by For now, Europe’s Euclid spacecraft sits quietly in a sterilized room in southern France, its gold trim gleaming in the neon lights.
But in a few months, the space telescope will embark on the first mission in history, looking for two of the universe’s greatest mysteries: dark matter and dark energy.
Despite making up 95 percent of the universe together, almost nothing is known about either one – a glaring hole in scientific understanding that Euclid project manager Giuseppe Racca called a “cosmic embarrassment”.
Aiming to shed light on these dark mysteries, the European Space Agency’s mission will draw a 3D map of the Universe, spanning two billion galaxies across more than a third of the sky.
The third dimension of this map will be time – as Euclid’s gaze will extend to a distance of 10 billion light-years, it will offer new insights into the evolution of the 13.8 billion-year-old Universe.
The two-ton spacecraft, which is 4.7 meters (15 feet) high and 3.5 meters (11 feet) wide, was unveiled to the media for the first time this week in a clean room at Thales Alenia Space in the southeastern French city of Cannes.
Few final tests remain before heading to Cape Canaveral in the United States for a launch scheduled between July 1 and July 30 on a SpaceX Falcon 9 rocket.
Euclid was originally slated to fly into space on a Russian Soyuz rocket, but last year Moscow withdrew its launchers in response to European sanctions over its invasion of Ukraine, delaying launches.
– think outside the box –
Euclid will join fellow space telescope James Webb at a stable, floating point about 1.5 million kilometers from Earth, dubbed the second Lagrange point, where it can keep its solar-panel-covered spine permanently facing the Sun.
The first images are expected to arrive quickly once scientific operations begin in October, but larger discoveries will likely take months or years for scientists to sift through the “unprecedented amount of data,” Racca said.
The €1.4 billion ($1.5 billion) European mission is set to last until 2029, although “if nothing strange happens” it could be extended for a few more years, Racca told a news conference.
How will Euclid, named after the ancient Greek founder of geometry, observe something that cannot be seen? By searching for his absence.
Coming from the past billions of years ago, the light is slightly distorted by the mass of visible and dark matter in its path, a phenomenon known as weak gravitational lensing.
“By subtracting the visible matter, we can calculate the presence of the dark matter that’s in between,” Racca said.
To do this, Euclid has two main instruments, a 1.2-meter (4-foot) diameter telescope and the near-infrared spectrometer and photometer (NISP), which can split infrared wavelengths invisible to the eye.
– ‘Unique Tool’ –
Part of what sets Euclid apart from other space telescopes is its field of view, which occupies an area equivalent to “two full moons,” said David Elbaz, an astrophysicist at France’s Atomic Energy Commission.
This wide view will allow Euclid to locate massive structures like black holes, which the Webb telescope can’t find because its “field of view is too small,” Euclid’s project scientist Rene Laureijs told AFP.
But Euclid’s universe-spanning survey may point Webb in the right direction for a closer look, said Laureijs, who has been working on the project since the proposal phase in 2007.
The mission comes amid mounting evidence that there are some serious inconsistencies in our understanding of how the universe works.
Two very accurate measurements give two distinctly different answers about the rate at which the universe is expanding – a problem called the Hubble voltage, in which dark energy is believed to play an important role.
And just this week, the Webb telescope discovered six galaxies in the early Universe that appear to defy cosmological theory because they are far too massive to have formed so quickly after the Big Bang.
Euclid will be a “unique tool” in finding answers to such questions, Elbaz said.
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