The culprit behind the fracture of the densest bone in the center of our galaxy has been found.

The center of our Milky Way galaxy is a bustling place, teeming with stars and dominated by a supermassive black hole, Sagittarius A* . And right there, amidst the powerful magnetic fields that regulate star production, astronomers have been observing enormous, elongated structures, similar to cosmic 'bones,' for years. These are long filaments of gas, and they are known to play a crucial role in star formation.

But these aren't mere cosmic curiosities. Quite the contrary, the 'bones' play an active role in galactic dynamics. They act, in fact, as bridges connecting the Milky Way's spiral arms , where the gas density is greatest, with regions where star formation is underway. Furthermore, their kinematic properties—that is, the way they move—are similar to those of molecular clouds in general, making them particularly valuable objects of study for astronomers.

To better understand the importance of this discovery, we can imagine the galaxy as a vast metropolis whose spiral arms are its main avenues. Along these, and sometimes connecting them, are gigantic molecular clouds, the cradles where stars are born . And within these clouds are even denser and more filamentary regions, the aforementioned "bones," which are the densest structures associated with the spiral arms, of which, so far, around twenty have been identified.

Now, one of those bones in particular, nicknamed the "Galactic Center Serpent" due to its shape, has caught the attention of scientists. This enormous, elongated structure, which stretches 230 light-years across, has a disconcerting characteristic: it appears to be "fractured" in two different places.

After analyzing recent data from NASA's Chandra X-ray Observatory and various radio telescopes, a team of researchers has proposed a surprising explanation for these "fractures." Their research, just published in the Monthly Notices of the Royal Astronomical Society , suggests that the culprit behind this cosmic warping could be a high-speed collision with a pulsar, a highly magnetized neutron star.

The Galactic Center Serpent (also known as G359.13) stands out for its length and its brightness in radio waves. But what really sets it apart from other filaments are the two "humps" or "fractures" it presents in two different locations. These deformations, very significant in its linear magnetized structure, which normally extends perpendicular to the galactic plane, have puzzled astronomers for years.

"The Serpent," the authors write in their study, "is a remarkable radio filament in the galactic center with a morphology characterized by two breaks along its length. The major and minor breaks are located where the filament is most distorted and least resembles a magnetized linear structure running perpendicular to the galactic plane."

To unravel the mystery, researchers meticulously analyzed radio and X-ray data from the Cosmic Serpent. And right at the site of one of the "fractures," they identified a bright source in both X-rays and radio waves. After a thorough analysis of its properties, they came to the surprising conclusion that the "culprit" behind the deformation is most likely a fast-moving pulsar.

A pulsar is a rapidly spinning neutron star that emits beams of electromagnetic radiation from its magnetic poles. These incredibly dense stars are the result of the gravitational collapse of massive stars at the end of their lives, in events known as supernovae. But only the most massive stars leave behind a black hole when they explode as supernovae. When they are not large enough, which is often the case, gravity is not enough to cause the entire star to collapse and compress into a single point, although it is enough to cause its mass to be "squashed" into a much smaller and extraordinarily compact sphere, a neutron star. Some of them, propelled by the explosions themselves, begin to spin very rapidly and are propelled at prodigious speeds through space. These are what we know as pulsars.

The researchers' calculations suggest that this intruding pulsar impacted the Serpent's filament at an astonishing relative speed, estimated at between 1.6 and 3.2 million kilometers per hour. This cosmic collision likely disturbed the galactic bone's internal magnetic field, which in turn distorted the radio signal it emits. Furthermore, the interaction would have accelerated electrons and their antimatter antiparticles, positrons, to extremely high energies, making them an additional source of the observed signals.

"The radio luminosity and steep spectrum of the compact source are consistent with a pulsar," the researchers write. "We also show a flattening of the spectrum and increased synchrotron emissivity away from the position of the main kink along the Snake, suggesting the injection of relativistic particles."

Synchrotron emission occurs when charged particles, such as electrons, move at speeds close to the speed of light in the presence of a magnetic field, releasing energy in the form of electromagnetic radiation. The increase in this emission away from the main point of impact supports the idea that the collision scattered energetic particles along the entire filament.

The researchers therefore argue that the Serpent's main 'fracture' was caused directly when this high-speed object 'hit' the filament, distorting its magnetic structure and generating the detected X-ray emission.

Interestingly, they also propose that the secondary "fracture" could have been triggered by the impact of the same high-speed object that produced the primary deformation. It's as if the shock wave from the initial collision had reverberated through the filament, creating a second disturbance.

While this new research offers a compelling explanation for the mystery of the "fracture" in the Cosmic Serpent, the scientists emphasize that more observations are needed to fully confirm this scenario. "Future sensitive, high-resolution radio and X-ray imaging," the researchers conclude, "will examine the interaction we describe here. These measurements will provide insight into the origin of one of the most remarkable radio filaments in the Galactic Center."

Therefore, keeping an eye on this gigantic cosmic 'serpent' that, 26,000 light-years from Earth, stretches through the heart of our galaxy, remains a priority for astronomers. Understanding the processes that shape these structures and the forces acting on them allows us to delve deeper into the complex and fascinating dynamics of the Milky Way. Future observations promise to reveal even more secrets of this enigmatic cosmic 'bone' and the violent encounters that can occur in the crowded galactic heart.