The universe is expanding, a fact confirmed by astronomical observations. But why is the universe expanding? The European Space Agency’s Euclid mission aims to shed light on this fundamental question by mapping the distribution of dark matter and dark energy, the mysterious forces driving cosmic expansion.
Euclid, equipped with powerful cameras and a spectrometer, will survey a vast portion of the sky, observing billions of galaxies across immense distances. Its primary objective is to measure redshift, a phenomenon crucial for understanding the universe’s expansion.
Redshift occurs when light from distant objects stretches as the universe expands, shifting towards the red end of the spectrum. Similar to the Doppler effect with sound waves, where the pitch changes as a source moves relative to the observer, redshift indicates how fast objects are receding from us. The faster the recession, the greater the redshift.
Euclid’s instruments are designed to detect minute changes in redshift, allowing scientists to precisely measure the rate of cosmic expansion. This data will help determine how the expansion rate has changed over time, providing clues about the nature of dark energy, the force believed to be accelerating the expansion.
By mapping the distribution of dark matter and galaxies, Euclid will also reveal how these structures interact with dark energy, creating areas of varying gravitational pull. These variations influence the expansion rate in different regions, providing further insights into the dynamics of the universe. This mapping will include not just the height and width of the sky, but depth and time as well.
The information gathered by Euclid will complement future missions like NASA’s Nancy Grace Roman Space Telescope. Launching in 2026, Roman will delve deeper into specific areas identified by Euclid, providing even more detailed observations of distant galaxies and further illuminating the mysteries of dark energy and the accelerating expansion of the universe. Together, Euclid and Roman will probe the nature of the 90% of the universe we can’t see, uncovering clues to its composition and evolution. This combined effort will revolutionize our understanding of the cosmos and our place within it.
The Euclid mission is poised to revolutionize our understanding of the universe’s expansion. By precisely measuring redshift and mapping the distribution of dark matter and dark energy, it promises to unlock the secrets of cosmic acceleration and shed light on the fundamental forces shaping our universe.
