The largest image ever taken with the ALMA telescope in Chile has revealed the hidden chemistry at the heart of the Milky Way.
The colossal image captures 650 light–years of the Central Molecular Zone (CMZ) – one of the most extreme environments in the entire galaxy.
This crowded region, located 28,000 light–years from Earth, is a vast reservoir of swirling matter and stars that contains almost 80 per cent of the galaxy’s dense gas.
Dubbed the ALMA CMZ Exploratory Survey (ACES), the image gives scientists an unprecedented look into the complex processes taking place within.
The researchers discovered an array of different molecules, from simple chemicals such as silicon monoxide to more complex organic ones like methanol, acetone or ethanol.
Co–author Dr Ashley Barnes, of the European Southern Observatory, told the Daily Mail: ‘One of the most exciting aspects is the rich chemistry we detect.
‘We see dozens of different molecules, including some complex organic molecules that contain carbon, the same element that forms the basis of life on Earth.
‘From ACES, we are learning more about how the ingredients for planets, and potentially life itself, can arise in the universe.’
The largest image ever taken with the Atacama Large Millimeter/submillimeter Array (ALMA) in Chile (pictured) has revealed the hidden chemistry at the heart of the Milky Way
The very heart of the galaxy contains the supermassive black hole Sagittarius A*, which has a mass around four million times greater than that of the sun.
The intense gravitational pull and radiation produced by Sagittarius A* create dense, turbulent conditions that cannot be found anywhere else in the Milky Way.
Although this region is shrouded in dust, the ALMA telescope is capable of imaging the CMZ’s cold gas – the raw material from which stars are born.
By stitching together a mosaic containing dozens of individual images, researchers have managed to create an extremely detailed view of this elusive region.
Seen from Earth, the resulting image would cover an area of sky as long as three full Moons side–by–side.
As the survey now reveals, the intense conditions in the core mean the CMZ can produce molecules that are bigger and more complex than those found in the clouds of gas near Earth.
The researchers believe that some of these molecules could even be the progenitors of amino acids – the basic building blocks of proteins found in all forms of life.
However, tracking the movement of molecules also helps astronomers understand the dynamic processes unfolding within the core itself.
The image captures a region spanning 650 light–years of the so–called Central Molecular Zone (CMZ), which is located around 28,000 light–years from Earth in the direction of the constellation Sagittarius
‘These molecules form under particular conditions of temperature and pressure, so by mapping them we can understand what the environment is really like,’ says Dr Barnes.
Mapping these ‘molecular tracers’ allows ACES to reveal the flows, turbulence, and chemistry from the massive scale of the galactic core down to the individual clumps of gas where a star may one day form.
Dr Barnes says: ‘It shows a region that is constantly being reshaped by gravity and by the life cycles of massive stars, and their interactions with exotic things like black holes.
‘The image reveals a vast web of long, thread–like filaments of gas stretching across hundreds of light–years. We also see dense clouds where new stars are forming, along with huge cavities and bubbles carved out by powerful stellar explosions.’
The researchers say that these filaments are a particularly exciting discovery, as they appear to act like rivers of gas, funnelling material into the densest clouds where stars can grow.
Co–author Dr Daniel Walker, an astronomer from the University of Manchester, told the Daily Mail: ‘These structures were previously observed in individual regions, but ACES shows they are widespread.
‘Their origin is still uncertain, but they may trace magnetic fields, large–scale gas flows, or previously unrecognised dynamical processes.’
What makes this image so important for astronomers is the fact that the conditions inside the CMZ could reveal how our solar system, and others like it, originally formed.
Researchers used the ALMA telescope to track the distribution of multiple chemicals, ranging from simpler molecules like sulphur monoxide (top) to more complex, organic ones like HC3N (bottom)
The distribution of chemicals like HNCO (illustrated), also known as isocyanic acid, allows astronomers to chart the flows of cold gases through the CMZ
Principal investigator Professor Steven Longmore, of Liverpool John Moores University, told the Daily Mail: ‘It is the best laboratory we have to understand how our sun and solar system formed.’
This is because, when our solar system formed 4.5 billion years ago, conditions in the universe were much more extreme than those we find near Earth today.
‘The CMZ is the nearest region to Earth with conditions similar to those in the early Universe,’ Professor Longmore says.
‘As the CMZ is so close, we can observe the stars and planets currently forming there in exquisite detail and therefore understand our own origins better.’
