Building a solar system on your living room ceiling? The secret of this ancient planetarium is in the attic

The picture shows the solar system pendulum model in the astronomy room. (Picture from the official website of the Essa Esinger Planetarium)

The Eise Eisinga Planetarium is located in Friesland, the Netherlands. It was founded in 1781 by Eise Eisinga, known as an "amateur astronomer". Its biggest highlight is the pendulum model of the solar system hanging from the ceiling. It is the oldest planetarium in the world that is still in operation.

In 2010, the Eisai Esinger Planetarium was included in the UNESCO World Heritage Tentative List as a living example of the new science and rationalism of the European Enlightenment.

Popularization of astronomy in the Enlightenment

In the 17th and 18th centuries, Europe saw a popular anti-feudal and anti-church ideological and cultural movement aimed at promoting the use of science and reason to dispel the darkness of feudal ignorance. However, most people at that time were still relatively ignorant. For example, "On May 8, 1774, when Mercury, Venus, Mars, Jupiter and the Moon were relatively close, the Earth would be thrown out of orbit by the interaction of these celestial bodies and burned by the Sun, and the end of the world would come." The rumor caused panic and anxiety among local people.

Essa Esinger, who is engaged in wool combing business, likes to study astronomy and mathematics in his spare time. In order to let people intuitively see the position and relative movement of planets in the solar system, he spent 7 years making a solar system pendulum model and placed it on the top of his living room, attracting a large number of people to visit. Later, Essa Esinger's house became the Netherlands Essa Esinger Planetarium, and the living room became the core exhibition hall of the planetarium, the "astronomy room".

A masterpiece that combines science and craftsmanship

Entering the "astronomy room", the sky-blue walls and golden orbits above the head are in sight. On the side walls of the room are dials that display the date, constellations, moon phases, and sunrise and sunset times. The entire room displays the solar system in an image, and the audience can touch the starry sky.

How does the pendulum model get its power? The secret lies in the attic on the second floor. There is a gear mechanical power system here, which is composed of simple and solid parts such as iron pins, discs, and wooden hoops. It is powered by a clockwork device to drive the movement of the celestial bodies in the model.

Except for a few parts such as the gear bearings made by Essinger's father and the clock made by the watchmaker, the remaining more than a thousand parts were designed, manufactured and assembled by Essinger himself. Since its completion in 1781, this model has accurately displayed the relative motion trajectories of Mercury, Venus, Jupiter, Saturn, Mars and the Earth in the solar system.

Scientific development requires craftsmanship. The precise and beautiful solar system model exhibit in this planetarium combines science and art. The production of this exhibit is not just a simple combination of various parts. Its maker must have a firm scientific belief, rich knowledge of astronomy and mathematics, strong hands-on ability and perseverance.

The Eissinger Planetarium in the Netherlands provides a platform for the public to appreciate celestial bodies and astronomical landscapes, demonstrating the infinite charm of the vast universe and the scientific spirit of human exploration. The research of scientists from generation to generation continues to break through the boundaries of human cognition of the world. Just as the Chuci asked, "Where is the sky? Where are the twelve? Where do the sun and the moon belong? Where are the stars arranged?", human exploration of the universe will continue.

(The author Wang Wenyuan is an engineer in the Logistics Department of the China Science and Technology Museum)