. Salaries and bonuses of top executives skyrocketed during the past decade, while the average worker’s inflation-adjusted hourly wage has not changed much in thirty years. The upward economic mobility that has long been part of the American dream has almost disappeared; very few children who grow up poor now make their way even to moderate affluence.
Worldwide, the inequalities are stark and increasing in much of the world. The richest 1% of adults in the world own 40% of the planet’s wealth, according to the largest study yet of wealth distribution, by the United Nations World Institute for Development Economics Research, 2006. Half the world’s adult population, however, owned barely 1% of global wealth. If current trends continue and the rich get richer while the poor get poorer, either in the United States or internationally, it may become impossible to persuade most people to cooperate in solving problems of population, resource use, and pollution.
Among the rich, as among the poor, there are certainly some corrupt people and criminals, but in many cases it is no more the fault of the rich that they get richer than it is the fault of the poor that they get poorer: it’s in the nature of wealth. However, the responsibility of a society with higher values than money—such as life, liberty, and the pursuit of happiness—must be to cultivate and uphold those economic forces that can counterbalance this natural tendency toward concentration of wealth and play a role analogous to motion in opposing gravity.
What could be the economic force that counterbalances the Ultimate Scrooge Principle of wealth? We will answer this in our next blogpost.
Originally published on the SFGate.com City Brights Blog.
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