If your car is pulling to one side of the road, your tire treads are wearing out unevenly, or your steering wheel vibrates when accelerating, you need a wheel alignment to adjust the angles of your car’s wheels so they spin straight and true again. However, what if it’s your black hole that spinning wildly? Can black holes be realigned? Is that covered under the warranty? And how did you get a black hole in the first place?
"We did not expect there to be a large misalignment in this system. This discovery challenges our understanding of black hole formation in binary systems and will affect the way we determine the properties of black holes."
This discovery of a badly-aligned black hole is so big and unexpected, it warranted two papers in the journal Science as Helen Jermaka, co-author of one and a researcher at the Astrophysics Research Institute at Liverpool John Moores University, explained in Newsweek. While on a galactic scale, the spinning of space objects from planets to supermassive black holes follow the principle of an automobile tire rotating on an axis – our own solar system is a good example. This should even apply to oddball binary systems like MAXI J1820+70, which consists of a black hole and a star orbiting around each other – their axes should be aligned and perpendicular to the bodies. However, new observations by researchers from Tuorla Observatory in Finland show that the difference between the axes of MAXI J1820+070 was more than 40 degrees – resulting in what one study calls a “crooked spinning black hole” while Gizmodo describes it as a “funky black hole” and astronomers in general refer to it as the most misaligned black hole they've ever seen.
"The expectation of alignment, to a large degree, does not hold for the bizarre objects such as black hole X-ray binaries. The black holes in these systems were formed as a result of a cosmic cataclysm – the collapse of a massive star."
Juri Poutanen, Professor of Astronomy at the University of Turku and lead author of one study, explains in a press release how astronomers could see the axis of an invisible black hole. As MAXI J1820+070’s black hole absorbed matter from its companion star, bright optical and X-ray radiation was emitted as the matter fell in and radio jets were expelled from black hole. Light from the companion star illuminated the jets and confirmed the massive misalignment of the black hole. (A moving illustration can be seen here.)
“The only reasonable explanation is that the misalignment was formed when the black hole was formed. The neutrino rocket was ejected in one direction more than the other.”
An imbalance in the force of neutrino rockets expelled when the black hole was formed is the best explanation Poutanen can come up with for this “funky black hole,” and, since it’s still wobbling at a 40 degree angle millions of years later, there doesn’t appear to be a cosmic wheel alignment service for black holes.
In astronomy, if there’s one, there’s more … so the researchers in these studies expect to find more “funky black holes” using NASA’s new Imaging X-Ray Polarimetry Explorer (IXPE) observatory that will search for X-ray polarization and measure the symmetry in the most extreme objects in space. These observations, and the fact that misaligned black holes are real and no longer theoretical, may help explain other black hole anomalies. As Poutanen puts it:
“So now if we do have misalignment and we observe it then these models actually have a good support because before it was just theoretical imagination. If we assume that we have misalignment, then maybe it’s not so crazy.”
Crazy? Who knew astronomers were so sensitive?