The European Space Agency (ESA) will release five new images from the Euclid Space Telescope today (May 23). And if the previous images are anything to go by, space fans are in for a treat.
“During Euclid’s early observation phase, five new portraits of our cosmos were captured, each providing astonishing new insights,” ESA officials said in a statement. “Euclid’s ability to unlock the mysteries of the cosmos is not to be missed.”
The new images will be unveiled at 5:00 a.m. EDT (12:00 p.m. CEST) and will be accompanied by an incredible 10 scientific papers. You can watch the data release live on ESA’s YouTube channel.
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As a foretaste of this occasion, we may recall the incredible cosmic images this mission has delivered so far.
Euclid’s history so far
Euclid is a wide-field space telescope launched on July 1, 2023, from Cape Canaveral, Florida, atop a SpaceX Falcon 9 rocket. It has a 600-megapixel camera that observes the cosmos in visible light, a near-infrared spectrometer, and a photometer is used to determine the redshift of galaxies. Knowing redshift allows scientists to figure out how fast distant galaxies are moving away from our planet.
Euclid’s main task is to study the two most mysterious elements of the universe: dark energy and dark matter. Together, these phenomena form what is often referred to as the “dark universe.”
Dark energy is the placeholder name for the force that is accelerating the expansion of the universe. Dark matter, on the other hand, is a form of matter that is virtually invisible because it doesn’t interact with light. This means that scientists know that stars, planets, moons, and our bodies aren’t made of “ordinary” matter, which consists of electrons, protons, and neutrons. Dark matter can only make its presence known through its interactions with gravity, which in turn can affect ordinary matter and light. To be clear, neither dark matter nor dark energy are necessarily made of a single material. Both can be made of many things—or perhaps they are actually each made of one homogeneous thing.
The point is, we just don’t know.
Still, dark energy is thought to make up about 68% of the universe’s energy and matter budget, while dark matter makes up about 27%. This means that the dark universe makes up 95% of the things in the universe, and things we actually understand make up only about 5%.
Euclid, dubbed the “dark universe detective” because of his special tools, clearly has his hands full. But the space telescope’s first official images, released on November 7, 2023, after its first four months in space, certainly showed it was up to the task.
Directly above is one of the first images the public saw from the Euclid Telescope. It’s a snapshot showing about 1,000 galaxies, all belonging to the Perseus cluster. Located about 240 million light-years from Earth, this cluster is one of the largest structures in the known universe.
Mapping galaxies in such large volumes is key to understanding the distribution of dark matter and how this distribution has influenced the evolution of the universe.
In addition to the abundance of galaxies in the Perseus Cluster, the image also reveals another 100,000 galaxies much more distant, each containing up to hundreds of billions of stars. Observations of distant galaxies in large numbers like this one are crucial for Euclid to decipher how dark energy is pushing these galaxies away at an ever faster rate by accelerating the expansion of space between them.
Just because Euclid has distant galaxies in its sights doesn’t mean it can’t also impress with images of individual galaxies.
Another of the first Euclid images we saw was somewhat ironic for an instrument tasked with revealing dark elements of the universe. That’s because it identified the galaxy IC 342, also known as the “Hidden Galaxy.”
Located about 11 million light-years from Earth, this galaxy is difficult to image because it lies behind the bright, dusty disk of the Milky Way. However, that didn’t stop Euclid from capturing an incredible image of this once-hidden spiral galaxy. For this purpose, the space telescope used its near-infrared instrument, which is advantageous because the gas and dust of the Milky Way disk are less effective at absorbing infrared light compared to other wavelengths of electromagnetic radiation.
To unlock the mysteries of the dark universe and create a detailed 3D map of the cosmos, Euclid must view galaxies up to 10 billion light-years away by seeing the 13.8 billion-year-old universe as it appears less than 4 billion years after the Big Bang.
These galaxies are unlikely to have the neat, spiral arrangement of the Milky Way or even the Hidden Galaxy. Most galaxies in the early Universe are “lumpy,” poorly formed, irregular galaxies that served as building blocks for larger galaxies.
To prepare for observing these distant and early galaxies, Euclid’s first images also included a look at the closer irregular galaxy NGC 6822, which lies just 1.6 million light-years from Earth.
Although they offer us spectacularly scintillating images, Euclid will not only focus on galaxies during his mission.
As the image of NGC 6397 above shows, the space telescope will also observe globular clusters. And luckily, globular clusters are just as beautiful. These are collections of hundreds of thousands of stars bound together by gravity and are among the oldest structures in the known universe.
NGC 6397 is the second closest globular cluster to Earth, at a distance of only about 7,800 light years. Globular clusters like NGC 6397 orbit the disk of the Milky Way and may contain clues about the evolution of our galaxy or at least other galaxies in which such structures are found.
Euclid is ideal for studying globular clusters because, unlike other telescopes, it has a field of view large enough to capture entire globular clusters in one image, as was the case with NGC 6397.
Much of Euclid’s mission will focus on the unknown, but the final image from the first series of Euclid releases actually showed us a familiar celestial object in a completely new light. The detective of the dark universe managed to create a stunningly detailed panoramic image of the Horsehead Nebula, also known as Barnard 33.
Located about 1,380 light-years from Earth and close to the east of Orion’s Belt, the Horsehead Nebula is one of the closest star-forming clouds of gas and dust to the Solar System. It’s also a real feast for the eyes.
Although numerous telescopes have imaged the Horsehead Nebula in the past, none have captured this region of the Orion Molecular Cloud with such a wide and sharp view. What’s even more amazing about this image is that it took Euclid just an hour of observing time to create it. It’s no wonder that professional and amateur astronomers, as well as space fans alike, are excited about the upcoming data release on May 23.
As stunning as the images listed above are, there’s a good chance the best is yet to come from Euclid as it begins to achieve its mission goals while shining a strange light on the dark universe.
We’ll have to wait until early Thursday to see what the next batch of Euclid images delivers and how this dark universe detective begins to live up to its enormous mission expectations after nearly a year in space. But if its past is any indication of its future, it’s difficult to imagine anything other than information-rich beauty from these images.