The Weikersheim Planetary Trail begins on the Tauber Valley Cycling Route at the northern edge of the city of Weikersheim. A yellow sphere, about one and a half meters in diameter, represents the sun at a scale of 1:1,000,000,000.
From there you start walking or cycling slightly uphill towards the Karlsberg (Charlie’s Hill) and Queckbronn.
The amazing thing, if you haven’t thought about it for a while, is that the sun and the planets are so small in comparison to the huge distances between them. Walking or cycling the Planetary Trail is a good way to get a feeling for the true proportions of our solar system — highly recommended!
The text panels are attractive and very informative. They are in German only, but even if you don’t understand that language you can still appreciate the photos and understand some of the statistics.
The first panel gives a mnemonic in German for remembering the names of the planets: Mein Vater erklärt mir jederzeit Sonnensystem und Nachthimmel. This means “My father explains to me at any time the solar system and the night sky”, but the point of it is that the eight words of the German sentence begin with the same letters as the eight planets: Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus and Neptune.
This panel also says that by walking the trail at a leisurely pace we are in effect racing through the solar system at nearly five times the speed of light.
From the Sun to Mercury, the first planet, you have to walk (or cycle, as I did) 58 meters, representing 58 million kilometers at a scale of 1:1,000,000,000.
At this scale Mercury is only about the size of a small pea. You can see it on the left, as a small bump on the upright rod that represents its axis.
The text panel (in German only, sorry) points out that there is an extreme difference in temperature between the side of Mercury that faces the sun (+400 degrees Centigrade) and the side facing away.
Being so close to the sun, Mercury is difficult to observe, but it can sometimes be seen through the telescopes of the Weikersheim Observatory as a small disk near the horizon.
Venus is similar to the Earth in some ways — mass, diameter and orbital duration — but with an atmosphere consisting of 96 % carbon dioxide Venus is a terrifying example of what can happen to a planet with a runaway greenhouse effect. Huge clouds of sulfuric acid surround the planet, sending down acid rain which evaporates before it hits the hot surface — hotter even than the daytime side of Mercury, which is much closer to the sun.
The text panel goes on to explain that Venus is often visible as the “Morning or Evening Star” in the form of a large bright disk which shows phases like the moon (half moon, full moon, etc.)
When you walk the Weikersheim Planetary Trail, each step you take represents a million kilometers in outer space — assuming you have longish legs and each stride is about one meter.
On a bicycle you can feel the force of gravity because the trail goes uphill away from the sun, sort of like an illustration of Einstein’s theory that the sun, like all clumps of matter, distorts the geometry of space-time rather than exerting some kind of pulling effect on distant objects.
You have to walk or cycle another 42 meters to get from Venus to the Earth, the “largest and most massive stony planet, and the only one with detectable life on it.”
The text panel points out that the Earth is probably also the most geologically active planet in the Solar System, with continental plates moving around and constantly forming new mountain ranges and ocean basins, also with hot magma forcing its way up from the interior and spewing out in the form of volcanoes.
In the photo you can see that the Earth’s axis is tilted more than Venus’s and much more than Mercury’s — and that the Earth is blue, like the flowers blooming behind the model.
Here some people on bicycles are riding past the sun on the Tauber Valley Cycling Route, as seen from the model of the Earth.
The distance from the Earth to Mars, the next planet, is 78 meters on the Planetary Trail, corresponding to 78 million kilometers in the real Solar System.
From the model you can see that Mars is represented by a small red ball, about the size of a marble, even smaller than the blue ball back at Earth.
Like Earth, Mars has a tilted axis of rotation, which means it has different seasons in its northern and southern hemispheres. The models on the Planetary Trail were carefully made to show the tilt (or not) of each planet’s axis. (Wait till you see the one at Uranus!)
After Mars, the distances start getting longer. You have to walk or cycle 551 meters to get to the next planet, Jupiter, by way of the Asteroid Belt.
There isn’t any model at the Asteroid Belt, but there is a text panel which explains that between Mars and Jupiter there are numerous small and larger rocky boulders circling the sun.
The largest of these, Ceres, was the first to be discovered (in 1801) and was first thought to be a star but was soon afterwards identified as an object orbiting the sun within our solar system.
In 2006 the International Astronomical Union decided to classify Ceres as a “dwarf planet” along with Pluto (discovered in 1930) and the even more distant Eris (discovered in 2005). Eris is slightly larger than Pluto and 27 % more massive, so if Pluto qualified as a full-fledged planet, Eris would logically have to be classified as a planet, too. Instead, the IAU decided to make the new category “dwarf planet” for spherical objects smaller than Mercury that orbit the sun.
Looking out across the corn fields from the Asteroid Belt we can see Weikersheim, a small city with 7,333 inhabitants (as of 2017).
In the center of the second photo we can see Weikersheim Castle, where open-air opera performances are held every second summer, in the odd numbered years.
Jupiter in the model is about the size of a baseball, which doesn’t seem terribly gigantic unless you recall the tiny spheres that represented Mercury, Venus, Earth and Mars further down the hill.
