A Family Scrapbook of the Universe
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An Overview of New Worlds, New Horizons in Astronomy and Astrophysics About the National Academies
2020 VISION An Overview of New Worlds, New Horizons in Astronomy and Astrophysics About the National Academies The National Academies—comprising the National Academy of Sciences, the National Academy of Engineering, the Institute of Medicine, and the National Research Council—work together to enlist the nation’s top scientists, engineers, health professionals, and other experts to study specific issues in science, technology, and medicine that underlie many questions of national importance. The results of their deliberations have inspired some of the nation’s most significant and lasting efforts to improve the health, education, and welfare of the United States and have provided independent advice on issues that affect people’s lives worldwide. To learn more about the Academies’ activities, check the website at www.nationalacademies.org. Copyright 2011 by the National Academy of Sciences. All rights reserved. Printed in the United States of America This study was supported by Contract NNX08AN97G between the National Academy of Sciences and the National Aeronautics and Space Administration, Contract AST-0743899 between the National Academy of Sciences and the National Science Foundation, and Contract DE-FG02-08ER41542 between the National Academy of Sciences and the U.S. Department of Energy. Support for this study was also provided by the Vesto Slipher Fund. Any opinions, findings, conclusions, or recommendations expressed in this publication are those of the authors and do not necessarily reflect the views of the agencies that provided support for the project. 2020 VISION An Overview of New Worlds, New Horizons in Astronomy and Astrophysics Committee for a Decadal Survey of Astronomy and Astrophysics ROGER D. -
Glossary of Terms Absorption Line a Dark Line at a Particular Wavelength Superimposed Upon a Bright, Continuous Spectrum
Glossary of terms absorption line A dark line at a particular wavelength superimposed upon a bright, continuous spectrum. Such a spectral line can be formed when electromag- netic radiation, while travelling on its way to an observer, meets a substance; if that substance can absorb energy at that particular wavelength then the observer sees an absorption line. Compare with emission line. accretion disk A disk of gas or dust orbiting a massive object such as a star, a stellar-mass black hole or an active galactic nucleus. An accretion disk plays an important role in the formation of a planetary system around a young star. An accretion disk around a supermassive black hole is thought to be the key mecha- nism powering an active galactic nucleus. active galactic nucleus (agn) A compact region at the center of a galaxy that emits vast amounts of electromagnetic radiation and fast-moving jets of particles; an agn can outshine the rest of the galaxy despite being hardly larger in volume than the Solar System. Various classes of agn exist, including quasars and Seyfert galaxies, but in each case the energy is believed to be generated as matter accretes onto a supermassive black hole. adaptive optics A technique used by large ground-based optical telescopes to remove the blurring affects caused by Earth’s atmosphere. Light from a guide star is used as a calibration source; a complicated system of software and hardware then deforms a small mirror to correct for atmospheric distortions. The mirror shape changes more quickly than the atmosphere itself fluctuates. -
GSMT and JWST: Looking Back to the Future of the Universe
GSMT AND JWST: Looking Back to the Future of the Universe istory will record that American scientists We see now that the history of the Universe is the launched one of humankind’s greatest back story to our own existence. We have met all the Hintellectual adventures early in the 20th major characters in this story, from the trillions of century. Building giant telescopes that dwarfed their common stars to the exotic massive black holes in predecessors, astronomers began to wrestle with our galaxy cores that power the phenomenal blasts of ancient, most compelling mysteries: Where are we? quasar light. Now, as the 21st century begins, astrono- What are we? And where do we come from? These mers prepare to read the final chapter in this great giant machines of glass and steel, growing decade by mystery story. They seek to use astronomy’s powerful decade, revealed a Universe of intimidating size and magic—looking out into space to see back in time—to imponderable age, but more remarkably, one within see how our modern Universe came to be. Brought to human understanding. the threshold of this final step by amazing telescopes— With an explosion of tools, observations, and ideas notably the Hubble Space Telescope (HST) and the building to a crescendo by century’s end, astronomers Keck ground-based telescopes—we examine the feeble succeeded beyond their expectations: today, we light that emerged long ago when the Universe was in routinely describe the size, age, and contents of a its youth. Yet we must go further out, further back. -
The Keck Observatory the Keck Observatory
The Keck Observatory Portal to the Universe Keck Observatory at sunrise on Maunakea, Hawai’i. CREDIT: ANDREW RICHARD HARA PORTAL to the UNIVERSE Keck brings us views of our solar system, our galaxy, and beyond. From bottom to top: The Great Red Spot of Jupiter, the Egg Nebula, and a picture of four planets around HR 8799 Keck Observatory and the night sky over taken December 8, 2010 (CREDIT: NRC-HIA, Maunakea, Hawai’i. C. MAROIS/W. M. KECK OBSERVATORY). CREDIT: ANDREW RICHARD HARA ii K EC K : P ORTAL TO THE U NIVERSE Contents QUICK FACTS The W. M. Keck Observatory: A Portal to the Universe ....................... 3 about the Keck: A Chronology .....................................................................................6 Close to Home: Keck and Our Solar System .............................................8 Keck Observatory Galactic Neighborhood: Keck and the Milky Way .............................. 10 Distant Worlds: Keck and Extrasolar Planets .........................................14 OBSERVATORY STATS Deep Voyage: Keck and Extragalactic Space ...................................... 18 • Location: Maunakea, Hawai’i Discovering the Past and Future: Keck and Cosmology ................... 21 • Altitude: 4,145 meters (13,599 ft) Collaborative and Complementary: • Mirror diameters: 10 meters (33 ft) each 2 2 Keck’s Place in the Astronomical Community ....................... 24 • Collecting area: 72 m (820 ft ) each Meet the Instruments ......................................................................... 28 • Angular resolution: -
