September 14, 7:00PM Bigelow Physics Building, BPB-102. University Forum Lecure: Mario Livio on Human Curiosity.

Human Curiosity

Thursday, September 14 - 7:00 PM Bigelow Physics Building, BPB 102
Please note the location change.

Mario Livio
Internationally known astrophysicist and bestselling author

The ability to ask "why?" makes us uniquely human. Curiosity drives basic scientific research, is the engine behind creativity in all disciplines from the arts to technology, and a necessary ingredient in every form of storytelling (literature, film, TV, or even a simple conversation) that delights rather than bores. In a fascinating and entertaining lecture, renowned astrophysicist and author Mario Livio surveys and interprets cutting-edge research in psychology and neuroscience that aims at exploring and understanding the origin and mechanisms of human curiosity. As part of his research into the subject, Livio examined in detail the personalities of two individuals who arguably represent the most curious minds to have ever existed: Leonardo da Vinci and Richard Feynman. He also interviewed 9 exceptionally curious people living today, among them linguist Noam Chomsky and the virtuoso lead guitarist of the rock band Queen, Brian May (who also holds a PhD in astrophysics), and presents fascinating conclusions from these conversations

Co-sponsored by the Department of Physics and Astronomy

Prof. Livio is an Adjunct Professor in Physics & Astronomy at UNLV. He is the author of numerous books and academic papers, including his latest: Why? What Makes Us Curious. Simon & Schuster. 2017. ISBN 978-1476792095. He was interviewed recently on NPR's Talk of the Nation Science Friday.

August 21, 2017. 9:00AM. BPB roof. UNLV Physics & Astronomy Eclipse activity.

The Aug 21, 2017 Eclipse

Around 9:00AM we'll set up a couple telescopes on the Bigelow Physics Building roof. The scopes will project an image of the Sun onto screens that can be safely viewed. We'll live stream one of the screens on to the net. The URL is: https://www.twitch.tv/horizonsci/

The scopes will be up from about 9AM to 12 noon which spans the whole eclipse maximum which will be at about 10:30 with 72 % coverage.

Drs. David Jeffery and Jason Steffen will be around to answer questions and demonstrate pinhole projection. Other students, faculty, and staff may also be on site to answer questions.

Postscript

Obviously, we didn't have an optimal day for viewing the eclipse in Las Vegas as a storm front moved through the valley. However, some time around 10:30AM clouds began clearing, glasses came out, a telescope was hastily set up and we had some quite good viewing from the roof and the area surrounding Bigelow Physics with "pinhole effects" from the tree canopy. Some images:

August 18, 2017. 2:00PM. BPB-217. Timothy Waters. Properties, Dynamics, and Spectral Signatures of Clouds in AGN.

Ph.D. Defense

Understanding the high-pressure behavior of transport properties has been a driving force in the study of materials under extreme conditions for well over a century being pioneered by P.W. Bridgman in the early 20th century. Research dedicated to the study of these properties leads to a variety of important applications: exploration of insulator to semi-conductor to metal structural and electronic phase transitions, correlation of structural phase transitions and the electronic properties along phase boundaries, testing validity of theoretical models, understanding the effects of chemical pressure, among a slew of other applications. This work has designed and developed a specialized sample cell assembly for use with a Paris-Edinburgh press capable of performing high-pressure and high-temperature (HP-HT) electrical resistance, Seebeck coefficient, thermal conductivity measurements alongside energy-dispersive X-ray diffraction and X-ray radiography imagining up to 6 GPa and 500�C to fully characterize the electrical, thermal, and structural properties of materials simultaneously at extreme conditions. This system has been installed at Argonne National Laboratory at the Advanced Photon Source at the Sector 16 BM-B beamline of the High-Pressure Collaborative Access Team and is now available to general users as a measurement technique. Application of this system has been applied to thermoelectric materials: PbTe, SnTe, TiCoSb, and TiNiSn. Thermoelectric materials provide a valuable means of converting waste heat into useful electrical energy and studying their HP-HT properties allows a better understanding and identification of greater efficiency through tuning of transport properties. The detailed discussion of the design and development of this system alongside the important results on the thermoelectric materials mentioned will be presented in this dissertation.

August 11, 2017. 10:00AM. BPB-217. Ye Li. Understanding Progenitors of Gamma-Ray Bursts with Multi-wavelength Properties.

Ph.D. Defense

Gamma-ray bursts (GRBs) are the most luminous explosions in the universe. They are generally classified into two types according to the durations of their Γ-ray emission. Progenitors of short-duration GRBs (SGRBs) are believed to be compact stars binaries (e.g., neutron stars and black holes; also known as Type I GRBs by their physical origin). For long-duration GRBs (LGRBs) they are thought to be originated from core-collapse of massive stars (Type II). However, the duration criterion is not always reliable. In this dissertation, I propose a multi-parameter method based on multi-wavelength data of GRBs to classify them by their physical nature, i.e., Type I or Type II. With a similar method, we search for SGRB-less X-ray transients with neutron star binaries as progenitors. The multi-wavelength studies of GRBs also allow for a study of the evolution of GRB population through the cosmic time.

