Solar System model

A 1766 Benjamin Martin mechanical model, or orrery, used at Harvard

Solar System models, especially mechanical models, called orreries, that illustrate the relative positions and motions of the planets and moons in the Solar System have been built for centuries. While they often showed relative sizes, these models were usually not built to scale. The enormous ratio of interplanetary distances to planetary diameters makes constructing a scale model of the Solar System a challenging task. As one example of the difficulty, the distance between the Earth and the Sun is almost 12,000 times the diameter of the Earth.

If the smaller planets are to be easily visible to the naked eye, large outdoor spaces are generally necessary, as is some means for highlighting objects that might otherwise not be noticed from a distance. The Boston Museum of Science placed models of the planets in major public buildings, all on similar stands with interpretive material.^[1] For example, the model of Jupiter, shown, is located in the cavernous South Station waiting area. The properly scaled, basket-ball sized model is 1.3 miles (2.14 km) from the model Sun which is located at the museum, graphically illustrating the immense empty space in the Solar System.

The objects in such large models do not move. Traditional orreries often did move and some used clockworks to make the relative speeds of objects accurate. These can be thought of as being correctly scaled in time instead of distance.

Permanent true scale models[]

Many towns and institutions have built outdoor scale models of the Solar System. Here is a table comparing these models with the actual system.

