Archive for the ‘Cosmology’ Category


The Early History of the Observatory on Cerro San Cristóbal: 1900-1929

November 1, 2013

Nora Mills Boyd

Abstract:   History tends to forget the patient and diligent episodes of cooperative science, which are eclipsed by the biographies of great individuals and their most brilliant discoveries and novel explanations.  This is too bad, since it means forgetting the careful cumulative work of long term research programs.  Resisting this trend, I look closely at the early history of astrophysics in Chile, focusing on the first few decades of an observatory originally established by astronomers from the Lick Observatory near Santiago, which today is called the Manuel Foster Observatory.  The observatory was initially funded as a short term “expedition” to collect the spectra of the approximately 200 brightest stars in the Southern sky with the aim of measuring the motion of the solar system with respect to the galaxy.  I will present some details of the physical construction and installation of the observatory and emphasize the motivation for the expedition.  I conclude by suggesting that this observatory emerges as a pivot-point on the eve of observational cosmology.



How to Kill a Phoenix: Problems with an eternal cyclic universe model

March 29, 2013

Nora Boyd

Despite significant criticism, inflation is a fixture of our standard model of cosmology.  Paul Steinhardt and Neil Turok have introduced an eternal cyclic model as an alternative, which they claim avoids some of inflation’s most significant afflictions.  Instead of providing a cosmology where the particular features of our universe are in some sense accidental (that is, unexplained by anything other than anthropic reasoning, insofar as that counts as an explanation at all), these theorists hope to demonstrate how the features of our universe are to be expected.  In this talk I will show that such features are “mathematically necessary” according to the cyclic model only if we already agree that the universe cycles eternally with cycles like our own.  I argue that this does not constitute reason to prefer the cyclic model over merely stipulating initial conditions.