Written by Rebecca Hutchins, Curator of Collections
An orrery from the Museum’s collection will be on display July 20, 2019 at the “Firsts in Flight: A Hidden History” exhibit at Old City Hall, in honor of the 50th anniversary of the moon landing.
The mechanical model of the solar system shows the relationships between celestial bodies and works by simulating the orbits and speeds of planets, the moon, and the sun.
Humanity’s early fascination with the heavens is well documented and continues to endure. Around 600 B.C., Greek philosophers began to focus on the laws of nature and the universe to explain the world around them. Thales of Miletus (c. 620 – 546 B.C.) is credited by some with predicting the solar eclipse on May 28, 585 B.C. Some consider this prediction to be the beginning of science and the study of astronomy.
Through the years, philosophers, mathematicians and astronomers used drawings and models, sometimes called planetariums or orreries, to help describe and understand planetary movement and relationships. In Greek Society, the earliest such model is attributed to Archimedes (c. 287 – c. 212 B.C.). Later, Campanus of Novara (1220–1296) described a planetary model in his publication Theorica Planetarum and included instructions on how to build one.
Astronomy continued to be a changing science and the historic planetary models reflect the growth of understanding in the field. Most early astronomers such as Plato (428-348 BCE), Aristotle (384–322 BCE) and Ptolemy (90–168 AD), favored the concept of a geocentric solar system. In that system, Earth was the central and unmoving center of all other orbits.
Copernicus (1473-1543) and later Galileo Galilei (1564-1642), developed and published works that described the solar system as heliocentric, or centered around the Sun. Galileo is also credited with creating the first detailed drawings of the Moon and describing its specific orbit around Earth. With the invention of the reflecting telescope by Sir Isaac Newton (1643-1727) and his publication of Philosophiae Naturalis Principia Mathematica in 1687, heliocentrism was no longer up for debate.
The rise of the orrery
The public discourse that followed this publication and its popularity inspired people to learn more about this “new” heliocentric solar system. In 1704, two London clock makers, George Graham and Thomas Tompion, began making affordable solar models. These models had hand cranks and moving orbs representing the Earth, Moon, and Sun. As a result, complex phenomena was turned into mechanical models that became fixtures in households and classrooms.
The orrery gets its name from the fourth Earl of Orrery, Charles Boyle, who commissioned his own model in 1713. These models inspired continued exploration of the solar system and helped predict day and night, seasons, eclipses, and more. The orrery at the Museum is an example of a common model used at home or in the classroom at the turn of the century.
In addition to the orrery, the Museum has other special programming planned to celebrate the Apollo 11 moon landing anniversary. Join us for a screening of the new Smithsonian Channel movie The Day We Walked On the Moon. The screening will take place Saturday, July 20 at 1pm in the Rotunda Room of Old City Hall. The screening is included with admission and free to members.
Kids ages 8-14 can take part in a rocket-making workshop at the Lightcatcher building. In addition to making and firing rockets, students will learn how chemical reactions work. The workshop takes place Saturday, July 20, from 10am – noon. Registration is $25 for Museum members and $30 for the general public. Register here by July 17.