The first all-sky X-ray map of our galaxy, made available by ESA's eROSITA spacecraft, shows two massive bubbles. These bubbles stretch up to 50,000 light years above and below the Milky Way and are believed to be the remains of a massive eruption that occurred millions of years ago.
We have long known that the inner core of the Milky Way can be a pretty violent place. Clusters of supernovae and the hellish work of our central supermassive black hole can wreak havoc and wreak havoc for light years.
And now we can see some of the scars from our galaxy's violent past with a new all-sky x-ray map from the European Space Agency's eROSITA mission.
The map shows two gigantic bubbles, filled with a hot but thin gas that glows in x-rays, on opposite sides of the galactic disk. The northern bubble, known as the "North Pole Spur", had been known to astronomers for decades. However, the southern counterpart is new and will only be determined by the eROSITA survey.
eROSITA's X-ray view of our galaxy shows two massive bubbles spanning thousands of light years. Photo credit: MPE / IKI
Each bubble spans 50,000 light years, making the structures as large as the Milky Way.
What could cause these bubbles to form? Astronomers have long suspected that a pair of smaller, hotter bubbles called Fermi bubbles were launched when our central supermassive black hole forcibly expelled gas from its surroundings in a single burst. However, these bubbles, and the recently discovered larger X-ray bubbles, can also be caused by a series of supernova explosions in the galactic core.
Whatever the cause, it took a lot of energy to blow these bubbles out of the Milky Way – that's the equivalent of 100,000 supernovae detonating at the same time.
Because of its incredible delicacy, it is extremely difficult to observe the hot, thin gas that is believed to surround all galaxies. However, astronomers hope to use these new maps to understand this gas and its role in galactic evolution.