The text panel points out that Jupiter, the largest and most massive planet in our solar system, consists mainly of hydrogen and helium. It has a strong magnetic field. In the atmosphere there are large storms that can be seen even with small telescopes. The largest of these storms is The Great Red Spot, a huge storm which has been raging for over three hundred years.
645 meters further on, up the hill, is the next planet, Saturn.
Up near the top of the Karlsberg (Charlie’s Hill) is the Weikersheim Observatory, which is run by over a hundred amateur astronomers who are members of the Weikersheim Astronomical Society.
At least once a month (weather permitting) the society conducts observation evenings which are open to the public free of charge.
Since 2007 the observatory has also been the site of the planet Saturn on the Weikersheim Planetary Trail. Before then Saturn was located a few dozen meters further up the hill, but in 2007 they decided to fudge the distances just slightly to bring Saturn down to the observatory.
As you can see here, the model of Saturn includes the rings circling its equator. Saturn’s axis has a quite noticeable tilt of 26.7 degrees.
At the top of the Karlsberg, between Saturn and Uranus so to speak, is a walled-in forest area called the Nature and Leisure-Time Park Karlsberg.
This park is home to what the Germans somewhat poetically call “Hochwild”, meaning tall wild animals, known more prosaically to us English-speaking people as deer.
Since I was there at high noon on a warm summer day, I didn’t see any animals of any sort, wild or otherwise, but I’m sure they must be in there somewhere.
As you can see from the model, the rotational axis of Uranus is so tilted that it is nearly horizontal (97.9 degrees of tilt), so the planet is practically lying down as it orbits the sun.
The stone wall behind the Uranus model is the wall that surrounds the Nature Park Karlsberg.
In the outer reaches of the solar system, the planets are further apart than they are in our neighborhood. So after leaving Uranus you have to walk or cycle more than a kilometer and a half — 1,623 meters to be exact — before reaching the next and last planet, Neptune.
Between Uranus and Neptune there are several recently-installed windmills for generating electricity.
Some conservative Germans object to these new windmills on aesthetic grounds, saying they mar the landscape, though these same people have never objected to the much more numerous metal towers for high-voltage transmission lines.
Queckbronn was a separate village for most of its history, but in January 1972, along with nearby Schäftersheim, it was incorporated into the city of Weikersheim, which in turn belongs to the Main-Tauber-Kreis (sort of like a county) in Land Baden-Württemberg.
Local historians estimate that Queckbronn is around a thousand years old, though the first mention of the village in a written document was not until the year 1261.
Like Weikersheim (but unlike nearby Tauberrettersheim), Queckbronn is a predominantly Protestant village, and has been ever since Duke Wolfgang I of Hohenlohe–Weikersheim decreed its conversion in the sixteenth century.
This was a result of the Peace of Augsburg that was negotiated in 1555 to put an end to religious strife within the loosely-knit “Holy Roman Empire of the German Nation”. Under this agreement, all the princes and dukes and margraves and other local rulers agreed not to make war against each other for religious reasons. In the countryside, the common people were required to accept the religion of their local ruler, but in the cities both Catholics and Protestants were allowed to have churches and practice their own religion.
This agreement did in fact keep the peace, more or less, for over sixty years, until the pent-up antagonisms exploded in the unimaginable destruction of the Thirty Years War (1618-1638), which resulted in the death of eight million people in Germany — two thirds of the population.
More recently, Queckbronn was badly damaged by shelling at the end of the Second World War in 1945 (not by aerial bombing as in most other places), so that many of the farmhouses had to be completely rebuilt after the war was over.
From the text panel we learn that Neptune is now considered the outermost planet in the solar system, now that Pluto no longer qualifies as a planet.
The existence of the planet Neptune was predicted by two astronomers in 1845 and was actually sighted through a telescope in Berlin in 1846.
The prediction was based on irregularities in the orbit of Uranus, which suggested that there must be another large planet out there somewhere.
In the model Neptune is represented by a blue ball on a somewhat tilted orbit (29.6 degrees of tilt). The model is now located directly in the ex-village of Queckbronn.
Except for being the site of Neptune on the Planetary Trail, Queckbronn looks very much like any other German village, with a nice fountain, flowers and well-tended farm houses.
My impression is that Queckbronn is not as affluent as some of the other villages in the vicinity, like Tauberrettersheim or Schäftersheim, but it is nonetheless a pleasant and reasonably prosperous place.
Several families in Queckbronn have rooms to rent for vacationers, at very reasonable prices.
From the ex-village of Queckbronn it is possible to continue along the Planetary Trail and return to Weikersheim by a different route, with a stop at a new station representing the ex-planet Pluto, but I didn’t have time for that because I had been invited for lunch back in Weikersheim, so I returned the fast way via the regional highway L-1003. This was downhill all the way, and got me back to Weikersheim on my bicycle in a matter of minutes.
My photos in this post are from 2009. I revised the text in 2019.
See more posts on the Thirty Years’ War (1618-1648).