The Birth of the Earth
Overview information on meteorites and on the history of meteoritics is from Edward Scott, “Meteorites: An Overview,” Elements 7 (2011): 47–48; and Christopher Cokinos, The Fallen Sky: An Intimate History of Shooting Stars (New York: Penguin, 2010).
A very helpful, accessible overview of the way meteorites have come to help us understand the origins of the Solar System is Dante S. Lauretta, “A Cosmochemical View of the Solar System,” Elements 7 (September 2011): 11–16.
The story of the Allende meteorite's arrival and initial study is compiled from Elbert King, Moon Trip: A Personal Account of the Apollo Program and Its Science (Houston: University of Houston, 1989); Arch Reid, “Elbert Aubrey King, Jr. (1935–1998),” Meteoritics & Planetary Science 34 (1999): 677; “Blue-White Fireball Sighted in Mexico,” Washington Post, UPI, February 9, 1969, http://www.mnh.si.edu/onehundredyears/featured_objects/AllendeMeteorite.html; and from the Smithsonian Institution, where a large piece of Allende is on display: “Allende Meteorite,” Smithsonian National Museum of Natural History, http://www.mnh.si.edu/onehundredyears/featured_objects/AllendeMeteorite.html (accessed January 17, 2011).
The scientific papers documenting Allende's age are Jamie Gilmour, “The Solar System's First Clocks,” Science 297 (September 6, 2002): 1658–59; Yuri Amelin et al., “Lead Isotopic Ages of Chondrules and Calcium-Aluminum-Rich Inclusions,” Science 297 (September 6, 2002): 1678–83; Hubert Reeves, “Cosmochronology after Allende,” Astrophysical Journal 231 (July 1, 1979): 229–35; and Typhoon Lee et al., “Aluminum-26 in the Early Solar System: Fossil or Fuel?” Astrophysical Journal 211 (1977): 107–10.
The Men Who First Held Stardust
This story of the discovery of the first pre-solar diamonds is compiled from a wide range of perspectives.
Information about Edward Anders comes from Ursula Marvin, “Oral Histories in Meteoritics and Planetary Science: I. Edward Anders,” Meteoritics & Planetary Science 36 (2001): A255–67; and Edward Anders, “Origin, Age, and Composition of Meteorites,” Space Science Reviews, 3. no. 11 (March 12, 1979): 321, http://garfield.library.upenn.edu/classics1979/A1979HZ32600001.pdf. Anders's powerful memoir recounting the experience of Latvian Jews during the Holocaust is widely available from online bookstores: Edward Anders, Amidst Latvians during the Holocaust (Riga: Occupation Museum Association of Latvia, 2010); and I’m indebted to Dr. Anders for sharing part of an unpublished autobiography for my background information: “Chicago: 1964–1991,” chap. 13, pp. 218–89. Anders's key early paper outlining the origin of meteorites in the asteroid belt between Jupiter and Mars is Edward Anders, “Origin, Age, and Composition of Meteorites,” Space Science Reviews 3 (1964): 583–714.
The description of Solar System theorist Viktor Safronov's work is based on Alan Boss, Looking for Earths: The Race to Find New Solar Systems (New York: John Wiley & Sons, 1998), pp. 39–42.
The process of how pre-solar diamonds were discovered is compiled from the original research paper of Roy S. Lewis et al., “Interstellar Diamonds in Meteorites,” Nature 326 (March 12, 1987): 160–62; Anders's description of the process is found in Edward Anders and Ernst Zinner, “Interstellar Grains in Primitive Meteorites: Diamond, Silicon Carbide, and Graphite,” Meteoritics 28 (1993): 490–514; and two media accounts come from Patrick Huyghe, “Stardust Memories,” Discover, November 1991, pp. 58–64; and Faye Flam, “Seeing Stars in a Handful of Dust,” Science 253 (July 26, 1991): 380–81.
