Launch of the European space telescope Euclid to explore the “dark universe”

By Steve Gorman

(Reuters) – A SpaceX rocket in Florida was set to launch on Saturday, carrying an orbiting telescope built to shed light on mysterious cosmic phenomena known as dark energy and dark matter, unseen forces that , according to scientists, make up 95% of the known universe.

The telescope dubbed Euclid, a European Space Agency (ESA) instrument named after the ancient Greek mathematician called the ‘father of geometry’, has been bundled inside the payload bay of a ready Falcon 9 rocket to take off around 11 a.m. EDT (1500 GMT). ) from Cape Canaveral Space Force Station.

The new insights from the $1.4 billion mission, designed to last at least six years, are expected to transform astrophysics and perhaps the understanding of the very nature of gravity itself.

If all goes as planned, Euclid will be released after a short trip into space for a month-long trip to its destination in solar orbit nearly 1 million miles (1.6 million km) from Earth. – a position of gravitational stability between the Earth and the sun called the Lagrange point two, or L2.

From there, Euclid is designed to explore the evolution of what astrophysicists call the “dark universe”, using a wide-angle telescope to study galaxies as far away as 10 billion light-years from Earth. across a huge expanse of sky beyond our own Milky Way galaxy.

The 2-ton spacecraft is also equipped with instruments designed to measure the intensity and spectra of infrared light from these galaxies in a way that will accurately determine their distances.

The mission focuses on two fundamental components of the Dark Universe. One is dark matter, the invisible but theoretically influential cosmic scaffold believed to give shape and texture to the cosmos. The other is dark energy, an equally enigmatic force believed to explain why the expansion of the universe, as scientists learned in the 1990s, has been accelerating for a long time.

The possibilities of the mission are reflected in the enormity of Euclid’s investigation. Scientists estimate that dark energy and dark matter together make up 95% of the cosmos, while the ordinary matter we can see only makes up 5%.


Euclid was entirely designed and built by ESA, the American space agency NASA providing photodetectors for its near-infrared instrument. The Euclid Consortium globally includes more than 2,000 scientists from 13 European countries, the United States, Canada and Japan.

A decade in the making, the mission was originally supposed to have flown into space using a Russian Soyuz rocket. But launch plans were transferred to SpaceX, Elon Musk’s California-based company, after war broke out in Ukraine, and because no slots were immediately available in Europe’s Arianne rocket program.

While the James Webb Space Telescope launched by NASA late last year allows astronomers to focus on particular objects in the early universe with unprecedented clarity, Euclid is intended to expose the fabric and mechanics hidden from the cosmos by meticulously mapping a huge swath of the observable. 3-D universe, over 1 billion galaxies in all.

Dark matter and dark energy can’t be detected directly, but their properties “are encoded in the shapes and positions of galaxies,” said astrophysicist Jason Rhodes, lead scientist for Euclid at NASA’s Jet Propulsion Laboratory. near Los Angeles.

“Measuring the shapes and positions of galaxies allows us to infer the properties of dark matter and dark energy,” Rhodes said on Friday.

The data will be collected as Euclid maps the last 10 billion years of cosmic history across a third of the sky, looking outward, and therefore stretching back in time, to an era in the universe that astronomers call “cosmic noon”, when most stars were forming.

Observing subtle but distinct changes in the shapes and positions of galaxies over vast stretches of time and space will reveal fine variations in cosmic acceleration, indirectly exposing dark energy forces, scientists say.

Euclid will also help reveal the nature of dark matter by measuring an effect called gravitational lensing, which produces small distortions in the visible shapes of galaxies and is attributed to the presence of invisible materials warping the fabric of space around it. .

With knowledge of dark energy and matter, scientists hope to better understand the formation and distribution of galaxies across the so-called cosmic web of the universe.

Beyond Euclid’s primary goals, it will provide “a gold mine for all areas of astronomy for several decades to come,” said Yannick Mellier, head of the Euclid Consortium and astronomer at the Institut d’Astrophysique de Paris. Paris.

(Reporting by Steve Gorman in Los Angeles; Editing by William Mallard)

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