Scientists find holes between stars in space. Located about 700 light years away, it lies between the constellations Perseus and Taurus.
Astronomers have discovered a huge spherical vacuum with a diameter of more than 500 light years. Surrounding it are the molecular clouds Perseus and Taurus - dense clouds of cold gas and dust where stars form.
This object is called the Per-Tau Shell, and appears to be the result of a giant supernova explosion millions of years ago. It is likely that this phenomenon suppresses and triggers star formation in the two molecular clouds.
"Hundreds of stars are either forming or already on the surface of this giant bubble," said theoretical astrophysicist Shmuel Bialy of the Harvard-Smithsonian Center for Astrophysics (CfA).
"We have two theories - one of the supernovae exploded at the core of this bubble and pushed the gas out to form what we now call the 'Perseus-Taurus Super Shell', or a series of supernovae that occurred over millions of years that created it."
To find this alone takes energy, but scientists are still curious. How deep is this empty space?
To explore the Perseus and Taurus molecular clouds, the researchers used data from Gaia, the European Space Agency's satellite observatory, which has been working since 2013 to map the Milky Way galaxy in three dimensions with the most detail and the highest possible precision. This is one of the most up-to-date tools at our disposal.
This data is analyzed using visualization software called glue, which allows scientists to create interactive 3D visualizations. From here, astronomers can build 3D maps of gases in these and other molecular clouds.
"We've been looking at these clouds for decades, but we've never known their true shape, depth, or thickness. We're also not sure how deep the cloud is," said astronomer Catherine Zucker, also of the Harvard-Smithsonian CfA.
According to the Bialy team's analysis, the nearly spherical void is likely the result of a powerful supernova explosion. This explosion sent shockwaves in all directions into interstellar space. As this shock wave expands, it pushes and compresses matter in the interstellar medium, sweeping it upwards to form a spherical shell.
But there is another theory, namely this is the process of the formation of new stars. Star formation is thought to occur when denser regions of molecular clouds collapse, rotating, under their own gravity. When the shock wave from a supernova extends into the surrounding space, it can sweep gas in the interstellar medium to form molecular clouds with dense regions and then begin to form stars.
This is what the team says happened with Per-Tau Shell. Between 6 and 22 million years ago, scientists' reconstructions show that a supernova event created a cavity in the interstellar medium. It is also what creates the molecular shells and clouds of Perseus and Taurus. At this time, the bubble doesn't look like it's expanding anymore, in other words it's still the same shape.
"This suggests that when a star dies, its supernova produces a chain of events that can eventually lead to the birth of a new star," Bialy said.
An interactive 3D model of the Per-Tau shell can be explored on the Harvard website. This paper has been published in 'The Astrophysical Journal Letters', as reported by Science Alert.