Stardust Memories
This section is based on Ann Nguyen and Scott Messenger, “Presolar History Recorded in Extraterrestrial Materials,” Elements 7, no. 1 (February 2011): 17–22; Andrew M. Davis, “Stardust in Meteorites,” Proceedings of the National Academy of Sciences 108 (November 29, 2011): 19142–46; Donald Clayton and Larry Nittler, “Astrophysics with Presolar Dust,” Annual Review of Astronomy and Astrophysics 42 (2004): 39–78; and Douglas Rumble III, “Stable Isotope Cosmochemistry and the Evolution of Planetary Systems,” Elements 7 (February 2011): 23–28.
The description of Solar System formation from stardust clumping is based on Daniel Apai and Dante S. Lauretta, “Planet Formation and Protoplanetary Dust,” pp. 9–15, in Protoplanetary Dust: Astrophysical and Cosmochemical Perspectives, ed. Daniel Apai and Dante S. Lauretta (Cambridge: Cambridge University Press, 2010); Jonathan Williams and Lucas Cieza, “Protoplanetary Disks and Their Evolution,” Annual Review of Astronomy and Astrophysics 49 (2011): 67–117; C. H. Chen et al., “Spitzer IRS Spectroscopy of IRAS-Discovered Debris Disks,” Astrophysical Journal Supplement Series 166 (September 2006): 351–77; and Thorsten Kleine and John F. Rudge, “Chronometry of Meteorites and the Formation of the Earth and Moon,” Elements 7 (February 2011): 41–46.
Sagan's Dream
The description of Sandford's cold cosmic cloud–chemistry research is based on a tour he gave me of the NASA-Ames astrochemistry lab. Related scientific papers include Michel Nuevo et al., “Formation of Uracil from the Ultraviolet Photo-Irradiation of Pyrimidine in Pure H2O Ices,” Astrobiology 9 (2009): 683–95; Max P. Bernstein et al., “Racemic Amino Acids from the Ultraviolet Photolysis of Interstellar Ice Analogues,” Nature 416 (March 28, 2002): 401–403; and Max Bernstein et al., “Organic Compounds Produced by Photolysis of Realistic Interstellar and Cometary Ice Analogs Containing Methanol,” Astrophysical Journal 454 (November 20, 1995): 327–44.
Sagan's goal of taking the Miller-Urey experiment cosmic is described in James Strick, “Creating a Cosmic Discipline: The Crystallization and Consolidation of Exobiology, 1957–1973,” Journal of the History of Biology 37 (2004): 131–80; see p. 135.
DNA from Space
This section draws on the following research papers: Zita Martins, “Organic Chemistry of Carbonaceous Meteorites,” Elements 7, no. 1 (February 2011): 35–40; Sandra Pizzarello, “The Cosmochemical Record of Carbonaceous Meteorites: An Evolutionary Story,” Journal of the Mexican Chemical Society 53, no. 4 (2009): 253–60; Michael P. Callahan et al., “Carbonaceous Meteorites Contain a Wide Range of Extraterrestrial Nucleobases,” Proceedings of the National Academy of Sciences (published online August 11, 2011): 13995–98, http://www.pnas.org/content/early/2011/08/10/1106493108 (accessed August 11, 2011); Philippe Schmitt-Kopplin et al., “High Molecular Diversity of Extraterrestrial Organic Matter in Murchison Meteorite Revealed 40 Years after Its Fall,” Proceedings of the National Academy of Sciences 107 (February 16, 2010): 2763–68; and George Cooper et al., “Carbonaceous Meteorites as a Source of Sugar-Related Organic Compounds for the Early Earth,” Nature 414 (December 27, 2001): 879–83.
For the organic content of comets, see Scott Sandford, “Terrestrial Analysis of the Organic Component of Comet Dust,” Annual Review of Analytical Chemistry 1 (2008): 549–78; Scott Sandford et al., “Organics Captured from Comet 81P/Wild 2 by the Stardust Spacecraft,” Science 314 (December 15, 2006): 1720–24; Michael Mumma and Steven Charnley, “The Chemical Composition of Comets—Emerging Taxonomies and Natal Heritage,” Annual Review of Astronomy and Astrophysics 49 (2011): 471–524; and Matthieu Gounelle, “The Asteroid-Comet Continuum: In Search of Lost Primitivity,” Elements 7 (2011): 29–34.
