PALS - 2019-20

Speaker: Gerard Williger, University of Louisville

Abstract: Asteroids are remnants from the early solar system and little changed for the past 4 billion years, so they hold clues to the formation of the planets and possibly even to life. Come listen to the latest news about these small but important bodies, including from the Japanese Hayabusa 2 sample return mission, and (3-D printer willing) hold some asteroid models in your hands!

Speaker: Timothy Dowling, University of Louisville

Abstract: Jupiter has dozens of alternating jet streams that have now been extensively observed by the two Voyager flybys, the Galileo entry probe, the Cassini flyby, and the Juno proximity orbiter. This has revealed that the analogue of the Mach number for vorticity waves, ‘Ma’, is central to understanding the long-mysterious properties of shear instability. The results have far-reaching consequences for large, fluid systems involving shear, including the meandering of jet streams, the formation of planets in protoplanetary disks, and the confinement of hot plasma in fusion reactors.  We will examine how the concept of ‘Ma’ clarifies the physics and makes specific predictions, including about Jupiter’s deep jets and Saturn’s length of day. The lessons from Jupiter have taken most of the guesswork out of the prediction and control of shear instability.

Speaker: Benne Holwerda, University of Louisville

Abstract: 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. I study this dust, specifically how it dims and reddens the starlight in galaxies other than our Milky Way. It is tricky to identify if a part of a galaxy is dark because the stars are hidden by dust or simply because there is nothing there. I will talk about some of the techniques I’ve used to find where and how much dust there is in the swirls of spiral galaxies. Lately, accidentally overlapping galaxies show in vivid detail where the dust spread throughout the foreground galaxy. These make for some spectacular Hubble images. 

Speaker: Christopher Graney

Abstract: The Star Wars universe is a “Thing of the Past.” The ideas upon which that universe is built are fading rapidly. They are ideas that are truly, as the phrase goes, “on the wrong side of history,” and of science. Today, we seem to be in the midst of a great revolution in our view of the universe — and Star Wars is pre-revolution. Star Wars is set in a wonderfully imaginative universe that features a profusion of cool planets, cooler alien life forms, and the coolest space ships. But that universe, with Tatooine, Dagobah, Naboo, Jakku, Endor, and all their fantastic creatures and “people” is a well-worn idea, and an idea whose time has passed. Science and history are twin Dreadnoughts closing in on and crushing the Star Wars universe like the First Order picking off the last remnants of Princess/General Leia Organa’s little fleet. This presentation will argue that science and history strongly suggest that the universe seen in Star Wars — universe full of intelligent, technologically advanced extraterrestrial life; that is, full of Space Aliens — is simply not plausible.

Speaker: James T. Lauroesch, University of Louisville

Abstract: The Event Horizon Telescope is an international collaboration to observe the environment of Black Holes. Utilizing telescopes on 4 continents extremely high angular resolutions can be achieved. The first image of the black hole in the center of the galaxy M87 provides tests of Einstein's theory of General Relativity.

Speaker: Lutz Haberzettl, University of Louisville

Abstract: Moons or natural satellites are a common occurrence in our Solar System. Except for Mercury and Venus all planets and most of the dwarf planets have at least one moon. The Earth moon is one of over 200 moons in the solar system and together with the Sun is the largest object on the sky. With over 50 confirmed and about 30 provisional moons, Jupiter and Saturn lead the list of planets with the largest number of moons. What makes the Earth moon special in comparison to all other bodies in the Solar System, is the fact that it is the first and so far the only body in outer space humans have set foot on. With this presentation we will learn about how the Moon has formed and evolved and the history of the Moon landing.