College of Arts and Sciences

We regretfully are cancelling this talk due to the COVID-19 outbreak.
Our Universe
Jeremy Darling (University of Colorado, Boulder)

What is the Universe?  What does it contain?  What is its history?  Its future?  This talk will explore the scale, age, and fate of the Universe.  We will learn how we observe the Universe, how we know what we know, and what is still not known.  We will also explore alternate Universes as a portal to understanding our own.

Bio: Jeremy Darling is an Associate Professor of Astrophysics at the University of Colorado,

Continue reading… Frontiers of Astronomy: Jeremy Darling

Star Smog: The role of dust in how we perceive galaxies
Benne Holwerde (University of Louisville)

Galaxies are made up of stars, gas, dark matter and dust. That last ingredient is only a small amount of the total but radically changes our view of galaxies. Up to half the starlight in a given galaxy could be invisible thanks to the small amount of dust. Over decades, astronomy has sought to get away from dust to study the galaxies’ stars and to study the dust itself. This talk will focus on how dust dims and reddens the starlight in galaxies other than our Milky Way.

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Planet Hunters and the Most Mysterious Star in the Galaxy
Tabetha Boyajian (Louisiana State University)

Abstract: The NASA Kepler Mission provided 4 year long, ultra-precise light curves for over 150,000 stars with a primary science goal of finding transiting planets. In Kepler’s field of view was KIC 8462852, a star citizen scientists identified to have unusual brightness variations.  This otherwise seemingly normal F star underwent erratic and completely unpredictable dips in flux ranging from <1% to more than 20%, with each event lasting from days to weeks at a time.  In addition to this puzzling variability,

Continue reading… Frontiers of Astronomy: Tabetha Boyajian

The Future of the Cosmos
Chris Mihos (CWRU Astronomy)

Abstract: The universe around us is ever-changing: stars are born and die, galaxies collide and merge with one another, titanic explosions rock our galaxy, and the very fabric of the universe itself expands at an ever-increasing rate, carrying galaxies across the universe at breakneck speeds. In this talk, CWRU Astronomy’s Chris Mihos will give us a peek into the far future, using the physical laws of the universe to explore the changes in store for the Sun, the Galaxy, and the Universe as a whole.

Bio: Chris Mihos is a Professor of Astronomy at Case Western Reserve University.

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What’s inside the Moon?
Peter James (Baylor University)

Abstract:  The Moon’s deep interior hides many clues about its formation and evolution. Unfortunately, it is easier to observe a star many light-years away than it is to peer through hundreds of miles of solid rock. We can nevertheless use geophysical techniques like seismic wave propagation, electromagnetic induction, and tidal deformation to learn about the interiors of planetary bodies. This talk will focus on recent exciting developments in the use of gravity anomalies; that is, geographic variations in the strength of the Moon’s gravitational pull, to study the Moon’s interior.

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Black Holes and Globular Clusters
Stephen Zepf (Michigan State Univ)

Black Holes have long excited the imagination of both scientists and the broader public. However, black holes are not easy to find because they emit very little light of their own. Often the best way to find a black hole is through its gravitational effect on a very nearby star. Seemingly excellent places to look for these interactions between stars and black holes are globular clusters with many stars all located very close together. I will talk about this search for black holes in globular clusters,

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Lions, Archers, and Bears: Dwarf Galaxies in the Local Group
Bill Janesh (Case Western Reserve University)

The Local Group is our cosmic neighborhood — home to the Milky Way, the Andromeda Galaxy, and dozens of smaller objects called dwarf galaxies. Dwarf galaxies are valuable tools for answering questions about how the Universe works. How do stars and galaxies form and change over time? How do galaxies interact with each other? What is a galaxy, anyway? In this talk, we will take a closer look at some of the dwarf galaxies in the Local Group and how they can contribute to our knowledge of the Universe.

