There's a massive, invisible shockwave screaming through the edge of our galaxy at over 1.5 million miles per hour.
March 24, 2026
Original Paper
Southern eROSITA bubble as a forward shock and the low-metallicity CGM. South-east side story
arXiv · 2603.20740
The Takeaway
New data reveals that giant radiation bubbles surrounding the Milky Way are actually a forward shockwave triggered by an ancient explosion at the galactic center. This shock is currently plowing through the extremely thin gas in the galactic halo, acting as a continent-sized laboratory for high-energy physics.
From the abstract
Unlike the complicated X-ray and radio structure observed in the North Polar Spur area, the South-Eastern part of the eROSITA bubbles can be reasonably well described as a propagating forward shock, plausibly created by the transient energy release at the Galactic Center. In this model, the physical radius of the bubble is $R_{\rm b}\sim 7-8\,{\rm kpc}$ and the age of the outburst is $t_{\rm age}\sim 5-8\,{\rm Myr}$. The visible segment of the shock front (located at a distance of $\sim 10-12\,{