The project "Space Time Travel" is a contribution to teaching relativity. It is run by the physics and astronomy education group at Hildesheim university. The centre of the project is the website
At the beginning of the 20th century the theory of relativity was regarded as one of the most difficult and abstract theories. This is expressed, e.g., in Einstein's well-known question "Why is it that nobody understands me, yet everybody likes me?" or in the well-known anecdote about Sir Arthur Eddington, who, when somebody called him one of the three men in the world who really understood the theory of relativity, replied that he did not know who might be the third.
Yet, in the following decades relativity found its way into university teaching and increasingly also into secondary school curricula. Roman Sexl analyzed this transition from a seemingly incomprehensible theory to a widely taught one ("Relativitätstheorie als didaktische Herausforderung", Sexl (1980)). His conclusion in 1980 is that now suitable audiovisual media should be developed to make further progress in teaching relativity.
Since then, the visualization of relativity has grown into an independent area of research. Methods of computer graphics were extended in order to display relativistic scenes in images and movies. Increasingly powerful computers and graphics hardware made it possible to simulate and visualize increasingly complex scenes.
In the theoretical astrophysics section of Tübingen university and subsequently at Hildesheim university we have been working on visualizations of special and general relativity and of relativistic astrophysics since 1988. These visualizations are at the centre of our project. We provide them with explanatory material and make them accessible on our website to students and teachers.
The starting point of the visualizations is the question: What would it be like to directly experience relativistic effects? For example: To move at nearly the speed of light and look around. We create physically correct computer simulations of scenes of this kind in the form of pictures, movies and interactive simulations. These visualizations allow to "experience" and "experiment with" relativistic phenomena, at least virtually.
The results of the simulations are often perplexing, even for experts in the field. This is well illustrated by early textbook illustrations of the visual appearance of objects moving at nearly the speed of light that were not correct (e.g. Gamov (1940)). Only from 1959 onwards, a series of investigations clarified what such an object would really look like (Penrose (1959), Terrell (1959), Boas (1961), Kraus (2000) and others). We therefore put equal emphasis on computing the simulations and on providing explanatory material. With many sketches and animations the computer simulations are explained in detail.
M. L. Boas, Apparent Shape of Large Objects at Relativistic Speeds, Am. J. Phys. 29, 283-286 (1961).
G. Gamov, Mr. Tompkins' seltsame Reisen durch Kosmos und Mikrokosmos, Vieweg Verlag, Wiesbaden, 1984. Original: Mr Tompkins in wonderland, 1940.
U. Kraus, Brightness and colour of rapidly moving objects: the visual appearance of a large sphere revisited, Am. J. Phys. 68, 56-60, 2000.
R. Penrose, The Apparent Shape of a Relativistically Moving Sphere, Proc. Cambr. Phil. Soc. 55, 137-139, 1959.
Roman Sexl, Relativitätstheorie als didaktische Herausforderung, Die Naturwissenschaften 67, 209-215, 1980.
J. Terrell, Invisibility of the Lorentz Contraction, Phys. Rev 116, 1041-1045, 1959.
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