July 10, 2017. 10:00AM. BPB-217. Jason Baker. Instrumentation and Measurement of Thermoelectric and Structural Properties of Binary Chalcogenides and Half-Heusler Alloys at Extreme Conditions Using a Paris-Edinburgh Press.

Ph.D. Defense

Understanding the high-pressure behavior of transport properties has been a driving force in the study of materials under extreme conditions for well over a century being pioneered by P.W. Bridgman in the early 20th century. Research dedicated to the study of these properties leads to a variety of important applications: exploration of insulator to semi-conductor to metal structural and electronic phase transitions, correlation of structural phase transitions and the electronic properties along phase boundaries, testing validity of theoretical models, understanding the effects of chemical pressure, among a slew of other applications. This work has designed and developed a specialized sample cell assembly for use with a Paris-Edinburgh press capable of performing high-pressure and high-temperature (HP-HT) electrical resistance, Seebeck coefficient, thermal conductivity measurements alongside energy-dispersive X-ray diffraction and X-ray radiography imagining up to 6 GPa and 500°C to fully characterize the electrical, thermal, and structural properties of materials simultaneously at extreme conditions. This system has been installed at Argonne National Laboratory at the Advanced Photon Source at the Sector 16 BM-B beamline of the High-Pressure Collaborative Access Team and is now available to general users as a measurement technique. Application of this system has been applied to thermoelectric materials: PbTe, SnTe, TiCoSb, and TiNiSn. Thermoelectric materials provide a valuable means of converting waste heat into useful electrical energy and studying their HP-HT properties allows a better understanding and identification of greater efficiency through tuning of transport properties. The detailed discussion of the design and development of this system alongside the important results on the thermoelectric materials mentioned will be presented in this dissertation.

March 30, 2017. 4:30PM. BPB-102. Prof. Isaac F. Silvera on Metalic Hydrogen

Hydrogen is the simplest and most abundant element in the Universe. Over 80 years ago Wigner and Huntington predicted that if solid molecular hydrogen was sufficiently compressed in the T=0 K limit, molecules would dissociate to form atomic metallic hydrogen. We have observed this transition at a pressure of 4.95 megabars. MH in this form has probably never existed on Earth or in the Universe; it may be a room temperature superconductor and is predicted to be metastable. Hydrogen makes up ~90% of the planet Jupiter. It is believed to occur as a layer of liquid metallic hydrogen surrounding Jupiter's core, responsible for Jupiter's magnetic field, with molecular hydrogen as the outermost layer. Descending through the atmosphere, a phase transition from liquid molecular to liquid atomic metallic hydrogen occurs as the pressure and temperature increase. This first-order phase transition to liquid metallic hydrogen is at intermediate pressures (~1-2 megabars) and temperatures of ~1000-2000 K. We have also observed this liquid-liquid transition, known as the plasma phase transition. We shall discuss the methods used to observe these phases of hydrogen at extreme conditions of static pressure in the laboratory, extending our understanding of the phase diagram of the simplest atom in the periodic table.

Prof. Isaac F. Silvera is the Thomas D. Cabot Professor of the Natural Sciences at the Lyman Laboratory of Physics at Harvard University

Prof. Lepp delivered the University Forum lecture: Supernova 1987A: Thirty Years Later

University Forum lecture looks back 30 years to the first time anyone since the days of Queen Elizabeth I was able to see a supernova with the naked eye.^*

Stephen H. Lepp is the chairman of UNLV's department of physics and astronomy. At 7:30 p.m. March 23, he will present "Supernova 1987A: Thirty Years Later" at the Marjorie Barrick Museum as part of the University Forum lecture series. Here, Lepp discusses what we learned from the first supernova visible to the naked eye in 400 years.

On Feb. 24, 1987, a supernova was discovered in the Large Magellanic Cloud. A supernova is an explosive end to a massive star. This supernova was bright enough to see with the naked eye, the first such in nearly 400 years and the first since the invention of the telescope. As such, this was the first bright supernova to be observed with modern scientific instruments. It was the first from which neutrinos were detected, the first in which molecules have been detected and the first where we have observations of the star before it blew up.

Stars begin their life in dense molecular clouds. These clouds, which exist between stars in our galaxy are basically star forming factories. Parts of the cloud can collapse to form dense objects which eventually burn hydrogen up to helium in the process of nuclear fusion. This is the most common configuration for stars, and almost all the stars you see in the night sky are undergoing this burning of hydrogen to helium.

Most of these stars are not massive enough to get temperatures high enough to burn anything beyond hydrogen, but the most massive stars will undergo a series of nuclear reactions burning elements all they way up to iron. Iron is the most tightly bound nuclei and so you cannot produce energy by converting iron to higher mass elements. The massive stars can undergo a processes called core collapse and the energy released out shines for a short time the entire galaxy. These explosions look like new stars and so were called nova or supernova.

In this talk we will cover the history of supernova observations and some interesting results from Supernova 1987A, along with some modern supernova research.

^{* From UNLV News Center}