The solar system exists in a huge and mysterious space, and we finally know why

The solar system exists in a huge and mysterious space, and we finally know why.The solar system floats in the middle of a strange empty space in the universe.This region of low-density, high-temperature plasma over a period of about 1,000 light-years is surrounded by cold, high-density neutral gas and dust shells. This is called a local bubble and is floating in the middle of the solar system, and it was a challenge to explain exactly how and why it happened.

The solar system exists in a huge and mysterious space, and we finally know why

A team of astronomers, led by Harvard University and the Smithsonian Astrophysics Center (CFA), mapped local bubbles with the highest accuracy ever. He discovered that local bubbles could have been carved from interstellar media by millions of supernova explosions. Many years ago.

This is consistent with previous studies and has an additional puncture wound on the tail. Statically expanding local bubbles are responsible for the higher star-forming regions around it.

"This is really a source story. For the first time, I can explain how all the stars began to form close together," said Catherine Zucker, an astronomer at the Space Telescope Science Institute, who studied at CFA. I did.

Local bubbles were discovered relatively recently in the 1970s and 1980s by a combination of optics, radio and X-ray astronomy. Gradually, these studies and observations revealed a vast area of ​​density about one-tenth that of the average interstellar medium of the Milky Way galaxy.

This seems to be a rational explanation for local bubbles, as we know that supernovae can form cavities in the universe and expand outwards, producing gas and dust.However, when and how to assemble was more difficult. For one thing, it is difficult to measure the dimensions of an area when you are in space. And when you are surrounded by bright stars and other cosmic objects, measuring voids is twice as difficult.

Zucker and his team used data from a recent Gaia data release-an ongoing project to map the position and movement of the Milky Way stars with the highest accuracy ever-200 parsecs (gas and young). About 650 light-years to the stars) years from the sun ..They found that all young stars and star-forming regions were on the "surface" of local bubbles.

I understand this time. When a supernova expands outwards, it pushes and compresses the expanding material. This creates a tight knot in the molecular gas that floats between the stars, which breaks under its own weight and forms a baby star.

The researchers then simulated the movement of the star-forming region and performed tracebacks to model the expansion of the bubbles. This allows you to reconstruct the history by collating the calculation results with the bubble map.

They discovered that the history of bubbles began about 14.4 million years ago, first at the time of the birth of the star, followed by a giant, short-lived supernova."We calculated that about 15 supernovae were millions of years old to create the local bubbles we see today," Zucker explained.

Currently, it has a radius of about 165 parsec (538 light-years) and is expanding outwards at a rate of about 6.7 km (4 miles) per second, albeit relatively slowly.

So why is the solar system in the middle? Well, that's a complete coincidence.

"Our sun was far away when the first supernova that produced local bubbles stopped," said Joao Alves, a physicist and astronomer at the University of Vienna, Austria.

"But about 5 million years ago, the Sun's path through the galaxy carried it to the bubbles, and now the Sun-fortunately-is sitting almost in the middle of the bubbles."

According to researchers, this suggests that the Milky Way may be full of similar bubbles. This is because it is unlikely to occur if the bubbles are rare. The concept is reminiscent of a milky way that resembles a flat wheel of sponge, or perhaps Swiss cheese.

The next step along this search line is to find and map other bubbles. Their location, size, shape, and how they interact with each other provide a good source of information to better understand the structure of the stars and the evolutionary history of the Milky Way.

The next Gaia data release, scheduled to be removed later this year, should prove very effective for this. Alyssa Goodman, an astronomer at Harvard University, said:

She "can combine the history of surrounding star formation with a variety of independent formulas, including supernova models, stellar movements, and nice new 3D maps of the elements surrounding local bubbles."This study was published in the journal Nature.