We all live in a big bubble, and it created thousands of stars in the night sky.

A bubble spanning 1000 light-years surrounds our solar system, where thousands of young stars are born. It is called a local bubble and is produced by the gorgeous death of stars-supernova bursts-providing conditions for the formation of new stars. However, in the 50 years since its discovery, due to the limitations of observation technology, the overall image of the local bubble has been blurred to astronomers. Recently, someone has finally unveiled its mystery.

There are thousands of young stars near the solar system, all born from a bubble 1000 light-years wide. Astronomers realized this decades ago and called it a local bubble (local bubble). This is a low-density, high-temperature plasma bubble, on the boundary of the bubble, is a layer of cold, dense neutral gas and dust in which stars can form.

Local bubbles: the Origin of Stars

Through a series of new data and data science and technology, the team found that it was a series of supernova explosions that created the bubble-like structure. The first supernova explosion occurred 14 million years ago, when the supernova pushed aside interstellar gas to create this bubble-like structure, and since then, intense star formation has begun on its surface. Today, seven famous star-forming regions or molecular clouds (dense regions of the universe in which stars can form) are located on the surface of the bubble.

"We have calculated that the local bubble we see today is caused by the explosion of about 15 supernovae over thousands of years." Catherine Zucker of STScl said.

Astronomers have also noticed that this strangely shaped bubble is not static and is still growing slowly. "it expands about 6 kilometers per second, but it doesn't have much momentum and has been stable at this speed." Zucker said. The expansion rate of the local bubble, and the trajectory of newly formed stars on its surface in the past and now, is derived from data from the Gaia astronomical satellite, a space telescope launched by the European Space Agency in 2013.

"the detection process itself is an incredible story, in which theory and data are very important." Alyssa Goodman, a professor at Harvard University and an astronomer at the Center for Astrophysics, said she is also the founder of the visualization software glue. "We can use a large number of independent clues to piece together the star formation history around us. Clues include a supernova model, stellar motion, and a detailed three-dimensional distribution of matter around the local bubble. "

Ubiquitous bubble

Today, when humans peep out into space from near the sun, they can see the star formation process that takes place around the surface of the bubble. While watching this star blockbuster, we happened to be sitting in the front row of our seats.

Astronomers first proposed the theory that superbubbles are ubiquitous in the Milky way nearly 50 years ago. "now, we have evidence of our chances of being in the middle of these bubbles," Goodman asked. Statistically, if such bubbles are not common in the Milky way, then we are less likely to be right in the middle of it, she explained.

Goodman likens the Milky way to Swiss cheese with holes in which holes are blown up by supernova explosions from dying stars, and at the edges of these holes, dead stars provide conditions for new stars to form.

Next, the team, including co-author and Harvard doctoral student Michael Foley, plans to draw more maps of interstellar bubbles to obtain a complete three-dimensional view of their location, shape and size. Mapping bubbles and their relationships will eventually enable astronomers to understand the role of dying stars in the generation of new bubbles and in the structure and evolution of galaxies such as the Milky way.

Zucker has a lot of questions: "where do these bubbles extend, how do they interact and how superbubbles promote the birth of stars such as the sun in the Milky way?" to find out, the team will continue to explore the stories of other "local bubbles."