The Milky Way’s Largest Gas Structure: Will Change Understanding the Shape of Matter in the Milky Way

BEIJING, March 20 (UPI) — Astronomers have discovered the largest gas structure ever observed in the Milky Way, which could change human understanding of the shape of matter in the Milky Way. The wave-like structure is observed to be about 9,000 light-years long and about 400 light-years wide, extending about 500 light-years up and down the central plane of the Milky Way’s disk.

The Milky Way's Largest Gas Structure: Will Change Understanding the Shape of Matter in the Milky Way

This image from WorldWide Telescope software overlays research data from the Milky Way and the Sun with an artistic imagination

On the other hand, the structure is long and thin, shaped like a “pond slug”, containing a huge “star nursery” (also known as a molecular cloud), a region of star formation.

The Milky Way's Largest Gas Structure: Will Change Understanding the Shape of Matter in the Milky Way

Colored dust fibers form part of the Gould Belt. The Gould Belt consists of a group of bright and huge stars that form a circular projection in the sky, which was first observed by humans in 1879

The Harvard team used new data from the European Space Agency (ESA) Gaia mission to create a 3D map of interstellar matter in the Milky Way. “We don’t know what caused this shape, but it could be like a ripple in a pond, like something of a supermassive mass falling into our galaxy,” said Joao Alves, one of the study’s authors and a professor of stellar astrophysics at the University of Vienna in Austria. What we do know is that the sun interacts with this structure. When it passed through Orion 13 million years ago, it experienced a supernova explosion; “

The newly discovered giant wave-like gas cloud and dust is the largest known in the Milky Way. Observational evidence suggests that large, star-forming clouds of gas are largely bound by their own gravity (such as stars, planets, and galaxies) rather than by external gravity (such as the Earth’s atmosphere).

The Milky Way's Largest Gas Structure: Will Change Understanding the Shape of Matter in the Milky Way

Gaia maps the location of the Milky Way’s stars in two ways. It can pinpoint the location of stars and map their trajectories by scanning each star about 70 times, allowing scientists to calculate the distance between the Earth and each star.

The structure is made up of interconnected nebulae, mainly dense gas and dust. Its discovery changed the way the Milky Way has been viewed for 150 years. Previous researchers have thought that the Milky Way is made up of dense molecular clouds that form an expansionary ring around the sun, called the Gould Belt.

In 1879, The American astronomer Benjamin Gould first described the Gould belt as a group of bright and huge stars that projected a ring in the sky.

Scientists call edgy the newly discovered wave-like structure “Radcliffe wave” and are named after the Radcliffe Institute for Advanced Studies at Harvard University, which discovered it.

“No astronomer has expected our neighbor to be a huge, wave-shaped gas cluster, nor did they expect it to form a partial branch of the Milky Way,” said Professor Alyssa Goodman, co-director of the Science Project at the Radcliffe Institute for Advanced Studies. The existence of this structure forces us to rethink our understanding of the three-dimensional structure of the Milky Way. “

The Milky Way's Largest Gas Structure: Will Change Understanding the Shape of Matter in the Milky Way

The Gaia mission’s full-sky observations of our Milky Way and its neighboring galaxies, which included measurements of nearly 1.7 billion stars. This map shows the total brightness and color of the stars in each part of the sky observed by the mission from July 2014 to May 2016. Brighter regions represent particularly bright stars with higher densities, and darker regions represent areas with fewer bright stars in the sky. The color in the figure is obtained by combining the total amount of light in each small area of the sky with the total amount of blue and red light recorded by the Gaia mission.

The study was made possible by the European Space Agency’s Gaia mission. Launched in 2013, this is a space telescope tasked with accurately measuring the position, distance and motion of stars. The new structure contains most of the star-forming regions of the nearby Milky Way, with a total gas mass equivalent to about 3 million solar masses.

The structure also contains many of the “star nurseries” previously thought to be part of the Gould belt. For a long time, astronomers have been trying to figure out whether a bright star that forms an arc in the sky really forms a ring in three-dimensional space.

“Instead, what we’re observing is the largest coherent gas structure we know in the Milky Way, not organized by a ring structure, but in a large, wave-like filament structure,” Professor Alves said. It’s always in front of our eyes, but we haven’t seen it until now. “

The researchers’ three-dimensional map shows the Milky Way in a whole new light, providing a new view of the Milky Way and potentially paving the way for other major discoveries. Details of the new discovery, published in the recent journal Nature, can also be seen in WorldWide Telescope, a free astronomical observation site launched by Microsoft.

Earlier, a team led by Harvard graduate student Catherine Zucker published two related research papers using advanced statistical techniques to map the three-dimensional distribution of dust in gas clouds and to investigate the color of stars, detailing “star nursery” “The distance. These two papers laid the foundation for this new discovery. The Gaia mission, on the other hand, has helped astronomers measure the distance of 1 billion stars in the Milky Way since its launch in 2013.

What is a “star nursery”?

A “star nursery” is a region in space with a dense nebula, consisting mainly of gas and solid dust. This nebula, also known as the “molecular cloud”, in which gas and dust are shrinking. Eventually, the dense regions of these nebulae shrink and collapse into stars. In the currently known universe, new stars are formed in molecular clouds.

Gaia Mission

The Gaia space telescope at the European Space Agency is an ambitious mission to map the Milky Way in three dimensions and reveal its composition, formation and evolution. Since its launch in December 2013, the Gaia mission has been orbiting the sun nearly 1.6 million kilometers outside Earth’s orbit.

The Gaia mission has been carefully taking pictures of the Milky Way during its journey, identifying stars in small galaxies that were swallowed up by the Milky Way long ago. Gaia is expected to discover hundreds of thousands of new objects, including asteroids that could one day threaten Earth, planets orbiting nearby stars, and supernova eruptions.

Astrophysicists also hope to learn more about the distribution of dark matter through the Gaia mission. Dark matter is presumed to be an invisible matter that holds the observable universe together. They also plan to examine Einstein’s general theory of relativity by looking at how stars and their planets deflect light.

With a 1 billion-pixel lens, the Gaia Space Telescope is by far the largest camera in space and is so powerful that it can measure the diameter of a human hair 1,000 kilometers away. This means that it has unprecedented accuracy in positioning nearby stars.

Gaia maps the location of the Milky Way’s stars in two ways. It can pinpoint the location of stars and map their trajectories by scanning each star about 70 times, allowing scientists to calculate the distance between the Earth and each star. This is a vital measurement.

In September 2016, the European Space Agency released the first data collected by the Gaia mission, including information on the brightness and location of more than 1 billion stars. In April 2018, the technology will be extended to high-precision measurements of nearly 1.7 billion stars.