Podcasts

Origin of the Universe: The Big Bang

Lecture Series: Cosmic Origins

Christopher D. Impey, Distinguished Professor, Astronomy/Steward Observatory, The University of Arizona. The scientific story of creation begins 13.7 billion years ago in a circumstance of incredible temperature and density, when all matter and radiation was contained in a region smaller than an atom. The big bang is now a mature theory, with a web of observational evidence supporting it; and the size, shape and age of the universe have been measured with impressive accuracy. This talk will tell the story of how an iota of space-time turned into a vast cold universe of 100 billion galaxies.

Dark Matter, Dark Energy and Inflation: The Big Mysteries of Cosmology

Lecture Series: Cosmic Origins

Michael S. Turner, Professor, Kavli Institute for Cosmological Physics, University of Chicago

Our current cosmological model describes the evolution of the universe from a very early burst of accelerated expansion (known as inflation) a tiny fraction of a second after the beginning, through the assembly of galaxies and large-scale structure shaped by dark matter, to our present epoch where dark energy controls the ultimate fate of the universe. As successful as it is, this model rests upon three mysterious pillars: inflation, dark energy and particle dark matter. All three point to exciting and important new physics that have yet to be revealed and understood – or possibly, to a fatal flaw in the paradigm.
 

Astronomical Alchemy: The Origin of the Elements

Lecture Series: Cosmic Origins

Philip A. Pinto, Associate Professor, Astronomy/Steward Observatory, University of Arizona

One of the greatest achievements of twentieth-century science is an understanding of the origin of matter. While hydrogen and helium were produced in the Big Bang, the origin of the heavier elements—the silicon in rocks, the iron in our blood, and the oxygen we breathe–lies in the lifecycle of stars. Nuclear reactions, which transform light elements into heavier ones, cause stars to shine and ultimately to explode, seeding the universe with their production. These newly formed elements, the building blocks of ordinary matter, play a central role in the formation of planets and the evolution of life.

Origins of Black Holes: Gravity at Its Extreme

Lecture Series: Cosmic Origins

Feryal Özel, Associate Professor, Astronomy/Steward Observatory, University of Arizona

Gravity is the most important force in the universe, holding together planetary systems, stars, and galaxies. It is what makes the stars hot enough to shine and what keeps the Earth close enough to the Sun for life to form. It is also what ends the life of every massive star with a spectacular collapse and the formation of a black hole. Finding and studying hundreds of black holes within the Milky Way and in other galaxies brings us closer to understanding gravity at its extreme.

Building Brains, Making Minds

Lecture Series: Mind and Brain

Lynn Nadel, Regents' Professor, Psychology

What does the brain do? The ancients thought it was a radiator, cooling the blood. Modern views see it as an activator, using inputs from the environment in combination with prior knowledge to generate behaviors (walking, talking, eating and drinking) and mental states (feelings, desires and beliefs). Recently the idea has emerged that the brain acts as a predictor, using inputs and stored knowledge to generate models of the world, and of the consequences of possible actions we and others might pursue. These models can predict what will happen in the next minute, hour or decade, and allow us to behave in the most adaptive way.

The Plastic Brain

Lecture Series: Mind and Brain

Leslie P. Tolbert, Regents' Professor, Neuroscience and Vice President for Research

The human brain is the most complex object known to us. It contains billions of nerve cells, each of which may make thousands of connections, in immense networks of circuitry that control our sense of self and our appreciation of – and interaction with – the world around us. In the last half century we learned that we are born with raw circuitry that quickly tunes itself to the environment we encounter. Now we are learning that the properties that allow nerve cells to achieve this "plasticity" in response to the early environment are controlled by the very same genes that drive learning and memory in adults.

Evolution of Mind and Brain

Lecture Series: Mind and Brain

Anna Dornhaus, Assistant Professor, Ecology and Evolutionary Biology

What does anybody need a brain for? Brains are energetically expensive to make and to use, and susceptible to making mistakes. Accordingly, not learning, i.e. sticking to an innate or random strategy, is often the best thing to do. Still, humans and other animals display sophisticated learning and cognition. Recent research shows that each animal has specific learning abilities and lacks others according to its environment and evolutionary history. Understanding what different brains are used for can help us understand why they evolved.

The Making of a Mind

Lecture Series: Mind and Brain

LouAnn Gerken, Professor, Psychology and Director, Cognitive Science

We're all born with a brain, but when does our brain begin to construct a model of the world – a mind? Research now suggests that infants not only absorb a remarkable amount of information about the physical and social world, they also use this information much like scientists to make guesses about the structure of that world. By creating tentative models of different aspects of the world based on very small amounts of data, infants use their developing models to predict the behavior of objects, people and the world around them.

Metamemory: How Does the Brain Predict Itself?

Lecture Series: Mind and Brain

Alfred W. Kaszniak, Professor and Head, Psychology

Our brains recreate past experience, monitor recall efforts, and predict our chances of remembering things in the future. The knowledge we each possess about our own memory, and strategies to aid memory, form what is called metamemory. Studies of persons with impaired metamemory due to neurological illness, along with brain imaging studies of healthy adults making judgments about memory, indicate that the brain systems active in retrieving information are distinct from those that self-monitor memory. Metamemory research is helping build an understanding of a wide range of experiences from tip-of-the-tongue forgetfulness to the symptoms of Alzheimer's disease.

Morality and the Emotional Brain

Lecture Series: Mind and Brain

Shaun Nichols, Professor, Philosophy

Does morality come from the emotions, or from rational thought? Philosophers have struggled with this question for centuries. Recent work in cognitive science suggests that emotions play a critical role in the normal ability to think about morality. Studies indicate that psychopaths have a deficient understanding of morality, and when abnormalities are found in brain regions associated with emotions, these same patients make atypical decisions about difficult moral problems. Emotions alone do not completely account for moral judgment, but the emotional brain shapes our models of what it is to be moral.

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