ESA’s Euclid probe successfully launched: it aims to “make the invisible visible”

It’s the big, influential unknowns in space: dark matter and dark energy. The European space probe Euclides must now take a major step forward in research into these two phenomena, about which almost nothing is known until now.

The plane of the European space agency ESA took off on Saturday from the American spaceport Cape Canaveral aboard a Falcon 9 rocket from the American company SpaceX.

Less than an hour later, the probe sent its first signal from space. “Euclid is on track to reveal the cosmic mystery of dark matter and dark energy,” ESA wrote on Twitter. “The mood here is very, very good,” says ESA Director General Josef Aschbacher.

Dark matter and dark energy together form an extremely large part of the universe. All other known components – stars, planets, our Milky Way, other galaxies – only make up about five percent, as Giuseppe Racca, ESA’s program manager for Euclid, previously explained. “Cosmology is in a situation that could be described as an embarrassment.”

Dark matter and dark energy are determining factors in space. In the universe, astrophysicist David Elbaz explained, there is more gravity than would be assumed based on the visible parts. “The sun is spinning around the center of the Milky Way at such a speed that it should be breaking out of the galaxy. And if it doesn’t break out, that means it’s being attracted to some other mass that we don’t see.” That’s the dark matter. Dark energy, on the other hand, describes a kind of anti-gravity that makes galaxies appear to repel each other. Both are extremely difficult to research.

Euclid should now bring some light into the darkness. “Making the invisible visible”, astrophysicist Elbaz summarizes the core of the mission. At the heart of the probe, which is about 4.7 meters long, 3.5 meters wide and weighs just under two tons, is a high-resolution telescope. It is equipped with two cameras – one for the visible wavelength range and one for the near-infrared range.

With the telescope, ESA wants to take a look at the past of the universe and its development over the past ten billion years. Also try to make a 3D map where time is the third dimension. In total, data on billions of galaxies must be collected.

Researchers hope the mission will show how the universe has expanded and how individual structures have emerged. From this they want to draw conclusions about dark matter and dark energy and also understand how dark matter and gravity are related.

First of all, the mission of about 1.4 billion euros, involving more than 20 countries, is planned for six years. Euclid will fly about 1.5 million kilometers into space. It will take about a month for the probe to get there. A few more tests will follow before the mission starts its actual work in the autumn and must provide the first images.

Swiss research institutes are also significantly involved in the mission. These include the University of Zurich (UZH), the University of Applied Sciences Northwest Switzerland (FHNW), the Swiss Federal Institute of Technology in Lausanne (EPFL), and the University of Geneva (UNIGE).

For example, parts of the measuring device Visible Instrument have been developed in Switzerland. This is a high resolution camera that detects visible light in space.

But Swiss institutions are also involved in the field of software: The FHNW has contributed the software infrastructure that enables the management and distribution of large amounts of space data via a global data network.

The information collected by Euclid could be of great use to research. Racca, Euclid’s program manager, expects more data on extragalactic astronomy in the mission’s first year than has been obtained from any other comparable mission to date. “I expect Euclid to flood the scientific community with an unprecedented, massive amount of data.”

Astrophysicist Elbaz believes that about a year and a half after the launch of Euclid, a better understanding of dark matter can be obtained for the first time. But what the mission will yield in terms of findings in the long term cannot be foreseen. “Knowing today what the impact will be of our better understanding of physics and of what Euclid will tell us (…) is impossible.”

(sda/afp/dpa)