As the end of World War II brought about a housing boom, the market for consumer home lending expanded significantly, and the financial institutions that had traditionally provided mortgages to working-class Americans faced new competitive pressures. Although the United States League of Local Buildings and Loans in America (USLLBLA), an association of institutions focused on savings accounts and homeowner lending, did not oppose the entry of other lenders into the market, it did lobby to retain the privilege of offering higher interest rates on savings accounts than banks were allowed to give.

     These efforts were spurred in part by the expansion of the Federal Housing Administration (FHA), a federal agency that began to insure mortgages with increasingly consumer-friendly terms. The FHA rules, like USLLBLA, allowed people to afford homes who otherwise could not have done so. It did this in part by relaxing the regulations governing the maximum length of a mortgage and the minimum down payment required, making the loans available to those who accrued capital more slowly than the typical homeowner previously had. In response, the USLLBLA also formed the Voluntary Home Mortgage Credit Program (VHMCP), taking advantage of the new regulations to offer the more affordable loans to people in rural areas in hopes of forestalling further expansion of federal agencies into the mortgage business.

     The general theory of relativity posits that major events in the universe, such as the creation of a black hole, create ripples in the space-time continuum, also known as gravitational waves, which were recently detected for the first time by the Laser Interferometer Gravitational Observatory (LIGO). Though the interferometer was invented in 1887, not until 2002 was one used in an attempt to detect gravitational waves. The instrument splits a laser beam so that the two resulting beams travel down perpendicular arms—perfectly identical tubes that are four kilometers long—then hit mirrors and return to their shared origin point. This allows the instrument to detect extremely minute changes in the lengths of the arms. In the absence of a gravitational wave, the wavelengths of the two beams match up perfectly. However, if something interferes with the beams' paths, their peaks and valleys no longer align, and the instrument registers the interference.

     Gravitational waves cause space to shrink in one direction and expand in a perpendicular direction. If the interferometer is hit by a gravitational wave, one arm will grow and the other will shrink by normally imperceptible amounts, but the differing distances traveled by the laser beams are registered by the instrument. The LIGO actually consists of two interferometers, thousands of kilometers apart, which compare data in order to rule out localized vibrations and flickers. In September 2015 it detected its first gravitational wave, which was determined to have been generated by the collision of two black holes between one and two billion years ago. Another gravitational wave was detected in December 2015.

      Despite views that globalization has reached its peak, a period beginning in the nineteenth century and extending into the early-twentieth century, in fact, is the interval during which international barriers to trade fell most steeply, as can be seen in the case of price convergence in commodities. The prices of cloves, pepper, and coffee failed to converge between Amsterdam and East Asia or between England and India from as far back as 1580 but began in 1820 to draw closer. Similarly, the difference in wheat prices in the United States and England fell from one hundred percent in the early-nineteenth century to negligible levels late in the century and to no difference at all in the early-twentieth century. A similar story unfolded during this period for bacon, cotton, and rice.

     Peter Lindert and Jeffrey Williamson have summarized the price gaps in commodity markets between continents as evolving in three phases. From 1820 to 1914, these gaps fell by 81 percent; they attribute 72 percent of this decline to cheaper transport and 28 percent to trade policies. Second, during the wartime period of 1914 to 1950, the gaps doubled, due to a reversal in trade policies. Finally, from 1950 to 2000, they fell again by 76 percent, ending up 92 percent lower than in 1820, with about four-fifths of the total change attributable to cheaper transport and one-fifth to more favorable trade policies.

     Trade data for this period are typically articulated in terms of ratio of total trade volume to gross domestic product, since commodity price information is not universally available. These ratios in many advanced economies were higher in the mid-1990s than in the early 1900s, but not by much. In Japan, notably, the percentage of GDP for which trade accounted in 1995 was 17 percent, far under its 1910 level of 30 percent, as measured in current prices. Sure enough, the ratios have risen somewhat in other economies over that same time period—by 13 percentage points in the United Kingdom, 8 points in France, and from 11 percent to 24 percent in the United States; this latter spike may explain why the attention to globalization has been especially acute in America. These increases, nevertheless, are modest given the fact that the world economy grew roughly twice as quickly in the twentieth century as in the nineteenth.

     The ratios above, and hence the substantiation for the argument that globalization peaked a century ago, grow much more dramatically if they are computed in constant prices rather than in current prices, because the prices of goods relative to services fell due to sustained increases in productivity in the sectors producing these goods. Trade has grown most in those sectors in which prices have most strikingly fallen, so the proportions of GDP in constant prices have risen more than those in current prices.