Origins of the Expanding Universe: 1912-1932

September 13-15, 2012

Flagstaff, Arizona

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: Slipher 1913 Lowell Obs 2, 56

We are bringing together astronomers and historians of science to explore the beginnings and trajectories of the subject, at the place where it began.

Important Dates Registration  Abstract Submission
Scientific Program Participants Travel and Lodging

The Scientific Organizing Committee:
                Michael Way (NASA/GISS)                  Joe Patterson (Columbia)
Owen Gingerich (Harvard)                    John Peacock (ROE)
Mario Livio (STScI)                                Matt Stanley (NYU)
Priyamvada Natarajan (Yale)                Robert Smith (Alberta)
Margaret Geller (SAO/CfA)                   Karl Glazebrook (Swinburne, Australia)

Local Organizing Committee:
Travis Barman
Kevin Covey
Jeffrey Hall
Deidre Hunter
Kevin Schindler

Further information:

Conference questions can be directed to anyone on the organizing committee or to the organizers, Mike Way and Joe Patterson:
jop at
michael.way at

Questions regarding Flagstaff logistics and Lowell Observatory can be directed to anyone on the local organizing committee, and especially Deidre Hunter: dah at

Important Dates

May 14, 2012:Registration and Abstract Submission open
August 10, 2012:Early Registration Deadline
August 31, 2012:Final Registration Deadline
August 31, 2012:Last day to cancel registration and receive full refund
August 30, 2012:Abstract Submission Deadline
September 13, 2012:Reception, 7:00-9:00 pm, Lowell Observatory
September 14-15, 2012:Conference sessions, Radisson Woodlands Hotel
September 14, 2012:Banquet, Radisson Woodlands Hotel
September 16, 2012:Area tourism

Invited Talks, Contributed Talks, Posters, Panel Discussion

There will be short talks ("contributed"), long talks ("invited"), posters, and panel discussions. Allocation of these talks into sessions will take place when we have a good census of the various talks. Every speaker should submit a short abstract of their talk.

This conference will be a mixture of astronomers and historians, with a few journalists. The resultant collision of cultures should be stimulating to all of us. And just to make sure it is, this conference will have an unusual feature: homework. People giving invited talks should accompany their abstracts with references for suggested reading. A regular scholarly paper is fine, but ideally you should accompany it with a shorter piece written for the general reader. And if nothing of that description exists, consider that as motivation to write one. This will be a useful launching pad for discussion, and session chairs will be asked to fire questions around the room, so that discussion need not be speaker-centric. At least 30% of conference time will be allocated to discussion.

The organizing committee will brew up some key questions for panel discussion, but suggestions for this are warmly solicited.


Registration and payment for the workshop is now available on-line. The registration fee of $190 includes the opening reception, breakfast buffets on Friday and Saturday, lunch buffets on Friday and Saturday, and the conference banquet, as well as break beverages and snacks during the meeting. When you register, you will be given the option of adding accompanying persons to the reception, breakfasts, lunches, or the banquet. Please also indicate any dietary restrictions.

Not included is a book emerging from the conference if we decide to publish one (uncertain right now). Payment for these will be collected separately later. Also extra is an optional Sunday trip to area sights (Meteor Crater, Grand Canyon, Sunset Crater), but this will be quite inexpensive.

Note that the registration will take you to paypal in order to pay, but you do not have to have a paypal account to pay, just a credit card. Paypal will send you a receipt if your payment is successful. You may also choose to send a check instead and instructions are given for that.

Abstract Submission

Abstracts will be accepted on-line when you register beginning May 14. If you register and need to change your title or abstract later, send the update to Deidre (dah at lowell dot edu).