Name	Location	Scale	Sun dia.	Earth dia.	Sun–Earth	Sun–Pluto	Description
Actual Solar System		1:1	1.392 Gm	12.76 Mm	149.6 Gm	5.914 Tm
Sweden Solar System	Sweden	1:20,000,000	71 m	65 cm	7,600 m	300 km	permanent; country-wide (begun 1998)
Solar System Drive	Coonabarabran, Australia	1:38,000,000	37 m	34 cm	4,100 m	205 km	permanent; drivable (est. 1997)
Maine Solar System	University of Maine	1:93,000,000	15 m	13.7 cm	1,600 m	64 km	permanent; drivable (est.2003)
Mont Megantic Dark Sky Reserve Great Solar System	Parc national du Mont-Mégantic	1:100,000,000	14 m	12.4 m	1,450 m	57 km	permanent; drivable (est.2018)
Riverfront Museum Solar System	Peoria, Illinois	1:125,000,000	11 m	10.0 cm	1,200 m	47 km	permanent; drivable (est. 1992?)
Vienna Solar System	Vienna, Austria	1:163,764,706	8.5 m	7.78 cm	913 m	36 km	under construction since 2018. Physical + Augmented Reality
Planet Lofoten	Lofoten, Norway	1:200,000,000	7 m	?	?	30 km	under construction
Planet Trek Dane County	Madison, Wisconsin	1:200,000,000	7 m	6.6 cm	777 m	38.3 km	permanent; fully accessible by foot and bike paths (est. 2009)
Sunspot Solar System Model	Sunspot, New Mexico	1:250,000,000	5.6 m	5.1 cm	1.5 m	23,6 km	permanent, drivable
If the Earth were a Ping-Pong ball^{[citation needed]}	Westminster, London	1:318,905,000	4.36 m	40 mm	?	?	In construction; Walk & Drive (est. 2018) Centered around Deans Yard, Westminster
Light Speed Planet Walk	Anchorage, Alaska	1:350,000,000	?	?		16.6 km	permanent; drivable (est. 2005)
Moab's Scale Model of the Solar System	Moab, Utah	1:400,000,000	3.6 m	?	?	15.3 km	permanent; Walk and Drive (est. 2007)
Community Solar System Trail	Boston, Massachusetts	1:400,000,000	3.5 m	3.2 cm	380 m	15.3 km	permanent; drivable
The Solar System to Scale	Estremoz, Portugal	1:414,000,000	3.4 m	3.1 cm	361 m	14.3 km	permanent; drivable; bikeable
Somerset Space Walk	Bridgwater Canal, Somerset UK	1:530,000,000	2.5 m	? cm	? m	11 km	permanent; bikeable (est. 1997)
York’s Solar System model	York, England	1:575,872,239	2.4 m	2.2 cm	260 m	10.3 km	permanent; bikeable (est. 1999)
Traverse Bay Community Solar System	Traverse City, Michigan	1:592,763,356	0.9 m	0.9 m	209 m	10.0 km	permanent; bikeable (est. 2004)
Michigan Solar System Model	Coleman, Michigan	1:608,000,000	2.3 m	2.1 cm	324 m	9.8 km	permanent; bike trail Sun and Pls. Spheres (2017)
Nine Views	Zagreb, Croata	1:680,000,000	2.0 m	1.9 cm	225 m	8.7 km	permanent; bikeable (est. 2004)
Walk the Solar System	Fort St. John, British Columbia, Canada	1:682,353,000	2.0 m	1.9 cm	219 m	8.6 km	under construction
McCarthy Observatory	New Milford, Connecticut	1:761,155,000	1.8 m	1.7 cm	195 m	7.1 km	permanent; bikeable (est. 2009)
Planet Walk	Glen Burnie, Maryland.	1:781,000,000	?	?	191.5 m	7.56 km	Walkable, bikeable (est. 2008). Part of the permanent Baltimore & Annapolis Trail.
Trilho do Sistema Solar	Paredes de Coura, Portugal	1:831,000,000	1.675 m	1.533 cm	180 m	5.42 km (Neptune)	permanent; walkable; bikeable (est. 2016)
Planetenpad Utrecht	Utrecht, Netherlands	1:1,000,000,000	1.3 m	1.3 cm	150 m	7.4 km (Neptune)	Leads from Centre Utrecht to Rhijnauwen, on foot, on bike or on kayak
Model of the Solar System	Helsinki, Finland	1:1,000,000,000	1.4 m	1.2 cm	149.6 m	6.1 km	permanent; bikeable
Planetenmodell Hagen	Hagen, Germany	1:1,000,000,000	1.4 m	1.3 cm	150 m	5.9 km	permanent; bikeable (est. 1959)
Planetenweg Schwarzbach	Kriftel, Germany	1:1,000,000,000	1.4 m	1.3 cm	150 m	5.9 km	permanent; bikeable (est. 1998)
Uetliberg Planetenweg	Zurich, Switzerland	1:1,000,000,000	1.4 m	1.3 cm	150 m	5.9 km	permanent; bikeable
Planetenwanderweg	Ehrenfriedersdorf, Germany	1:1,000,000,000	1.4 m	1.3 cm	150 m	5.9 km	permanent; bikeable
Solar System	Opava, Czech Republic	1:627,000,000	2.2 m	2.0 cm	239 m	9.42 km	permanent; bikeable; walkable; drivable (est. 2006)
Planetary Trail	Hradec Králové, Czech Republic	1:1,000,000,000	1.4 m	1.3 cm	150 m	5.9 km	permanent; bikeable (est. 2005)
