Science

Photos show electrons from galaxies about a billion light-years away creating 2 ‘dancing ghosts’ in the sky

Summary List PlacementResearchers have discovered a cosmic phenomenon that looks like two people dancing in deep space, according to a study published last week. The structure, named PKS 2130-538 and nicknamed the "dancing ghosts," is about a billion light-years away from Earth. The annotated image below shows the outline of the phenomenon: A version of the study before peer review was published last week on the pre-print server aRXiv. A peer-reviewed version of the study is due to be published at an unspecified date, according to a statement accompanying the study.  "When we first saw the 'dancing ghosts' we had no idea what...

An annotated image of the 'dancing ghosts' green clouds of electrons shaped like people dancing

Summary List Placement

Researchers have discovered a cosmic phenomenon that looks like two people dancing in deep space, according to a study published last week.

The structure, named PKS 2130-538 and nicknamed the “dancing ghosts,” is about a billion light-years away from Earth.

The annotated image below shows the outline of the phenomenon:

Annotated picture of the 'dancing ghosts' green clouds of electrons shaped like people dancing

A version of the study before peer review was published last week on the pre-print server aRXiv. A peer-reviewed version of the study is due to be published at an unspecified date, according to a statement accompanying the study

“When we first saw the ‘dancing ghosts’ we had no idea what they were,” Professor Ray Norris of Western Sydney University, the lead author on the research project, said in the statement.

After weeks of analysis, the scientists found that the clouds were made up of electrons spewed by two “radio galaxies” at each end of the structure, as can be seen here:

Arrows the galaxies pushing the electron clouds into the dancing ghosts.

But what really intrigued the scientists was the shape of the clouds, one expert told Insider.

“What baffled the scientists is these structures are so complex and extremely distorted,” said Dr. Kai Noeske, the communications officer for the European Space Agency and distant galaxy researcher.

The shape of the ‘ghosts’ challenges what science knows about this type of galaxy

Radio galaxies revolve around a massive black hole, which is billions of times bigger than the sun. 

Black holes eat up the matter they come across. As the matter spirals into black holes, particles carrying electric charges are accelerated to incredible speeds. They then start emitting a certain kind of electromagnetic radiation that’s called synchrotron, which creates a magnetic field.

Meanwhile, matter that is not absorbed is ejected along the magnetic poles of the black hole.

“The high energy jets coming out are moving at high velocities, not far from the speed of light. You have electrons and probably also protons,” Noeske told Insider.

Noeske said that normally, these jets spew straight out of the galaxies, as can be seen in this picture of the radio galaxy Hercules A:

a picture of radio galaxy Hercules A shows the galaxy in the center and two plumes of matter jetting out of it straight either way

There is no air in space, but gas blowing out of galaxies can rush around the universe at breakneck speed, traveling hundreds of miles per second. 

As the jets hit this intergalactic gas, they can bend.

“But [the dancing ghosts] are a complete mess,” Noeske said. “They are highly distorted and the astronomers are baffled because at this point they have no understanding where these probably very complex motions come from.”

In a blog post in The Conversation, Norris — the study’s lead author — said he thinks the winds from the two galaxies are causing some of the shapes of the dancing ghosts (annotated below). However, he said he does not understand what is causing one arm of the cloud, annotated below with the number 3. 

Arrows show how the winds are leaving the galaxies to push the electron clouds into the dancing ghosts. An arm of the ghosts is annotated with the number 3 and a question mark

The “dancing ghosts” were picked up by the Australian Square Kilometre Array Pathfinder (ASKAP) radio telescope, one of the most sensitive telescopes ever made and part of the Evolutionary Map of the Universe (EMU) project. 

The project, launched in 2009, was designed to help scientists understand the birth of stars. According to Norris, these are some of the first results from the project. 

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