In a remarkable discovery that challenges our understanding of galactic processes, astronomers have spotted a colossal, hourglass-shaped structure of radio emissions surrounding a seemingly ordinary galaxy. The galaxy, known as ESO 130 G012, is located a cosmic stone's throw away at about 55 million light-years from Earth.
A Faint Shape Emerges from the Cosmic Background
At first glance, ESO 130 G012 is an unremarkable edge-on spiral galaxy with a steady but modest rate of star formation. The spectacle began to unfold when scientists were analyzing deep-sky radio images from Australia's powerful ASKAP (Australian Square Kilometre Array Pathfinder) telescope. Part of the Evolutionary Map of the Universe project, these observations are designed to reveal faint cosmic features.
What slowly came into view was not a dramatic explosion, but a vast, balanced structure. A faint shape stretched above and below the galaxy's thin disk of stars, growing clearer with prolonged observation. The sheer scale of the discovery only became apparent after careful inspection. This was no minor feature; it was a symmetrical, hourglass-like formation spanning nearly 160,000 light-years from top to bottom.
Anatomy of a Galactic Hourglass
The structure, visible only in radio light at a frequency of 944 MHz, shows material flowing upward from the galactic plane and spreading outward. It forms a wide funnel on both sides, creating the distinct hourglass shape standing upright in space. The waist of this cosmic hourglass aligns with the galaxy's star-forming disc and spans roughly 33,000 light-years.
According to a study published on arXiv, the outflow is a layered system. At the galaxy's core is a compact radio source, surrounded by knots of emission linked to an inner stellar ring. Beyond this lies a thin disk and a thicker, box-shaped structure. From the edges of this box, radio "wings" stretch outward in an X-like pattern, forming the walls of the immense hourglass.
What Could Power Such a Vast Structure?
The discovery is puzzling because ESO 130 G012 is not an extreme galaxy. It forms stars at a modest rate of about 0.2 solar masses per year. One leading theory suggests that steady star formation across the entire disk, over eons, could be the driver. The combined effect of stellar winds, supernova explosions, and cosmic ray pressure might slowly push material outward, sculpted by the galaxy's own disk structure.
This challenges the long-held notion that only violent, concentrated starbursts can create galaxy-scale winds. Another intriguing possibility involves the galaxy's central black hole. While currently quiet, this supermassive black hole has a mass of about 50 million Suns. The X-shaped radio wings are often associated with past activity from such black holes. A more energetic phase in the distant past could have launched material, leaving this fading radio echo.
Why This Discovery Matters for Astronomy
Finding such a large, bipolar outflow in a nearby, settled galaxy is exceptionally rare. These structures are more commonly associated with distant, violently evolving galaxies. ESO 130 G012 shows no signs of recent collisions or major disturbances in optical light; its stellar disk appears intact and orderly.
This stark contrast between its calm optical appearance and its dramatic radio halo makes it a prime target for study. It suggests that galaxy evolution can be a quieter, slower process than previously thought, yet still capable of producing enormous, structured outflows. The discovery opens a new window to understand how galactic disks interact with and energize their surrounding haloes over cosmic time.
For now, the giant hourglass remains suspended in radio silence—a subtle yet profound reminder that even ordinary-looking galaxies can hold extraordinary histories written far beyond their visible edges.