Planetary Trail	Prague, Czech Republic	1:1,000,000,000	1.4 m	1.3 cm	150 m	13 km (Sedna as discovered) (Pluto 5.9 km)	permanent; bike & walk; all objects above 1000km; (est. 13.5.2018)
Melbourne Solar System	Melbourne, Australia	1:1,000,000,000	1.4 m	1.3 cm	150 m	5.9 km	permanent; bikeable (est. 2008)
Scale Model Solar System	Eugene, Oregon	1:1,000,000,000	1.4 m	1.2 cm	150 m	5.9 km	permanent; bikeable (est. 1997)
Planetstien, Sandnes	Sandnes, Norway	1:1,000,000,000	1.4 m	1.2 cm	150 m	5.9 km	permanent; walkable, bikeable (est. 2010)
Planetstien, Lemvig	Lemvig, Denmark	1:1,000,000,000	1.4 m	1.2 cm	150 m	5.9 km	permanent; walkable
Planet Walk	Munich, Germany	1:1,290,000,000	1.1 m	1.0 cm	116 m	4.6 km	permanent; walkable (est. 1995)
Strolling at the speed of light	La Malbaie, Quebec, Canada	1:1,500,000,000	0.9 m	0.8 cm	100 m	3 km (Neptune)	permanent; walkable (est. 2009) (temp?)
Rymdpromenaden ("Spacewalk")	Gothenburg, Sweden	1:2,000,000,000	0.7 m	0.6 cm	75 m	3 km	permanent; walkable (est. 1978)
Akaa Solar System Scale Model	Akaa, Finland	1:3,000,000,000	0.46 m	0.4 cm	49.9 m	1,958 m	permanent; walkable (est. 2017), Proxima Centauri in Yulara, Australia
Elmhurst Scale Model of the Solar System	Elmhurst, Illinois	1:3,044,620,000	0.5 m	0.4 cm	49.1 m	1,929 m	permanent; walk & drive (est. 2013)
Wooster Planet Walk	Wooster, Ohio	1:5,000,000,000	0.3 m	0.3 cm	30 m	1.2 km	permanent; walkable (est. 2014)
Meteoria Söderfjärden	Vaasa, Finland	1:2,000,000,000	0.7 m				permanent; walkable
Planetenweg Göttingen	Göttingen, Germany	1:2,000,000,000	0.70 m	0.65 cm	75 m	3.2 km	permanent; walkable/bikeable (est. 2013)
Solar System Walking Tour	Gainesville, Georgia	1:2,000,000,000	0.7 m	0.6 cm	75 m	2.9 km	permanent; walkable (est. 2000)
Montshire Museum of Science	Norwich, Vermont	1:2,200,000,000	0.6 m	0.6 cm	68 m	2.7 km	permanent; walkable
Ride to Pluto: Boise's Solar System	Boise Greenbelt, Boise, Idaho	1:2,200,000,000	0.5 m	n/a		2.4 km	permanent; walkable & bikeable;
The Solar walk	Longview, Washington	1:?	0.6 m	0.6 cm	? m	2.7 km	permanent; walkable (est. 2001)
Milky Way path	Westerbork, The Netherlands	1:3,700,000,000	?	?	?	2.5 km	permanent; walkable
Solar Walk	Gainesville, Florida	1:4,000,000,000	0.3 m	0.3 cm	37.4 m	1.5 km	permanent; walkable (est. 2002)
Otford Solar System Model	Otford, England	1:4,595,700,000	0.3 m	0.3 cm	32 m	0.9 km	permanent; walkable
The Sagan Planet Walk	Ithaca, New York	1:5,000,000,000	0.3 m	0.3 cm	30 m	1.2 km	permanent; walkable (est. 1997)
Delmar Loop Planet Walk	University City, Missouri	1:5,000,000,000	0.3 m	0.2 cm	30 m	0.87 km (Neptune)	permanent; walkable (est. 2009)
The Solar Walk	Cleveland, Ohio	1:5,280,000,000	0.3 m	0.2 cm	28.4 m	1.1 km	permanent; walkable
Solar System Walk An Exploration of Scale	Carlsbad, California	1:5,280,000,000			28 m	1,119 m	Located near Lake Calavera [Trailhead]
O Sistema Solar no Parque	Natal, Brazil	1:7,000,000,000	20 cm	1.8 mm	22 m	875 m	permanent; walkable/bikeable (est. June 3rd, 2016)
Voyage	National Mall, Washington, D.C. (2001) Kansas City, Missouri(2008)}}^[a] Space Center Houston, Texas (2008) Corpus Christi, Texas (2009)	1:10,000,000,000	0.1 m	0.1 cm	15 m	0.6 km
NJ Botanical Garden	Ringwood, New Jersey	1:10,000,000,000	0.2 m	2.0 cm	23.8 m	927 m	walkable
Colorado Scale Model Solar System	Fiske Planetarium, Boulder, Colorado	1:10,000,000,000	0.1 m	0.1 cm	15 m	0.6 km	permanent; walkable (est. 1987)
Anstruther Model Solar System	Anstruther, Scotland	1:10,000,000,000	0.1 m	0.1 cm	15 m	0.6 km	permanent; walkable (est. 2014)
Le Chemin Solaire	La Couyère, Brittany	1:10,000,000,000	1 m	0.1 cm	-	0.45 km	permanent; walkable (est. 2011)
Solar Walk UofT Scarborough	Toronto, Ontario and Eureka, Nunavut	1:10,000,000,000	0.14 m	0.13 cm	15 m	0.591 km	permanent; walkable/bikeable (est. 2017)
Grand Trunk Pathway Solar System Model	Terrace, British Columbia	1:1,000,000,000	1.4 m	1.3 cm	150 m	6 km	permanent; walkable/bikeable (est. 2018)

