When scientists peer into the universe with their powerful telescopes, they can only observe a tiny proportion of its composition. Not because of its enormous dimensions, but because its visible part is only 5%. The remaining 95% is what is called dark matter and energy. To investigate this part that is only known for the effects it has on what we can see – for example, it affects the movements of celestial bodies – the European Space Agency (ESA) launched last month July the ‘Euclid’ mission, which will create the largest and most precise 3D map of the universe. This Tuesday the first results arrived. “Dark energy and matter are some of the biggest enigmas of modern physics and it is exciting to think that we are one step closer to understanding their nature thanks to the high-quality images that Euclid is providing,” says Raúl Angulo, researcher at the Donostia International Physics Center (DIPC), center that participates in the project.
These are five high-resolution images that have never been captured before, due to their sharpness and because they cover such a distant distance, up to 10,000 million light years. All celestial objects can be observed in them, from bright stars to faint galaxies. Experts consider them an invaluable source to better understand how galaxies form and evolve throughout the history of our universe. «In a single image we can see thousands of galaxies in exquisite detail. With them, we can test various ideas about how stars and black holes interacted over billions of years,” says Silvia Bonoli, researcher at the aforementioned DIPC.
After taking off last July aboard a SpaceX Falcon 9 rocket from the Cape Canaveral Space Force Station in Florida, the ‘Euclid’ has traveled for a month to reach its destination, 1.5 million kilometers from the Earth. The mission will last for the next six years and has involved an investment of more than 1.4 billion euros over more than a decade. More than 300 institutions from 21 countries are involved in the project, as well as 80 companies (nine of them Spanish) and a total of 3,500 people.
THE FIVE IMAGES
ESA experts say that this image is a revolution for astronomy. It shows 1,000 galaxies belonging to the Perseus cluster and more than 100,000 additional galaxies even further away in the background. Many of these faint galaxies have not been observed before. Some of them are so distant that their light has taken 10 billion years to reach us. By mapping the distribution and shapes of these galaxies, experts will be able to discover more about how dark matter shaped the universe we see today.
Over its lifetime, the telescope will image billions of galaxies, revealing the hidden influence that dark matter and energy have on them. Hence IC 342 or Caldwell 5, one of the first that has been observed, receives the nickname ‘Hidden Galaxy’. The reason it is difficult to observe is because of its location, as it lies behind the busy disk of our Milky Way, so dust, gas and stars obscure our view.
Most galaxies in the early universe, formed about 10 billion years ago, are irregular and small, and are the building blocks of larger galaxies like our own. It is still possible to find some of them relatively close to Earth. This is the case of NGC 6822, located 1.6 million light years from our planet.
Globular cluster NGC 6397
Globular clusters are collections of hundreds of thousands of stars held together by gravity. Located about 7,800 light years from Earth, NGC 6397 is the second closest to us. Together with other globular clusters it orbits in the disk of the Milky Way, where most of the stars are located. Globular clusters are some of the oldest objects in the Universe. That is why they contain many clues about the history and evolution of their host galaxies, such as this one in the Milky Way.
The Horsehead Nebula
Also known as Barnard 33, this nebula is 1.375 million light years away and is part of the Orion constellation. It is the closest giant star forming region to Earth. It lies just south of the star Alnitak, the easternmost star of Orion’s famous three-star belt, and is part of the vast Orion molecular cloud. It took only an hour for the telescope to capture this image.