Lost Nucleotides
Although Alexander S. Bradley’s article “Expanding the Limits of Life” provides a fascinating account of the discovery of microbes in a previously unknown kind of hydrothermal vent ecosystem on the seafloor, it does not substantiate his claim that the findings hint that life may have originated in an environment like the Lost City hydrothermal vent.

Bradley suggests that Lost City produces “small organic acids such as formate and acetate” and that similar vents might have produced “simple organic acids” and “even more complex fatty acids” or “at least simple organic compounds.” Such statements do not begin to address the conditions and processes that led to the assembly of the nucleotides—adenine, guanine, cytosine, thymine and uracil—nor do the statements indicate that the materials necessary to form the nucleotides might be present in hydrothermal vents.

Studies of life in hydrothermal vents and of the chemistry of hydrothermal vents have provided no information about the evolution of RNA and DNA and of their nucleotides from inorganic and simple organic molecules.

Richard A. Ely
Dallas, Tex.

BRADLEY REPLIES: The reader calls attention to a long-standing question in origins of life research. Scientists widely agree that RNA preceded DNA as the molecule of heredity. But it is not clear whether RNA preceded or followed the origin of metabolism, which relies on the chemistry of much simpler organic compounds. Reconciliation of the geochemical requirements for the origins of RNA and metabolism has remained elusive—we do not yet have a theory for the origin of life. Until we do, sites like Lost City provide critical constraints on the range of potential prebiotic environments on Earth and beyond.

Zoned In
Having long argued that tradable rights and subleasing options are critical components of ocean zoning, I was encouraged to see these ideas displayed so prominently in “Zoning for Oceans” [Perspectives]. The ability to trade and negotiate encourages participation in what otherwise could be a very rigid top-down management approach. It can also encourage more efficient use of fish and other resources that are prone to shift over space and time, reducing the necessity during the design phase of trying to match the ecosystem scale with the policy scale—nearly impossible given the myriad socioeconomic and ecological considerations. For more details, please visit Resources for the Future (www.rff.org/oceanzoning).

James N. Sanchirico
Department of Environmental Science and Policy
University of California, Davis

The Incredible Mechanism
After the marvel, shock and awe of the Antikythera mechanism described by Tony Freeth in “Decoding an Ancient Computer,” there are more questions. This machine was obviously not a one-off or even the first of its kind; there had to be predecessors. Otherwise it would be as if someone 1,000 years from now found an Infiniti Q45 buried in mud and said we must have got tired of walking. We need to find the “Ardi” of the Antikythera.

Then there is the manufacturing. Making machine gears requires precision tools and considerable expertise. These were not Rolex watches, but they had to have a high level of precision to operate so many gears in the drive train. Below a certain level of precision the inefficiency of the gearing would make the whole thing inoperable. To make a large, thin gear on a shaft with very small gear teeth mesh without wobbling, run in both directions, and control dials and pointers several gear sets away without much play or lash requires a level of sophistication in metallurgy, machine design and precision machining on a level with the concept, design and purpose of this incredible mechanism.

Lowndes Whatley
Roswell, Ga.

Exit Strategy
In “Portrait of a Black Hole,” Avery E. Broderick and Abraham Loeb explain that inside the event horizon of a black hole everything moves toward the singularity. In particular, any virtual gravitons emitted by the singularity will be trapped inside that singularity. Therefore, there could be no gravitation field outside the singularity, and the space around the singularity must be flat. But in that case, nothing would hinder the virtual gravitons from freely propagating. Is there a solution to this conundrum?

Moshe Rozenblit
Jersey City, N.J.

EDITOR GRAHAM P. COLLINS REPLIES: The question reminds me of the one time in my life I spoke to Richard Feynman. I was in 7th form in high school, and after Feynman gave a public lecture at Auckland University I went up and asked him: If nothing can get out of a black hole, how could the gravitons that create its gravitational field get out? The answer is that the gravitons are virtual particles, which can move faster than the speed of light and thus can escape from the black hole.

War or Peace
I was disappointed and dismayed by Lawrence M. Krauss’s “War Is Peace” [Critical Mass]. I agree with his political positions, but the way he presented them was shallow, unthoughtful and insulting to people who have genuinely held positions that differ from his own.

Krauss’s piece makes the magazine look like a liberal blowhard—especially because Krauss provides no thoughtful policy analysis, no new insights into the science of health care or politics, and it treats anyone with whom he disagrees with great disrespect. (“Zombielike protesters”? No—active citizens who disagree with him.)

David G. Haskell
Department of Biology
University of the South
Sewanee, Tenn.

KRAUSS REPLIES: I appreciate the concerns expressed by Haskell, but I think he misinterpreted the point. My piece was not about health care or climate change per se. It was about disinformation replacing information in the media regarding such issues. It was in this regard that I expressed contempt for both right-wing fanatic radio hosts (if I knew of any really left-wing fanatic radio hosts I might respond equally negatively) and ex-politicians who fabricate claims about “death panels.” Thus, it is not their views that I tried to express contempt for. It is their lies and distortion. No doubt I could have been more polite, but I think it is an issue we need to be upset about.