Mapping the Universe
Systematic surveys cover millions of galaxies that have spread out in space over billions of years. Based on the patterns that emerged, important questions about the development of the universe could be answered.
Given the unimaginable dimensions of the cosmos, finding out how big it really is and how it works in detail is a daunting task. Many astronomers have dedicated their careers to creating maps of the Universe at all scales. Meanwhile, after two decades of work, the Sloan Digital Sky Survey (SDSS) project, in which we worked, has produced the largest three-dimensional overview of the cosmos ever available. While the project is already in the next phase of data collection, the material to be released by 2021 covers all regions of space - from our immediate vicinity to the most distant objects still visible - and includes the positions of several million galaxies. Like landmarks, these are spread over many billions of light years and reach back to the earliest epochs of the universe.
The galaxies do not appear to be completely randomly scattered. Instead, they form structures: in some areas thread-like "filaments" and layers of densely packed galaxies, in others largely empty "voids". The basic patterns probably formed before the first galaxies formed, less than a billion years after the Big Bang. By mapping space as extensively as possible, we can understand the growth of structure and deduce the underlying laws that led to it. Such a galactic atlas may provide answers to some of the biggest questions in physics, such as the nature of the dark energy that is making the cosmos expand ever faster…