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Center for Relativistic Astrophysics Distinguished Lecture

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Now showing 1 - 5 of 5
  • Item
    The Case for Cosmic Modesty
    (Georgia Institute of Technology, 2018-03-12) Loeb, Abraham (Avi) ; College of Sciences ; School of Physics ; Center for Relativistic Astrophysics
    Based on the premise that we are not special, Loeb argues for modesty from a cosmic perspective. His “principle of cosmic modesty” implies that both primitive and intelligent forms of life should exist away from Earth, and we should therefore search for them without prejudice.
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    Aeons Before the Big Bang?
    (Georgia Institute of Technology, 2009-03-24) Penrose, Roger ; College of Sciences ; School of Physics ; Center for Relativistic Astrophysics
    There is much impressive observational evidence, mainly from the cosmic microwave background (CMB), for an enormously hot and dense early stage of the universe referred to as the Big Bang. Observations of the CMB are now very detailed, but this very detail presents new puzzles of various kinds, one of the most blatant being an apparent paradox in relation to the second law of thermodynamics. The hypothesis of inflationary cosmology has long been argued to explain away some of these puzzles, but it does not resolve some key issues, including that raised by the second law. In this talk, I describe a quite different proposal, which posits a succession of universe aeons prior to our own. The expansion of the universe never reverses in this scheme, but the space-time geometry is nevertheless made consistent through a novel geometrical conception. Some very recent analysis of the CMB data, obtained from the WMAP satellite, will be described, this having a profound but tantalizing bearing on these issues.
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    Ice Fishing for Neutrinos
    (Georgia Institute of Technology, 2016-09-12) Halzen, Francis ; College of Sciences ; School of Physics ; Center for Relativistic Astrophysics
    The IceCube project at the South Pole has melted eighty-six holes over 1.5 miles deep in the Antarctic icecap for use as astronomical observatories. The project recently discovered a flux of neutrinos reaching us from the cosmos, with energies more than a million times those of the neutrinos produced at accelerator laboratories. These neutrinos are astronomical messengers from some of the most violent processes in the universe associated with starbursts, giant black holes gobbling up stars in the heart of quasars and gamma-ray bursts, the biggest explosions since the Big Bang. We will discuss the IceCube telescope and highlight its first scientific results.
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    The Data and Compute-Driven Transformation of Modern Science
    (Georgia Institute of Technology, 2011-10-13) Seidel, Edward ; College of Sciences ; School of Physics ; Center for Relativistic Astrophysics
    We all know that modern science is undergoing a profound transformation as it aims to tackle the complex problems of the 21st Century. It is becoming highly collaborative; problems as diverse as climate change, renewable energy, or the origin of gamma-ray bursts require understanding processes that no single group or community alone has the skills to address. At the same time, after centuries of little change, compute, data, and network environments have grown by 9-12 orders of magnitude in the last few decades. Moreover, science is not only compute-intensive but is dominated now by data-intensive methods. This dramatic change in the culture and methodology of science will require a much more integrated and comprehensive approach to development and deployment of hardware, software, and algorithmic tools and environments supporting research, education, and increasingly collaboration across disciplines.
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    The Birth of the Universe
    (Georgia Institute of Technology, 2015-04-07) Efstathiou, George ; College of Sciences ; School of Physics ; Center for Relativistic Astrophysics
    Modern physics attempts to explain the full complexity of the physical world in terms of three principles: gravity, relativity and quantum mechanics. This raises important fundamental questions such as why is our Universe so large and old? Why is it almost, but not perfectly, homogeneous and isotropic? I will describe how recent measurements of the cosmic microwave background radiation made with the Planck Satellite can be used to answer these questions and to elucidate what happened within the first split second of the creation of our Universe. The main aim of the lecture is to persuade the audience that we really can test what happened shortly after the birth of the Universe.