The censoring of Galileo’s Sunspot Letters and the first phase of his trial

Galileo’s Sunspot Letters, published in 1613, underwent extensive censorship before publication. It seems likely that the Roman Inquisition had charge of the pre-publication review of Galileo’s work, rather than the usual organ, the Master of the Sacred Palace. A study of that process demonstrates that the issue to which the censors objected was Galileo’s use of the bible, not his allegiance to Copernicus. In the course of the first phase of Galileo’s trial, orchestrated by one of the most powerful Cardinal Inquisitors, two propositions allegedly drawn from the book were judged either “formally heretical” or “at least erroneous in the faith.” These judgments might have come not from the published book but from the Inquisition’s censorship of its drafts. They supported Galileo’s silencing in 1616.     

From centripetal forces to conic orbits: a path through the early sections of Newton’s Principia

In this study, we test the security of a crucial plank in the Principia’s mathematical foundation, namely Newton’s path leading to his solution of the famous Inverse Kepler Problem: a body attracted toward an immovable center by a centripetal force inversely proportional to the square of the distance from the center must move on a conic having a focus in that center. This path begins with his definitions of centripetal and motive force, moves through the second law of motion, then traverses Propositions I, II, and VI, before coming to an end with Propositions XI, XII, XIII and this trio’s first corollary. To test the security of this path, we answer the following questions. How far is Newton’s path from being truly rigorous? What would it take to clarify his ambiguous definitions and laws, supply missing details, and close logical gaps? In short, what would it take to make Newton’s route to the Inverse Kepler Problem completely convincing? The answer is very surprising: it takes far less than one might have expected, given that Newton carved this path in 1687.     

Induction of cyst formation by low temperature in the dinoflagellateGonyaulax polyedra Stein: Dependence on circadian phase and requirement of light

Encystment, which at a temperature of 15°C is photoperiodically controlled inGonyaulax polyedra, can also be induced by a decrease of temperature, from 20 to 10 or 8°C in the absence of photoperiodic signals. The cyst-inducing capacity of the decrease in temperature depends on the circadian phase: in constant light, the maximum of sensitivity was found at the beginning of subjective night. In a light/dark cycle, however, cyst formation was reduced during dark phase, indicating that light is required for the process of encystment. A similar light dependence was seen in the effect of the physiologically occurring cyst inducer 5-methoxytryptamine, but not in the encystment response to the protonophores monensin and nigericin.