Colloquia

February 21st

Speaker: Scott Tremaine

Topic: The dynamics of comets, and modified gravity in the solar system

Abstract: This talk has two (related) parts: 1. Comets have inspired awe since prehistoric times, but even today there are only afew thousand comets with well-determined orbits. Nevertheless, the analysis of this limited sample yields acompelling “standard model” for the formation, evolution and present distribution of comets. This model impliesthat the primary source of comets is the Oort cloud, containing over 100 billion comets at 5,000 to 100,000 timesthe Earth-Sun distance. I will review our current understanding of the history and structure of the Oort cloud. 2. The hypothesis that most of the matter in the universe is in some unknown dark form is fundamental tomodern cosmology. A speculative alternative is that our understanding of the law of gravity is incomplete. Themost influential theory of this kind is modified Newtonian dynamics (MOND), which postulates a breakdown ofNewton’s law of gravity below some critical acceleration threshold. We explore the predictions of the simplestversion of MOND for the formation and evolution of the Oort cloud, and conclude that this is not the correctdescription of gravity.

SPEAKER BIO: Scott Tremaine received his PhD degree from Princeton. He has been on the faculty at the MassachusettsInstitute of Technology, the University of Toronto, Princeton University, and the Institute for Advanced Study. Hewas the first Director of the Canadian Institute for Theoretical Astrophysics from 1985 to 1997 and the Chair ofthe Department of Astrophysical Sciences of Princeton University from 1998 to 2008. He has received the DirkBrouwer Award and the Henry Norris Russell Lectureship of the American Astronomical Society, the Tomalla Foundation Prize for Gravity Research, and fellowship in the RoyalSociety of London, the Royal Society of Canada, the US National Academy of Sciences.

Time: 12:30 PM

Location: Science Complex P-117

March 4th

Speaker: Philip Nelson

Topic: Physics of human and superhuman vision

Abstract: Scientists often seem to be asking obscure theoretical questions. But often, when we look carefully enough at experiences that go even just a bit beyond the everyday, we get surprises that lead to deeper understanding. Sometimes, asking “what is going on” and doggedly following the answers leads to unexpected practical payoffs. I’ll explore how the question, “What is light?” leads us to deeper understanding of how we see, and also to some powerful new ways to see things. These advances have recently given us breathtaking results in biomedical imaging, including new ways to break through a resolution barrier that was
considered inviolable for over a hundred years.

SPEAKER BIO: Philip Nelson teaches and researches at University of Pennsylvania. He is the author of Biological Physics Student Edition (2020) and other textbooks on biophysics. More information: https://www.physics.upenn.edu/~pcn/Links to an externalsite.https://live-sas-physics.pantheon.sas.upenn.edu/people/standing-faculty/philip-nelson

Time: 12:30 PM

Location: Science Complex P-117

April 1st

Speaker: TCNJ Physics Alumni Panel

Topic: TCNJ Physicists Paths to Jobs

Abstract: This colloquium will feature a panel of TCNJ Physics alumni who will give us their insight into life after graduation. We will be joined by Christian Balevski (2015), Nicholas Erickson (2014), Jaylond Martin (2016), Sean Potter (2023), and AJ Richards (2007).

Time: 12:30 PM

Location: Science Complex P-117

April 18th

Speaker: Juan Maldacena

Topic: Quantum Gravity

Abstract: General Relativity, which is Einstein’s theory of gravity, is based on the idea that spacetime is a dynamical entity. It can be deformed by gravity waves, it can expand, it can locally collapse into black holes. It is a surprising theory that has been receiving spectacular confirmation in the last few years. In this talk we will describe how to incorporate quantum mechanics. In the simplest approximation this leads to very interesting results for black holes and the expanding universe. We will also superficially mention some of the more recent ideas such as string theory and holographic correspondence.

BIO OF THE SPEAKER: Juan Maldacena was born in Argentina and did his undergraduate there, then came to Princeton University to do his PhD in Physics, which he finished in 1996. After that he became a professor at Harvard. Since 2001 he has been a professor at the Institute for Advanced Study at Princeton University. He has written about 200 scientific papers. His most famous one is on holographic correspondence, relating gravity theories to more standard quantum theories. He is a member of the National Academy of Sciences and has received several prizes and awards.

Time: 12:30 PM

Location: Science Complex P-101