On Thursday, May 23, the European Space Agency (ESA) and its collaborators released a series of five images constructed by its revolutionary Euclid space telescope. The Euclid consortium previously released five images from the space telescope on November 7, 2023.
Euclid has been nicknamed Europe’s “dark universe detective” because his wide field of view allows him to track billions of galaxies across 10 billion years of cosmic history, providing astronomers with tools that can reveal more about two mysterious elements of our cosmos: dark energy and dark matter.
Before even getting to work on collecting scientific data to unravel the mysteries of dark energy and dark matter, collectively called the “dark universe,” Euclid demonstrated his potential with these two incredible sets of images.
As such, Space.com asked several scientists from different fields to explain which of the images of Euclid from both versions are their favorites so far, and why.
Related: Euclid’s Dark Universe Detective Telescope has revealed new images of the cosmos – and they are remarkable
But first, dark universe 101
Dark energy is the name given to the force that accelerates the expansion of the universe, pushing galaxies away from each other faster and faster. Examining galaxies that existed when the 13.8 billion-year-old universe was only 4 billion years old could reveal how this force evolved over time, helping to determine its true nature.
Dark matter, on the other hand, is a form of the universe that is practically invisible because it does not interact with light. This means that it cannot be composed of the particles that constitute “ordinary” matter. However, because they have a gravitational influence, dark matter halos have affected the development of the largest structures in the universe. Euclid’s field of view is wide enough to capture these structures in a single image, meaning it could help understand how dark matter influenced galactic evolution.
Dark energy makes up about 67% of the universe’s energy and matter budget, while dark matter makes up about 27%. This means that the “dark universe” collectively makes up about 95% of the contents of the universe, with stars, planets, the moon, humans, cats, and the rest of the everyday “stuff” that we understand (maybe). not be the cats, to be fair) accountants. for only 5% of the universe. This makes the “dark universe” a big deal, to put it lightly.
Euclid takes a walk on the dark side
Luz Ángela García Peñaloza is a cosmologist at ECCI University of Colombia who studies the mystery of dark energy and its influence on cosmic evolution. This means that she follows Euclid’s development with great interest.
“Euclid is observing the universe in a whole new way, and it will generate a gigantic census of galaxies. Personally, I find the beauty of these first photos fascinating, as well as all the astonishing information they will reveal.” García Peñaloza told Space.com. “I had to take a deep breath when I saw the images because of their beauty and high resolution.”
When asked to choose his favorite image among Euclid’s images, García Peñaloza selected that of the galaxy cluster Abell 2390 (below).
“It’s just breathtaking,” she said. “Any image revealing information about the distribution of galaxies in the large-scale structure of the universe will provide a handful of insights into the nature of the ‘dark side’ of the cosmos.”
Italian astrophysicist Andrea Botteon of the Istituto di Radioastronomia: IRA (INAF-IRA) also selected the Abell 2390 image as his favorite from the new Euclid set.
“As an astrophysicist working on galaxy clusters, I can tell you that my favorite from the new release is the image of Abell 2390,” Botteon said. “Together with the previously published image of the Perseus Cluster (below), it shows Euclid’s ability to recover the very low surface brightness of galaxies and in particular the intra-cluster light!”
Amateur astronomer Giuseppe Donatiello discovered 11 galaxies in astronomical survey data, nine of which bear his name, cementing his place in astronomy textbooks. He explained that each expert will choose a different image of Euclid as their favorite depending on their field of study. He certainly has a top pick himself, and it comes from Euclid’s November 2023 image batch.
“As a fan of the Local Group and dwarf galaxies in the local universe, I was impressed by the details of NGC 6822,” Donatiello told Space.com. “I have seen images of this galaxy taken with all the most powerful ground-based instruments, but the detail and depth of Euclid is at a much higher level. The clusters, nebulae and (globular clusters) are easily recognizable in the image of Euclid of blurred details. I got lost in this field of vision for hours!
Donatiello also selected his favorite image from Euclid’s latest releases.
“Among the new ones, the most interesting for me is NGC 6744 because of the fine details of the galaxy’s spiral arms,” Donatiello continued. “I also do work on stellar fluxes (stars and gas being pulled out of their galaxies by tidal forces), and the Euclid images contain information about stellar fluxes that I simply can’t get in conventional low-resolution images I hope the first public data will be released (DR1) from Euclid is as usable as data from other extensive surveys.
“If so, I’ll have fun!”
David Kipping is an assistant professor of astronomy at Columbia University who studies the existence of moons around planets outside the solar system. He also chose an image from the previous version as his favorite Euclid photo so far.
“These are stunning images that really show off the impressive field of view. The Horsehead Nebula has to be my favorite!” Kipping told Space.com. “Of course, these images are mainly intended for the public rather than for science, which is why I am particularly looking forward to seeing the first scientific results.”
This new series of images and the previous one are among the first observations of Euclid and were collected before February 14, 2023, when the space telescope began its main scientific operations. So the two sets of spectacular images represent only a tiny fraction of the observations the telescope will make over the next six years during its primary mission.
García Peñaloza said that although these new and previous images show that Euclid meets expectations, the space telescope still has much to offer.
“This is only the beginning of what we will be able to see during Euclid’s lifetime,” concluded García Peñaloza. “I am sure that Euclid will enlighten us on many cosmic mysteries. The best is yet to come from Euclid!”