Bigger Is Better?
I am concerned that, like most of our renewable efforts recently, Matthew L. Wald’s overview of renewable energy technology, “The Power of Renewables,” is oriented toward projects made by large corporations. This strategy will further entrench vested energy interests, when energy should be diffused to the general public. Windmills on your roof need not generate anywhere near the number of volts required by big windmills, which need to be matched and phased to the grid. And a rooftop windmill’s output can be stored in batteries or large condensers that can be used as insulation. We should not miss an opportunity to capitalize on the ingenuity of individuals worldwide to provide local solutions.
Jeremy Gorman
Wilmington, Vt.

WALD REPLIES: The dollars available for renewable energy equipment are finite and should be spent where they will produce the most energy and displace the most fossil fuels. Big windmills make more kilowatt-hours per dollar than small ones. Big solar installations cost less per megawatt than small ones (and big arrays in the deserts of the Southwest are a better investment of taxpayer subsidies than small rooftop arrays).

Opposition to big corporations and opposition to global warming are two separate things; mixing them does not sit well with everybody.

Healthy Habitats
The narrow focus of Clifton E. Barry III and Maija S. Cheung’s article “New Tactics against Tuberculosis” on “bugs and drugs” as the cause of and solution to TB infections misses the larger point of what works best to combat epidemic diseases. Only a small percentage of the decrease in TB infections can be attributed to microbe-specific interventions such as antibiotics and vaccines. Most of the decline has come from broader improvements in public health. That is not to say that pharmaceuticals are useless, but other factors are even more important. Moreover, nonspecific public health measures help with many unrelated diseases and are generally cheaper than medical care.
C. Andrew Aligne
University of Rochester

Electrodynamic Duo
In “A Quantum Threat to Special Relativity,” David Z Albert and Rivka Galchen question the viability of special relativity because quantum mechanics demonstrates nonlocality, which special relativity does not allow. But the most successful physical theory we have—quantum electrodynamics—is a fully consistent amalgam of both theories that correctly predicts the results of practical experiments.
Lawrence R. Mead
University of Southern Mississippi

ALBERT AND GALCHEN REPLY: Although quantum electrodynamics is mind-bogglingly good at predicting what the outcomes of a wide variety of experiments on quantum-mechanical systems are going to be, it is silent on the question of how such outcomes actually mechanically emerge. And this question is manifestly one to which any complete fundamental account of nature must provide an answer. Irish physicist John S. Bell’s theorem discussed in our article demonstrates that any such answer must ineluctably introduce nonlocality into the world. And that nonlocality is the source of the tension with
special relativity.

The Conqueror Worm?
Crawling to Oblivion,” by Michael Tennesen [News Scan], presents the viewpoint that earthworms are detrimental to North American hardwood forests—a position that is not accepted by many earthworm scientists. The University of Minnesota research group of ecologist Cindy Hale referred to in the article has been making statements about the damaging invasion of U.S. forests by European earthworms over the past few years, but its claims are based on very little well-planned research.

Exotic earthworms in U.S. hardwood forests function similarly to those in Europe and many other places. They break down the undecomposed mat of organic matter (which in Europe is considered characteristic of relatively nonproductive soil), turning it into soil that promotes rapid tree growth. The conversion of leaf detritus to mineral compounds is a key process in the recycling and utilization of organic matter and does not rob plants of nutrients.
Clive A. Edwards
Ohio State University

HALE REPLIES: Tennesen’s article represents the consensus of many researchers and peer-reviewed publications, in particular a set of articles in the September 2006 Biological Invasions with over a dozen authors.

Edwards has built a career on the beneficial impacts of earthworms, based on research in agricultural systems, which we do not disagree with. I make a point of telling my audiences that everything they have heard about earthworms being good for agricultural systems is true. But our research is based on native forest ecosystems of North America. Edwards’s contention that earthworms function basically the same in European forests as in North American forests is correct insofar as where earthworms are present they consume the litter layer, but beyond that the parallel falls apart. Earthworm-free, cold-temperate North American hardwood forests are diverse and naturally reproducing forests. Most hardwood forests in Western (and parts of Eastern) Europe, however, are beech-dominated. Earthworms are often absent in these forests because of very low pH. And when pH is increased, earthworms invade: the litter layer decreases, fertility and tree growth increases, but the increase in fertility is largely the result of the change in pH, not the earthworms.

Note: This article was originally printed with the title, "Letters."