April 18, 2018 –
The globally homogeneous, monomineralic lunar crust suggests the Moon formed after a giant impact between Earth and another body. This energetic event would have produced a whole-Moon magma ocean. Petrologic and geophysical models argue the lunar magma ocean crystallized from the bottom up, forming a gravitationally unstable cumulate mineral pile, with the densest phases overlying less dense phases in the lunar interior. Dense minerals may have flowed toward the core as solids, displacing lower density minerals that flowed upward toward the crust in a process known as cumulate mantle overturn. Cumulate mantle overturn has important consequences for the petrogenesis of the lunar basalts, the spatial distribution of heat-producing radionuclides in the lunar interior, and the efficiency of a lunar core dynamo. This talk presents new experimental constraints on physical and chemical properties of lunar minerals and silicate melts, improving our understanding of lunar magma ocean crystallization, cumulate mantle overturn, and the ways that present-day lunar surface and interior features came to be.
For biographical information on Dr. Dygert, view his University of Tennessee faculty profile here
February 21, 2018 – Glass Plates and Glass Ceilings: The Women of the Harvard Observatory. Jennifer Hartwig, ORION Member
February 11, 2018 marked the third celebration of the International Day of Women and Girls in Science. With data from multiple sources showing that the percentage of bachelor’s degrees awarded to men in a STEM related field is double that of women, one has to ask the question ‘why’? The intellectual capability is the same and some will point to studies that indicate that the discipline of women is better. There is some evidence that part of the problem may relate to a lack of female role models in STEM-related fields as well as a reduced rate of exposure to STEM-related career options during a young girl’s formative years. Women have been making large contributions to science for millennia, but many people have never heard of them or their stories. As amateur (and some non-amateur) astronomers, we need to be more well-versed in the role that these women played. This presentation will focus on the contribution of several women at the Harvard Observatory in the early 1900’s who provided solid ground work in the realm of stellar classification. They performed calculations on over half a million 8×10 glass plates, each of which contained the negative image of a small slice of the entire night sky. It is upon this work that many other scientific ideas were founded (i.e., the Hertzsprung-Russell Diagram), most of which are still extremely important to our understanding of the universe today. Is there a glass ceiling in astronomy? In science in general? Come and listen to the science that these women used to crack whatever glass ceiling was there. “Don’t ever let anyone turn your sky into a ceiling.” I wish I knew who to attribute that quote to (it certainly wasn’t me). Young girls, listen up: take away the notion of a glass ceiling. The sky is the limit, not a ceiling (real or imaginary).
Jennifer Hartwig is an Exercise Physiologist by trade, but an amateur astronomer at heart. Currently, she works as an academic advisor for the Mechanical, Aerospace and Biomedical Engineering department at the University of Tennessee, Knoxville. She is a former instructor of Kinesiology at both the University of Tennessee and Carson Newman University, and has found that her studies of physiology, astronomy and physics complement each other in a somewhat unexpected – but much welcomed – fashion. She works with two local astronomy clubs as often as possible participating in public outreach events; has a strong interest in promoting the love of science and astronomy to children and adults; and recently served as a middle-school Science Olympiad coach in the astronomy event.