Euclid: Understanding dark energy and our expanding universe
One of the greatest mysteries of astronomy is why the universe is expanding at an accelerating rate. Astronomers understand that there must be some force causing the expansion. They have called this mysterious force "
Astronomers want to understand the nature of dark energy, and they hope that the Euclid astronomy mission will help them do just that. Euclid is a space telescope being developed by the ESA that will give researchers the information they need to map out the large-scale structure of the universe with greater accuracy than ever before.
By mapping up to 2 billion galaxies, and peering 10 billion light-years back into the universe's history, astronomers will be able to see how dark energy and dark matter affected and continues to influence the growth and structure of the universe.
Euclid is a 1.2-metre diameter telescope that houses two scientific instruments: a visible-wavelength camera and a near-infrared camera/spectrometer. These instruments will measure the "
redshift" of galaxies. Redshift allows astronomers to determine how much the light emitted by an object is stretched, or shifted toward the red part of the light spectrum as the object moves away from us. This data enables a calculation of the rate of expansion of the universe.
The Euclid mission aims to:
- Measure the shapes of galaxies at varying distances from Earth
- Use data to accurately measure the acceleration of the universe
- Better understand dark energy and dark matter
Canada's role in the mission
The Canadian Space Agency is funding three scientists' participation in the Euclid mission:
- Dr. Will Percival, who holds Distinguished Research Chair in Astrophysics at the University of Waterloo, is using advanced statistical techniques to analyse the 3D pattern of galaxies in the universe, finding a "
standard ruler" that can be used to measure the expansion of the universe. Dr. Percival's team will use Euclid data to build their maps and understand why the expansion is accelerating at present day. "
We will be able to understand the physics driving this acceleration. While this has a name, dark energy, the processes behind it are not presently understood," he says.
- Dr. Mike Hudson, professor of astronomy at the University of Waterloo, is a researcher in observational and theoretical cosmology. He studies galaxy formation in order to better understand and measure the properties of dark matter and dark energy. The Euclid space mission will measure the distortion of the shapes of distant galaxies caused by gravitational lensing, the influence of gravitational fields that can bend light. He and his team will use Euclid data to study this shape-bending effect around galaxies and compare it with predictions made using their computer simulations.
- Dr. Douglas Scott, professor of astronomy and astrophysics at the University of British Columbia, studies cosmology, which examines the universe at the largest scales. The main science goal of the Euclid mission is to learn about the dark universe by using the bright universe, including how the matter in front of galaxies distorts light through gravitational lensing, and about particular signatures in how galaxies are clustered together, which together can tell us about the dark matter and dark energy that dominates the universe.
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