And now, researchers have found out how this bubble and the young stars around us were born.
Our solar system is located in what is called the “local bubble”; a 1000 light-year-wide “bubble” made up of hot, almost empty space. Remarkably, we are surrounded by thousands of young stars, which have clung to the surface of the giant bubble. An urgent question, however, is how the local bell, as well as the young stars around us, came to be. In addition, we are also located in the heart of La Cloche Locale. How’s it going ? A new study sheds light.
In the study, astronomers looked at the evolutionary history of our galactic backyard. Earth is at the heart of a gigantic star bubble. But we don’t know much about it yet. While astronomers have known about the existence of young stars for decades, the birth of the local bubble and its impact on the surrounding gas was a mystery until recently. “It’s really an origin story,” said researcher Catherine Zucker. “For the first time, we can explain how all nearby star formation began.”
It is generally believed that our local bell – but also other cavities; we are not alone – the result of supernova explosions. Millions of years ago, huge explosions of massive stars would have made the surrounding space even more empty than it already was. Researchers find in the new study that a series of supernovae that occurred 14 million years ago pushed interstellar gas. And that created the great “bubble” around us. “We calculated that there were around 15 supernovae over millions of years that ultimately formed the local bubble as we see it today,” Zucker said.
However, the oddly shaped bell is not sleeping. It grows slowly and steadily, astronomers note. “It expands at about 4 miles per second,” Zucker said. “However, he lost most of his strength and now remains roughly stable in terms of speed.”
Today, there are seven known regions of star formation or molecular clouds – regions of space where stars appear – on the surface of the local bubble. In fact, all of the young stars and regions of star formation – within 500 light years of Earth – are found here. This is not by chance. The supernova explosions that formed the local bubble simultaneously create an ideal surface for star formation.
cheese with holes
To explain the research a little more simply; think of a cheese with large holes. The holes in the cheese were created by supernova explosions. New stars then form in the cheese around the holes left by the dying stars.
Interestingly enough, Earth is right at the heart of the local bell. Incidentally, we shouldn’t be looking for more than mere coincidence. “When the first stars exploded as a supernovae, our sun was still far from any action,” said researcher João Alves. “About five million years ago, the sun’s path passed through the bell. And now our sun is – coincidentally – almost exactly at the heart of the local bell. “
Knowing that super bubbles like the local bubble are not uncommon, the researchers plan to map more interstellar bubbles. That way, they want to get a full picture of their locations and all of the shapes and sizes that they’re performing in. By studying these superbubbles and their relationships to each other, astronomers hope to eventually understand the role that dying stars play in the “birth” of new stars. Researchers are also interested in getting a better idea of the structure and evolution of galaxies such as our own Milky Way.
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