As this article has shown, astroparticle physics – being at least a very dominant interdisciplinary field, if not a discipline of its own (see Section 5.2) – was “founded” in 1987, when researchers from particle physics, astrophysics and cosmology decided to advance the current problems of their disciplines collectively (see Section 5.1). Still, astroparticle physics has more deep-reaching roots, starting with the discovery of ionizing rays of cosmic origin (see Sections 2.3, 2.4 and 2.5). Usually this discovery is ascribed to Hess’ experiments conducted on balloon flights in 1911 and 1912, which is an oversimplification that might be alright when talking about the scientific results (see Section 2.4), but, historically speaking, one has to realize that Hess’ work belongs to a broader context of experiments investigating the various phenomena of electricity and radioactivity (see Sections 2.2, 2.3 and 2.4). Right from the very beginning early cosmic-ray studies have been strongly influenced by technical developments, e.g. the invention of the cloud chamber (see Section 2.5) or the improvements that made long-distance manned balloon flights possible (see Sections 2.4 and 3.3). But during the 1920s and 1930s further progress in the technical aspects of experimental set-ups, from the invention of Geiger counting tubes to better equipment for unmanned balloons, not only helped to find new ways of analyzing penetrating rays (see Sections 3.1, 3.2 and 3.3), but also in the long run became a means of detecting new particles and asked for new theoretical approaches to this field of physics (see Sections 2.6, 2.7, 2.8, 3.5 and 3.8). Thus cosmic-ray studies became the forerunner of modern particle physics (see Sections 2.8, 3.6, 3.7 and 3.8). After World War II cosmic-ray studies appear to have declined in favor of particle physics using man-made accelerators, the reasons for which are so far unclear (see Sections 4 and 4.1). Nevertheless, different types of astrophysics using cosmic rays were conducted in new scientific contexts (see Sections 4.2, 4.3, 4.4 and 4.5) and finally marked the starting point for the formation of modern astroparticle physics. This formation was mainly made possible by the interconnections that were established between particle physics, astrophysics, and cosmology (see Section 5) through the 1960s and 1970s. The cooperative dealing with problems finally led to the establishment of the interdisciplinary field of astroparticle physics (see Section 5.1). Yet, though this field of study does seem to fulfill many of the common characteristics of a discipline of its own, the status of astroparticle physics as a discipline is still somewhat ambiguous (see Section 5.2). Thus, astroparticle physics provides good reason to invest more historical and philosophical energy on this topic (see Sections 6.1 and 6.2). The main tasks for the near future are:
Of course, there are many more points on the agenda, especially concerning the open questions physicists are trying to cope with. The most urgent one is certainly the problem of dark matter, but also other findings beyond the Standard Model of particle physic are to be made. For historians there is a rich corpus of material to write some very interesting chapters in the history of physics. All in all one might say that astroparticle physics still has a lot of potential to keep people busy for quite a while, no matter whether they are physicists, philosophers or historians.
This work is licensed under a Creative Commons Attribution-Noncommercial-No Derivative Works 2.0 Germany License.