Gigantic bubbles, each half the size of our galaxy, have been found above and below the Milky Way. What could they be?

Scientists have discovered two pairs of bubbles located above and below the center of the Milky Way. These bubbles are of colossal size and are composed of hot gas. These structures are only visible in X-ray and gamma-ray light. Astronomers have proposed a new theory that explains what inflated these gigantic bubbles, each half the size of our galaxy. The research has been published in the journal Nature Astronomy, as reported by Earth.

In 2010, the Fermi Space Telescope detected a pair of enormous bubbles made of hot gas situated above and below our galaxy's center. The bubbles form an eight shape with an intersection point at the galactic core. According to estimates, each bubble has a height of approximately 25,000 light-years. For comparison, the diameter of the Milky Way is about 100,000 light-years. These structures have been named the Fermi bubbles.

In 2020, the eROSITA space telescope discovered another similar pair of bubbles and hot gas, also located above and below the center of the Milky Way. Estimates suggest that each of these bubbles has a height of around 36,000 light-years. These structures have been named the eROSITA bubbles.

Despite several theories already existing regarding how these strange bubbles were formed, scientists have introduced a new theory. They propose that both pairs of bubbles were created due to a plasma outflow from the supermassive black hole Sagittarius A*, located at the center of the Milky Way. This outflow released an immense amount of energy, facilitating the formation of such unique structures.

Researchers believe that a powerful jet of plasma began erupting from the supermassive black hole approximately 2.6 million years ago, and this outflow lasted for about 100,000 years, as indicated by modeling. Astronomers think that the black hole's jet displaced a vast amount of gas from the galaxy's center and inflated both pairs of bubbles. This process prevented the black hole from growing unrestricted.

This theory contradicts the assumptions that the Fermi and eROSITA bubbles were formed as a result of supernova explosions at the center of our galaxy.

Modeling based on observational data has shown that the Fermi bubbles were initially created, but later a shock wave emerged, leading to the formation of even larger structures. While it was previously thought that the bubbles were formed over approximately 10,000,000 years, the new research suggests that this process was completed in just 100,000 years.

According to astronomers, the processes involved in the creation of these bubbles influence how galaxies grow and evolve, which in turn affects the formation of stars and planets.