The European Euclid Space Telescope is due to lift off on Saturday to try to shed light on one of science’s biggest mysteries: dark matter and energy, which makes up 95% of the universe but about which almost nothing is known, reports said. AFP.

The satellite should take off from Cape Canaveral in Florida at 11.12 local time (18.12 in Romania) aboard the Falcon 9 rocket of the American company SpaceX.

The two-ton telescope will be placed at a distance of 1.5 million kilometers from Earth.

Euclid, named after the father of geometry, “will be the first space mission to study the properties of dark energy,” Michael Seifert, chief scientist at NASA, which is participating in the European Space Agency (ESA) mission, told AFP.

Dark matter makes up 25% of the universe

Within six years, the probe will compile a three-dimensional map of the universe that will encompass approximately two billion galaxies and cover a third of the sky. The observed distant galaxies will allow us to travel in time as much as 10 billion years – that’s how long it took their light to reach us.

The vast amount of data collected will be made public so that the scientific community can take full advantage of it, following the approximately 2,600 researchers from 15 countries who are members of the Euclid consortium.

Dark matter (25% of the universe) and dark energy (70%) have opposite effects: while dark matter pulls cosmic objects together, dark energy causes them to disperse.

It is known that dark matter exists due to a mysterious fact: it is impossible to explain how a galaxy or a group of galaxies does not disperse, taking into account only the gravitational force of their visible elements (planets, stars, etc.).

“We have to assume that there is an additional amount of matter, invisible to our telescopes, as a gravitational component that holds everything together,” explains Michael Seifert. This cosmic “cement” has been called dark matter.

Dark energy, a great mystery

Never observed directly, according to some hypotheses, these could be subatomic particles. Dark energy is perhaps even more mysterious.

From the discoveries of the famous astronomer Edwin Hubble in the 1920s, it became known that the universe is expanding. And since the 1990s, this expansion has been accelerating.

This “means that on very large scales, gravity actually has a repulsive component that pushes things outward,” Seifert explains. This force is known as dark energy, “the great mystery of physics.”

The lack of knowledge about these two dark components was called an “awkward situation” by ESA’s Euclid mission chief Giuseppe Rakka.

What will the Euclid telescope do?

However, the purpose of the satellite is not to determine their nature (that is too ambitious), but to better understand their properties and how they act and evolve over time.

Thanks to the 3D map, the telescope will be able to make accurate measurements of the distribution of galaxies and the expansion of the Universe.

“From these observations, dark matter and dark energy will be deduced ‘indirectly’,” explained Giuseppe Racca. Dark matter can be calculated by ‘subtracting’ visible matter.

Regarding dark energy, David Elbaz, an astrophysicist at the French Atomic Energy Commission (CEA) and a member of the Euclid collaboration, draws a balloon parallel: dark energy is the breath that inflates the balloon. Therefore, watching the balloon expand will be very instructive.

It is believed that the accelerated expansion of the universe began six billion years ago. Going back 10 billion years, Euclid could see the first effects of dark energy.

All this data may also provide new clues about the fate of the universe. The theory of the “Big Crisis” (compression of the universe into itself) was weakened after the discovery of the accelerated expansion of the universe.

But how it continues to expand—perhaps over several tens of billions of years, until it pushes planets away from the Sun or even shatters atoms—will depend on the properties of dark energy, which Euclid should help measure, notes Michael Seifert.

The telescope is equipped with two instruments: a visible light camera (VIS) and an infrared spectrometer (NISP).

It just needs to deploy its antenna in flight and should be up and running in about three months. The European mission, which costs 1.5 billion euros, will last until at least 2029.

NASA also plans to launch a mission dedicated to studying dark matter, the Nancy Grace Rome Space Telescope, in the coming years. (News.ro)