The $1.5 billion Euclid space telescope, which was ordered by the European Space Agency, was successfully launched by SpaceX on Saturday. This ground-breaking mission aims to shed light on the mysteries of dark matter, an unidentified material that permeates the cosmos, and dark energy, a puzzling force that hastens the expansion of the cosmos.
In light of the fact that there are currently observations without a comprehensive theory to account for them, Henk Hoekstra, a researcher at the University of Leiden and the coordinator of the Euclid science project, compared the problem to trying to find a black cat in a dark room, especially if there is no cat.
“So far, nobody has come up with a good explanation for dark matter, dark energy and other challenges also related to particle physics. … The launch of Euclid by European space telescope really (carries) cosmology into the future. It represents the first space mission specifically designed to study dark energy.
Mapping the Expansion of the Universe
In 1998, astronomers mapping the expansion of the universe expected to see it slowing down due to the gravity of all its constituents.
They discovered the expansion of space. Also the expansion of everything in it began speeding up 5 to 6 billion years ago. Scientists named the force driving the acceleration as dark energy.
Researchers have since concluded dark energy accounts for nearly three quarters of the mass-energy budget of the entire universe. Dark matter makes up about 24% of the universe, while the atoms and molecules making up normal matter — Earth, human beings, stars and galaxies — account for just 5%.
By studying subtle changes in the light from galaxies over the past 10 billion years, Euclid’s cameras will help scientists find out if dark energy is consistent with an unchanging “cosmological constant” once predicted by Einstein’s theory of general relativity or whether the current understanding of gravity needs revision.
Yannick Mellier, an astronomer at the Institut d’Astrophysique de Paris and a member of the Euclid science team, said it this way:
“The objective of the Euclid mission is to provide answers to the following questions: why is expansion of the universe accelerating, which translates into what is the nature of dark energy? Is it a cosmological constant? Is it a dynamical dark energy with properties that may vary with time? Or it is a deviation to general relativity on cosmological scales?”