Vol. 47, No. 2 April 2018 PHYSICS SOCIETY A Publication of The Forum on Physics and& Society A Forum of The American Physical Society From the Editor ood news: we are getting some controversy stirred up. We also have some news The article by Lieber and Press in the last issue has gen- for you: the Forum is orga- eratedG one reply article, by Frank von Hippel plus two letters nizing a session on arms con- to the Editor, one of which is by Alvin Saperstein, who also trol at the APS April meeting. wrote an article on that issue. I hope our good luck continues. One of the speakers is Ted For several reasons, most of them troubling, the issues of Postol and the other two will nuclear proliferation and disarmament are becoming of great have articles in the July issue. current interest again. We have in this issue two articles on the Remember again that topic: one is by Ted Postol, a well-known arms control expert this newsletter is dependent from MIT. Because of the importance of this article I have on contributions obtained given it a very major exemption of the length limit rules. My largely by the readers and acquaintance with Ted goes very far back to the time when members of the Forum and Oriol T. Valls, the current P&S he was doing academic Physics, trying to figure out how to their friends. My definition of newsletter editor, is a Condensed obtain neutron scattering results from 3 He without turning the what is an appropriate topic Matter theorist. sample into 4 He too fast. The second article on North Korea is very broad: we past issues, is by Prof. Bell, a political scientist who knows how to talk to particularly October 2017, for some specifics. Physics audiences: I met him when he gave a Physics Collo- Oriol quium in my Department. We also have articles on the Mather Oriol T. Valls University of Minnesota congressional Fellowship program for undergraduates (I owe [email protected] this one to Tabitha Colter, our Media editor) and on innovations in Physics teaching, which comes via Laura Berzak Hopkins. IN THIS ISSUE EDITOR'S COMMENTS 30 North Korean Nuclear Capabilities and U.S. Foreign Policy, Mark S. Bell FORUM NEWS 32 Why Undergraduates Can Improve Physics Through Policy, Riley Troyer 2 2018 April Meeting Forum 33 Innovations in High School Science and Mathematics LETTERS Classrooms, Mary Beth Dittrich 2 Letters to the Editor REVIEWS ARTICLES 35 Louis Harold Gray: A Founding Father of Radiobiology, Sinclair Wynchank 4 North Korean Ballistic Missiles and US Missile Defense, 36 Nuclear Weapons and Related Security Issues, Pierce Theodore A. Posto Corden, Tony Fainberg, DavidHafemeister and Allison Macfarlane 28 Comments on “The New Era of Nuclear Arsenal Vulnerability” by Lieber and Press, Frank von Hippel FORUM NEWS 2018 April Meeting Forum t the 2018 APS April meeting the forum is sponsoring “North Korean Long-Range Ballistic Missiles and US ASession C06 “Nuclear Weapons and Ballistic Missile Missile Defenses” by Ted Postol Defense.” Joel Primack will be the chair. The venue is room “Missile Defense and Space Weapons” by Laura Grego B130 and the session goes from 1:30 to 3:18, on Saturday “US Nuclear Weapons Modernization” by Roy Schwitters April 14. The titles and speakers are LETTERS Dear Editor: Dear Editor, Since the beginning of the nuclear weapons age, there has In the January issue, Keir A. Lieber and Daryl G. Press been a continuous “intellectual;” dispute between advocates argue that emerging technologies are creating a “New Era of of “nuclear war” and of “nuclear deterrence”. Equivalently, Nuclear Arsenal Vulnerability.” We share the authors’ interest the dispute is between the reliance upon “counter force” in how new technologies can influence nuclear security, but technology – relying upon increasing missile accuracy, we are not convinced that critical shifts have occurred or are knowledge of target locations, and C3I – and “counter value inexorably on their way. technology – relying upon survivability of the retaliatory The longest section of Lieber and Press’s article recounts forces. Over the years the U.S. has developed both capabili- how missile accuracy has improved since the 1980s, making ties, though its publically issued governmental policies have hardened missile silos more vulnerable to attack. Here the more frequently emphasized “MAD” – mutually assured technical point is credible, but the strategic importance is deterrence”. Lieber and Press cite increasing capabilities of limited. Only the US and Russia keep a significant fraction required counterforce technology to seemingly press for a of their nuclear weapons in silos, and their vulnerability has decreasing emphasis on nuclear weapon limitation and an been recognized for decades. This is one reason why nuclear increase of reliance on counter force security policies because weapons are deployed on submarines, land-based mobile of their seemingly increased ability to wipe out the retaliatory launchers, and bombers, which maintain a retaliatory capabil- weapons required for effective deterrence. (They do admit ity largely immune to the “accuracy revolution.” that such