An excellent account of the arrival and collection of the Tagish Lake meteorite is James Scott Berdahl, “Morning Light—The Secret History of the Tagish Lake Fireball,” (masters of science writing thesis, Massachusetts Institute of Technology, 2010).
From Eternity to Here
The original science paper outlining the possible cosmic delivery of Earth's organic material is Christopher Chyba and Carl Sagan, “Endogenous Production, Exogenous Delivery and Impact-Shock Synthesis of Organic Molecules: An Inventory for the Origins of Life,” Science 355 (January 9, 1992): 125–31. More recent evidence is recounted in Stephen Mojzsis, “Bio-Essential Element Inventories to Earth (and Earth-Like Worlds) in Late Heavy Bombardments,” paper presented at the Delivery of Volatiles & Organics: From Earth to ExoEarths in the Era of JWST, Space Telescope Science Institute, Baltimor
e, September 13–15, 2010, http://www.stsci.edu/institute/conference/volatile/talksList.
Information on cosmic delivery of Earth's water is from Karen Meech, “Origins of Earth's Water,” presented at the Delivery of Volatiles & Organics: From Earth to ExoEarths in the Era of JWST, Space Telescope Science Institute, Baltimore, September 13–15, 2010; and Karen Meech, “Origins of Earth's Water,” STScI Webcasting, broadcast December 2, 2011, https://webcast.stsci.edu/webcast/detail.xhtml;jsessionid=FA8292C5A45296C351F4B1FE55CDECA7?talkid=2825&parent=1 (accessed April 27, 2012).
Stephen Mojzsis and T. Mark Harrison, “Vestiges of a Beginning: Clues to the Emergent Biosphere Recorded in the Oldest Known Sedimentary Rocks,” GSA Today 10, no. 4 (April 2000), http://www.geosociety.org/pubs/gsatoday/archive/sci0004.htm (accessed January 23, 2012).
Tracing Our Cosmic Carbon Ancestry
An overview paper is Eric Herbst and Ewine F. van Dishoeck, “Complex Organic Interstellar Molecules,” Annual Review of Astronomy and Astrophysics 47 (2009): 427–80.
Key scientific papers on the origins of the organic molecules in carbonaceous chondrites are George D. Cody et al., “Establishing a Molecular Relationship between Chondritic and Cometary Organic Solids,” Proceedings of the National Academy of Sciences 108 (November 29, 2011): 19171–76; Keiko Nakamura-Messenger et al., “Organic Globules in the Tagish Lake Meteorite: Remnants of the Protosolar Disk,” Science 314 (December 1, 2006): 1439–42; and Christopher Herd et al., “Origin and Evolution of Prebiotic Organic Matter as Inferred from the Tagish Lake Meteorite,” Science 332 (June 10, 2011): 1304–1307.
For the possible stellar and interstellar origins of organic molecules that arrive on Earth, see Lori Stiles, “Arizona Radio Observatory Team Discovers Supergiant Star Spews Molecules Needed for Life,” UA News, University of Arizona, July 3, 2007, http://uanews.org/node/13463 (accessed January 23, 2012).
“Astrobiologists Discover ‘Sweet Spots’ for the Formation of Complex Organic Molecules in the Galaxy,” Rensselaer Polytechnic Institute press release, November 2, 2011, http://news.rpi.edu/update.do?artcenterkey=2941 (accessed April 27, 2012).
The discussion of the possible existence of pre-solar organic stardust is from Sun Kwok, “The Synthesis of Organic and Inorganic Compounds in Evolved Stars,” Nature 430 (August 26, 2004): 985–91; and Sun Kwok and Yong Zhang, “Mixed Aromatic-Aliphatic Organic Nanoparticles as Carriers of Unidentified Infrared Emission Features,” Nature 479 (November 3, 2011): 80–83.
