Sagan Planet Walk

The scaled size of the Sun is given by a {{Convert|27.8|cm|in|abbr=on|adj=on}} diameter circular frame repeated at the top of each {{Convert|6|ft|m|abbr=on|adj=on|sp=us}} tall obelisk. Centered within each sun-sized frame, the proportional size of each planet is represented by a small sphere affixed in a glass window. All of the original planet locations were chosen not only for accuracy to scale but also to highlight local landmarks and public spaces within Ithaca. However, since the original installation of the Planet Walk the public library has moved to a new location, leaving Saturn no longer attached to a local landmark. Additionally, as of 2016-2017, the original planets in plexiglass at each station have been replaced by simple yellow disks with the planet simply represented by a relatively-sized hole. Some attendant moons are now represented by tiny holes in the disks.

The Sun Obelisk is located in the center of the Ithaca Commons, a pedestrian shopping area in the heart of downtown Ithaca. The round window representing the size of the Sun at this station is roughly the size of a basketball and, in this obelisk only, contains no glass. All the subsequent obelisks in the Solar System model have Sun-sized glass windows containing their respective planets for the sake of comparison.

The obelisks for the four inner planets are all contained within the commons area stretching north towards Seneca Street. Mercury is situated to scale about {{Convert|12.7|yd|m|abbr=off|sp=us|adj=off}} away from the Sun, Venus another {{Convert|10|yd|m|abbr=off|adj=off|sp=us}} away, Earth another {{Convert|9.3|yd|m|abbr=off|sp=us|adj=off}} away, and Mars another {{Convert|17.1|yd|m|abbr=off|sp=us|adj=off}} away. This keeps the four inner planets within eyesight of the Sun, yet the representations of each planet appear quite small within their glass windows, and can even be somewhat hard to see. The contrast between the size of the Sun and the size of the inner planets coupled with the visible distance between them illustrate the vastness and emptiness of space.

File:SaganWalk.4.5.AsteroidBelt.jpg

Once leaving the inner planets, a visitor to the Planet Walk turns west along Seneca Street to continue towards Jupiter. Between Mars and Jupiter lies the asteroid belt. The obelisk representing the asteroid belt was added several years after the initial installation. Its display contains the only public, unguarded meteorite in the world.{{cite web|last=Nocella|first=Michael|title=When Big Is Walkable: Sciencenter's Sagan Planet Walk|url=http://www.ithaca.com/visit_ithaca/article_cd5c7c46-b57f-11e1-8585-0019bb2963f4.html|access-date=19 November 2012|work=Ithaca Times}}

The Jupiter Obelisk sits at the corner of Seneca Street and Cayuga Street, outside the downtown Dewitt Mall, and not far from the famed Moosewood Restaurant. The model of Jupiter within the glass window is the first planet representation on the walk that is easily visible, demonstrating how much bigger than the inner planets it is.

To reach the Saturn Obelisk, visitors turn north and continue along Cayuga Street. At the corner of Cayuga Street and Court Street, Saturn's obelisk sits outside the former location of the Tompkins County Public Library. The rings of Saturn are clearly visible within the circular window.

Visitors continue northward along Cayuga Street from Saturn, reaching the Uranus Obelisk just across Cascadilla Creek at the entrance to Thompson Park.

File:SaganWalk.8.5.Bridge.jpg

From Uranus, visitors follow Willow Avenue northwest and cross the Carl Sagan Bridge at Adams Street to reach the Neptune Obelisk. The Carl Sagan Bridge, built in 2000, features nine circular windows adorned with the signs of the nine planets.{{cite web|last=Brand|first=David|title=Cornell undergrads salute Sagan and technology by building bridge from new, lightweight material|url=http://www.news.cornell.edu/releases/Nov99/petrina.fibers.deb.html|access-date=19 November 2012|work=Cornell News}} The obelisk for Neptune is located just across the bridge in Conley Park.

The Planet Walk was conceived and built prior to Pluto losing its planetary status in 2006, and the model includes the Pluto Obelisk, which is located just outside the Sciencenter on First Street.

The model was expanded {{Convert|4740|mi|km|abbr=out|disp=flip|sp=us}} in 2012 to include Alpha Centauri, the star system closest to the Sun. The Alpha Centauri Obelisk is exhibited at the ʻImiloa Astronomy Center in the University of Hawaiʻi at Hilo in Hilo, Hawaii. The volcanic stone Hawaiian figure representing Alpha Centauri in female form has a {{convert|280|mm|abbr=out}} semicircle under its chin to represent its scale size.[http://academic.oup.com/astrogeo/article/53/6/6.6/216447 Astronomical model is world's biggest], Astronomy & Geophysics, Volume 53, Issue 6, December 2012, Page 6.6 This extension made the Sagan Planet Walk the world's largest exhibition.

