It is 1,000 light-years wide and is the source of all our star friends.
Once upon a time in galactic history, a group of stars exploded to form a hypothetical supernova. The explosions were so strong that their sparkly remnant pushed the surrounding shroud of interstellar gas outward until it slammed into a 1,000 light-years-wide cosmic bubble—a giant blob that’s still growing. As you are reading this.
Experts say that just by chance, our own sun blew right into this bubble. Now we live smack in the middle of this, giving the globule an apt name: the local bubble. And in a paper published Wednesday in the journal Nature, scientists present a novel description of the bubble’s saga using a 3D map of the giant structure.
Most surprisingly, they found that this is the main reason we have an oddly rich neighborhood of young stars.
“It really is an origin story,” study author Katherine Zucker, an astronomer and data visualization specialist at Harvard and the Smithsonian Center for Astrophysics, said in a statement.
Astronomers typically study seven locations in space where stars seem to form most often – Zucker’s study saw each one sitting on the surface of a local bubble. The team believes that bubbles of stars around us are visible throughout the universe, but also that our position directly in the center is extremely rare.
The concept is comparable to the fabric of space which resembles a cheddar Swiss cheese, with each hole representing a star formation centre. Somehow, we are in one of the lousy holes. As our home star has set up shop inside the local bubble, every time we look up at the sky, we are witnessing the birth of hundreds of stars.
Beyond that stellar serenity, the team at Local Bubbles’ awesome 3D animation — which you can play here — sheds light on the evolution of the structure.
For example, researchers calculated that about 15 supernovae are responsible for the origin of the blob that occurred about 14 million years ago. The Sun appears to have entered orbit about 5 million years ago, and the bubble appears to be coasting at about 4 miles (6.5 kilometers) per second. “It’s lost most of its oomph … and remains largely stable in terms of speed,” Zucker said.
Harvard and Smithsonian Center for Astrophysics and study author Alyssa Goodman called the team’s findings “an incredible detective story driven by both data and theory.” Goodman is also the founder of Glu, the data visualization software that enabled discovery.
In the future, the researchers hope to continue to unlock the secrets of interstellar bubble-like local bubbles by applying their software to 3D-maps that lie deep in the universe.
“We can piece together the history of star formation around us using a variety of independent clues: supernova models, stellar motion and excellent new 3D maps of the material surrounding the local bubble,” Goodman said.
Zucker wonders, “Where do these bubbles touch? How do they interact with each other? How do superbubbles drive the birth of stars like our Sun in the Milky Way?”