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Giant, Mysterious “Cavity” In Space Reveals How Supernovas Make New Stars


Stephen Luntz

Freelance Writer

clockSep 23 2021, 18:27 UTC
hole in the galaxy

The bubble on whose shell the Taurus and Perseus molecular clouds sit is placed not far from the Solar System halfway between the Galactic center and the outskirts of the galaxy. Image Credit: Alyssa Goodman/Center for Astrophysics | Harvard & Smithsonian

Astronomers have identified a giant cavity in space where for about 500 light-years the interstellar medium becomes almost invisibly thin. This void is thought to have been caused by supernova explosions around 6-22 million light-years ago. Incredibly, the first use of augmented reality in a peer-reviewed astronomical paper allows anyone to use these observations to visualize the way stars rise phoenix-like from the ashes of their predecessors.

The Perseus and Taurus molecular clouds are two enormous regions filled with gas. Although bright in the infrared they are extremely faint at visible wavelengths and so have only been subject to intense study since space telescopes arrived. The Taurus molecular cloud is possibly the nearest large star formation region to Earth, at around 430 light-years away. Both form part of the recently discovered Radcliffe Wave, the nearest gaseous structure to the Sun's location within the Milky Way.


In The Astrophysical Journal, astronomers report that between these clouds they have found an empty area, something closer to a true vacuum than the clouds, which are themselves so diffuse they would seem like a vacuum to a visitor.

What we see as two independent clouds form the shell of this void or bubble.

“Hundreds of stars are forming or exist already at the surface of this giant bubble,” said Dr Shmuel Bialy of the Harvard and Smithsonian Center for Astrophysics (CfA) in a statement. “We have two theories—either one supernova went off at the core of this bubble and pushed gas outward forming what we now call the ‘Perseus-Taurus Supershell,’ or a series of supernovae occurring over millions of years created it over time.”


Although they have been considered separate clouds, Bialy and co-authors believe the Perseus and Taurus molecular clouds were probably both the product of the same supernova or supernovas.

“We’ve been able to see these clouds for decades, but we never knew their true shape, depth or thickness. We also were unsure how far away the clouds were,” said co-author Dr Catherine Zucker.

The project marks the most detailed 3D mapping of galactic dust. This in turn has been used to produce the first 3D reconstruction of how gas forms stars after supernova explosions based on observations, rather than simulations.


The work has been published with augmented reality visualizations, which anyone can see and interact with using this link here to scan a QR code, also available in an accompanying paper. This is the first time this has been done for an astronomical paper, but the authors think it will not be the last.

Still from the interactive reconstruction of the molecular clouds with the bubble created by one or more supernova explosions shown in green. The direction to Earth shows why it was hard to see the relationship between the two clouds. Image Credit: Alyssa Goodman/Center for Astrophysics | Harvard & Smithsonian.

“We need richer records of scientific discovery,” said Professor Alyssa Goodman, who led the creation of glue, the data visualization software. Visualizations like this will help other astronomers gain a better grasp of what they are studying, but they also represent an opportunity for non-scientists to gain much better insight than is usually possible.

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