Markarian 231: A Tale of Two Black Holes

In 1969, the Markarian 231 Galaxy was discovered while researchers at NASA were looking for galaxies in the Ursa Major constellation that emitted strong ultraviolet radiation. Markarian 231 is found about 600 million light years from Earth.

To put that into perspective, 600 million light years is equal to just about: 3,527,175,223,910,164,638,511 miles. Right down the road…

So What Makes Markarian 231 so Special?

In an edition of The Astrophysical Journal published August 14, 2015, it was revealed that the (Markarian 231) Mrk 231 Galaxy has two black holes whirling around each other at the center of it. This discovery was made using NASA’s Hubble Space Telescope, one of the most amazing and powerful telescopes in NASA’s fleet.



“Hubble Interacting Galaxy UGC 8058 (2008-04-24)” by NASA, ESA, the Hubble Heritage (STScI/AURA)-ESA/Hubble Collaboration, and A. Evans (University of Virginia, Charlottesville/NRAO/Stony Brook University) – (direct link). Licensed under Public Domain via Commons –


According to this new discovery, Markarian 231 is the nearest galaxy to Earth that has a quasar, which is powered by two central black holes rotating around one another at its center.

Definition of a Quasar: extremely distant objects in our known universe. They are the furthest objects away from our galaxy that can be seen. Quasars are extremely bright masses of energy and light. The name quasar is actually short for quasi-stellar radio source or quasi-stellar object.



“Artist’s rendering ULAS J1120+0641” by ESO/M. Kornmesser – Licensed under CC BY 4.0 via Commons –


Definition of a Black Hole: a place in space where gravity pulls so much that even light can’t escape. The gravity of a black hole is so strong because matter has been squeezed into a tiny space. This can happen when a star has died and gone supernova, resulting in a black hole. To learn more about how the life cycle of massive stars result in black holes, check this out.



“BH LMC” by User:Alain r – Own work. Licensed under CC BY-SA 2.5 via Commons –


Definition of a Binary Black Holes: a system consisting of two black holes in close orbit around each other. Sub-types include stellar binary black holes, which are remnants of high-mass binary star systems, and binary supermassive black holes, which are believed to be the result of galactic mergers.

Quasar is actually short for quasi-stellar object or quasi-stellar radio source. We don’t recommend that you go outside tonight and spend hours looking in the night’s sky for these distant objects. Regardless of how long or how hard you try to find one of these astronomical objects, you’re not going to have any luck. It’s going to require an incredibly powerful tool such as NASA’s Hubble telescope.

What Do Binary Black Holes Look Like?

What makes Markarian 231 unique is its binary black hole center. A binary black hole system has two black holes which orbit one another, as if they are dancing and twirling around each other. Based on the description by the Astronomers who discovered this binary black hole system, their appearance can be described similar to that of a doughnut.



“Black Hole Merger” by NASA – Taken from credit is listed to NASA.. Licensed under Public Domain via Commons –


Before you go and get a fork and napkin, what this means is that if there were only one black hole at the center of this quasar, the whole accretion disc (hot gas) would be glowing in ultraviolet rays of light. This would look more like a Frisbee of light. Rather, what they’re seeing is slightly unique and different, ultraviolet rays of light are only glowing around the edges of the disc, making its center blackish-ly dark. This suggests that the two black holes are orbiting one another and not allowing any of the light at the dead center escape their event horizon(s).

How the Heck Did They Get There?

In a statement from one of the Astronomers at the University of Oklahoma, they explained that the current theory for the formation of a binary black hole system at the central core of a galaxy is a natural occurrence and a consequence of two galaxies colliding and merging together.

It isn’t terribly uncommon for galaxies to collide with one another, even though they can be millions and billions of light years from one another. For example, the Andromeda galaxy is roughly 2.5 million light years from the Milky Way galaxy and our closest (galaxy) neighbor. It’s believed that the Andromeda galaxy is a super-galaxy, a galaxy which collided with another galaxy in its past.




In fact, it’s also speculated that the Andromeda galaxy and the Milky Way galaxy will collide with one another. The Andromeda galaxy is moving towards the Milky Way galaxy as you read this, at roughly 4,080 miles per hour! If you’re around when they collide, let us know how it goes.

How Can we See the Center of a Galaxy?

As you can imagine, a binary black hole system at the center of a galaxy is going to generate a massively tremendous and awesome amount of light and energy. Because of this rare phenomenon, the quasar from this binary black hole system sheds so much light that it literally outshines the light being emitted from the billions of stars in its galaxy.



“Hubble sequence photo”. Licensed under CC BY-SA 3.0 via Commons –


This is exciting for another reason, this method of detecting binary black holes through the emission of ultraviolet rays is new. This will allow Astronomers to search for binary black hole systems using one more method of detection and looking for quasars that have a black emptiness at the center of its disc, surrounded by ultraviolet rays of light at its edges.

Are These Binary Black Holes Big?

You bet they are! Astronomers shed a little more light on the situation, pun intended.

The binary black hole system at the center of the Markarian 231 galaxy is gigantically massive. Their early measurements suggest that the true-center black hole is about 150 million times the mass of our Solar System’s star, the Sun. The other black hole circling the central black hole is estimated to weigh about 4 million times the mass of our Sun.

However, these two black holes are still small compared to other super massive black holes, which can be billions of times bigger than the mass of our Sun.

What Will Happen to These Black Holes?

Astronomers are hypothesizing that the two black holes in Mrk 231 are expected to eventually collide with one another. Don’t get too excited, it’s going to be a while. This collision is expected to happen a few hundred thousand years from now.

At that time, it’s hypothesized that the amount of energy and light produced from the two black holes spiraling around each other will produce the equivalent amount of energy and light of more than all of the stars in the Milky Way combined. #bringsunscreen


Featured image:
“Artist’s concept of double black hole” by ESA/Hubble. Licensed under CC BY 3.0 via Commons –

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