How many planet trails are there in Switzerland? A planet trail (chemin des planètes, sentiero dei pianeti, Planetenweg, via da planets) is a walking route that represents the Solar System to scale, with stations marking each planet’s position. OpenStreetMap currently shows about two dozen.

List

Here is the current list:

• Aargau
• Arosa
• Bülach
• Burgdorf-Wynigen
• Disentis-Sedrun
• Effretikon-Kyburg
• Emmen
• Falera-Laax
• Frauenfeld
• Kreuzlingen Nord
• Kreuzlingen Süd
• Lägern
• Laufen BL
• Locarno
• Marly
• Monte Generoso
• Ringgenberg-Goldswil
• Ringgenberg-Oberried
• Schwanden/Sirius
• Solothurn Weissenstein
• St-Luc
• St. Gallen
• St. Stephan
• Visp
• Zürich Uetliberg

The same as overpass query

There is one along the Swiss border at Vaduz.

State of mapping

How detailed is our cartography?

• All stations mapped: Bülach, Effretikon-Kyburg, Falera-Laax, Frauenfeld, Kreuzlingen Süd, Lägern, Locarno, Marly, Monte Generoso (?), St. Gallen, St-Luc, St. Stephan, Vaduz, Visp, Weissenstein, Zürich Uetliberg
• Some or most stations mapped: Aargau, Burgdorf-Wynigen, Emmen, Kreuzlingen Nord, Laufen BL, Ringgenberg (both), Schwanden/Sirius
• Only a single node mapped: Arosa
• Entirely missing: ?

We have a couple of lonely Pluto nodes that haven’t made it into a trail yet: 1, 2.

For OSM tags on these features, see the wiki pages about:

• Tag:educational=planet_trail
• Tag:board_type=planet_walk

Planets

Which Solar System objects are included? A typical sequence is: Sun → Mercury → Venus → Earth → Mars → Jupiter → Saturn → Uranus → Neptune

Most trails predate 2006 and include Pluto, and some even show it at more than one position. Currently, we can find 22 Plutos.

Some of the following can be included:

• asteroid belt
• Ceres
• Halley’s comet
• separate models for moons

One hiker complained that most planets are, unsurprisingly, clustered near the start of the trail. Multiple positions of Pluto and comets help alleviate this, providing landmarks on what would otherwise be a long, empty walk.

For many trails, the nearby observatory of the astronomical society that created the trail serves as additional point of interest. A few trails are school projects (notably Disentis, St. Stephan).

Sun at Weissenstein (Picture by Adrian Michael, CC BY-SA 4.0, via Wikimedia Commons)

Scale

What scale do the trails use? For the distances between the stations, the scale is generally 1:1,000,000,000 (one billion or milliard). At this scale, the Sun–Pluto distance produces a trail roughly 6 km long.

The planet models may use the same scale as the distances, or they may be enlarged for visibility.

Other scales found:

• 1:10,000,000,000 (Monte Generoso)
• 1:5,000,000,000 (Bülach)
• 1:4,000,000,000 (Falera)
• 1:2,800,000,000 (Arosa)
• 1:900,000,000 (Disentis)

At the 1:1,000,000,000 scale:

• 1 metre on the trail represents 1 million km
• Earth is represented by a sphere approximately 1.3 cm in diameter
• Neptune is about 4.5 km from the Sun
• Pluto is about 5.9-6 km from the Sun

Route types

A few are arranged as round trips (Marly, Frauenfeld), but many follow a roughly linear route away from the Sun.

Kreuzlingen and Ringgenberg have trails extending in two different directions from their starting areas.

Some routes are mostly flat, while others climb or descend.

Maintenance

An important consideration is when the trails were last maintained. Occasionally signs and models need to be replaced.

As some trails have been mapped in OSM for many years, it’s possible that they no longer exist.

Some entries use start_date to record the original installation date or, in some cases, the date of a later renewal.

Coverage elsewhere

The Swiss Astronomical Society has a list on its website. It includes trails at Landquart, Mollis, Lumino and Le Locle that are not mapped. Astro Ticino lists 3 (or 4), this list includes 2.

Trekky.ch lists 8 trails, while the Map includes 3 of them. The other 5 aren’t described much elsewhere.

Local tourist offices and municipalities feature trails in Vallorbe, Le Locle-Les Brenets, Landquart, Lumino, Morgins and Willisau.

Wikipedia lists 2 in English, 1 in French, 3 in Italian, 20/21 in German and 6 in pictures. A few trails also have individual articles. The Willisau-Schötz and Landquart trails do not appear to be included in our Map.