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How were the most ancient objects in the universe formed?
Kelsey Johnson (University of Virginia)

Ancient remnants from the early universe surround our galaxy. These relics, know as “globular clusters” have the potential to provide insight into the prevailing physical conditions during an epoch that cannot be directly observed. While some progress has been made, and we now know globular clusters can still be formed during extreme episodes of star formation in the relatively nearby universe, the actual physical conditions that give rise to globular clusters has vexed both observers and theorists for decades. With the new capabilities of the Atacama Large Millimeter Array (ALMA) we have the ability to probe the birth environments of that gave rise to these ancient objects for the first time.

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Galaxy Cannibals: The Evolution of Massive Galaxies Through Cosmic Time
Rachel Bezanson (University of Pittsburgh)

Massive galaxies reside in the densest and oldest regions of the Universe, yet we are only beginning to understand their formation history. Once thought to be relics of a much earlier time, the most massive local galaxies are red and dead elliptical galaxies, with little ongoing star formation or organized rotation. In the last decade, observations of their assumed progenitors have demonstrated that the evolutionary histories of massive galaxies have been far from static. Instead, billions of years ago, massive galaxies looked completely different –

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Galaxy dynamics: a tale of light and darkness
Benoit Famaey (CNRS/University of Strasbourg)

Galaxy dynamics is confronted with one of the deepest problems of modern physics: the dark matter problem. The motions of stars and gas observed exceed what can be explained by the mass visible in those same stars and gas. Either (i) there is a vast amount of unseen mass in some novel form – dark matter – or (ii) the data indicate a breakdown of our understanding of dynamics on the relevant scales, or (iii) both. We shall review the observational evidence for an intimate connection between the baryonic surface density and the total gravitational field in galaxies.

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Other Earths and Origins of Life
Dimitar Sasselov, Harvard University

The lecture will discuss the new field of scientific research on the emerging frontier where astronomy meets biochemistry. In the past year astronomers have discovered planets that resemble Earth around nearby stars and now prepare to explore them with a new generation of telescopes. In the meantime, chemists and biologists have narrowed down the environments necessary for early forms of Earth life and are helping the astronomers in defining their targets. The search is on!

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The New Moon
Brett Denevi, Johns Hopkins University Applied Physics Laboratory

Although we may not think of the Moon as a dynamic place (the first lunar explorers described the landscape’s “magnificent desolation”), its past was one of intense bombardment, floods of lavas, and intrusive volcanism, and even today it continues to change. Understanding the Moon’s past and present may provide our best opportunity to gain new insights topics as diverse as the early evolution of the Solar System and the timeline of the first development of life on Earth. The Moon also yields insights into how a planetary body evolves from a fiery magma ocean to a solid world still cooling off today,

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Simulating the Universe
Mark Vogelsberger (MIT)
Modern supercomputer simulations model the evolution of the Universe starting briefly after the Big Bang until today – spanning about 13.7 billion years. These simulations describe correctly the growth, structure, and composition of galaxies. I will give an overview of recent simulation efforts, and demonstrate that the virtual universes are nearly indistinguishable from the real Universe. However, our models are still not perfect and I will also show where simulations disagree with observational data and how we can improve our models to arrive at a better understanding of the evolution of our Universe.

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The Universe on A Computer: The Formation of Galaxies, Stars, and Planets in a Violent Cosmos
Philip Hopkins, California Institute of Technology

Astronomers have now discovered planets around distant stars, the relics of the “first generation” of stars in the Universe, and the light from the first galaxies when the Universe was but a fraction of its present age. However, a human life is infinitesimally small compared to the cosmic time scales over which these systems evolved, so we see only snapshots, instants in time. To link them together and understand how our Universe evolved,

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Mapping the Universe: New Vistas, New Lands
David Silva, National Optical Astronomy Observatory