Sources of Direct Quotations by Page
(page 200) “was so bright we had to shield…” “Blue-White Fireball Sighted in Mexico,” p. 3.
(page 200) “The people, especially the people…” Ibid.
(page 212) “They would barely make…” Flam, “Seeing Stars in a Handful of Dust,” p. 381.
(pages 212–13) “no one had seriously…” Lewis et al., “Interstellar Diamonds in Meteorites,” p. 161.
(page 214) “As a young graduate…” Marvin, “Oral Histories in Meteoritics and Planetary Science,” p. A262.
(page 214) “Until recently people could study…” Huyghe, “Stardust Memories,” p. 58.
CHAPTER 8. OTHER WORLDS
This chapter draws heavily on my interviews over the past several years with the principal scientists in this story, as listed in the interviews section.
Two of the best historical overviews of the search for exoplanets were written by leading exoplanet theorist Alan Boss, who both participated in and watched the events unfold and who tells the story in a detailed chronological account in Alan Boss, Looking for Earths: The Race to Find New Solar Systems (New York: John Wiley & Sons, 1998); and Alan Boss, The Crowded Universe: The Search for Living Planets (New York: Basic Books, 2009). An accessible introduction to the broad topic of exoplanets is my book: Jacob Berkowitz, Out of This World: The Amazing Search for an Alien Earth (Toronto: Kids Can Books, 2009). A concise, engaging recent overview of our understanding of exoplanets is provided by Geoff Marcy, the astronomer who's found more exoplanets than any other, in Geoffrey W. Marcy, “Other Earths and the Search for Life in the Universe,” Proceedings of the American Philosophical Society 154, no. 4 (December 2010): 422–38.
The classic nineteenth-century perspective on the abundance of planets around other stars is Richard Proctor, Other Worlds Than Ours: The Plurality of Worlds Studied under the Light of Recent Scientific Researches (Akron, OH: Werner, 1870). Two key twentieth-century scientific papers that influenced astronomers' perspectives that such planets were there for the finding are Otto Struve, “The Cosmological Significance of Stellar Rotation,” Popular Astronomy 525 (May 1945); and Gerard Kuiper, “On the Origin of the Solar System,” Proceedings of the National Academy of Sciences 37, no. 1 (January 15, 1951).
Sources by Sections
A New Vision
The section profiling the pioneering modern exoplanet search from the mid-1970s to the late 1980s led by Bruce Campbell and Gordon Walker draws from my feature newspaper article: Jacob Berkowitz, “Lost World: How Canada Missed Its Moment of Glory,” Globe and Mail, September 26, 2009. Walker has also described this period in a popular account: Gordon Walker, “In Search of Other Worlds,” Cosmos Magazine, August 16, 2007; and in a scientific recollection: Gordon Walker, “The First High-Precision Radial Velocity Search for Extra-Solar Planets,” December 16, 2008, Cornell University Library, http://arxiv.org/abs/0812.3169, also published in New Astronomy Review 56 (2012): 9–15. The other key scientific papers covering this period include Bruce Campbell, “Precision Radial Velocities,” Publication of the Astronomical Society of the Pacific 95 (September 1983): 577–84; Bruce Campbell, G. A. H. Walker, and S. Yang, “A Search for Substellar Companions to Solar-Type Stars,” Astrophysical Journal 331 (August 15, 1988): 902; Gordon Walker et al., “γ Cephei: Rotation or Planetary Companion?” Astrophysical Journal 396 (September 10, 1992): L91–94; and Alan Boss, “Proximity of Jupiter-Like Planets to Low-Mass Stars,” Science 267, no. 5196 (June 1995): 360–62.
A fascinating perspective on the era of exoplanet errors comes from two former American Astronomical Society public relations officers who watched the astronomers squirm at press conferences: Laurence Marschall and Stephen Maran, Pluto Confidential: An Insider Account of the Ongoing Battles over the Status of Pluto, chap. 10 (Dallas: BenBella Books, 2009), pp. 164–81.
