Northern Arizona astronomy: A new rogue black hole

Although the Webb Telescope has recently been grabbing all the current astronomical news, the Hubble Space Telescope is still up there making exciting discoveries.

Recently, it spotted a unique rogue super-massive black hole rapidly rushing through outer space. A black hole is the densest of objects in space; the gravity is so intense that even light cannot escape. Although rogue black holes are nothing new to science, astronomers have never before seen one move this fast or act as this one does anywhere in the universe.

This black hole weighs as much as 20 million Suns and is travelling at 3.5 million miles an hour — so fast that if it were in our solar system it would travel 240,000 miles (the distance between the Earth and the Moon) in 14 minutes.

The creation of stars is commonly observed in the gas and dust within the arms of spiral galaxies. However, this black hole, rather than just devouring material in its path due to its great velocity, appears to be dragging newly-collected gas and dust. This gas and dust is able to cool off, creating a string of newly formed stars in its wake as it moves through the universe.

Effectively, what astronomers were observing was the aftermath, like the wake behind a ship with waves, eddies and flowing currents. This string of stars and material stretches 200,000 light years (twice the width of our Milky Way galaxy) from the location of the black hole in the direction of the galaxy researchers believe it originated from.

As sometimes happens in astronomy, observing this object was pure serendipity. The astronomers had been scanning through Hubble images originally looking for something called a globular cluster and noticed a small streak, which they originally thought was the result of a cosmic ray hitting the camera detector, causing a linear imaging artifact. However, after examination, they eliminated the possibility of cosmic rays and realized it was actual data which did not look like anything they ever had seen before.

But how was this unique rogue black hole created?

The current hypothesis is that the runaway black hole was probably formed by a group of black holes that merged together over time. The first two were probably formed when two galaxies collided about 50 million years ago with two super-massive black holes at their center, forming a binary pair. Then, another third rogue black hole flew into the mix. This destabilized the orbits of the binary pair and one of them was thrust out into space (though scientists do not know which one).

Astrophysicists assume that this is the point at which the black hole achieved its impressive velocity within that galaxy. Researchers have also determined that one of the other black holes was probably thrown in the opposite direction.

Wanting to confirm its location in future observations, astronomers expect that this discovery will be followed up using the Webb Telescope and the Chandra X-ray Observatory to corroborate the data.

This phenomenon has been hypothesized and predicted for decades, and if confirmed, will be the first time that a black hole has been proven to have been kicked out of its home galaxy.