In the early Universe, the matter was evenly distributed throughout space. But as time went on, regions with more matter began to attract even more matter due to gravity. These dense regions became galaxies and clusters of galaxies, while voids emerged in between them. The distribution of matter in the Universe today is not random—it’s filaments and voids separated by walls of galaxy clusters.
The light from distant galaxies carries information about their three-dimensional positions and how they are moving. By mapping out where these galaxies are located and how fast they are moving away from us, we can reconstruct the structure of the Universe back in time. This allows us to study how it has evolved over cosmic history.
The Dark Energy Survey (DES) is a project that uses an imaging camera attached to a 4-meter telescope to map 300 million galaxies over one-eighth of the sky. DES covers an area nearly 500 times larger than any previous galaxy survey at this depth and will take approximately 5 years to complete.
The data from DES will be used to answer some of the most pressing questions in cosmology today: What is dark energy? How did structures like galaxies form? And what does our Universe look like on large scales?