Why Is Earth Sitting in the Center of a ‘Local Bubble’ Surrounded by Baby Stars? Here's What Experts Say

A new study shows that Earth is surrounded by a gigantic bubble roughly 1,000 light-years across.

The solar system is located within the "Local Bubble," a massive gap surrounded by hundreds of newborn stars. However, there is still a mystery surrounding this bubble, from its specific size and structure to its origins and growth.

Researchers looked into this bubble in a new study and discovered some surprising new information about how it aids star formation.

They detailed the study's findings, "Star Formation Near the Sun Is Driven by Expansion of the Local Bubble," in Nature.

ISRAEL-ASTRONOMY-METEOR — The Milky Way galaxy is pictured as a Perseid meteor streaks across the sky above the Negev desert near the Israeli city of Mitzpe Ramon, on August 12, 2021, during a yearly meteor shower, which occurs when the earth passes through the cloud of debris left by the comet Swift-Tuttle. MENAHEM KAHANA/AFP via Getty Images

Milky Way Has Full of Local Bubbles

Study co-author Catherine Zucker told Gizmodo that supernovae can 'sweep up' gas into thick clouds that eventually become new stars. Zucker, an astronomer at the Harvard-Smithsonian Center for Astrophysics, stated that their finding provides the best observable evidence in favor of this idea to date.

Instead of being on the edge of the bubble, Zucker said the Solar System is in the middle. That's because, unlike the stars on the border of the Local Bubble, our solar system was created far earlier than the previous 14 million years.

These kinds of bubbles have been theorized for decades. Still, new technology allows researchers to test them in ways they couldn't before. The researchers also believe that the Milky Way is likely to be packed with these bubbles, since if they were rare, the solar system would not be sitting in the middle of one.

The next step in understanding how these structures work as nurseries for stars throughout the galaxy is to figure out how the bubbles interact with one another.

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Local Bubble Continues to Expand

Astronomers from the Center for Astrophysics, Harvard & Smithsonian (CfA) and the Space Telescope Science Institute (STScI) used computer modeling to recreate the development of the Local Bubble.

It appears that a large number of supernovae were required. A relatively quick succession of supernova explosions - around 15 in all - pushed interstellar gas and dust outward. Afterward, the process carved out a low-density void with a dense gas and dust-rich "edge." It gave several circumstances for the birth of new stars.

Stars don't just appear out of nowhere, TechRadar said. To cause clouds of gas and dust to cluster together enough to start fusing hydrogen and ignite into full-fledged stellar furnaces, they typically need a push of some sort.

The Local Bubble's expansion is causing just the right amount of disruption in the molecular cloud to launch the star-formation process, and it's continually expanding.

What Local Bubble Looks Like

The Local Bubble is a 1,000-light-year-wide bubble, ABC.net.au reported. It contains sparse, hot gas on one of the Milky Way's long, looping spiral arms. The temperature is too hot within the bubble, and there's not enough gas to make new stars.

However, its chilly, compressed hydrogen gas shell, which has been blasted outwards by the force of many supernovae, provides ideal star nursery material.

Roughly the bubble's surface are seven clusters of "baby" stars that are around 10 million years old or younger. Consider the entire procedure to be similar to making Swiss cheese.

The Local Bubble, despite its name, is not spherical; instead, it resembles a lumpy hourglass or a peanut. Our solar system is currently in the Local Bubble, but this hasn't always been the case.