Photo by: Event Horizon Telescope collaboration et al.

Event Horizon Telescope collaboration et al.

Want to See a Black Hole’s Magnetic Field? Now’s Your Chance

A couple years ago, the team of astronomers with the Event Horizon Telescope wowed the world by providing our first-ever snapshot of a real-life black hole. Now they’ve done one better and mapped out the swirling magnetic fields around the monster. It’s our first ever glimpse of the forces that power the largest engines in the universe.

May 20, 2021

First, some introductions are in order. I’d like you to meet Powehi, the informal name for the supermassive black hole sitting in the center of the galaxy known as M87. Powehi is a Hawaiian word roughly translating to “unfathomable dark creation”, and the name is truly apt. Powehi weighs 6.5 billion times the mass of our Sun, and if you were to place it in our own solar system, it would extend beyond the orbit of Pluto. Good thing it sits a comfortable 55 million light-years away.

The Event Horizon Telescope isn’t really a single telescope, but rather a network of dishes scattered across the globe that worked in concert to deliver their stunning image of the superheated gas and dust swirling around the black hole itself.

The Event Horizon Telescope Collaboration released the first image of a black hole with observations of the massive, dark object at the center of galaxy Messier 87, or M87, April 2019. This black hole has a mass of about 6.5 billion times that of the sun and is located about 55 million light years from Earth. The black hole has been called M87* by astronomers and has recently been given the Hawaiian name of “Powehi.”

Photo by: NASA/CXC/SAO/B. Snios et al.

NASA/CXC/SAO/B. Snios et al.

The Event Horizon Telescope Collaboration released the first image of a black hole with observations of the massive, dark object at the center of galaxy Messier 87, or M87, April 2019. This black hole has a mass of about 6.5 billion times that of the sun and is located about 55 million light years from Earth. The black hole has been called M87* by astronomers and has recently been given the Hawaiian name of “Powehi.”

The light from that gas and dust (known as the accretion disk) is polarized. Just like your polarized sunglasses filter out certain kinds of light to reduce glare, astronomers can use similar physics to study the mixture of light coming from Powehi’s accretion disk. From there, they can reconstruct the magnetic field in the disk, because the magnetic field elaves an imprint in the polarization (the same way a bar magnet can leave an imprint in a bunch of iron filings scattered around it).

Why do we care so much about Powehi’s magnetic field? Good question. It’s because the accretion disks surrounding giant black holes are the most powerful engines in the universe. All that raw gravitational energy of the black hole pulls on the surrounding material, causing it to compress tightly around it and spin incredibly fast.

Chandra X-ray Observatory close-up of the core of the M87 galaxy.

Photo by: NASA/CXC/Villanova University/J. Neilsen

NASA/CXC/Villanova University/J. Neilsen

Chandra X-ray Observatory close-up of the core of the M87 galaxy.

Within the accretion disk, beefed-up electric, and magnetic fields drive some of that hot gas to follow swirling paths around the black hole itself, eventually ejecting that gas out of the poles of the black hole. These jets can extend for tens of thousands of light-years, far beyond the confines of the host galaxy itself.

These systems of black holes, accretion disks, and jets go by various names, like quasars, blazars, and active galactic nuclei. You just need to know that when black holes are active like this, they can outshine millions of galaxies put together. They are so bright that we can see them from literally across the universe.

NASA space telescopes have previously studied a jet extending more than 1,000 light-years away from the center of M87. The jet is made of particles traveling near the speed of light, shooting out at high energies from close to the event horizon. The EHT was designed in part to study the origin of this jet and others like it.

Photo by: NASA/CXC/Villanova University/J. Neilsen

NASA/CXC/Villanova University/J. Neilsen

NASA space telescopes have previously studied a jet extending more than 1,000 light-years away from the center of M87. The jet is made of particles traveling near the speed of light, shooting out at high energies from close to the event horizon. The EHT was designed in part to study the origin of this jet and others like it.

Right now, Powehi is relatively calm and docile – its accretion system is relatively small. Given the incredible forces involved, you won’t be surprised to learn that physicists don’t fully understand the whole jet-launching mechanism. Thankfully, the Event Horizon Telescope’s work gives us a vital picture to help understand this supreme process.

Dive Deeper into the Cosmos

Journey Through the Cosmos in an All-New Season of How the Universe Works

The new season premieres March 24 on Science Channel and streams on discovery+.

Paul M. Sutter

Paul M. Sutter is an astrophysicist at Stony Brook University and the Flatiron Institute, host of Ask a Spaceman and Space Radio, and author of How to Die in Space.

Next Up

Something Funky is Happening to the Earth’s Magnetic Field

Recently a weak spot in the Earth's magnetic field over the southern Atlantic Ocean has been getting weaker, which could signal the beginnings of a global magnetic reversal event. Or not. It’s complicated.

The Last Supermoon of the Year and How to See It

The Super Flower Moon of May is this year's last supermoon, when the Moon appears slightly larger and brighter in the sky because it is somewhat closer to Earth. Here's everything you need to know and how to watch it from home.

Who Wants to Be an Astronaut?

If you've ever wanted to travel into space, this is your chance. No, really. Even you.

The Nobel Prize Fell Into a Black Hole (and That’s a Good Thing)

The 2020 Nobel Prize in Physics is being awarded to scientists to have dedicated their careers to the study of black holes.

Do You Want to Go to Space?

Have you always dreamed of going to space? Former NASA astronaut Mike Massimino answers our questions about life at the International Space Station.

NASA and SpaceX to Launch a Crewed Mission to ISS in May 2020

For the first time since its conception 18 years ago, SpaceX, along with NASA, will launch a crewed mission to space.

NASA HQ to be Named in Honor of Mary W. Jackson

NASA announced Wednesday, June 24th that NASA's Washington, D.C. headquarters will now be named for Mary W. Jackson, the first black, female engineer at NASA.

Waste In Space: NASA's Lunar Loo Challenge

Would YOU like to design one of the next toilets used in space?

NASA Astronauts Take on Two Spacewalks at the International Space Station

Updated July 1, 2020 Six Days. Two spacewalks. Both Successful.

Large Rocket Debris Impacts Earth Off African Coast

The fourth largest piece of space debris ever re-entered the earth's atmosphere yesterday and made a splash just off the coast of Africa. Narrowly missing some major landmarks in its path, this piece of a rocket could have caused some major damage.
Related To: