The European Space Agency (ESA) will release five new images from the Euclid Space Telescope today (May 23). And if the previous set of photos is anything to go by, space fans would be in for an absolute treat.
"During Euclid's early observation phase, five new portraits of our cosmos were captured, each revealing astonishing new science," ESA officials said in a statement. "Euclid's ability to unravel the secrets of the cosmos is something you don't want to miss."
The new images will be unveiled at 5 a.m. EDT (12 p.m. CEST) and will be accompanied by as many as 10 scientific papers. You can watch the data release live on ESA's YouTube channel.
Related: The Euclid telescope from the 'dark universe' is thawed out a million kilometers away
As an appetizer for the occasion, perhaps we can remind ourselves of the incredible cosmic images this mission has produced so far.
Euclid's story so far
Launched on July 1, 2023 from Cape Canaveral in Florida atop a SpaceX Falcon 9 rocket, Euclid is a wide-angle space telescope with a 600-megapixel camera that observes the cosmos in visible light, a near-infrared spectrometer and a photometer used to measure the redshift of determine galaxies. By knowing the redshift, scientists can figure out how quickly distant galaxies are moving away from our planet.
Euclid's main mission is to investigate the two most mysterious elements of the universe: dark energy and dark matter. These phenomena together form what is often called the 'dark universe'.
Dark energy is the temporary name given to the force that is accelerating the expansion of the universe. Dark matter, on the other hand, is a form of matter that is effectively invisible because it does not interact with light. This means scientists know it is not 'ordinary' matter, made of electrons, protons and neutrons, that includes stars, planets, moons and our bodies. Dark matter can only make its presence known by interacting with gravity, which in turn can affect ordinary matter and light. To be clear, neither dark matter nor dark energy are necessarily made of one thing. Both could be made up of many things - or maybe they're all made up of one homogeneous thing.
The point is, we just don't know.
Nevertheless, dark energy is believed to make up about 68% of the universe's energy and matter budget, while dark matter makes up about 27%. That means the dark universe accounts for 95% of the things in the universe, and the things we actually understand only account for about 5%.
Euclid, who has been called a 'detective from the dark universe' because of his specific set of instruments, clearly has his work cut out for him. 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.
Above is one of the first images the public saw from the Euclid telescope. It is a snapshot of about a thousand galaxies, all of which belong to the Perseus Cluster. Located about 240 million light-years away from Earth, this cluster is one of the largest structures in the known universe.
Mapping galaxies in such enormous volumes is crucial to understanding how dark matter is distributed and how this distribution has affected the evolution of the universe.
In addition to the Perseus cluster's wealth of galaxies, the image also showed 100,000 much more distant galaxies, each containing hundreds of billions of stars. Observations of distant galaxies in large numbers like these are crucial to Euclid's unraveling of how dark energy is pushing these galaxies away faster and faster by accelerating the expansion of the space between them.
Just because Euclid has large swathes of galaxies in his sights doesn't mean he can't impress with images of individual galaxies.
Another of the first Euclid images we were shown was, somewhat ironically, for an instrument whose job was to reveal dark elements of the universe. That's because it identified the galaxy IC 342, also known as the 'hidden galaxy'.
This galaxy is located about 11 million light-years from Earth and is difficult to image because it lies behind the bright, dusty disk of the Milky Way. However, that didn't stop Euclid from taking an incredible photo of this once hidden spiral galaxy. To do this, the space telescope used its near-infrared instrument, which is advantageous because the gas and dust of the Milky Way's disk are less effective at absorbing infrared light compared to other wavelengths of electromagnetic radiation.
To unravel the mysteries of the dark universe and create a detailed 3D map of the cosmos, Euclid will need to view galaxies as far away as 10 billion light-years by viewing the 13.8 billion-year-old universe as it appears less than was 4 years old. billion years after the Big Bang.
These galaxies are unlikely to have the neat, spiral arrangements of the Milky Way or even the Hidden Milky Way Galaxy. Most galaxies in the early universe are "blobby," poorly formed, irregular galaxies that served as building blocks for larger galaxies.
In preparation for observing these distant and early galaxies, Euclid's first images include an image of the more local, irregular galaxy NGC 6822, located just 1.6 million light-years from Earth.
Although they give us spectacularly sparkling images, Euclid won't just focus on galaxies during its mission.
As the image of NGC 6397 above shows, the space telescope will also look at globular clusters. And fortunately, globular star clusters are just as beautiful. These are conglomerates of hundreds of thousands of stars connected by gravity, and are some of the oldest structures in the known universe.
NGC 6397 is the second closest globular cluster, at a distance of only about 7,800 light-years. Globular clusters such as NGC 6397 orbit the disk of the Milky Way and may hold clues about the evolution of our galaxy, or at least other galaxies in which such structures exist.
Euclid will excel in the study of globular clusters because, unlike other telescopes, it has a field of view large enough to capture entire globular clusters in a single image, just like NGC 6397.
Much of Euclid's mission will focus on the unknown, but the final image of the first wave of Euclid releases actually showed us a familiar celestial body in a whole new light. The dark universe detective managed to create a stunningly detailed panoramic image of the Horsehead Nebula, also known as Barnard 33.
The Horsehead Nebula, located about 1,380 light-years from Earth and near the east of Orion's belt, is one of the closest star-forming clouds of gas and dust in the Solar System. It is also a sight to see.
Although numerous telescopes have imaged the Horsehead Nebula in the past, none have captured this region of the Orion molecular cloud in such a wide and sharp view. What's even more amazing about this image is that it only took Euclid an hour of observation time to create it. It's no wonder that professional astronomers, amateur astronomers and space fans alike are excited about the upcoming data release on May 23.
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To that end, as breathtaking as the images described above are, chances are that the best is yet to come from Euclid as he begins to achieve his mission goals while shedding remarkable light on the dark universe.
We'll have to wait until early Thursday to see what the next set of Euclid images yields and to see how this dark universe detective begins to live up to his enormous mission expectations after almost a year in space. But then again, if his past is any indication of his future, it's hard to imagine anything other than the information-rich beauty from these images.
