Transcript Day 15
Announcements •Dark Sky Night tonight! Set-up starts at 7:30pm at The Farm. BE THERE!!! •Don’t forget about the second project. Presentations are only three weeks away! Astronomy Courses Next Semester (and beyond) Next Semester •Astr 2011: Introduction to Observational Astronomy •Astr 3005/3006: Observational Astronomy •Astr 4010: Astrophysics I Beyond •Astr 3020: Cosmology…Spring 2017 •Astr 3040: Astrobiology…Spring 2017 •Astr 4020: Astrophysics II…Spring 2017 •Astr 3030: Astronomical Methods and Instrumentation •Astr 4000/4001: Astrophotography…Fall 2017 The rise of scientific publications Before the Royal Society’s Philosophical Transactions, scientific advances were disseminated strictly by book or personal letters The French got into the act with La Connoissance des Temps Charles Messier published his famous catalogue here in 1783 Soon the Germans were doing it By 1820 the astronomers split from the Royal Society to form the Astronomical Society J. L. E. Dryer published his New General Catalogue in the Memoirs of the Royal Astronomical Society The American Benjamin A. Gould started publishing the Astronomical Journal but quit during the Civil War Astronomischer Jahsbericht eventually became Astronomy and Astrophysics Abstracts With all the astronomers and their publications, organizations were needed In 1899 George Ellery Hale formed the American Astronomical Society The International Astronomical Union was formed in 1919 In 1930 the IAU formally set the boundaries of all constellations The IAU recently demoted Pluto from planetary status The story of light Isaac Newton was one of the earliest to make a serious scientific study of light At first Newton simply examined the spectrum of sunlight Then he showed that the colors combine to make white light By the early 1800’s Joseph Fraunhofer began to examine the solar spectrum in more detail Later, his spectra became much more detailed By the 1850’s, Gustav Kirchhoff and Robert Bunsen had identified many of the lines in the solar spectrum Kirchhoff developed the science of spectroscopic analysis Kirchhoff’s 1st Law: a hot solid or dense gas will emit a continuous spectrum of light whose peak wavelength depends on the temperature Kirchhoff’s 2nd Law: a “cool” gas will absorb specific wavelengths of light dependent on the elements present in the gas. Kirchhoff’s 3rd Law: a hot gas will emit specific wavelengths of light dependent on the elements present in the gas. Julius Plucker studied the spectra of gas discharge tubes Anders Angstrom published a detailed compendium of the spectral lines in the Sun in 1868 In 1843 Heinrich Schwabe announced the discovery of a cycle in the number of sunspots The Naturalist Alexander von Humboldt drew attention to Schwabe’s cycle in Kosmos Humboldt had encouraged scientists around the world to map the Earth’s magnetic field Many of the geomagnetic observatories were started under Humboldt’s encouragement What they discovered is the Earth’s magnetic field isn’t constant The Earth’s magnetic field seemed to vary with the same periodicity as the sunspot cycle. In 1859 Richard Hodgson and R. C. Carrington made the first observation of a solar flare Eclipse chasing was how observers viewed the Sun’s atmosphere Flash Spectra of the Sun at eclipse showed a layer called the chromosphere J. Norman Lockyer was the first to attach a spectrograph to a telescope for solar observations Pierre Janssen discovered helium in the solar spectrum Simultaneously, Lockyer published a paper on helium using the same technique Others though there were even more “new” elements in the Sun The green color was thought to be due to coronium. We now know it is due to Fe XIV and Ni XVI