To be human is to explore. Today’s astronomers are cosmic explorers, creating maps of the Universe, near and far. The earliest star maps were painted thousands of years ago on the walls of caves. Our maps today are spectacular, full of objects and phenomena that were completely undiscovered even 20 years ago. Yet, great mysteries remain. Is a civilization ending asteroid lurking in the darkness? Do Earth‐like planets orbit nearby stars and do they harbor life? How did our home galaxy, the Milky Way,

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The Frontier From Space
Daniela Calzetti, University of Massachusetts – Amherst

In 2015 the Hubble Space Telescope celebrated its 25th anniversary. Hubble has produced a paradigm shift in how both astronomers and the general public understand the Universe, and it may be time to take stock of all the accomplishments of the many space missions undertaken by numerous agencies — ESA and NASA in particular — over the past 30 years. We will do this with an eye to set the stage for the next game‐changing space missions.

Daniela Calzetti is Professor of Astronomy at the Department of Astronomy,

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Our Future Off-Earth
Chris Impey, University of Arizona

The Space Age is half a century old. Its early successes were driven by a fierce superpower rivalry between the Soviet Union and the United States, which tended to obscure the fact that exploration and risk‐taking is built into human DNA. Decades after we last set foot on the Moon, and several years after the Space Shuttle was retired, the space activity is finally leaving the doldrums. A vibrant private sector led by SpaceX and Virgin Galactic plans to launch supplies cheaply into Earth orbit and give anyone the chance of a sub‐orbital joy ride.

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The Quest for Infinite Telescope Aperture: Are We There Yet?

Michael Skrutskie, University of Virginia

Since the invention of the telescope somewhere in the Netherlands around the end of the 16th century one thing has generally mattered most to builders and users of these instruments… larger apertures collect more light and reveal finer detail, ultimately opening the door to studies ranging from observations of the most distant observable universe, the direct detection and characterization of extrasolar planets, and “spacecraft quality” observations of Solar System objects. Individual institutions, entire nations, and now consortia of nations are striving to build bigger and better telescopes.

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A Space‐time Symphony of Gravitational Waves
Kelly Holley-Bockelmann, Vanderbilt University

On February 11, 2016, scientists announced the first detection of gravitational waves, a Nobel Prize‐level achievement and a profound moment for humankind. Prior to that moment, the only way we learned about the distant Universe is through the light we received. Light revealed that we live in an extraordinarily beautiful expanding and accelerating Universe — full of exoplanets, stellar explosions, other galaxies, and dark matter that pervades everything. And now, humanity has observed the ripples in space‐time caused by the motion of massive objects like black holes;

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Pluto’s Lonely Ice Cap

Doug Hamilton, University of Maryland

The icy white heart of Pluto became an instant sensation after the 2015 New Horizons flyby, featured on websites, blogs, and T‐shirts worldwide. The actual feature on Pluto is composed of frozen nitrogen, carbon monoxide, and methane, substances that can all be either in the solid or gaseous states at the cold temperatures of this distant world. Water plays the same role on Earth, being found as a solid in our twin polar ice caps, and Mars too has a pair of polar caps composed,

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Biography of the Milky Way

James Bullock, University of California, Irvine

The Universe on the grandest scales is a vast network of galaxies.  Dotted along an expanding cosmic web,  galaxies shine with the collective light of thousands to billions of stars.  More than just collections of stars however, galaxies are dynamic ecosystems.  They allow multiple generations of stars to build new atoms that had never before existed.  They foster complex chemistry, even organic chemistry, in an otherwise sterile universe.  One galaxy, the Milky Way, is special to us.  Without it, we would not exist. 

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Galactic Cannibalism

Kathryn Johnston, Columbia University

Galaxies! Images of these objects are awe-inspiring – spirals of billions of stars, along with the gas and dust from which stars form, spinning slowly in the sky. Yet these majestic objects are thought to have formed quite violently through the agglomeration of smaller objects. Even our own home – the Milky Way galaxy – seems to be in the process of devouring several smaller galaxies! This talk examines why we think galaxies are cannibals in general, and what this means about the past and future evolution of the Milky Way in particular.

