What is a Radcliffe wave, a cosmic structure that redefines our galaxy

Astronomers continue to discover strange objects in space, and the latest is what they have named Radcliffe wave. This string of wave-shaped star clouds is the largest coherent structure ever seen in our galaxy: 9,000 light-years from end to end, stretching across the night sky from Canis major until The swanwith Orion in the middle.

Now it turns out that the Radcliffe wave is indeed waving. This was stated in an article published on Tuesday in the magazine nature. Star-forming clouds rise high above the plane of the galaxy and then descend again. This type of oscillation is known as a traveling wave, and is similar to sports fans “wave” by getting out of their seats in a synchronized pattern around the field.

“This amazing thing… you can find articles alluding to it in the past, but now it's been nailed down. This is a brick in the wall and it won't come out,” said Bob Benjamin, an astronomer at the University of Wisconsin in Whitewater, who was not part of this new research. “. “This new work is a really important step in understanding the origin of this structure.”.

This structure is located within and almost adjacent to our galaxy. It's a spit, if you could spit 500 light-years away.

The story has another twist: our solar system appears to have passed through… Radcliffe wave About 13 million years ago it would have been Interesting time to live Land. These star-forming regions contain more than their share of exploding stars. “13 million years ago we thought we might witness a supernova festival.”he explains Catherine Zuckerco-author of the study and astrophysicist V Harvard Smithsonian Center for Astrophysics.

Until a few years ago, no one realized that the many star-forming clouds relatively close to the Sun were part of a coherent structure. This is because astronomers can see distant galaxies better than the galaxies surrounding us milky way. There is no telescope in intergalactic space, a few million light-years away, that can get beautiful images of our entire galaxy. (If there is, he's not one of us.)

“It's really hard to see the structure of your hand if you hold it close to your face,” explains Alyssa Goodman, a professor of astronomy at Harvard University and co-author of the new report. “We can't fly outside the galaxy.” Astronomers have known for a century that the Milky Way is just one of many galaxies. They also knew that our galaxy is a large spiral galaxy very similar to the neighboring Andromeda Galaxy.

The cloudy band of milky light that can be seen on a clear night – and which he discovered Galileo Four centuries ago, using a telescope, filled with individual stars, it is an edge-on view of the plane of our galaxy. A galaxy is a pancake-shaped disk, made of relatively thick dough. We are in the middle, and we can see the stars in all directions that are part of the pie.

But only in recent years has it become possible to create an accurate 3D map of the stars and gas in our sector of the galaxy. This is partly due to the spacecraft Gaia Subordinate European Space Agencydesigned to measure with unprecedented precision the distances to millions of stars in our galaxy and their relative motion with each other.

“Fixed stars,” as astronomers and sailors call them, do not actually exist in deep space. Everything is moving. Our solar system orbits the galactic center over the course of about 226 million Earth years.

Using data from Gaia, Joao Alves, Zucker, good man He described six of his colleagues Radcliffe wave In an article published in 2020 in nature. They named it in honor of early 20th century astronomers associated with the planet Radcliffe CollegeIncluding the graduate Henrietta LeavittWho discovered that the periodic brightness of some stars encodes information about their distance from the planet Land.

This discovery was instrumental in the discovery that the interesting “spiral nebulae” seen through telescopes are actually structures outside the universe. milky waydifferent galaxies in a universe that is more expansive than we can imagine.

The Radcliffe wave appears to be the backbone (or “gas tank,” as a 2022 article put it) of the spiral arm of our galaxy closest to the Sun, known as the Orion Arm or the Local Arm. Additional updates from Gaia have allowed scientists to create theoretical models to track the movement of star clusters within the wave, and detect their ripples.

The big question now is: Why does a Radcliffe wave ripple?

“Who ordered this?” Goodman asked.

Clearly something has happened to disrupt our galactic neighborhood and impose chaos in the skies. One possibility is that something — perhaps a dwarf galaxy — collided with the Milky Way and caused a big splash, and the ripple was a domino effect.

Another possibility is that a series of supernovas — star explosions that emit powerful bursts of radiation — shook things up. Or it could be a combination of factors. “It is possible that the stars exploded as supernovae and pushed gas and dust out of the plane of the galaxy.”he explains Ralph KonetzkaPhD student Harvard And the lead author of the new article. According to Konetzka, this wave pattern will disappear within a few tens of millions of years.

Zucker and his colleagues say there is still much to investigate More scientific articles are about to be published. There may be indications in the geological record that Land It was affected by supernova explosions on that ancient transit across the world Radcliffe wave.

the Land It contains a magnetic field that helps protect it from potentially harmful radiation from the sun, and the solar wind coming from the sun creates a large protective bubble around the entire solar system, which helps protect us from dangerous particles rushing through space from other points. galaxy.

But this is where “interstellar climate” complicates the picture. The nearby supernova may have compressed that bubble, called the heliosphere, to the point that our planet was completely exposed to the interstellar medium.

The next step is to search the geological record for evidence that Land They were dotted with an iron isotope consistent with a supernova exposure about 13 million years ago and then compared to anything of interest in the biological record. “Galaxies may be more dynamic than we thought.”it states Konetzka.

(c) 2024, The Washington Post