The space between the stars is not empty, but filled with interstellar matter.
Interstellar matter displays many very different physical properties.
On one hand, stars have their birthplaces in the densest parts of interstellar clouds, where we find molecules intermixed with dust. On the other hand, we observe interstellar medium full of fissures, caused by the explosion of a dying star at the of its life. The star returns mass and energy back to the interstellar medium. As a result, we see shock waves penetrating the interstellar medium and heating up the gas to millions of degrees Kelvin. Further information on the research topics of the Sternwarte can be found on the interstellar matter and Magellanic Clouds homepage.