http://stream.publicbroadcasting.net/production/mp3/wamc/local-wamc-954178.mp3
Albany – In today's Academic Minute, Dr. Heidi Newberg of the Rensselaer Polytechnic Institute reveals how much we have learned about galaxies in the last century, and the mysteries still awaiting discovery.
Dr. Newberg is a professor of physics, applied physics, and astronomy at the Rensselaer Polytechnic Institute in Troy, NY. She earned a Ph. D. from the University of California Berkeley where she worked on the Berkeley Automated Supernova Search. She has published papers in diverse areas of galactic and extragalactic astronomy, including: supernova phenomenology, measuring cosmological parameters from supernovae, galaxy photometry, color selection of QSOs, properties of stars, astronomy education, and the structure of our galaxy. Newberg's current research is primarily related to understanding the structure of our own galaxy.
Dr. Heidi Newberg - The Mystery of Galaxies
It has always astounded to me to think that only 100 years ago, no one knew that galaxies existed. The Universe consisted only of stars and nebulae. In the 1920's, Edwin Hubble made two important discoveries that profoundly altered our understanding of our Universe. He was able to measure the distances to some of the spiral "nebulae," and discovered that they were much, much farther away than any of the stars. This established that the stars were in our galaxy, the Milky Way, and the spiral nebulae were other galaxies. Also, he discovered that galaxies that are farther from us are moving away from us faster than galaxies that are closer. This discovery, coupled with Einstein's General Theory of Relativity, let to the concept of the "Big Bang," and the startling realization that the Universe evolves. We live in an unfathomably vast and ever-changing universe.
In the past hundred years we have learned much, but the most important discoveries have taught us how little we really know. Most of the mass in the Universe is a substance called "dark matter," which has never been discovered. The rate at which the Universe is expanding is increasing by a mechanism called Dark Energy that we do not understand.
I am personally working on understanding how galaxies form by studying stars in the Milky Way. In this archaeological project on grand scale, my colleagues and I are trying to figure out how and when stars formed, how they come to reside in galaxies, and how elements are formed and distributed in Galactic stars. Many of the older stars in our galaxy actually formed in other, smaller galaxies, which merged together to form the Milky Way. The Sun, however, was born out of gas in the Milky Way and is thus a native star.