a re-emphasis on counter force can be a significant The burden of the authors’ argument thus falls to the threat to global security.) However, it should be noted that “sensor revolution,” where the technical discussion is much nowhere in their article do they establish significant threats to weaker. This section amounts to a catalog of broad “techno- the SLBM force – the retaliatory missiles constantly prowl- logical trends,” all on the side of “seekers.” While it is reason- ing deep underwater in the Earth’s vast oceans. Nothing in able to predict that sensors and their platforms will improve, so their vaunted C3I improvements, given the known laws of will the tactics and technologies that counter them. Weapons physics, will be able to hinder a devastating retaliatory blow platforms will diversify, potentially to autonomous systems, following any possible counter force attack on the existing networked sensors may grow more vulnerable to electronic SLBM forces which will survive. Thus their apparent call for warfare, and anti-satellite capabilities will advance. Without a re-emphasis on counter force strategies, with consequent a comparative analysis between hiders and seekers, we are de-emphasis on nuclear arms limitation efforts, is not only not persuaded by the authors’ suggestion that seekers will dangerous to world stability but unnecessary for our national gain the edge. security - which should continue to depend upon MAD (Mu- Statements about the growing effectiveness of conven- tually Assured Destruction). tional weapons against nuclear forces (e.g., “conventional weapons can destroy most types of counterforce targets”) are Alvin M. Saperstein Wayne State University also too broad and unsupported to take at face value. [email protected] Certainly many types of technology are improving, but 2 • April 2018 PHYSICS AND SOCIETY, Vol. 47, No.2 it does not follow that a dramatically new era is dawning. building a new generation of submarines that must not merely Demonstrating that new technologies will “undercut the logic evade the sensors that Russia and China deploy today, but of future nuclear arms reductions” and make arms racing also those that will be developed over the next 30-40 years, “nearly inevitable” would, in our view, require much stronger a daunting challenge given the rapid pace of technological evidence than Lieber and Press provide. change. The problem for Russian and Chinese submarines is Sincerely, even greater, given the United States’ technological lead in undersea warfare and ongoing investments in those areas. Rachel Carr Rachel Carr and Thomas MacDonald note that although Department of Physics Massachusetts Institute of Technology hardened sites are growing more vulnerable, few countries [email protected] rely on missile silos to protect their nuclear forces. However, many nuclear-armed states store their aircraft and mobile mis- Thomas D. MacDonald siles in hardened shelters, protect their weapons in reinforced Department of Nuclear Science and Engineering bunkers, and control their arsenals from hardened command Massachusetts Institute of Technology [email protected] sites. Those facilities would be prime targets in any disarming strike. Moreover, as accuracy continues to improve, hardened sites are becoming more vulnerable to the lower-yield nuclear weapons that the United States and other countries are devel- ****** oping, as well as to conventional strikes. Carr and MacDonald also note that countermeasures can The computer revolution has transformed nearly every foil efforts to locate or strike nuclear targets. We agree, and aspect of our world. In “The New Era of Nuclear Arsenal for this reason we believe that countries with considerable Vulnerability” we describe how the dramatic improvements resources, such as the United States, will have an easier time in guidance systems and remote sensing are making nuclear keeping nuclear forces secure than poorer and technologically forces more vulnerable to disarming strikes, and hence com- 1 limited countries. Our point is that the computer revolution has plicating the mission of deterrence. transformed the competition between “hiders” and “seekers.” Alvin Saperstein shares our concern that efforts to exploit A few decades ago, the job of mobile missile operators was these new “counterforce” improving technologies may trigger simpler, because there were few feasible means for adversar- dangerous arms races, but his call to deemphasize such ca- ies to monitor large deployment areas, especially those deep pabilities overlooks two factors: First, effective counterforce in one’s own territory. Today, mobile missile operators have capabilities could be extraordinarily valuable if an adversary a much tougher job: for example, with timing their moves to (such as North Korea) began to threaten or employ nuclear avoid expanding constellations of radar satellites, countering weapons during a war. Second, counterforce capabilities – unattended ground sensors, and anticipating and blocking all including improved sensors, better command and control the other means of locating mobile forces.