Television host and former student of Carl Sagan, Bill Nye, narrated a podcast tour of the Planet Walk in 2006 which can be accessed free by calling 703-637-6237 as you walk through the scale-model representation of the Solar System.{{cite web|title=Audio Tour of the Sagan Planet Walk|url=http://www.sciencenter.org/saganpw/podcast.asp|work=Ithaca Sciencenter|access-date=19 November 2012|url-status=dead|archive-url=https://web.archive.org/web/20060702163616/http://www.sciencenter.org/SaganPW/podcast.asp|archive-date=2 July 2006}}{{cite web|url=http://www.news.cornell.edu/stories/March06/BillNye.bpf.html|title=Walk among the planets with a star: Bill Nye, the Science Guy, guides a tour of Ithaca's Sagan Planet Walk on March 7|date=March 1, 2006|work=Chronicle Online|publisher=Cornell University|access-date=2012-11-19|format=PDF}}

• 1997 Original Planet Walk created in Ithaca, with ten obelisks for the Sun and nine planets
• 2000 Carl Sagan Bridge built across Cascadilla Creek on the way to the Neptune Obelisk
• 2006 Audio Tour narrated by Bill Nye added
• 2009 Asteroid Belt Obelisk added between the inner and outer planets
• 2009 Newly designed Passport to the Solar System{{cite web|last=Maletz|first=Emily|title=The Sagan Planet Walk|url=http://www.emilymaletz.com/news_2009.html|work=Emily Maletz Graphic Design|access-date=21 November 2012|url-status=dead|archive-url=https://web.archive.org/web/20130914074810/http://emilymaletz.com/news_2009.html|archive-date=14 September 2013}} [http://www.sciencenter.org/documents/passport_s.pdf Passport]
• 2012 Station depicting Alpha Centauri erected in Hawaii{{cite web|last=vrecinto|title=Sagan Planet Walk coming to ʻImiloa: Kamailehope|url=http://blog.imiloahawaii.org/general-information/sagan-planet-walk-coming-to-imiloa|work=Around the Center|publisher=ʻImiloa Astronomy Center|archive-url=https://web.archive.org/web/20160611195238/http://blog.imiloahawaii.org/general-information/sagan-planet-walk-coming-to-imiloa|archive-date=2016-06-11}}
• Kepler-37d station to be installed on Moon (installation date TBD)

The models of the Solar System, in order:

{{Gallery

|width=145

|height=180

|File:SaganWalk.0.Sun.jpg|The Sun

|File:SaganWalk.1.Mercury.jpg|Mercury

|File:SaganWalk.2.Venus.jpg|Venus

|File:SaganWalk.3.Earth.jpg|Earth

|File:SaganWalk.4.Mars.jpg|Mars

|File:SaganWalk.5.Jupiter.jpg|Jupiter

|File:SaganWalk.6.Saturn.jpg|Saturn

|File:SaganWalk.7.Uranus.jpg|Uranus

|File:SaganWalk.8.Neptune.jpg|Neptune

|File:SaganWalk.9.Pluto.jpg|Pluto

}}

The Sagan Planet Walk has inspired the creation of other scale-model Solar Systems in the United States.

• The [http://loopplanetwalk.com/ Delmar Loop Planet Walk] in St. Louis, Missouri:

:: "In 2006, I became aware of the Sagan Planet Walk in Ithaca, NY, and as an amateur astronomy buff, I found the idea of a scale model solar system to be a fascinating concept. While researching other such models on the Internet, I developed the idea to build one in St. Louis."—{{Smallcaps|Stephen Walker}}{{cite web|last=Walker|first=Stephen|title=Building the Planet Walk|url=http://loopplanetwalk.com/construction.html|work=Delmar Loop Planet Walk|access-date=21 November 2012}}

• The [http://anchorageplanetwalk.org/ Anchorage Light Speed Planet Walk] in Alaska:

:: "The idea for this project was ignited by [Eli Menaker's] visit to the Carl Sagan Memorial Planet Walk in Ithaca, New York."{{cite web|title=History of the Anchorage Light Speed Planet Walk|url=http://anchorageplanetwalk.org/history.html|work=Anchorage Light Speed Planet Walk|access-date=21 November 2012}}

• Solar System model

• [http://www.sciencenter.org/sagan-walk.html Sagan Planet Walk at the Ithaca Sciencenter]
• [http://saganplanetwalk.wix.com/home Sciencenter Sagan Planet Walk Station Exploration]
• [https://web.archive.org/web/20120810192211/http://stephenfrug.blogspot.com/2006/12/carl-sagans-ithaca-memorial.html Carl Sagan's Ithaca Memorial]

• [http://montshire.org/exhibits/earth-astronomy/planet-walk Montshire Planet Walk, Norwich, Vermont]
• [http://northgeorgiaastronomers.org/scalemodel/ Solar System Walking Tour, Gainesville, Georgia]
• [http://www.clemetparks.com/recreation/hiking/solarwalk.asp Solar System Walk, Cleveland, Ohio]
• [http://www.jeffreybennett.com/co_scale.html Scale Model Solar System, Boulder, Colorado]
• [http://members.efn.org/~jack_v Scale Model Solar System, Eugene, Oregon]
• [http://loopplanetwalk.com/ Delmar Loop Planet Walk, St. Louis, Missouri]
• [http://anchorageplanetwalk.org/ Anchorage Light Speed Planet Walk, Anchorage, Alaska]
• The [http://www.friendsofaatrails.org/planet-walk/ B&A Trail Planet Walk] in Anne Arundel County, Maryland.
• The [https://rfo.org/index.php/planet-walk/ Robert Ferguson Observatory Planet Walk] in Kenwood, California.
• The [https://www.lansing.org/listings/planet-walk/1007/ Greater Lansing Planet Walk] in Lansing, Michigan.
• The [https://www.gi.alaska.edu/services/education-outreach/planet-walk/ University of Alaska Planet Walk] in Fairbanks, Alaska.
• The [https://crossroadsatbigcreek.org/planet-walk/ Planet Walk at Crossroads at Big Creek] at the Leif Everson Observatory, Sturgeon Bay, Wisconsin.

{{Carl Sagan}}

{{Solar System models}}

{{Ithaca, New York}}

{{University of Hawaii at Hilo}}

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Category:Carl Sagan

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Category:Scale modeling

Category:Solar System models

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