Press Release

Media Invited to ‘Origins of the Expanding Universe,’ Sept. 13-15

By SpaceRef Editor
August 5, 2012
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Join us for “Origins of the Expanding Universe: 1912-1932,” a conference being held in Flagstaff in September 13-15, 2012. There’s only one week left to register!

On September 17, 1912, Vesto Slipher obtained the first radial velocity of a “spiral nebula” — the Andromeda Galaxy. Using the 24-inch telescope at Lowell Observatory, he followed up with more Doppler shifts, and wrote a series of papers establishing that large velocities, usually in recession, are a general property of the spiral nebulae. Those early redshifts were recognized as remarkable by Slipher, and were critical to the discovery of what came eventually to be called the expanding universe. Surprisingly, Slipher’s role in the story remains almost unknown to much of the astronomical community.

The nature, and especially the distance, of spiral nebulae was fiercely argued — most famously in the 1920 Shapley-Curtis debate. Hubble’s 1923 discovery of Cepheids in Andromeda, along with Henrietta Leavitt’s period-luminosity relation for Cepheids, led to a distance scale for the nebulae, enabling Lemaitre (1927) to derive a linear relation between velocity and distance (including a “Hubble constant” and, by 1931, a Primeval Atom theory).

Meanwhile, a new concept of space and time was formulated by Einstein, providing a new language in which to understand the large-scale universe. By 1932, all the major actors had arrived on stage, and universal expansion — the most general property of the universe yet found — acquired a solid basis in observation and in the (relativistic) concept of space. “Space expands”… or does it? How did Lemaitre and Hubble interpret this concept? How do we interpret it? It continues to evolve today, with cosmic inflation and dark energy presenting new challenges still not fully assimilated.

This conference is in honor of Vesto Melvin Slipher and is timed to coincide with the 100th anniversary of the first measured Doppler shift in a galaxy (then known as a spiral nebula) on September 17, 1912.

We are bringing together astronomers and historians of science to explore the beginnings and trajectories of the subject, at the place where it began. However, you need not be an astronomer or historian to enjoy this timely and important conference.

Registration closes Friday, August 10.

Public information officers and accredited journalists can receive complimentary registration. Please contact Chuck Wendt (see below).

Media Contact:
Chuck Wendt
Deputy Director for Advancement
+1 928-233-3201

Conference website:

Conference registration/presenter contacts: Mike Way,; Joe Patterson,; and Deidre Hunter,

Lowell Observatory is a private, non-profit research institution founded in 1894 by Percival Lowell. The Observatory has been the site of many important findings including the discovery of the large recessional velocities (redshift) of galaxies by Vesto Slipher in 1912-1914 (a result that led ultimately to the realization the universe is expanding), and the discovery of Pluto by Clyde Tombaugh in 1930. Today, Lowell’s 20 astronomers use ground-based telescopes around the world, telescopes in space, and NASA planetary spacecraft to conduct research in diverse areas of astronomy and planetary science. The Observatory welcomes about 80,000 visitors each year to its Mars Hill campus in Flagstaff, Arizona for a variety of tours, telescope viewing, and special programs. Lowell Observatory currently has four research telescopes at its Anderson Mesa dark-sky site east of Flagstaff, and is testing and commissioning a four-meter class research telescope, the Discovery Channel Telescope.

SpaceRef staff editor.