Dr. Seuss's Universe
In such a rapidly developing field, what was earth-shattering yesterday is often old hat a week later. For the latest exoplanet results, a good place to start is with two up-to-the-day online scientific resources. The Extrasolar Planets Encyclopedia lists all confirmed exoplanets, including links to related literature for each exoplanet: http://www.exoplanet.eu/. The California Planet Survey provides an up-to-date, comprehensive, searchable listing with a bounty of additional resources: http://exoplanets.org/cps.html.
The following are key scientific papers documenting the golden age of results from the Kepler Space Telescope and the European Southern Observatory's HARPs spectrograph revealing the abundance and diversity of exoplanets, including “super-Earths” and multi-planet solar systems as profiled in the section “Dr. Seuss's Universe”: C. Lovis et al., “The HARPS Search for Southern Extra-Solar Planets. XXVIII. Up to Seven Planets Orbiting HD 10180: Probing the Architecture of Low-Mass Planetary Systems,” Astronomy & Astrophysics 528 (2011): 112L; Jack Lissauer et al., “A Closely Packed System of Low-Mass, Low-Density Planets Transiting Kepler-11,” Nature 470 (February 3, 2011): 53; A. Howard, “The Occurrence and Mass Distribution of Close-In Super-Earths, Neptunes, and Jupiters,” Science 330 (October 29, 2010): 654; “Fifty New Exoplanets Discovered by HARPS: Richest Haul of Planets So Far Includes 16 New Super-Earths,” European Space Agency press release eso1134, European Southern Observatory, September 12, 2011, http://www.eso.org/public/news/eso1134/ (accessed December 11, 2011); Joachim Wambsganss, “Astronomy: Bound and Unbound Planets Abound,” Nature 473 (May 19, 2011): 289–91; Hagai B. Perets and M. B. N. Kouwe
nhoven, “On the Origin of Planets at Very Wide Orbits from the Re-Capture of Free Floating Planets,” Astrophysical Journal 750 (April 2012): 83; Laurance R. Doyle et al., “Kepler-16: A Transiting Circumbinary Planet,” Science 333 (September 16, 2011): 1602; Kevin J. Walsh et al., “A Low Mass for Mars from Jupiter's Early Gas-Driven Migration,” Nature 475 (July 14, 2011): 206–209; and David Nesvorný, “Young Solar System's Fifth Giant Planet?” Astrophysical Journal Letters (September 13, 2011). The Hubble Deep Field image can be viewed here: http://www.hubblesite.org/newscenter/archive/releases/1996/01/.
Alien Earth
Veteran science writer Michael Lemonick wrote the Time magazine cover story about the discovery of the first exoplanet in 1995, and he tells the history of the search for an alien Earth in Mirror Earth: The Search for Our Planet's Twin (New York: Bloomsbury, 2012).
For the detailed backstory on the origins of the Kepler Space Telescope, the following journal articles mark seminal steps in the process: Frank Rosenblatt, “A Two-Color Photometric Method for Detection of Extra-Solar Planetary Systems,” Icarus 14 (1971): 71–93; W. J. Borucki and A. L. Summers, “The Photometric Method of Detecting Other Planetary Systems,” Icarus 58 (1984): 121; James Kasting, Daniel Whitmire, and Ray Reynolds, “Habitable Zones around Main Sequence Stars,” Icarus 101 (1993): 108; David Koch et al., “System Design of a Mission to Detect Earth-Sized Planets in the Inner Orbits of Solar-Like Stars,” Journal of Geophysical Research 101, no. E4 (April 25, 1996); and Ron Cowen, “Jumpy Stars Slow Hunt for Other Earths,” Nature 477 (September 6, 2011): 142–43, http://www.nature.com/news/2011/110906/full/477142a.html. Finally, one of the many press releases claiming the discovery of the first habitable-zone Earth-like exoplanet is “First Habitable-Zone Super-Earth Discovered in Orbit around a Sun-Like Star,” Carnegie Institution for Science, December 5, 2011, http://carnegiescience.edu/news/first_habitablezone_superearth_discovered_orbit_around_sunlike_star.
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