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Episode
10: with guest Dr. Rogier Windhorst, Arizona State University |
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The first stars and galaxies began forming several hundred million years after the Big Bang. Astronomers are now able to probe back almost that far – to study the light from these distant objects. Among their major tools of exploration are the images and data in large surveys taken using the Hubble Space Telescope. The upcoming James Webb Space Telescope will be able to look back even farther in time to see the births of those first stars and the creation of the earliest galaxies. In this episode, we explore the galaxies in the early universe and find out how astronomers know what they know about these very distant objects. |
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Listen (mp3, 12.2 MB) |
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Download Transcript (pdf) |
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Produced by Loch Ness Productions for the Astronomical Society of the Pacific
Written and narrated by Carolyn Collins Petersen
Soundtrack and original music by Mark C. Petersen
Additional resource materials by Andrew Fraknoi
Special thanks to Dr. Rogier Windhorst, Scott Smas, and Keith Jennings.
Searching for the First Galaxies
A Collection of Resources to Get Behind the Headlines
Andrew
Fraknoi (Foothill College & ASP)
May 2011
This episode of Astronomy Behind the Headlines is indeed ripped from recent headlines, when astronomers used the newly refurbished Hubble Space Telescope to see deeper into space (and thus farther back in time) than had ever been possible. What made an ever deeper look possible than even the Hubble telescope alone permits was that several galaxies in the foreground probably acted like a giant lens, amplifying the light of really distant objects and making outrageously faint galaxies discernible. When the next space telescope (the James Webb Space Telescope, which will collect far more light than the Hubble) goes into operation, we expect to be able to peer even deeper into the early moments of star and galaxy formation.
In this resource guide, you can learn more about the search for the first generation of galaxies (following the Big Bang and the so-called "Dark Ages" of the universe) and get introduced to how astronomers are already using gravitational lenses (first predicted by Einstein) and how they hope to use the Webb Telescope to use them to even greater effect.
B. A Few Web Resources for Formal and Informal Educators
A. Introductory Resources on the First Galaxies, Gravitational Lenses, and the Next Big Space Telescope
The Hubble Space Telescope news releases that go with this episode are at:
http://hubblesite.org/newscenter/archive/releases/2011/04/full/
and
http://hubblesite.org/newscenter/archive/releases/2010/2010/02/full/
A1. The First Galaxies and Stars
Talcott, R. "Galaxies Near the Dawn of Time" in Astronomy, May 2010, p. 56. Describes the work of two teams, including Rogier Windhorst’s, using the Hubble to search for very distant galaxies.
Villard, R. "In Search of the First Stars" in Astronomy, June 2011, p. 26. Discussion of the how the stars in the earliest galaxies formed and how the JWST will help us learn more about them.
Gardner, J. "Find the First Galaxies" in Sky & Telescope, Jan. 2010, p. 24. On Hubble observations and what will be possible with JWST.
Larson, R. & Bromm, V. "The First Stars in the Universe" in Scientific American, Dec. 2001, p. 64. On the "dark ages" after the big bang and before stars formed, and how these ages ended.
[For the more advanced reader] Loeb, Abraham How Did the First Stars and Galaxies Form? 2010, Princeton University Press. Requires background in physics and math.
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Distant Galaxies Seen by the Hubble: There is a green circle around some of the really faint galaxies on this deep Hubble image that are close to some brighter galaxies in the foreground. Rogier Windhorst's team estimates that about 1/5 of these galaxies are probably brightened
by the gravitational lensing effect. (NASA/ESA) |
Web Sites:
The First Galaxies web site (by some of the researchers involved):
http://firstgalaxies.org/
The James Webb Space Telescope page on finding the first stars and galaxies:
http://www.jwst.nasa.gov/firstlight.html
Petersen, C. "The Universe through Gravity’s Lens" in Sky & Telescope, Sept. 2001, p. 32. Good introduction with nice diagrams and photos.
Wambsganss, J. "Gravity’s Kaleidoscope" in Scientific American, Nov. 2001, p. 65. On gravitational lenses and micro-lensing.
Gates, Evalyn Einstein’s Telescope: The Hunt for Dark Matter and Dark Energy in the Universe. 2009, Norton. A book that focuses on some of the ways gravitational lensing is being used to explore the large-scale properties of the universe.
Overbye, D. "Lenses in the Sky" in Discover Magazine, May 1984, p. 30. An early overview.
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How Gravitational Lensing Works: Einstein's General Theory of Relativity predicts that, under the right circumstances, the gravity of a foreground galaxy can bend and focus light from a distant object whose light passes nearby. Thus the more distant galaxy can appear brighter than it otherwise would and become unexpectedly noticeable on a deep photograph taken with a large telescope. (NASA) |
Web Sites:
A Brief History of Gravitational Lenses at Einstein On Line:
http://www.einstein-online.info/spotlights/grav_lensing_history
University of Tennessee Tutorial:
http://csep10.phys.utk.edu/astr162/lect/galaxies/lensing.html
Hubble Space Telescope Archive of News Releases about Gravitational Lenses:
http://hubblesite.org/newscenter/archive/releases/exotic/gravitational-lens/
ESA Hubble Site Brief Introduction:
http://www.spacetelescope.org/science/gravitational_lensing/
A3. James Webb Space Telescope
Reddy, F. "The Next Great Space Telescope Takes Shape" in Astronomy, Sep. 2010, p. 24. On the construction of JWST and on its capabilities.
Web Sites:
The Webb Telescope Site at the Space Telescope Science Institute:
http://webbtelescope.org/webb_telescope/
NASA’s JSWT Pages:
http://www.jwst.nasa.gov/
JWST Pages at the European Space Agency:
http://sci.esa.int/science-e/www/area/index.cfm?fareaid=29
Space News story on delays and cost overruns in preparing JWST:
http://www.spacenews.com/civil/110412-jwst-launch-2018.html
B. A Few Web Resources for Formal and Informal Educators
Two lensing demonstrations to help students understand gravitational lenses, from "Einstein’s Universe" are at:
http://www.cfa.harvard.edu/seuforum/einstein/resources/
JourneyBlackHole/LensingDemos.pdf
Another version of the lensing demonstration can be seen at:
http://doversherborn.org/~bridger/Astronomy/projects/
radio/activities/demo/lensing/lensing.htm
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A Tiny, Youthful Spiral Galaxy, ESO 418-008. (NASA, Rogier Windhorst (Arizona State University, Tempe, AZ), and the Hubble mid-UV team) |
To learn more about galaxies in general, try the Galaxy Sorting activity at the Seeing in the Dark PBS special web site (scroll down to see the activities):
http://www.pbs.org/seeinginthedark/for-teachers/
For more on telescopes in general, and the Hubble Space Telescope (the precursor to JWST) specifically, see the "Telescopes from the Ground Up" web exploration at:
http://amazing-space.stsci.edu/resources/
explorations/groundup/