Scientists stare into the center of The Milky Way with one of the world’s largest radio telescope parrays has discovered thousands of mysterious string-like structures never seen before.
These structures, known as radiofilaments, protrude from the galactic center into long, thin vines – some of which extend up to 150 light years long, or almost 40 times the distance between the earth and the nearest star system next door, Proxima Centauri.
Some filaments come in pairs, others in sets of equal distances like the strings of a harp. All of them are bursting with energy, probably generated by billions of electrons jumping through a magnetic field at almost light speed, according to two upcoming studies approved for The Astrophysical Journal and The Astrophysical Journal Letters.
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While scientists have known that filaments exist around the galactic center for decades, this new set of high-resolution observations from the MeerKAT radio telescope in South Africa reveals that there are 10 times more of the flimsy structures than previously thought. Studying the mysterious structures in bulk could help scientists finally find out what these filaments are and how they were created.
“Just examining a few filaments makes it difficult to draw any real conclusions about what they are and where they came from,” said study lead author Farhad Yusef-Zadeh, a professor of physics and astronomy at Northwestern University in Evanston, Illinois. said in a statement. “Now we finally see the big picture – a panoramic view filled with an abundance of filaments … This is a watershed that promotes our understanding of these structures.”
Intergalactic energy spheres
The center of the Milky Way is littered with mysterious objects that are too hidden by gas and dust to properly study with visible light wavelengths. But by focusing on the energetic radio waves radiating from the galactic center, astronomers can catch a glimpse of some of the powerful structures and interactions that occur there.
Using the MeerKAT radio telescope – a series of 64 antennas in the Northern Cape province of South Africa – the authors of the new studies observed the galactic center’s radioactivity for 200 hours over three years. Based on these observations, the researchers composed a mosaic of 20 separate observations, each focusing on a different part of the radio sky.
The resulting panorama captures many known sources of radio waves – such as bright supernova remnants and the gas-filled areas of space where new stars flash to life – as well as the mysterious fingerprints of nearly 1,000 radio filaments.
What exactly are these finger-like structures? According to Yusef-Zadeh, the best working hypothesis is that the filaments are generated by cosmic rays – high-energy particles accelerated through space at almost the speed of light – moving through a magnetic field. Previous studies have shown that something lurking in the middle of the Milky Way acts as a giant particle accelerator that constantly blows cosmic rays into space – though the source of these rays remains a mystery.
One track may be the huge pair radio bubbles exhales from the galactic center, one threatens just above the galactic plane and the other whizzes below it. Discovered in a previous MeerKAT study, each bubble of radio energy towers about 25,000 light-years high (about a quarter of the width of the Milky Way itself) and is probably produced by an ancient explosion from the galaxy’s central black hole.
According to the authors of the new studies, many of the newly discovered radio filaments fall into the cavities of these huge bubbles. It is possible that the string-like filaments were created by the same ancient eruption of black hole activity that inflated the radio bubbles millions of years ago. But even this explanation leaves some big questions unanswered.
“We still do not know why they come in clusters or understand how [the filaments] separated, and we do not know how these regular intervals happen, “Yusef-Zadeh said.” Every time we answer a question, several other questions arise. “
Future radio studies of the region will focus on whether the filaments move or change position over time, the researchers said.
Originally published on Live Science.