PPT-Stars, Galaxies, and the Universe

Chapter 2 Stars Section 1 Vocabulary Spectrum Apparent Magnitude Absolute Magnitude LightYear Parallax Color of Stars Red and Yellow Cool Blue Warm Blue flame hotter than yellow flame. The Cosmic Time Machine. Astronomical telescopes can’t help viewing the past.. . Distance and time are always mixed in astronomical observations.. The finite speed of light means that we always see things after they have happened–a delay of 8 minutes for the Sun and about 12 billion years for the most distant galaxies we can observe. In other words,. Homogeneous and uniform cosmic expansion . Hubble constant determines scale factor . Hubble diagram was based on a limited distance scale calibrated by Cepheid variable stars in relatively nearby galaxies. H.-W. Rix IMPRS Galaxies Course March 11, 2011. Goal:. Determine . n. *. (M. *. ,. t. age. ,[Fe. /H],. R. ). . for a population of galaxies. How many stars of what mass and metallicity . formed when and where in galaxies?. Ms. Cordaro . SMHS . Earth Science. Review/Warm up – Write this in your journal. (Do not fill in the blanks yet!!). A light year = How far _ _ _ _ _ travels in _ _ _ year.. The electromagnetic spectrum is made up of different size _ _ _ _ _ that produce _ _ _ _ _ _ in the form of radiation.. The Hubble Tuning-Fork Diagram. This is the traditional scheme for classifying galaxies:. Elliptical Galaxies. Elliptical galaxies. have smooth, round distributions of stars. They resemble globular clusters, except they are much larger. They . Extraterrestrials. CELESTIAL BODIES. Astronomy that influence people’s lives and behavior. Astronomy – study of the night sky(planets, galaxies, stars, and other celestial bodies). UNIVERSE – it is everything that exists. Galaxy Morphology and Environment. Main relation – . E’s more common in clusters than field. f(E. ) = fraction of ellipticals . f(Sp. ) = fraction of spirals. regular, symmetric cluster – . f(E. Let’s look back at the rotational velocity equation:. v = (M. interior. G/r). 0.5. The rotational velocity is constant at big r values.. What must we conclude?. The mass interior to the orbit is still increasing. Even after the radius r has gone beyond the last of the stars. It must be increasing in order to hold v constant.. .. 1. First spiral nebula found in 1845 by the Earl of . Rosse. . Speculated it was beyond our Galaxy.. 1920 - "Great Debate" between Shapley and Curtis on whether spiral nebulae were galaxies beyond our own. Settled in 1924 when Edwin . The universe is a big place, perhaps the biggest. . –Kurt Vonnegut. Cosmology. Cosmology is the study of the nature of the universe, how the universe began and how it will end, if it does. There is religious cosmology, and scientific cosmology. The universe is a big place, perhaps the biggest. . –Kurt Vonnegut. Cosmology. Cosmology is the study of the nature of the universe, how the universe began and how it will end, if it does. There is religious cosmology, and scientific cosmology. Stars 1. Patterns of stars – constellations a. Ancient cultures used mythology or everyday items to name constellations 2. Modern astronomy studies 88 constellations 3. Some constellations are not The astonishing variety of galaxies derived from a few structural types. Sec 1.3. Irregulars. = misfits in any class. Edwin Hubble . The Realm of the Nebulae . (1936. ). ‘. Tuning Fork’ classification scheme of galaxies. The expanding Universe. Recap. Milky . Way. Distances in the Milky Way: our Galaxy is very large. Other galaxies. Galaxy . properties. Morphology: spiral and elliptical galaxies, spirals can appear different depending on viewing .