Letters to the editor

No thanks to glowing plants
Omri Amirav-Drory is a menace to dark skies (“A glowing green thumb,” SN: 8/24/13, p. 32). Although way too few cities or towns use them, full-cutoff street lights — which project light only downward, where it’s needed — do exist.  Glowing trees will certainly project in every direction, both wasting lumens and aggravating light pollution. If these trees become a reality, and if my town considers planting them, you can be sure I will oppose the move. Keep the glowing plants as curiosities in botanical gardens and protect us from dreamers and visionaries.
K.A. Boriskin, Bellingham, Mass.

There is a problem with using glowing trees to light cities: light pollution. Sky watchers are already up in arms over poorly aimed lighting (see, for example the International Dark-Sky Association, www.darksky.org), and glowing trees as shown in the illustration would certainly qualify. Fortunately there’s a simple solution: Genetically engineer the trees so only the undersides of the leaves glow, aiming the light downward where it is useful. This should be fairly easy to do since the top and bottom of leaves are often different. 
Bobby Baum, Bethesda, Md.

Quakes and fracking
It is not the wells that cause earthquakes we should be worrying about (“Huge quakes foretell smaller ones,” SN: 8/10/13, p. 16); it is the ones that don’t. If a well causes earthquakes, it is injecting into a pressure compartment that is strong enough to allow pressure to build. If that doesn’t happen, the pressure compartment is weak, circulating injected fluids more broadly. Once this happens, these fluids are at the whim of the basin’s hydrologic system. We need to rethink the long-term safety of the entire injection process. If that slows down fracking, so be it. It is being drilled up so fast it will be in severe decline in only about 20 years. That shortfall will help no one, not even the oil companies.
John Sales, Barre, Vt.

Space party
I might have been feeling a bit spacey this morning at 2 a.m. while I read “How molecules hook up in space” (SN: 8/10/13, p. 9) about the discovery that alcohols and sugars are among the organic chemicals floating in interstellar space. What a thrill imagining all that free moonshine and candy wafting around up there! Keep up the good work, astronomers, and perhaps we will have pie in the sky, by and by!
Shelley Goldbloom, Corbin, Ky.