Cosmology / Elementary Tour part 2: Reddening galaxies
Cosmic expansion has consequences for the light that reaches us from far-away galaxies - consequences that, in the 1920s, set astronomers on the track of an expanding universe in the first place. For an exact description of these effects, one would need a ...
Black Holes & Co. / Elementary tour: Conclusion
In the physics of neutron stars and black holes, we clearly see the central role of general relativity in modern astrophysics. Relativistic physics is necessary to fully understand the most energetic phenomena in the universe - from supernova explosions of ...
Black holes & Co. / Elementary tour part 3: Supermassive black holes
Soon after the beginning of radio astronomy came the discoveries of ever more variants of active galactic nuclei. An example is shown below: The image illustrates radio observations, showing a "radio galaxy" (the tiny dot in the center) which shoots beams ...
Black holes & Co. / Elementary tour part 2: Black holes
When even more massive stars explode in a supernova, the collapsing central region will generically have so much mass that even neutron matter cannot halt the collapse. The collapse continues, and when this happens, a black hole is born (more precisely: a ...
Gravitational waves / Elementary Tour: Conclusion
Gravitational waves promise a glimpse into regions of our cosmos that are inaccessible to regular astronomical observation. In the past, whenever astronomers have opened a new window to the universe (for example, at the beginning of radio astronomy or X-ray ...
Gravitational waves / Elementary tour part 4: Hunting for waves
The hunt for gravitational waves is one of the greatest adventures of modern physics. Worldwide, hundreds of scientists using cutting-edge technology are working toward a common goal: to detect gravitational waves, and in a second step, to open up the field ...
General relativity / Elementary Tour: Conclusion
The aim of this chapter was to give the reader a basic idea of what general relativity is all about. Einstein's theory of gravity led physicists to a variety of new models and phenomena. The most important examples - gravitational waves, black holes, the ...
