the earth It is a blow in the middle of a bubble 1,000 light-years wide with a dense surface that gives birth to thousands of young stars. Researchers have long wondered why this “super bubble” appeared. Now, a new study suggests that at least 15 powerful starbursts have inflated this cosmic bubble.
Astronomers first discovered the giant void, known as the local bubble, in the 1970s after realizing that no stars had formed inside the drop for about 14 million years. The only stars inside the bubble existed before the bubble appeared or formed outside the void and now pass through it; The Sun is one of those intruders. This formation was indicating that several supernovae were responsible for this void. These stellar explosions, according to the researchers, would have exploded the material needed to make new stars, such as hydrogen Gas, on the edge of a vast region in space, leaving behind a local bubble surrounded by a frenzy of star-born.
In the new study, published online January 12 in the journal natureThe researchers carefully mapped the star-forming regions surrounding the local bubble and, in doing so, calculated how fast the super bubble was growing. This allowed the team to determine exactly how many supernovae are needed to acquire the cosmic void, and to better understand how star-forming regions form across the globe. Milky Way.
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Principal investigator Katherine Zucker, a NASA member of the Space Telescope Space Telescope, told Live Science. Science Institute of Maryland: “By tracing the locations and motions of young stars nearby over the past millennia, we’ve reconstructed the history of our neighboring galaxy.”
Bubble expansion
The local bubble is not a uniform ball, because it did not form with a single explosion. Instead, it looks like a lumpy droplet caused by several supernovae.
“Powerful supernova explosions triggered an expanding shock wave, sweeping interstellar clouds of gas and dust into a dense crust that now forms the surface of the Local Bubble,” Zucker said. The shock wave continues to push the surface out, causing the bubble to expand.
The researchers used data obtained from the European Space Agency’s Gaia space observatory to create a 3D map of the local bubble’s surface and to calculate the trajectory of the seven major star-forming regions that make up the “skin” of the bubble. The observations also allowed the researchers to determine how fast the cosmic vacuum is expanding, which is currently about 4 miles per second (6.4 kilometers per second), according to Researchers statement.
“We were able to determine the number Pushing force It is currently at the expanding surface of the local bubble and compare that to the amount of momentum that must be injected by supernovae to fuel its expansion. Given the projectile’s current momentum, Zucker added, “that matches previous estimates made by similar studies. It is possible that these supernovae originated in two separate star groups over millions of years.”
Bubbles of “Swiss cheese”
The findings help deepen our understanding of how star-forming regions form.
“Astronomers have assumed for many decades that supernovae can swarm the gas in the dense clouds that eventually form new stars, but our work provides the strongest observational evidence to date to support this theory,” Zucker said.
Currently, Earth is at the heart of the local bubble, Zucker said, but that’s not what makes this place special. “It is a coincidence that the sun is concentrated inside the bubble,” she added. The Sun was about 1,000 light-years away when the bubble began to form and entered it only 5 million years ago.
According to the Copernican Principle, which states that humans are not distinct observers of the universe and that Earth does not have a “special” position in the galaxy, the location of our planet within the Local Bubble suggests that super bubbles are probably very common throughout the Milky Way, Zucker mentioned.
“We believe that these bubbles interact with each other, as the star-forming regions are located at the intersections of the bubbles,” Zucker said.
Therefore, the Milky Way “looks like a very sacred Swiss cheese, as holes in the cheese are drilled by supernovae, and new stars can form in the cheese around the holes created by dying stars,” co-author Alyssa Goodman, an astronomer at Harvard University, in a statement.
passage
the Solar system The team found that he wouldn’t always be stuck inside that bubble. “The sun is expected to emerge from the bubble within 8 million years,” Zucker said. “But at this point, the bubble may no longer be there.”
Zucker said it is believed that the expansion of the local bubble is slowing and will eventually disappear after reaching its maximum size.
“The local bubble is in later stages of its life and will not continue to expand indefinitely, and it has already stabilized in terms of the speed of expansion,” Zucker said. “Eventually, the local bubble will slow down enough to merge with the general ambient gas in its vicinity.”
Originally published on Live Science.