Past Events

  • Astro Seminar: "Mapping Magnetic Fields in Star Forming Regions with BLASTPol and BLAST-TNG "

    David Rittenhouse Laboratory, A6

    Laura Fissel (Northwestern)

    A key outstanding question in our understanding of star formation is
     whether magnetic fields provide support against the gravitational
     collapse of their parent molecular clouds and cores. Direct
     measurements of magnetic field strength using Zeeman splitting are
     extremely difficult and only a few clear detections have been made in
     high density molecular gas. Alternately, observations of polarized
     thermal emission from dust grains aligned with respect to the local

  • Dissertation Defense for Jing Cai: "Superior to One of Glass: Natural Gradient Index Lenses Via Patchy Particle Self-Assembly"

    DRL Room 3W2

  • Condensed Matter Seminar: "The life of a vortex knot: Linking coiling and twisting across scales"

    DRL A4

    William Irvine, University of Chicago

    Can you take a vortex loop - akin to a smoke ring in air - and tie it into a knot or a link?

  • An Introduction to Kirigami: Cutting, Folding, and Building with Triangles

    World Cafe Live, 3025 Walnut Street

    FeaturingVicki and William Abrams Professor of the Natural Sciences Randall Kamien; Professor Shu Yang; Xingting Gong, C'15; Daniel Sussman; Toen Castle; and Michael Tanis, members of a research team from the Departments of Physics and Astronomy and Materials Science and Engineering

    The team will explain how the mathematical rules they’ve outlined for this technique shows how to make all sorts of 3D structures from 2D designs. Attendees will also have a chance to try making their own kirigami creations.  It's an evening of engaging, stimulating conversation, with a Q&A session following each talk.

    Penn Café events are free and open to the public, but RSVPs are encouraged. Contact Gina Bryan at 215-898-8721 or email

  • Quaker Days-Arts & Sciences Faculty Talks: "The Evolution of the Universe"

    David Rittenhouse Laboratory Room A8

    Professor Masao Sako (University of Pennsylvania)

    talk will focus on Penn’s observational cosmology program and the mysteries we are hoping to solve within the next five years.turn determines its history and ultimate fate. What is the Universe made of? How was it created and what is our future? Thisspeeds. The large-scale properties of these motions are determined by the mass and energy content of the Universe, which inOur Universe is a surprisingly dynamic place with stars, planets and galaxies all moving around each other at unimaginable.

    *Open to the public*

  • Dissertation Defense: "Cerebral Blood Flow and Oxygen Metabolism Monitoring with Hybrid Diffuse Optical Techniques"

    University of Pennsylvania LRSM, Reading Room

    Wesley Baker (University of Pennsylvania)

  • The Henry Primakoff Lecture: Was Einstein Right? A Centennial Assessment

    DRL A8

    Clifford Will (University of Florida)

    A century after Einstein's formulation of general relativity, a remarkably diverse set of precision experiments has established it as the ``standard model'' for gravitational physics.   Yet it might not be the final word.  We review the array of measurements that have verified general relativity in the laboratory, in the solar system and in binary pulsars.   We then describe some of the opportunities and challenges involved in testing Einstein's great theory in strong-field regimes, in gravitational waves, and in cosmology.

  • Department Colloquium: The Cosmic Barber:"Counting Gravitational Hair in the Solar System and Beyond"

    David Rittenhouse Laboratory, Room A6

    Clifford Will (University of Florida)

    According to general relativity, every self-gravitating object has ``hair'', an array of multipole moments of various types that characterize the body's exterior geometry. In alternative theories of gravity, bodies could also be endowed with more exotic tresses, such as scalar hair. We review how solar system experiments, such as light deflection and time-delay measurements, have placed stringent limits on scalar hair. We describe how experiments such as GRACE have measured with high precision the vast head of Newtonian hair possessed by the Earth.

  • GR Math Seminar: "The graded Lie algebra of general relativity "

    Michael Reiterer (IAS and Penn)

    Several problems can be written as [x,x]=0 where the unknown x
    is an element of degree one in a graded Lie algebra. I show that general
    relativity (the Einstein vacuum equations) can also be put in this form.
    Using this language, I discuss formal perturbation theory; gauge-fixing;
    and some open problems. Familiarity with general relativity is not
    assumed, in fact this talk can be taken to be some kind of introduction
    to general relativity. Based on Joint work with
    Eugene Trubowitz. 

  • Dissertation Defense: "Single Cells Use Transcriptional Mechanisms to Compensate for Differences in Cell Size and DNA Content"

    David Rittenhouse Laboratory, Room A7

    Olivia Padovan-Merhar (University of Pennsylvania)