SoCal and Astronomical History: The Big Bang Theory, the Demise of Pluto & More

Astronomers gather outside the Mount Wilson Observatory, circa 1920. Courtesy of the Los Angeles Area Chamber of Commerce Collection, USC Libraries.

With L.A.'s night sky shrouded in a veil of smog and light pollution, Southern California might seem an unlikely place for star-gazing scientists to congregate. But before population growth and industrialization transformed the night sky into a dull glow, Southern California's generally cloudless climate attracted some of the world's finest astronomers.

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The region's most prominent observatory, in Griffith Park, has always been more of an educational facility rather than an active center for scientific research. Perched above Los Angeles in the Hollywood Hills, the Griffith Observatory opened on May 14, 1935 and was originally envisioned by mining baron Griffith J. Griffith, who became interested in astronomy after peering through the telescope of an observatory in the San Gabriel Mountains.

It was at that facility -- the Mount Wilson Observatory -- that many of Southern California's great astronomical discoveries were made. Plans for an observatory on the summit overlooking Pasadena dated to the 1880s, when businessman E. F. Spence, USC president Marion F. Bovard, and a team of Harvard scientists conducted the first observations from the peak with a 13-inch telescope. They were satisfied with their results; at 5,715 feet above sea level, Mount Wilson peeks through the inversion layer, leaving fog and airborne pollution below and calm, steady air above. Although the proposal gained wide approval among astronomers nationwide, financial troubles plagued the plan and forced USC and Harvard to shelve it in 1892.

It fell to George Ellery Hale, a solar astronomer who first heard about Mount Wilson as an MIT student, to bring Southern California its first scientific facility dedicated to stargazing. With backing from the Carnegie Institute, Hale founded the Mount Wilson Observatory in 1904. When it became operational in 1908, the observatory's 60-inch reflector telescope was the largest in the world. Nine years later, Hale added an even larger device, the 100-inch Hooker Telescope.

Circa 1904 photo of the Mount Wilson Observatory under construction. Courtesy of the William C. Barry Collection of Los Angeles Area Photography, Bancroft Library, UC Berkeley.

The inversion layer usually keeps fog and other airborne obstructions below Mount Wilson's telescopes. Courtesy of the William C. Barry Collection of Los Angeles Area Photography, Bancroft Library, UC Berkeley.

1944 aerial view of the Mount Wilson Observatory. Courtesy of the Frasher Foto Postcard Collection, Pomona Public Library.

Hickox inside the 100-inch telescope tower in 1955. Courtesy of the Los Angeles Examiner Collection, USC Libraries.

Mount Wilson telescope operator Joseph Hickox polishes a mirror while an Examiner photographer takes a self-portrait. 1955 photo courtesy of the Los Angeles Examiner Collection, USC Libraries.

An operator works the controls of one of Mount Wilson's telescopes in 1957. Courtesy of the Los Angeles Examiner Collection, USC Libraries.

Close-up view of a Mount Wilson telescope operator at the controls. Courtesy of the Los Angeles Examiner Collection, USC Libraries.

Boasting unparalleled powers of magnification, Mount Wilson added some of the world's finest astronomers to its roster of scientists. Hale himself was a noted scientist who helped transform what was then a vocational school named Throop University into the research university we know today as Caltech.

In 1917, Harlow Shapley used the 60-inch telescope to identify the center of the Milky Way, calculate the galaxy's size, and determine our solar system's location within it. In 1925, Edwin Hubble used observations from Mount Wilson to demonstrate that the Milky Way was merely one of many galaxies in the universe, and four years later Hubble found the first observational evidence for the Big Bang theory. The Hubble constant, which describes the relationship between how fast an object is receding from Earth and how distant it is from us, is one of the foundations of modern cosmology.

By the 1930s, light pollution from the growing metropolis of Los Angeles had compromised Mount Wilson's fitness for astronomy. Hale and Caltech searched for a replacement site and landed upon Palomar Mountain, 45 miles northeast of San Diego. Delayed by World War II, the new observatory took 15 years to build and cost millions of dollars. Hale would not live to see its completion, but when the Palomar Observatory opened in 1949 its 200-inch telescope, named in Hale's memory, displaced the Mount Wilson's Hooker Telescope as the world's largest. Hubble was the first to use the telescope.

1938 drawing by R. W. Porter of the Palomar Observatory's 200-inch telescope, then under construction. Courtesy of the Los Angeles Area Chamber of Commerce Collection, USC Libraries.

