European space telescope aims to solve the mystery of the ‘dark universe’

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The European Space Agency is set to launch a €1.4bn space telescope to map the billions of galaxies across the cosmos, providing vital clues for scientists trying to unravel the mystery of the “dark universe”.

The Euclid mission, the culmination of nearly 20 years of development, will travel 1.5mn km through space. From there, the telescope’s highly precise observational technology will map the past 10 billion years of cosmic history, helping experts identify the dark energy and matter they believe dominates the known universe.

The consensus view among cosmologists is that all visible matter known to scientists, from galaxies to subatomic particles, makes up only 5 percent of the mass and energy in the entire universe.

Dark energy, which makes up 70 percent, appears to be a property of the galaxy itself, expanding the cosmos at an increasing rate. Opposing this is the gravitational pull of dark matter, which accounts for 25 percent and has mass but no other measurable properties.

“There are hundreds of models for what dark matter and dark energy could be but we have no idea which one might represent reality,” said Adam Amara, director of the University of Portsmouth’s Institute of Cosmology and Gravitation, and an early proponent of the Euclid mission.

“In 2005 a small group of us proposed a space telescope to investigate the dark universe. Now, close to 3,000 people have worked together to make this dream a reality,” he said of Saturday’s planned launch.

Euclid — named after the ancient Greek mathematician considered the father of geometry — was originally slated for launch on a Russian Soyuz rocket but the plan fell victim to a breakdown in relations following the country’s widespread invasion of Ukraine.

Instead, a Falcon 9 from Elon Musk’s SpaceX will carry the 2-ton observatory into orbit from Cape Canaveral in Florida. Finding another launcher and reconfiguring the spacecraft delayed the mission for about a year.

In about a month, Euclid will reach its destination, the “second Lagrange point” 1.5mn km away, where the satellite’s orbital motion exactly balances the gravity from the Sun and Earth, so it appears to fly in the same place in space The James Webb Space Telescope is located near this point.

There it will spend six years mapping the universe by observing galaxies up to 10bn light-years away in the 36 percent of the sky not obscured by stars and dust in Earth’s own Milky Way galaxy.

“We will be able to reconstruct the cosmic history of the universe over the last 10bn years,” said Euclid consortium leader Yannick Mellier of the Institut d’Astrophysique de Paris.

Changes in the motion and distribution of galaxies and the way they cluster together will reflect the influence of the dark universe. Dark matter tends to pull galaxies by the force of gravity, while dark energy pushes them as it accelerates the expansion of the universe.

Two cameras are attached to Euclid’s 1.2 meter telescope. One, led by scientists in the UK, records visible light. Another, led by French researchers, operates in the near-infrared spectrum.

Mark Cropper of University College London has led the design and development of the visible camera for 16 years.

“The instrument will image a large part of the distant universe with nearly as good a resolution as the Hubble Space Telescope, which observes more of the universe in a day than Hubble. [has done] for 25 years,” he said. “The universe at this scale is invisible at this level of detail.”

Whether an intrinsic property of empty space, a “vacuum energy” of virtual particles as predicted by some quantum physicists or a previously unknown energy field, scientists hope that the telescope’s images will help identify dark energy. Their findings may offer evidence for a fundamental modification of Einstein’s theory of gravity.

Possible explanations for dark matter are also varied, Amara said. Candidates range from tiny particles that interact with ordinary matter only through their gravitational force, to black holes formed shortly after the Big Bang that are still spreading through the universe.

Amara doesn’t think dark matter has a single simple explanation. “If you think about all the ordinary matter in the universe, it takes an incredibly rich and complex diversity of forms,” ​​he said. “There could be equally diverse universes of dark matter out there.”

Although Euclid is the first observatory dedicated to studying the dark universe, it will be joined in space in 2027 by a US counterpart called the Nancy Grace Roman Telescope, which will use similar techniques to examine a more small part of the sky in greater depth and accuracy. .