The Einstein Tower is an icon of the modern age. It was built in 1920-22 by Erich Mendelsohn in a way that broke with all traditions. The Wüstenrot Stiftung has carried out the last two refurbishments of this significant monument. The Leibniz Institute for Astrophysics Potsdam (AIP) still operates the Einstein Tower in its original function: as a solar telescope.
Scroll through the history of science (above) and the history of architecture (below)!
Move the model and click on the buttons to learn all about the construction and function of the Einstein Tower!
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The Einstein Tower is a solar observatory operated by Leibniz Institute for Astrophysics Potsdam (AIP). The architect Erich Mendelsohn built the Einstein Tower between 1920 and 1922. The Wüstenrot Stiftung carried out the last two major restorations of the building between 1997 and 1999 and between 2021 and 2023, with care taken to preserve all the different historical layers. The digital exhibition »Einstein Tower revisited« invites you to immerse yourself in its history and the story of how it came into being, and gain an understanding of the building’s scientific programme. It also offers an insight into what is involved in preserving the tower as a monument.

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Start: Spectral Analysis


In 1859 Gustav KirchhoffRobert Kirchhoff (1824–1887) was a physicist. His work with Robert Bunsen led to the discovery of spectral analysis. Kirchhoff also conducted research into electricity and was the first to describe the dependent nature of electrical current, electrical voltage, and electrical resistance. and Robert BunsenRobert Bunsen (1811–1899) was a chemist. His work with Robert Kirchhoff led to the discovery of spectral analysis and the elements caesium and rubidium. He perfected the Bunsen burner, which was named after him. discovered that every chemical element in the light spectrum has a unique “signature”.

Foto von Gustav Kirchhoff und Robert Bunsen
Gustav Kirchhoff (left) and Robert Bunsen (right).
Schematische Darstellung eines Prismenspektrographen
The prism spectrograph, which Bunsen and Kirchhoff used to analyse the spectra of individual elements, channels the light from a light source (D) – in this case, a gas flame – directing it through the telescope B onto the rotating prism F. The prism breaks down the light into its entire spectrum, which can be seen through the telescope C.
Diagramm mit Darstellung der Spektren verschiedener Elemente
On this drawing you can see the spectra of the elements potassium, sodium, lithium, strontium, calcium, and barium, with the spectrum of sunlight shown at the top for comparison. The spectra of the elements are obtained by placing them, in the form of chlorine compounds, in a gas flame and analysing the light so produced through the spectrograph.

In their spectral analysis, Bunsen and Kirchhoff built on the discovery that Joseph von FraunhoferJoseph von Fraunhofer (1787–1826), optician and physicist, was a builder of telescopes and discovered the Fraunhofer lines – the absorption lines in the solar spectrum – which are named after him. He combined scientific precision with practical application and invented new instruments. On the basis of this, he also gave his name to the Fraunhofer Society. had made in 1813: that there are dark lines in the spectrum of the Sun and other stars. Bunsen and Kirchhoff now ascertained that these dark lines can be explained by the fact that particular chemical elements absorb particular wavelengths of light. In other words, if you look at the sunlight through a prism, these elements “obscure” parts of the light. Besides these dark absorption lines, there are also bright lines in the spectrum of stars. These occur when an associated chemical element is excited and emits light of a certain wavelength. By analysing these emission lines together with the absorption lines, it is possible to determine the chemical elements a star is composed of, even if it is light years away. All at once, it became clear that the same chemical elements that are found on Earth also occur on the Sun and other stars.

The spectral lines of the Sun and other stars were given added significance by the atomic model developed by Niels BohrNiels Bohr (1885–1962), physicist, made Albert Einstein’s acquaintance in Berlin in 1920. The atomic model he developed won him the Nobel Prize for Physics in 1922: it was based on the idea of light, negatively charged electrons moving in a closed orbit around a heavy, positively charged nucleus. His model anticipated elements of quantum mechanics – the assumption that electrons can “jump” from one orbit to another, causing the atom to emit radiation. in 1913. On the basis of Bohr’s model, a spectral line not only reveals the presence of a chemical element but also provides information about pressure and temperature on the star that is being observed.

Why was the discovery of spectral analysis and the spectrograph so important in the development of the Einstein Tower? Spectral analysis plays an essential role in the scientific experiments for which the tower was built.