The mysterious structures are almost four to five times longer than our own galaxy, with some filaments reaching 200 kiloparsecs in length.
The universe is vast. It is huge and based on what we know, it is expanding. Studying the universe, its composition, and its history is of great importance to astrophysicists. And the universe has more to offer than galaxies, stars, black holes, and planets. There are things out there that have puzzled astronomers for decades. And one of these mysteries is enigmatic structures found several decades ago. These are odd, massive structures, or filaments, that stretch beyond galaxies. Their exact composition, nature, and purpose are something still debated by astronomers.
After first discovering a family of large-scale, highly organized magnetic filaments dangling in the center of the Milky Way in the early 1980s, Northwestern University astrophysicist Farhad Zadeh became fascinated and puzzled by them. After 40 years, Zadeh still finds the subject fascinating, but perhaps with a little less astonishment. According to Zadeh and his collaborators, two possible explanations for the cosmic structures’ unknown origins have been suggested by the discovery of similar filaments in other galaxies. Earlier this month, Zadeh and his co-authors published a paper in The Astrophysical Journal Letters proposing that filaments might be formed when large-scale wind interacts with clouds or when turbulence occurs inside a weak magnetic field.
A puzzling set of cosmic structures
First discovered by Zadeh, these filaments stretched 150 light years. They were located near the Milky Way’s supermassive black hole in the galaxy’s center. Zadeh’s collection of observations this year has grown by nearly 1,000 filaments. This batch comprises one-dimensional filaments arranged as pairs and clusters, often equally spaced, parallel to each other, or sloping sidewise like ripples on a waterfall. According to Zadeh, the mysterious filaments are composed of electrons gyrating near the speed of light along a magnetic field. Despite putting together the puzzle of what they were made of, Zadeh still wondered where the cosmic structures came from. Researchers could study the physical processes in the space surrounding filaments when they discovered a new population outside our own galaxy.
In galaxies far, far away
These structures are located approximately one billion light-years away. The newly discovered filaments are part of a galaxy cluster comprised of thousands of galaxies. Active radio galaxies within the cluster may serve as breeding grounds for magnetic filament formation due to their ability to emit large amounts of radio waves. Zadeh was amazed to find these newly discovered filaments. “Having studied filaments in our own Galactic Center for so many years, I was very excited to see these remarkable structures,” Zadeh said in a statement. But Zadeh the new discoveries gave Zadeh a hunch that something universe was happening. Since now, for the first time, we have spotted the filaments elsewhere.
Similar but different
Although the new population of filaments resembles those in our Milky Way, they differ in some important ways. In contrast to the Milky Way, filaments outside the galaxy are much larger – 100 to 10,000 times longer. Furthermore, their magnetic fields are much weaker, and they are considerably older. The intracluster medium, or the area between galaxies within a cluster, is also filled with them, most of which hang – at a 90-degree angle – from black holes’ jets.