The European space telescope Euclid, whose mission is to study dark matter and dark energy in the Universe, reached its observation post and delivered its first test images on Monday, July 31, taken to check the functioning of instruments and calibrate them. They are therefore not representative of the telescope’s final capabilities, but already show that it will be able to fulfill its objectives, the European Space Agency (ESA) said in a press release. Scientific operations of the telescope are due to begin in about two months.
“After more than eleven years designing and developing Euclid, it is exhilarating and very moving to see these first images,” said Giuseppe Racca, Euclid Mission Manager at ESA. Once fully calibrated, Euclid will observe billions of galaxies, to create the largest 3D map of the sky ever made. »
After taking off from Florida on July 1, the European telescope, in which NASA also participated, traveled to its destination, located about 1.5 million kilometers from Earth. Euclid has two onboard instruments: a Visible Light Observing Imager (VIS) and a Near Infrared Observing Spectrometer (NISP). The first must determine the precise shape of the galaxies, the second their distance.
Infiltrated light
But when these instruments were turned on, the scientists had a big scare: the images were “contaminated” by an unexpected light source, the ESA said. Research carried out to detect the problem showed that “sunlight was leaking into the craft, probably through a small opening”, explained the European agency. However, to detect the faint light of distant galaxies, the bright light of our Sun (to which Euclid has its back) must absolutely be neutralized. “By turning Euclid, the teams understood that this light was only detected at certain orientations, so by avoiding certain angles the VIS instrument will be able to carry out its mission,” assured ESA.
Dark matter and dark energy make up 95% of the Universe, but their nature remains a great mystery to scientists. Dark matter would ensure the cohesion of galaxies and galactic clusters thanks to its gravitational influence, while dark energy is responsible for accelerating the expansion of the Universe.
The telescope will allow precise measurements concerning the distribution of galaxies and the expansion of the Universe. The distant galaxies observed will allow us to go back in time up to 10 billion years – the time needed for their light to reach us. The hope is that Euclid will be able to detect the traces left by dark matter and dark energy as galaxies form.
