A new photo taken by the world's most powerful radio telescope has revealed "extraordinary detail" in the most extreme region of the Milky Way galaxy.
The image, taken by the Atacama Large Millimetre/Submillimetre Array (ALMA) in Chile, shows a complex network of cosmic gas filaments in the galaxy's central region.
The region shown in the image spans 650 light-years — more than 6 quadrillion kilometres.
It was obtained by stitching together individual observations "like putting puzzle pieces together", according to the team responsible.
The finished puzzle — a complete image of the so-called "Central Molecular Zone" (CMZ) — spans the length of "three full moons side-by-side in the sky".
That makes it the largest photo ALMA has ever obtained.
The ALMA CMZ Exploration Survey (ACES) is a research team comprising more than 160 scientists from more than 70 institutions across Europe, North and South America, Asia, and Australia.
Studying the CMZ could reveal how galaxies grow and evolve, said ACES leader Steve Longmore, a professor of astrophysics at Liverpool John Moores University.
"The CMZ hosts some of the most massive stars known in our galaxy," he said.
"[Many of them] live fast and die young, ending their lives in powerful supernova explosions, and even hypernovae.
"We believe the region shares many features with galaxies in the early universe, where stars were forming in chaotic, extreme environments."
Their peer-reviewed research and more details about the photo have been published in the Monthly Notices of the Royal Astronomical Society.
'A place of extremes' at the centre of the universe
The image shows multiple gas structures, some spanning light-years across, and others only surrounding individual stars.
The CMZ harbours dense clouds of gas and dust near the supermassive black hole at the centre of the galaxy.
Ashley Barnes is an astronomer at the European Southern Observatory (ESO) in Germany and part of the team surveying the region.
"It's a place of extremes, invisible to our eyes, but now revealed in extraordinary detail," she said.
"It is the only galactic nucleus close enough to Earth for us to study in such detail."
The cold molecular gas inside the zone is the raw material from which stars form — a process the ACES team has been studying to better understand the birth of stars in such an extreme environment.
The ALMA telescope, located on the Chajnantor Plateau in the Atacama Desert, consists of 66 high-precision antennas operating at wavelengths of 0.32mm to 3.6mm.
The regions it photographs exist at temperatures of "just a few dozen degrees above absolute zero", —273 degrees Celsius.
Caroline Foster, an astronomer and associate professor at the University of New South Wales, said she was excited to see what the new map could mean for her own research.
"They're looking at clouds that are around individual newborn stars, or large star-forming complexes in an area of the galaxy where the gas is different to what we have looked at so far," Dr Foster said.
"We know that there's different chemistry, there's probably more turbulence towards the centre of the galaxy, [it's] something that we've not been able to see elsewhere.
"That's exciting for my research, because I work mainly on galaxies further away, not our own Milky Way. But I do look at things like star formation and how [it] changes across cosmic time … these [CMZ] conditions are probably closer to some of the stuff I look at in my day to day."
She added the image had been coloured, likely meaning the team involved had highlighted different chemistry, temperatures and structures in the gas.
"Basically, when we take an image on a telescope, typically what we'll do is put a filter in front of our detector," Dr Foster said.
"Somewhere inside the instrument, we put a piece of glass that only lets through very specific colours.
"If we put that filter on, that means it only lets through the light that's of those colours.
"And so even though our image appears in black and white on our screen, we can recolour it.
"The colours are fake, but they are reflective of what's actually going on there, so that our eyes can see the image because we cannot see in the radio."
Editor's note (26/02/26): An earlier version of this story incorrectly stated absolute zero as –2,730 degrees Celsius. This has been changed to –273 degrees Celsius.
