Lyman Spitzer: Life,times, and science

Lyman Spitzer was one of the major figures of twentieth century theoretical astrophysics. Over more than fifty years, he kept up sustained research of his own, on problems concerning the interstellar medium, star formation, and galaxies. In addition he was a major influence on observational programmes, and created a thriving school of theoretical astrophysics at Princeton University along with a strong plasma physics programme. This article brings out his contributions, placing them in context.     

Musth in elephants

Animal behaviour is intimately connected with chemical signaling, often through glandular secretions. This is very significant and obvious in Asian male elephants during their musth period when their temporal glands secrete a fluid with a characteristic odor. Musth gland activity greatly influences the elephant society as well as manelephant interaction.     

Fermi and the art of estimation

Fermi’s name is associated with a style — later much imitated — of making quick, approximate but surprisingly accurate estimates of answers to interesting questions, ranging from “How many piano tuners are there in Chicago?” to “What is the energy of a nuclear explosion?”. This article lists a few examples and goes into explosions in more detail, to bring out some aspects of order of magnitude estimation in physics.     

Child Schooling in India: A Multilevel Approach

It is been widely established that child schooling has far reaching influence on shaping their subsequent living, in particular, and social and economic development of the society, in general. Although the Constitution of India provides free and compulsory education for all children until they reach 14 years, the schooling of children – enrollment and completion of primary school – still remains far below than the expectations. Using data from National Family Health Survey [NFHS], we attempted to understand primary school enrollment and completion in India. Results reveal that household characteristics play a significant role towards child schooling. The study suggests the importance of adult educational programs and opening of new schools, particularly all-girls schools, in needed areas. This revised version was published online in July 2006 with corrections to the Cover Date.     

Bose-Einstein condensation

In 1924 Bose introduced a counting rule for the states of a gas of photons which explained Planck’s law for thermal radiation at one stroke. Einstein not only recognised the importance of this idea but immediately applied it to a more conventional gas like helium. In this case, unlike that of radiation, the number of particles is held fixed. He derived the stunning conclusion that a finite fraction of the particles could settle in the lowest energy state even above absolute zero. These ideas had to wait fourteen years for their first application. Seventy years later they are being used in atomic physics laboratories all over the world.