The European Space Agency (ESA) has adopted Euclid, a space-based dark energy and cosmology research mission, in its Cosmic Vision 2015-2025 program. Euclid was launched on July 1, 2023.

As an ESA-led mission with participation from NASA, Euclid will map the geometry of the dark Universe. Using two cosmological probes—weak lensing and baryonic acoustic oscillations—in a wide-field survey, Euclid will precisely measure the growth of large-scale structure and the expansion history of the Universe.

Mission Objectives:

1. Understanding the mechanism responsible for the apparent late time acceleration of the expansion of the Universe (“dark energy”)
2. Test the validity of general relativity on cosmic scales
3. Investigate the nature and properties of dark matter by mapping the 3-dimensional dark matter distribution in the Universe
4. Refine our understanding of the initial conditions at the beginning of our Universe, which seed the formation of the cosmic structures we see today