Last year, astronomers created the first-ever direct image of a supermassive black hole by collecting data from a network of observatories called the Event Horizon Telescope (EHT). Since then, the team has dug into additional data from the past decade to create more images using similar techniques. The sequence of images dating from 2009 to 2017 have been put together as a .gif that shows the activity and "wobble" of a black hole.
A report on the imaging work was published on Wednesday in The Astrophysical Journal.
When it was released last year, the first black hole image made headlines as the strongest proof of Albert Einstein's theory of general relativity. His theory, which attempts to explain how gravity is created through distortions in space-time, essentially predicted the gravity-laden, dark center of a black hole. This center is known as the event horizon, the area where gravity is so strong that not even light can escape.
It took the EHT team two years to create their breakthrough image of a supermassive black hole called M87. Scientists went into a tizzy, including one who had expected to see a mere "blob," as the pictures actually showed the bright ring of mass circling the center.
The same team decided to create similar images using older data, though they had to fiddle with their technique a little. Back in 2009, data was limited because they didn't have as many telescopes in their network to collect information. As the years went by, more observatories were constructed and added, and better images were possible.
Since the older data had less details, the astronomers had to fill that part in with speculation drawn from the images and data they produced in 2017. Thanks to their efforts, one can clearly see brighter spots on the ring moving around — also called a "wobble" — which has sparked additional questions.
It could be parts of the bright mass dimming and brightening as it's pulled into the center of the hole. Or it could be a mind-blowing optical trick that makes the bright part look like it's moving around, even if it's not.
The images, both moving and not, have taught researchers a lot about the dynamics of a black hole. The EHT team hopes to continue their research every year, producing new images with greater details. As technology continues to improve, perhaps the still images will eventually become actual videos.
"In a few years, it could really start to look like a movie," lead author Maciek Wielgus told Nature.