Largest ALMA Image Ever Spans 650 Light-Years, Revealing the Chaotic Heart of the Milky Way

An extraordinarily intricate new image presents the centre of the Milky Way in striking detail, complete with swirling clouds of cosmic dust, wisps of cold molecular gas, and a generous scattering of stars.

The image, taken by the Atacama Large Millimeter/submillimeter Array (ALMA), is the largest of its kind to date and displays a vast area spanning 650 light-years. Its subject is the Central Molecular Zone (CMZ) — a particularly chaotic and intense portion of the galaxy, filled with fast-lived stars and gas that moves at supersonic speeds.

Taken by researchers at the ALMA CMZ Exploration Survey (ACES), it offers astronomers an opportunity to study the mechanics of the early universe in a region a little closer to home.

“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,” ACES leader Steve Longmore, a professor of astrophysics at Liverpool John Moores University, UK, said in a statement.

“By studying how stars are born in the CMZ, we can also gain a clearer picture of how galaxies grew and evolved.”

Capturing the Central Molecular Zone

The CMZ lies in the centre of the galaxy, approximately 27,000 light-years from Earth. It is an extreme and tumultuous environment with a supermassive black hole at its centre and vast clouds of gas and dust invisible to the naked eye. According to the Harvard and Smithsonian Center for Astrophysics, it contains close to 80 percent of all the dense gas stored in the Milky Way.

Taken at millimeter wavelengths, ACE’s image captures an area that is 650 light-years end-to-end, which from our perspective here on Earth would look like three full moons side-by-side.

What’s exciting about this image is that researchers are now seeing everything in full detail for the first time, sort of like going from a black-and-white photo to a full color, 4K movie, explained Ashley Barnes, an astronomer at the European Southern Observatory (ESO) in Germany, in an ESO video.

An Insight Into The Early Universe

Thanks to the image’s impressive, unprecedented detail, researchers will be able to use it to explore the CMZ in depth, from gigantic gas structures spanning light-years to (relatively) tiny gas clouds that encase stars.

Astronomers at ACES have already studied the composition of the CMZ and identified several compounds, including carbon monosulfide, isocyanic acid, silicon monoxide, sulfur monoxide, and cyanoacetylene. In the image, different molecules are shown in different colors.

Moving forward, the researchers hope it will offer a rich new resource to assist astronomers studying the evolution of galaxies, the formation of stars, and the physics of the early universe

As for the technology itself, this might just be the start.

“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,” Barnes explained in a statement.

“In many ways, this is just the beginning.”

Read More: Unusual Snowfall Shuts Down One of Earth’s Most Advanced Telescopes in the Atacama Desert

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