Gigantic Bubbles in the Milky Way: Experts Have an Explanation for "Fascinating Structures"

Created: 03/08/2022, 16:14

By: Tim Vincent Dicke

Experts have been puzzling over mysterious bubbles in the Milky Way for years.

Now a research team provides an explanation for the amazing observation.

Frankfurt – It is a fascinating phenomenon in our galaxy.

Years ago, researchers discovered two gigantic bubbles stretching tens of thousands of light years on either side of the Milky Way.

Since then, experts have been wondering why the structures came about.

Now there might be an answer.

The X-ray telescope eROSITA, which was developed by the Max Planck Institute for Extraterrestrial Physics (MPE) in Munich, is particularly helpful when researching space bubbles.

"Thanks to its sensitivity as well as energy and angular resolution, eROSITA can map the entire X-ray sky with unprecedented depth and thus also clearly detect the southern bubble," explained Michael Freyberg, who has been working as a scientist at the institute for years, in a press release at the end of 2020.

Milky Way: why did the bubbles form in space?

A research team led by Hsiang-Yi Karen Yang, assistant professor of astronomy* at National Tsing Hua University in Taiwan, has now announced new findings about the giant bubbles.

They span a total distance of about 50,000 light-years across the Milky Way.

The bubbles first discovered by eROSITA in 2020 are very similar to the so-called Fermi bubbles, which the US space agency Nasa* discovered in 2010.

In a blog post on nature.com, Hsiang-Yi Karen Yang reports that she and her team believe the bubbles formed 2.6 million years ago.

They suspect that the black hole inside the Milky Way* must have absorbed a huge, massive clump.

Research in space: bubbles in the Milky Way "fascinating structures"

"It's a bit difficult to say what exactly engulfed the black hole a few million years ago, but the galactic center is a very dense environment full of stars and gas, so supply of matter shouldn't be a problem," Yang told the US magazine Vice.

The huge bubbles in the Milky Way are clearly visible in the image taken by the eROSITA telescope.

© picture alliance/dpa/MPE/IKI

Due to this event, there was a massive explosion, and the detonation was the origin of the bubbles, Yang said.

This applies to both the eROSITA and the Fermi structures.

Her research revealed "that these fascinating structures probably have the same origin," the scientist writes on nature.com.

The possibility that the bubbles were triggered by a single event at the center of the Milky Way has been debated by experts for some time.

"The sharp interfaces of these bubbles most likely travel along shock waves caused by a massive energy input from the interior of our galaxy into the galactic halo," said Peter Predehl of MPE 2020. "Such an explanation has been proposed previously for the Fermi bubbles ;

with eROSITA, its full extent and morphology has now become apparent.”

Bubble discovery in space: eROSITA project stopped due to Ukraine war

Hsiang-Yi Karen Yang sees it that way too.

The Taiwanese scientist told Vice that the images from eROSITA are "pretty stunning".

"The Fermi/eROSITA bubbles are unique because they are right in our (galactic) backyard, which allows us to study them in detail," Yang said.

And, of course, new research aspects arise from the observations.

Her team now wants to investigate how the fascinating phenomenon "fits into the broader picture of galaxy evolution." Meanwhile, researchers have discovered a free-flying black hole for the first time.

Incidentally, it is currently unclear when eROSITA will again produce insightful research results.

Background: The X-ray telescope is operated in a German-Russian cooperation.

In the wake of the Russian war of aggression in Ukraine, the German Aerospace Center* (DLR) announced that it would put all joint projects on hold.

"For us, violence must not be used as a means of achieving goals of any kind.

We are therefore very concerned about developments in Ukraine and condemn Russia's acts of war," DLR said on Thursday (03/03/2022).

(tvd)