On Thursday (May 23), the European Space Agency (ESA) and its collaborators released a set of five images constructed by its groundbreaking Euclid Space Telescope. The Euclid consortium previously released five images from the space telescope on November 7, 2023.
Euclid has been dubbed Europe’s “dark space detective” because its wide field of view allows it to track billions of galaxies over 10 billion years of cosmic history, allowing astronomers to use tools that can reveal more about two mysterious elements of our cosmos: dark energy and dark matter. mass.
Even before he began working to gather scientific data to unravel the mysteries of dark energy and dark matter, collectively known as the “dark universe,” Euclid demonstrated his potential with these two incredible sets of images.
So Space.com asked several scientists in various fields to explain which of Euclid’s images from the two versions is their favorite and why.
Related: The ‘dark space detective’ Euclidean telescope has revealed new images of the universe – and they’re remarkable
But first, dark space 101
Dark energy is a shorthand name for the force accelerating the expansion of the universe and pushing galaxies apart ever faster. Looking at galaxies that existed when the 13.8-billion-year-old universe was only about 4 billion years old could reveal how this force has evolved over time and help determine its true nature.
Dark matter, on the other hand, is a form in the universe that is virtually invisible because it does not interact with light. This means that it cannot be composed of the particles that make up “ordinary” matter. However, because it has a gravitational influence, the dark matter halo has influenced 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 crack the case for how dark matter affected galactic evolution.
Dark energy accounts for about 67% of the energy and matter budget of the universe, while dark matter accounts for about 27%. This means that the “dark universe” together makes up about 95% of the universe’s contents, with stars, planets, the moon, humans, cats, and the rest of the everyday “things” we understand (maybe not cats, to be fair). for only 5% of the universe. This makes “dark space” a big deal, to put it mildly.
Euclid takes a walk on the dark side
Luz Ángela García Peñaloza is a cosmologist at Universidad ECCI in Colombia who studies the mystery of dark energy and its influence on the evolution of the universe. This means that she followed the development of Euclid with great interest.
“Euclid observes the universe in a completely new way and generates a gigantic census of galaxies. I personally find it fascinating how beautiful these first photos look, as well as all the amazing information they reveal,” García Peñaloza told Space.com. “When I saw the pictures, I had to take a deep breath because of their beauty and because of their high resolution.
When García Peñaloza was asked to choose his favorite image from the Euclid issue, he chose one of the galaxy cluster Abell 2390 (below).
“It’s just breathtaking,” she said. “Any image that reveals information about the distribution of galaxies in the large-scale structure of the universe will provide several insights into the nature of the ‘dark side’ of the universe.”
Italian astrophysicist Andrea Botteon of the Istituto di Radioastronomia: IRA (INAF-IRA) also chose the Abell 2390 image as his favorite of the new Euclid set.
“As an astrophysicist working on galaxy clusters, I can tell you that my favorite image from the new release is Abell 2390,” Botteon said. “Along with the previously published image of the Perseus cluster [below]shows the ability of Euclid to recover the very low surface brightness emission from galaxies and especially the light inside the cluster!”
Amateur astronomer Giuseppe Donatiello discovered 11 galaxies in astronomical survey data, nine of which are named after him, cementing his place in astronomy textbooks. He explained that each expert would choose a different picture from Euclid as their favorite based on their area of study. He definitely has the best selection himself and comes from the November 2023 batch of images from Euclid.
“As a fan of the Local Group and dwarf galaxies in the Local Universe, I was impressed by the detail in NGC 6822,” Donatiello told Space.com. “I have looked at images of that galaxy taken by all the most powerful ground-based instruments, but the detail and depth of the Euclid is at a much higher level. The clusters, nebulae and [globular clusters] are easily recognizable in Euclid’s picture instead of blurred details. I was lost in that field of vision for hours!”
Donatiello also selected his favorite image from the latest editions of Euclid.
“Of the new ones, NGC 6744 is the most interesting to me because of the fine detail in the galaxy’s spiral arms,” Donatiello continued. “I also do work that deals with stellar streams [stars and gas pulled from their galaxies by tidal forces]and the Euclidean images contain information about the stellar streams that I just can’t get from the lower resolution images. I hope the first public release of the data [DR1] from Euclid is just as applicable as data from other deep surveys.
“If that’s the case, I’ll have fun!”
David Kipping is an assistant professor of astronomy at Columbia University who investigates the existence of moons around planets outside the solar system. He also chose an image from a previous issue as his favorite Euclidean image.
“These are beautiful images that really show an impressive field of view. The Horsehead Nebula has to be my favorite!” Kipping told Space.com. “Of course, these images are mostly for public consumption rather than science, so I’m particularly looking forward to the first scientific results.”
This new set of images and the previous set are part of Euclid’s Early Release Observations and were collected before February 14, 2023, when the space telescope began major science operations. Both sets of spectacular images therefore 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 while these new images and the previous set show that Euclid lives up to expectations, the space telescope still has a lot to offer.
“This is just the beginning of what we will be able to see during Euclid’s lifetime,” concluded García Peñaloza. “I am confident that Euclid will clarify our understanding of many cosmic mysteries. The best of Euclid is yet to come!”