Other models of the Solar System: historic, temporary, virtual, or dual-scale[]

hideName	Location	Scale	Sun dia.	Earth dia.	Sun-Earth	Sun-Pluto	Description
Kirkhill model 1776^[b]	Scotland	1:778,268,620.8	1.8 m	1.6 cm	197 m	-	decayed
Planetenpad Utrecht	Utrecht, Netherlands	1:1,000,000,000	1.3 m	1.3 cm	150 m	7.4 km (Neptune)	Leads from Centre Utrecht to Rhijnauwen, on foot, on bike or on kayak
Sorghvliet	The Hague, Netherlands	1:696,000,000	2.0 m	1.8 cm	215 m	6.5 km (Neptune)	(temporary)
Sol Chicago	Illinois, Chicago	1:73,660,000	19 m	17.3 cm	2,050 m	61 km (Neptune)	(temporary) proposed
Le Chemin des planètes	Saint-Luc, Switzerland	1:1,000,000,000	1.4 m	1.3 cm	150 m	5.9 km	uses two different scales for distance and size
The Madison Planet Stroll	Madison, Wisconsin	1:4,000,000,000	0.3 m	0.3 cm	37 m	1.5 km	(virtual)
Solar System Stroll	Perth, Western Australia	1:5,000,000,000	0.3 m	0.3 cm	30 m	1.2 km	permanent; walkable (est. 2016)
The Thousand-Yard Model	(virtual)	1:6,336,000,000	0.2 m	0.2 cm	25 m	1 km	(virtual)
(dismantled)	Saint-Louis-du-Ha! Ha!, Quebec	1:10,000,000,000	0.1 m	0.1 cm	15 m	0.6 km	(dismantled) (est. 1985)
Lafayette Walk	Detroit, Michigan	1:6,336,000,000	23 cm	0.2 cm	25 m	983 m	A Walking Demonstration of (un)imaginable distances. "It's nowhere near Graham's Number."
Planets on the Path	Chicago, Illinois	1:2,195,000,000			457 m	11.4 m	(2015, temporary)
The Solar System, to scale, for a school yard	PDF for printing	1:11,945,400,000	11.6 cm	0.1 cm	12.5 m	492 m	PDFs, A4 and 8½″×11″, to be printed, affixed to cards which are affixed to sticks; then to be held by children standing in a school yard. Includes major moons and asteroids.

Several sets of geocaching caches have been laid out as Solar System models.

