A brand new image captured by one of Earth's biggest astronomical observatories shows the centre of our Galaxy in detail never seen before.
The new image of the middle of the Milky Way was captured using an array of telescopes located in the Chilean desert, under some of the darkest skies in the world.
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Astronomers say the image will enable them to study the births, lives and deaths of stars in the chaotic centre of our Galaxy, close to its central supermassive black hole.
What the image shows
"It’s a place of extremes, invisible to our eyes, but now revealed in extraordinary detail," says Ashley Barnes, an astronomer at the European Southern Observatory in Germany and part of the team that captured the image.
The data was gathered using the Atacama Large Millimeter/submillimeter Array in the Chilean desert.
It shows cold gas – the raw ingredient from which stars form – in what astronomers call the Central Molecular Zone of our Milky Way galaxy.
This is the first time the cold gas across the whole region has been explored in such detail.
The image spans over 650 lightyears, which means it would take a beam of light 650 years to pass from the region on one side of the image to the other.
We can see dense clouds of gas and dust around the supermassive black hole at the centre of our galaxy.
Astronomers say the vast majority of major galaxies have a supermassive black hole at their centre, and ours is no exception.
It's not yet fully understood the exact role these supermassive black holes play in the formation and evolution of galaxies.
"It is the only galactic nucleus close enough to Earth for us to study in such fine detail," says Barnes.
The dataset reveals gas structures dozens of lightyears across, but also small gas clouds around individual stars.
The ALMA CMZ Exploration Survey, the scientific study that captured the data, explores cold molecular gas, detecting dozens of different molecules to understand the chemistry occurring at the centre of our Galaxy.
This cold molecular gas flows along filaments and gathers into larger clumps of matter, out of which stars may grow.
While scientists understand how this process occurs in the outer edges of the Milky Way, it's less understood how it happens at the centre of the Galaxy.
"The CMZ hosts some of the most massive stars known in our galaxy, many of which live fast and die young, ending their lives in powerful supernova explosions, and even hypernovae," says ACES leader Steve Longmore, professor of astrophysics at Liverpool John Moores University in the UK.
"By studying how stars are born in the CMZ, we can also gain a clearer picture of how galaxies grew and evolved.
"We believe the region shares many features with galaxies in the early Universe, where stars were forming in chaotic, extreme environments."
How the image was captured
Astronomers used ALMA, which is located in the Atacama Desert.
The team say this is the first time such a large area has been scanned with ALMA, making it the largest ALMA image ever.
It's a mosaic image produced by stitching together lots of individual images, amounting to a region of the sky equivalent to three full Moons side-by-side.
"We anticipated a high level of detail when designing the survey, but we were genuinely surprised by the complexity and richness revealed in the final mosaic," says Katharina Immer, an ALMA astronomer at ESO who is also part of the project.
"The upcoming ALMA Wideband Sensitivity Upgrade, along with ESO’s Extremely Large Telescope, will soon allow us to push even deeper into this region — resolving finer structures, tracing more complex chemistry, and exploring the interplay between stars, gas and black holes with unprecedented clarity," says Barnes.
"In many ways, this is just the beginning."
This research was presented in a series of scientific papers. Find out more via the ESO website.
