Two rings of dust & gas are revolving around the supermassive black hole in the opposite direction
The scavengers of the Universe usually sit at the center of the galaxies making a meal of anything & everything that comes their way. Even the light can’t escape them. These supermassive celestial bodies called the black holes, which sit at the center of the galaxies and are one of the biggest cosmic mysteries of the known Universe. The one at the center of our Milkyway galaxy is called Sagittarius A*.
If the mystery of the Fermi bubbles sandwiching our Milkyway galaxy had the astronomers scratching their heads, a recent discovery of two rings of clouds orbiting the black hole of the galaxy NGC 1068 has them even more bewildered. This is because contrary to the expectation, the two rings of dust & gas are orbiting the black hole in the opposite direction.
NGC 1068 — which is about 47 million light-years from Earth, had the view of its black hole obscured due to these large clouds of dust & gas. The strange circulation pattern of these clouds was discovered recently with the help of ALMA telescope at the National Radio Astronomy Observatory (NRAO).
According to the observations made, there are two gas disks which stretch out from the center of the black hole. The inner cloud is 2–4 light-years from the black hole and is rotating in the same direction as the galaxy itself, while the outer ring is located between 4–22 light-years from the black hole spinning in the opposite direction to the inner ring & the galaxy.
“Counter-rotating gas streams are unstable, which means that clouds fall into the black hole faster than they do in a disk with a single rotation direction, this could be a way in which a black hole can grow rapidly.”~ Violette Impellizzeri, lead author of the study
Although these counter rotations have been seen happening before to stars and around the edges of the galaxies, but never on this scale & never so close to the center of the galaxy. In those cases, it is usually caused by a collision with another galaxy rotating in the opposite direction.
Researchers speculate something similar here — the outer gas & dust cloud in this gas might be remnants of a smaller colliding galaxy. They also believe that this new mystery might explain a different mystery. The increasing discovery of supermassive black holes at a distance of billions of light-years from Earth, explains how they appeared in the early years of the universe — as we see them now.
But the current understanding of the formation of these black holes suggests that it should take billions of years for these black holes to grow to this size — the bigger question that remains is how they got so big so quickly? The only plausible answer right now is that the clouds from these bi-directional rings feed the black hole quicker increasing their size dramatically.