A model based on a classroom globe[]

If the Earth were reduced to the size of a typical classroom globe, 41 cm (16 inches) in diameter, the Moon would be a 10 cm (4 in) baseball floating 12 metres (40 feet) away. The Sun would be 14 stories tall (somewhat smaller than the Spaceship Earth ride at Epcot) floating 5 kilometres (3.1 mi) away. While a complete model to this scale has never been built, a Solar System built centered in Washington DC, London, or Sydney, to that scale (approximately 1:31 000 000) would look like this:

Body	Diameter	Object comparison	Semi-major axis	Scale model location (U.S.)	Scale model location (U.K.)	Scale model location (Australia)
Sun	44.6 m (146 ft)	14 story tall sphere, Spaceship Earth (Epcot)	zero	White House, Washington DC	Buckingham Palace	Sydney Opera House
Mercury	15 cm (6 in)	large grapefruit	1.9 km (1.2 mi)	National Air and Space Museum	Covent Garden	Elizabeth Bay
Venus	38 cm (15 in)	beach ball	3.5 km (2.2 mi)	John F. Kennedy Eternal Flame, Arlington National Cemetery	Regent's Park	Sydney Football Stadium
Earth	41 cm (16 in)	classroom globe	4.8 km (3.0 mi)	Ronald Reagan Washington National Airport	Tower of London	Rozelle Hospital
Moon	10 cm (4 in)	baseball	12 m (40 ft) from Earth
Mars	23 cm (9 in)	dodgeball	7.2 km (4.5 mi)	Rock Creek Park Golf Course	King's College London	Bondi Beach
Ceres	3 cm (1 in)	golf ball	13.3 km (8.3 mi)	West Falls Church Metro station	London City Airport	Macquarie University
Jupiter	4.55 m (15 ft)	Commercial van	24.9 km (15.5 mi)	George Mason University, Fairfax, Virginia	Heathrow Airport	Scotland Island
Saturn	3.81 m (12 ft 6 in)	Roundabout (merry-go-round)	45.5 km (28.3 mi)	Marine Corps Base Quantico, Triangle, Virginia	Luton	Copacabana
Uranus	1.63 m (5 ft 4 in)	average 8th grade boy	92.2 km (57.3 mi)	Aberdeen Proving Ground, Aberdeen, Maryland	Waterlooville	Bombo
Neptune	1.55 m (5 ft 1 in)	average 6th grade boy	144.4 km (89.7 mi)	Newark, Delaware	Leicester
Pluto	7 cm (3 in)	baseball	190 km (118 mi)	Wildwood, New Jersey	Hereford	Bulahdelah
Eris	8 cm (3 in)	baseball	325 km (202 mi)	Brooklyn, New York	Blackpool	Port Macquarie
Heliopause			571 km (355 mi)	Toronto, Ontario, Canada	Stirling, Scotland	Cobar, New South Wales
α Centauri A	49.5 m (162 ft)	Spaceship Earth (Epcot)	1,323,500 km (822,400 mi)	over 3 times the distance to the Moon	over 3 times the distance to the Moon	over 3 times the distance to the Moon

If the scale of the above model is increased to 1:310 000 000, i.e. all distances and sizes reduced by a factor of 10, then the Earth and Venus can be modeled by ping pong balls, the Moon and smaller planets by various size marbles or lumps of modeling clay, the gas giants by balloons or larger playing balls, and a circle the diameter of the Sun can be drawn on the floor of most classrooms. The scale distance to Alpha Centauri would be 1/3 of the way to the Moon.

Some planetaria and related museums often use a scale model of the Solar System featuring a planetarium dome representing the Sun. Examples of this can be seen in planetaria like the Adler Planetarium, the Hayden Planetarium at the American Museum of Natural History, the Clark Planetarium, the Griffith Observatory, the Louisiana Arts and Science Museum, the Adventure Science Center, etc.

A commonly-portrayed scale model of the Solar System would use fruits of varying sizes to represent the planets: The Sun would be represented by an adult human, Mercury would be represented by a pea, Venus by a cherry or a grape, Earth by a strawberry or an apricot, the Moon by a peppercorn, Mars by a blueberry, Jupiter by a watermelon or a medium-sized pumpkin, Saturn by a grapefruit or a large melon like a cantaloupe or a honeydew, Uranus by an apple or an orange, and Neptune by a lime or a plum.