An army of tiny robots that tracks galaxies

30. Why is the universe expanding at an increasing rate? Scientists will attempt to gain a better understanding of this phenomenon by mapping the distribution of galaxies in the universe. Astrophysicists and robotics engineers from EPFL are taking part in this scientific adventure. Where is the universe headed? How is it possible that the galaxies are moving farther apart from each other at an increasing rate, defying the force of gravity that should at least slow this movement? To answer this question, researchers are going to map the distribution of galaxies in the universe very precisely. DESI, the Dark Energy Spectroscopic Instrument, is a project aimed at identifying the position of more than 30 million galaxies - out of the 100 to 200 billion that probably exist. It is based at the Lawrence Berkeley National Laboratory (LBNL, USA). The goal is to improve our understanding of dark energy: an ingredient that physicists added to their equations in order to account for the surprising fact that the expansion of the universe is accelerating.