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Gamma Ray Bursts: The Biggest Explosions Since the Big Bang

Edo Berger, Harvard University

Representing Nature’s biggest explosions since the Big Bang itself, gamma-ray bursts were first accidentally spotted in the 1960s by Department of Defense satellites hunting for terrestrial nuclear blasts. Prof. Berger will describe the ensuing decades-long quest to decipher the origin and energy source of these mysterious explosions.

Edo Berger is a professor of astronomy at Harvard University.  He received his B.S. degree from the University of California, Los Angeles in 1999, and his Ph.D. from the California Institute of Technology in 2004. 

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The History of the Milky Way Written in Stars

Jennifer Johnson, Ohio State University

Our Galaxy, the Milky Way, did not always look as it does now, a multi-armed spiral galaxy with at least one neighborhood hospitable to life. The Galaxy has been growing and evolving for the last 13 billion years, creating billions of stars throughout its life. These stars, through their age, chemical composition, and motions, record the history of the Galaxy and provide a “fossil record” if we can observe enough of it to interpret it. The Sloan Digital Sky Survey has been observing stars,

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25 Years of the Hubble Space Telescope

Frank Summers, Space Telescope Science Institute

In April 1990, astronauts aboard the Space Shuttle Discovery deployed the Hubble Space Telescope into Earth orbit, and launched a new era of astronomical discovery. Now, 25 years later, we celebrate a remarkable milestone for a space observatory whose ground-breaking investigations have brought revolutionary changes in our understanding from planets, stars, nebulae, and galaxies to the very frontiers of the cosmos. Explore the trials and triumphs of NASA’s first Great Observatory, and experience a compendium of some of the greatest imagery the universe has ever known.

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Stellar Mergers and Interactions: Yes, Virginia, Stars Do Collide

Alison Sills, McMaster University

Professor Sills will discuss strong interactions between stars in a variety of environments. Despite the vast (average) interstellar distances, stars are social creatures and tend to live in pairs, multiples, or groups. Under these circumstances, stars can, and do, modify each other’s mass, radius, composition, and overall evolution through gravitational encounters ranging from wind mass transfer in a binary system to complete stellar collisions and mergers. She will show how such events can change our understanding of particular stellar systems, how they can explain the properties of many unusual objects,

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Stars and Galaxies at the Dawn of Time

Volker Bromm, University of Texas, Austin

How and when did the cosmic dark ages end? I will present the remarkable story of how the first stars and galaxies formed, a few hundred million years after the Big Bang. These first sources of light fundamentally transformed the early universe from an initially very simple state to one of ever increasing complexity. Until now, our knowledge of this period of cosmic dawn relies on supercomputer simulations. But over the next decade, a number of new-generation observational facilities, such as the James Webb Space Telescope and the Giant Magellan Telescope,

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Probing the Dark Universe

Josh Frieman, University of Chicago / FermiLab

Over the last two decades, cosmologists have made a remarkable discovery about our Universe: only 4% is made of ordinary matter—atoms, molecules, etc. The other 96% is dark, in forms unlike anything with which we are familiar. About 25% is dark matter, which holds galaxies and larger‐scale structures together, and may be a new elementary particle. And 70% is thought to be dark energy, which is driving the expansion of the Universe to speed up. This talk will introduce the Dark Universe, overview what we have learned about it,

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Directions to the Nearest Alien Earth-like Planet

Sarah Ballard, University of Washington

Astronomers used to hedge at the question of whether the Sun and its system of planets are unusual in the cosmos. The study of exoplanets – planets around other stars – is relatively new. State-of- the-art instruments just brush up against the sensitivity to find planets similar to our very own planet Earth. I will summarize findings from the past couple years that contextualize Earth as one potentially habitable, rocky planet among many. However, the environments of these worlds are by-and-large astoundingly different from the conditions that have nourished life here at home.

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