On November 25th of 1915, Albert Einstein presented a paper on his General Theory of Relativity that by its end had conclusively shown that the Vulcan hypothesis was not necessary to explain the precession of the perihelion of the orbit of Mercury.  It also completely reimagined the structure of space and time and remade the universe.  In this episode of the podcast, we follow Einstein's journey of discovery from the work of James Clerk Maxwell to the eclipse observations of Arthur Stanley Eddington.

In 1925, the astronomer Henry Norris Russell read a paper at the 33rd meeting of the American Astronomical Society.  The paper, written by Edwin Hubble, a staff astronomer at the Mt. Wilson observatory, detailed observations of Cepheid variable stars in the Andromeda Nebula. These observations and the analysis of them showed that the spiral was a million light years outside the Milky Way Galaxy, thus establishing it as an island universe once and for all.  The Great Debate was settled and the size of the universe was expanded to a scale unimaginable just a decade earlier.

On April 26th of 1920, Harlow Shapley and Heber Curtis presented talks on the idea of island universes to the National Academy of Sciences.  Held at the Smithsonian Museum of Natural History, the Great Debate, as it would come to be known, would showcase two differing views of the scale and structure of the universe.

In 1914, Harlow Shapley moved to work at the Mt. Wilson Observatory.  Over the course of five years, using the 60 inch reflector there, he observed the 75 visible globular clusters and developed a whole new model of the Milky Way Galaxy and our place in it.

In our final episode of this mini-series on the women who worked at the Harvard College Observatory, we dive into the life of Cecilia Payne-Gaposchkin from her time at Cambridge University to her life in Cambridge, Massachusetts.

In this episode we take a look at the history of the development of the metric system out of the French Revolution.

Annie Jump Cannon and Henrietta Swan Leavitt would form the core of the calculation staff at the Harvard College Observatory for nearly two decades.  They oversaw the transition of the Observatory from the directorship of Edward Charles Pickering to Harlow Shapley and established the dominant classification systems and physical laws for stellar spectra and variable stars in the early 20th century that would lead to foundational discoveries in the fields of astronomy and astrophysics.

In the first part of a multi episode series, we look at the lives of two very different women.  Williamina Fleming and Antonia Maury both made significant contributions to the field of stellar spectroscopy by developing classification systems to better understand the light from stars but their different backgrounds and training meant that they understood the role of being a calculator very differently.

This week we take an in-depth look at the work done at the Harvard College Observatory on cataloging and classifying variable stars under the direction of Charles Edward Pickering.  We examine the contributions of Williamina Fleming, Annie Jump Cannon and Henrietta Swan Leavitt that resulted in the the period luminosity relationship, also known as Leavitt's Law.

This week we take a look at weather forecasting after the Navigator's trip to Boulder, CO for the NASA Social event for the launch of the JPSS-1 polar orbiting satellite.  We discuss a brief history of weather forecasting, the roles of both geosynchronous and polar orbiting satellites in that endeavor and the JPSS program.  Specific attention is given to the five instrument packages that will be places on the vehicle: CrIS, ATMS, VIIRS, OMPS and CERES.