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Modern Telescopes and Ancient Skies New Views of the Universe An IU Lifelong Learning Class Tuesdays, May 10, 17, 24 Size and Scale Surveying the Universe from the Earth to the farthest reaches of the visible Universe Our closest neighbor Galileo Galilei's "The Phases of the Moon" Image courtesy of Biblioteca Nazionale Florence, Italy Visualizing the Earth from Space • What do you see? – Earth – Moon – Sun – Stars Copyright 1980 by DC Comics Inc. Welcome to Outer Space! Moon Radius: ¼ Earth’s radius Distance from Earth: 384,000 km Earth Radius: 6400 km Distance from Sun: 150,000,000 km 1 AU, 8 light minutes Sizes of planets NOT to scale Solar Distance to Pluto: about 40 AU (about 320 light minutes) System The Nearest Stars The closest star to our Sun is Proxima Centauri, about 4 light years distant. Most of the stars we see in the sky are within 250 light years Our Sector of the Galaxy The Sun lies along one of our Galaxy’s spiral arms, known as the Orion Arm View of the Milky Way Galaxy Our Milky Way galaxy contains two hundred billion stars. The Sun is about 26,000 light years from the center. Our Milky Way Galaxy is part of a small cluster of galaxies. Our Local Group of galaxies is part of a larger supercluster of galaxy groups. Virgo Supercluster Galaxies and clusters of galaxies collect into vast streams, sheets and walls of galaxies. The Visible Universe On the largest scales, the universe seems to be more or less uniform With thanks to Bill Watterson, 1990 What will we cover????? How telescopes work Modern telescopes Space telescopes Future Visiting the Gemini Observatory telescopes Kirkwood Obs Sky viewing This sketch of a telescope was included in a letter written by Giovanpattista della Porta in August 1609 Beginnings… Thomas Harriet’s Drawings of the Moon and Sun Telescopes and how they work to mirrors from lenses… Technology moves forward… The 3.5-meter WIYN telescope Kitt Peak, Arizona New Telescope Technology “Fast” mirror Lightweight mirror Mirror shape controlled Mechanically simpler mount Temperature control Casting the WIYN Mirror Polishing the WIYN Mirror The WIYN New Technology “Dome” Compact telescope chamber Open for ventilation Insulated to keep cool Heated spaces kept separate Breaking the “cost curve” New technology provides better performance at lower cost WIYN WIYN TECHNOLOGY in 6-8 meter telescopes The importance of image quality text typical groundbased image Hubble image WIYN image The Ring Nebula Connecting the First Nanoseconds to the Origin of Life How is the Universe put together? The Wilkinson Microwave Anisotropy Probe tells us about the state of the Universe 400,000 years after the Big Bang. How did the Universe evolve from this… …to this? Observing the assembly of galaxies Intergalactic gas Galaxy building blocks observed with Hubble Clumps concentrated by dark matter lead to galaxies Simulation The cosmic web of intergalactic gas and galaxies in a young universe WMAP also provides evidence of the first stars Tiny fluctuations in polarization About 200 million years after the Big Bang We can almost see the first stars Green=hot gas yellow=stars What we might see with a 30-meter telescope (Barton et al., 2004) Simulation 4 million LY hydrogen emission from hot stars What is the Universe made of? The composition of stars and gas: 90% hydrogen atoms 10% helium atoms Less than 1% everything else everything else But ordinary matter is only part of the story… 96% of the Universe is something else Galaxy interactions require more mass than we can see Computer simulation The real thing Antennae Galaxy (HST) Dark Matter The universe contains additional matter we cannot see Dark matter interacts with normal matter through gravity Dark matter does NOT interact with light the way the normal matter does The Universe contains 5 or 6 times MORE dark matter than normal matter All galaxies are embedded in clouds of dark matter We do not know what it is! “Redshift” of Galaxies The spectra of galaxies are shifted to the red: galaxies are moving away from us. The farther away a galaxy is, the faster it recedes from us! Hubble’s Law Distance (LY) 3000 2000 1000 Distance - Velocity Relation 0 0 20000 Velocity (km/sec) 40000 The brightness of stellar explosions tells us how far away galaxies are The speeds of very distant galaxies tell us the Universe is expanding faster today than in the past The Universe is speeding up! The universe is expanding faster today than it did in early times This expansion cannot be caused by ordinary or dark matter, which slows expansion. The acceleration suggests a new repulsive force (anti-gravity) acting on very large scales The New Force Is Called “Dark Energy” Dark energy accounts for 73% of the content of the universe Dark matter accounts for 23% The content we’re familiar with is only 4% What is Dark Energy? We don’t know Identifying what dark energy is requires bigger telescopes and new techniques Connecting the First Nanoseconds to the Origin of Life Kirkwood Observatory Viewing Tuesday evenings, weather permitting Night Sky Viewing • Scheduled nights –Tuesday, May 17 –Tuesday, May 24 • Roof of Swain West Next Week • Telescopes in Space, including the Hubble Space Telescope • New Views of the Universe – Planets around other Suns • Kirkwood Obs and Rooftop, weather permitting Is there life elsewhere? More than 150 planets found around other stars Most are vastly different from our Solar System Artist’s conception of 55 Cancri’s planetary system Detecting Planets detecting planets directly is hard planets are small and dim planets are near much brighter stars detecting planets directly requires large telescopes (30-meters) and/or special instruments Imaging planets around other stars Gemini/Keck AO detection by Michael Liu (IfA), 2002 “Brown Dwarf” orbiting a star at the same distance as Saturn from our Sun Simulation of the spectra of 55 Cancri’s planets With a 30-meter telescope we can obtain the spectra of planets around other stars to search for the signatures of life Simulation by Sudarsky et al. 2003