The universe is ready for its close-up.
Breathtaking images of thousands of galaxies taken by a 609-megapixel camera have been released this morning by space officials.
The images were taken by Euclid, a European Space Agency (ESA) telescope launched in 2023 that hopes to capture the ‘dark universe’.
‘Not only are these images pretty, they’re delivering on the science,’ Adam Amara, chief scientist at the UK Space Agency, who first proposed the idea for Euclid, told Metro.
‘We’re doing astronomy in a way we’ve never done before.’
Euclid’s sharp eyes have been peering at the Perseus Cluster, one of the largest structures in the known universe 240,000,000 light-years from Earth. (One light-year is 24,000,000,000,000 miles.)
Euclid has so far spotted 26,000,000 galaxies, the farthest up to 10,500,000,000 light-years away.
But this is just 0.4% of the galaxies the telescope is expected to image over the next six years.
More than 500 galaxies seen in today’s release seem to experience strong lensing, where the galaxy’s gravity warps the light of another behind it.
This is manifested in the panoramic pictures as arcs, halos, smears, streaks and, in extreme cases, mirror images of a single source.
What sets today’s photos apart from others, such as those taken by Nasa’s Hubble Telescope, is how they are panoramas, Amara said.
‘Find something interesting and zoom right in and figure it out there and there,’ he said.
And there’s a lot to look at. On top of galaxies, Euclid snapped ‘transient phenomena’, grand cosmic events that are nevertheless a fraction of a fraction of what the universe has been and will become.
Think supernovae, a star blowing itself to smithereens; gamma-ray bursts, sporadic high-energy radiation considered one of the most violent events in the universe and fast radio bursts, fleeting fireworks of radio waves from unknown places in space.
Euclid also helped experts find 70,000 globular clusters – ancient groups of stars – in the Perseus Cluster.
These are, Amara said, the ‘known unknowns’ of the universe, quoting former US Secretary of Defence Donald Rumsfeld. ‘The kind of things that we know exist but are really hard to find in a normal way,’ he said.
Among them are strong lenses. ‘Where a galaxy bends the light of something in the background so much that it messes it up,’ Amara explained.
‘These are very rare. You need a galaxy and something interesting right behind it to align perfectly. They’re also teeny tiny.’
Astronomers are also intrigued by what’s not visible in the images: dark matter, the groovy, invisible glue that keeps galaxies together.
Researchers have long looked into dark matter to explain why the universe is the way it is, thinking of it as gravitational scaffolding.
However, the aloof material has yet to be directly detected, making it one of the biggest challenges in modern physics.
‘When you’re a teenager, you learn all the science from textbooks and become a bit cocky,’ Amara said. ‘You learn all this fancy, brilliant stuff and then you hit dark matter and dark energy and you’re humbled.
‘In terms of the physics and the fundamentals of reality, we understand 5% of it all. Human knowledge explains just 5% of what’s out there.
‘Dark matter does stuff. It moves stars. It moves galaxies. It bends flight. We know it’s out there but we have no idea what it is. We have a long way to go.’
The galaxies that seem to experience strong lensing are a key way to understanding dark matter. How the light bends indicates the total mass of the visible matter and, potentially, its shady counterpart surrounding it.
One observation could suggest that dark matter is objects 20 times larger than our solar system and radiates next to no energy, Amara said.
Equally, he half-jokes, an academic paper published today could also suggest these cosmic beams are smaller than anything we could imagine.
‘Our scope of ignorance is very, very big,’ he added. ‘But if we manage to measure a physical property of dark matter, which Euclid could easily do, then, boom, we’ll suddenly have a clear understanding of what we’re hunting for.’
The same goes for dark energy, the unseen force doing everything to push the cosmos apart.
‘Imagine a balloon. When it inflates, it gets bigger. The tension on the balloon stops it getting bigger,’ Amara explained.
‘A balloon filled with dark energy, if it gets bigger, it would push out even more and get even bigger. Then it’s like, “Oh, I’m bigger now,” so it pushes even more out and gets even bigger.
‘It’s just weird. We think we’re so smart and brilliant but we have no idea what 70% of reality does.’
By studying the density of dark matter across the cosmos, astronomers hope to learn how dark energy shapes our universe.
Euclid’s findings were looked over by new artificial intelligence (AI) methods and thousands of volunteers and experts.
So far, 14% of the total survey area (14,000 square degrees) has been observed and will be used to create a 3D map of the universe.
Amara hopes that, in the end, Euclid helps scientists look at the ‘unknown unknowns’ of the universe, again quoting Rumsfeld.
One such thing is whether the ‘equation of state’ rings true. The parameter states that dark energy is exerting ‘negative pressure’ on the cosmos and causing it to expand.
In this mind-bending equation, this is expressed as minus one.
‘It has to be minus one. If we find it’s not, we’ve got a huge revolution in physics,’ Amara said. ‘If it is minus one, we have to sit quietly in a room and try to come to terms with the fact the universe has this constant for no reason.’
Until then, Amara is simply relieved. After all, the University of Portsmouth professor and his peers came up with the idea of Euclid in 2005.
‘I used to wake up in a sweat thinking, “Oh my, God, we’ve wasted billions of pounds.”‘ he said.
‘But to see the science start to come out and outperform all the things we were expecting, to see the discoveries coming through now, thick and fast, is brilliant.
‘It’s a huge relief we didn’t mess this up.’
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