Hubble Space Telescope Clocks up 20 Years : Nature News 26/04/10 09:19
Hubble Space Telescope clocks up 20 years : Nature News 26/04/10 09:19 Published online 22 April 2010 | Nature | doi:10.1038/news.2010.195 News Hubble Space Telescope clocks up 20 years Nature looks at a troubled history, some remarkable discoveries and the future of the instrument. Katharine Sanderson It was an instrument that much of the astronomical community didn't want, but times change: to get time now on the Hubble Space Telescope, which is celebrating its 20th anniversary this week, an astronomer usually faces competition from at least 11 other eager scientists. Hubble, named after American astronomer Edwin Hubble, has been orbiting Earth for 20 years, sending back images in the visible, near-infrared and ultraviolet parts of the spectrum. In that time it has undergone major surgery, proved the existence of dark matter, given insight into the life and death of supernovae, and captured the public's imagination with its pictures. And throughout all this, the instrument's very survival has been threatened more than once. Hubble's recent history began in 1962, when the National Academies of Science recommended a space telescope be built, although astrophysicist Lyman Spitzer had put forward the idea in the 1940s. In 1970 NASA began to investigate the feasibility of such an instrument. This led Bob O'Dell, now at Vanderbilt University in Nashville, Tennessee, to take a risk: in 1971 he left See Nature's Hubble anniversary his job at the University of Chicago to become Hubble's first project scientist. "I gave up a slideshow for more stunning images. -
"First Light" in the NTT R
No. 56 - June 1989 "First Light" in the NTT R. WILSON, ESO On the night 22-23 March 1989, "First Light" was achieved in the NlT in the sense that the first direct images of astronomical objects were produced with the optics in an optimized state near the zenith position. The fact that the quality of these im- ages turned out to be the best ever ' recorded in ground-based astronomy certainly made it the most memorable event in the ESO career of the author and his colleagues whose work on the NTT had led to this remarkable success. But this result did not drop out of the sky! Many years of hard work by a small group of dedicated colleagues were necessary to achieve it. The principal new technology feature of the N7T was its Active Optics control system, the background and principles of which were described in The Messenger No. 53 (September 1988), page 1. The i other new technology feature of funda- mental importance for the optical quality was the design of the building. Although its basic concept is the same as that of the MMT (a building rotating with the alt- az mounted telescope), the new I features were crucial, particularly the opening of the telescope area on both sides to allow maximum natural ventila- tion. These two new technology features, together with the excellent work of Carl Zeiss in figuring the optics, were the key to the image quality achieved at First Light. The Basic ("Passive") Alignment of the Optics This false-colour photo shows one of the best CCD frames obtained with the ESO NTduring the night of "first light" on March 23, 1989. -
Cosmic Microwave Background Radiation Which Still Pervades the Universe and Is Visible to Microwave Detectors As a Uniform Glow Across the Entire Sky
Wilkinson Microwave Anisotropy Probe Cosmology: The Study of the Universe Cosmology is the scientific study of the large scale properties of the universe as a whole. It endeavors to use the scientific method to understand the origin, evolution and ultimate fate of the entire Universe. Like any field of science, cosmology involves the formation of theories or hypotheses about the universe which make specific predictions for phenomena that can be tested with observations. Depending on the outcome of the observations, the theories will need to be abandoned, revised or extended to accommodate the data. The prevailing theory about the origin and evolution of our Universe is the so-called Big Bang theory. This primer in cosmological concepts is organized as follows: The main concepts of the Big Bang theory are introduced in the first section with scant regard to actual observations. The second section discusses the classic tests of the Big Bang theory that make it so compelling as the likely valid description of our universe. The third section discusses observations that highlight limitations of the Big Bang theory and point to a more detailed model of cosmology than the Big Bang theory alone provides. As discussed in the first section, the Big Bang theory predicts a range of possibilities for the structure and evolution of the universe. The final section discusses what constraints we can place on the nature of our universe based on current data, and indicates how WMAP furthers our understanding of cosmology. In addition, a few related topics are discussed based on commmonly asked questions. If you have a question about cosmology that you don't see answered here or on our FAQ page, please feel free to contact us directly. -
March 2014 a B O U T U S
s p r i n g . q u a r t e r / m a r c h . 2 0 1 4 R EFLECTIONS How the Spiral Nebulae Got Their Distances by tim thompson The 100-inch (2.5-meter) Hooker telescope at Mount is arguably the single most important fundamental dis- Wilson Observatory saw first light on November 2, covery in astronomical history). 1917, at which moment it became the world’s largest By 1919, Harlow Shapley had already determined the telescope, surpassing its younger sibling for that honor, extent of the Galactic system. He claimed a complete the 60-inch (1.5-meter) telescope, also at Mount Wil- census of globular clusters out to 30,000 parsecs (about son Observatory. It did not take long for the Hooker 100,000 light-years) and showed that a quarter of the telescope to flex its astronomical muscles and opera- globular clusters for which he had determined distances tionally redesign the entire universe, in the capable were farther away than that, and he asserted that “recent hands of Edwin Hubble. studies of the galactic system indicate that its greatest During the 1920s, Edwin Hubble set about the task of diameter is not less than 300,000 light-years.” So dis- finally determining, once and for all, the true nature of tances on this scale of a few hundred thousand light- the mysterious “spiral nebulae” — whether they were years were already in the minds of astronomers. But relatively nearby clouds of gas or extremely distant as- Shapley also asserted that for the spiral nebulae to be semblies of stars — and there were astronomers lined that large, and yet look as small as they do, then “that up on both sides of the issue.