Caltech workers grind the 200-inch lens for the Palomar Observatory in 1938. Courtesy of the Photo Collection, Los Angeles Public Library.

1948 postcard showing the Palomar Observatory. Courtesy of the Frasher Foto Postcard Collection, Pomona Public Library.

With Palomar's opening, Southern California remained a leading center of astronomical research. In the 1960s, astronomers at Palomar discovered quasars--bright, distant galaxies that are among the oldest visible objects in the universe--and established methods for measuring extragalactic distances.

While the advent of space-based astronomy and the opening of an even-larger telescope on Hawaii's Mauna Kea have introduced new rivals to Palomar, the observatory remains at the center of groundbreaking scientific discovery -- much to the sorrow of fans of Pluto, a distant object once considered the Solar System's ninth planet. In 2005, Palomar's Hale telescope captured the first images of Eris, a dwarf planet 27 percent more massive than Pluto. Astronomers at first considered naming Eris the Solar System's tenth planet, but eventually chose instead to evict Pluto from the list of planets--a decision that drew howls of protest from admirers of the diminutive orb of ice and rock.

Many of the archives who contributed the above images are members of L.A. as Subject, an association of more than 230 libraries, museums, official archives, personal collections, and other institutions. Hosted by the USC Libraries, L.A. as Subject is dedicated to preserving and telling the sometimes-hidden stories and histories of the Los Angeles region. Our posts here provide a view into the archives of individuals and cultural institutions whose collections inform the great narrative—in all its complex facets—of Southern California.

About the Author

A writer specializing in Los Angeles history, Nathan Masters serves as manager of academic events and programming communications for the USC Libraries, the host institution for L.A. as Subject.
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The "diminutive orb of ice and rock" you speak of is now, according to the data from The Paris Observatory, thought to be at least 7 miles wider in diameter than Eris. Yes, Eris is more massive, but Pluto is larger, something that you could have mentioned, but, instead implied it was not by using the adjective diminutive. It also must be noted, not all astronomers think Pluto isn't a planet, including one of Eris's three co-discoverers, David L. Rabinowitz, who actually signed an online petition protesting the IAU's decision in Prague, as did Dr. Alan Stern, Principal Investigator for NASA's New Horizons mission to Pluto. One IAU member who voted to deplanetize Pluto admitted publicly a veiled threat was made to him in Prague that his career as an astronomer would suffer greatly if he were to vote to save Pluto's planetary status, too. Even Dr. Neil deGrasse Tyson now believes the question of Pluto's correct status has yet to be forever resolved, I am told. In any event, the IAU meets every 3 years and I suspect the status of Pluto and other dwarf planets will arise in an upcoming General Assembly. If not this August in Beijing, then, hopefully, for the sake of Justice and True Science, in Honolulu in 2015, a month after New Horizons reaches the Plutonian System. Pluto may have life, too, so those who say Pluto is dead are a bit off.


There never was any demise of Pluto as a planet although it is the solar system's tenth rather than ninth planet. It is a disservice to portray one side in an ongoing debate as fact when this is not the case. The real fact is there is no consensus in the astronomy community on the status of Pluto and on a definition of planet. Only four percent of the IAU voted on the controversial resolution that demoted Pluto, and most are not planetary scientists. Hundreds of professional astronomers immediately signed a formal petition rejecting the IAU decision. That is hardly "howls of protest from admirers of the diminutive orb of ice and rock." There is a strong scientific argument for including dwarf planets as a subclass of planets. It is based on a much broader planet definition in which a planet is any non-self-luminous spheroidal body in orbit around a star or that once orbited a star. This is in line with the intention of Dr. Alan Stern, who first coined the term "dwarf planet" in 1991 to refer to a new class of planets, small planets large enough to be rounded by their own gravity but not large enough to gravitationally dominate their orbits. He never intended for dwarf planets to not be considered planets at all.

Your information about Eris's size is also out of date. In November 2010, Eris occulted a star, and astronomers were able to take more precise measurements of Eris's exact size. They found out that while Eris is denser than Pluto (meaning it is likely more rocky than Pluto, which, hardly an iceball, is estimated at 70 percent rock), it is marginally smaller than Pluto. For those of us who use this alternate planet definition, Eris is still a planet because it is well beyond the minimum mass and size for being squeezed into a round shape by its own gravity.