In "Nuclear Planet" [August 2002], geophysicist J. Marvin Herndon presents an intriguing theory about the interiors of planets. Then he goes on to speculate that stellar fusion cannot happen without an initial fission reaction to trigger it. If this is so, how did the first generation of stars ignite in a universe consisting entirely of hydrogen, helium, and a little lithium?
Andover, Massachusetts J. Marvin Herndon responds: That's a good question, the answer to which could lead to new insights into the nature of the universe. First, some background: Thermonuclear fusion reactions, thought to power stars, require temperatures of about 1 million kelvins. Since the 1930s, scientists thought the gravitational collapse of dust and gas that occurs during star formation would yield such temperatures. But in the 1960s, astrophysicists found that ignition temperatures would not readily be attained by that mechanism. The reason is that protostar heating is offset by radiation from the surface, which is a function of temperature raised to the fourth power. Thermonuclear ignition by nuclear fission, however, has been demonstrated with each hydrogen bomb detonation. The popular model by E. M. Burbidge et al. holds that heavy elements are produced only at the supernova end of a star's life. But the universe contains little-understood phenomena, such as star-size objects with galactic-scale energy emissions and galaxies that shoot out jets of matter. This raises the question: Are there mechanisms such as these that result in the production of heavy elements rather than simply star supernovas?
I read with interest the article on J. Marvin Herndon and his theory that a nuclear reactor can be found at our planet's core. Wouldn't such a reactor create enough neutrinos to be detected at Earth's surface? Perhaps a neutrino astronomer could posit a lower limit for the amount of nuclear fission happening inside our planet.
Columbus, Ohio J. Marvin Herndon responds: In principle, this is a good idea but one with some technical problems to overcome. Aside from the difficulty in detecting neutrinos, the geo-reactor is 4,000 miles away, and there is background from the sun, radioactivity, and 432 man-made nuclear reactors at Earth's surface. The likelihood for success seems small at present. But neutrino astronomers are very clever people and might succeed in the future. Because of the importance of such measurements, I am posting additional information and updates on my Web site: http://NuclearPlanet.com.
The "bad science" of bone marrow transplantation for breast cancer ["Bad Science and Breast Cancer," August 2002] was largely the result of the insurance industry's unwillingness to support "good science." Insurance companies pay for "standard" treatments even if only marginally effective but refuse to cover clinical trials on the grounds that they are "experimental." Had the insurance industry not fought transplantation treatments for breast cancer but rather encouraged participation in large comparative trials, everyone would have benefited. South African oncologist Werner Bezwoda's fraudulent science was inexcusable, but so is the ongoing obstruction of well-designed clinical studies by the insurance industry.
Stuart Goldberg, M.D.
Bone Marrow Transplantation Program
Hackensack University Medical Center
Hackensack, New Jersey
"Bad Science and Breast Cancer" combines hindsight with Monday-morning quarterbacking to condemn those oncologists who used high-dose chemotherapy followed by bone marrow transplantation in an attempt to eradicate breast cancer. As a physician, I know that what you describe typically happens in medicine. Science is always playing catch-up to clinical practice. Initial reports on a new therapy are preliminary and poorly controlled. However, we do not refuse to treat people until there is a randomized clinical trial to give a scientific basis for practice. Rather, we combine our best judgment and intuition with a patient's wishes while desperately waiting for the science to catch up and give us guidance.
William J. Meggs, M.D.
Chief, Division of Toxicology
Brody School of Medicine
at East Carolina University
Greenville, North Carolina
In Science Travel (August), we erroneously stated that "At 13,796 feet, Mauna Kea's telescopes lie at an elevation almost twice that of any other Earth-based telescopes." The Indian Astronomical Observatory in Hanle, India, sits at 14,800 feet above sea level. The accompanying image for "Climate on the Wing" (R&D;, August) shows particulate trails emitted by ships, not aircraft contrails, as was implied by the caption. In our July review of the PBS series Red Gold: The Epic Story of Blood,
we neglected to mention the book on which it was based: Blood: An Epic History of Medicine and Commerce
by Douglas Starr (Quill, March 2000).