Mesmerizing image of black hole reveals magnetic field

The first image of a black hole just became even more fascinating.

At the center of the Messier 87 (M87) galaxy is a supermassive black hole about 38 billion kilometers wide, a behemoth so dense that not even light can escape its gravitational pull.

By observing polarized light around M87, scientists working with Event Horizon Telescope, an international collaboration of researchers, were able to produce the image. It shows the spiral-like pattern of the black hole's magnetic fields, the first image of its kind.

The light comes from the superheated gas caught in the black hole's event horizon, the point of no return from which not even light can escape. It traveled 55 million light years to reach Earth.

The image can give the illusion of light being sucked into the center of the black hole, like water swirling down a drain, but that's not quite the case.

What it's really showing are magnetic field lines, Erin Macdonald said in an interview. Macdonald has a doctorate in astrophysics and is a science consultant for recent Star Trek productions.

Magnetic fields

Confused? Think about polarized sunglasses. They use a filter reminiscent of window blinds that only allows light waves traveling in a specific orientation to pass through.

"Light is really electromagnetic waves, and electromagnetic waves are shaped like a cross or an X," Macdonald said, crossing her arms perpendicularly. "When you're getting light from the sun, that's natural light, and that goes in all directions. When you use polarized sunglasses, it's filtering all the light shaped opposite of where your filters are [oriented]."

Filtering the light allowed scientists to view the electromagnetic radiation aligning itself along the black hole's magnetic field lines.

Macdonald compared it to using a magnet to manipulate iron filings. When iron is in the presence of a magnetic field, it will align itself along field lines, revealing the otherwise invisible influence. In the case of the M87 black hole, just replace iron with light.

"By seeing how the magnetic field is structured, we can see how strong it is and can then start to dig more information out about that black hole," Macdonald said. "We do have great models using Einstein's general relativity for what the structure of a black hole should look like, and getting this level of detail and information allows us to compare and contrast those models that we have."

More to come?

The original image of the black hole released in 2019 was created using a network of eight telescopes around the globe. They started recording the data for it in 2017.

That data was stitched together into an image that, while a bit blurry, is still impressive considering the vast distance.

This new polarized image is the first piece of additional information to come out of this observation, about two years after the initial image. The amount of data collected in those observations is immense, and while Macdonald isn't involved with the project, she wouldn't be surprised if more information came out in the future.

"I can only imagine that there's more data that people are continuing to analyze and piece together, and finding new ways to convey it," she said.