Black holes have captivated the imagination of people, especially scientists, for decades. I’m still geeking out about seeing the first image of a black hole. Technically, black holes are invisible because they swallow light. Since light is not emitted from black holes, scientists find them by the quasars that are being sucked into their massive gravitational pull.
Quasars are the spinning disk of stars that are being drawn into the black hole. Intense gravitational pull that consumes stars and stellar gases causes a great deal of friction. Swirling stellar material around the mouth of a black hole generates intense radiation that can be seen from billions of light years away.
The quasars extraordinary energy output is what allows them to be seen in spite of the huge distances from which they emanate. Last month astronomers in Japan discovered 83 new quasars that are about 13 billion light-years away from Earth. That means their light came to earth from 13 billion years ago which is the early years of the universe shortly after the Big Bang.
Quasars are the brightest points of light in the universe. Using a giant digital camera that was taller than a person and weighed three tons, Japanese astronomers mounted it on the world’s largest telescope in Hawaii and took pictures.
When quasars are consumed by the black hole, their brilliance is snuffed out and it allows the galaxy that it has over shown to become visible to powerful telescopes. Super massive black holes are found at the center of galaxies including the center of our Milky Way galaxy.
About a hundred years ago Albert Einstein’s relativity equations predicted the size and shape of the ring of a black hole. Black holes have been studied for decades as theoretical projects. The black hole picture unveiled last week verified his theory. Imagine trying to write an algorithm for how we define what the universe looks like.
Dr. Katie Bouman, computer scientist and MIT graduate student, developed the algorithm named CHIRP (Continuous High-Resolution Image Reconstruction using Patch priors) that was used to stitch together data from eight telescopes located about the world. International collaboration of 200 scientists and mathematicians in 20 countries was needed to collect and analyze all this data.
Connecting the eight sites created a telescope dish big enough to refine the image small enough to see the far distant black hole. She compared it to trying to take a picture of an orange on the moon or being able to read the date of a quarter in LA when standing in Washington DC. To see smaller they had to make the telescope bigger.
Scientists turned the whole planet into a radio telescope dish. They calculated the different rates that the individual scopes received the signals and wrote an algorithm to stitch those into a single image.
Dr. Bouman is not an astronomer but rather a computer scientist and researcher who worked on making computers see through images and video. With no background in astrophysics, her work resulted in the first image of a black hole. Katie created and refined the algorithm that fit the puzzle pieces of images together.
During the international press conference, Sheperd Doeleman of Harvard-Smithsonian Center for Astrophysics, the project director for Event Horizon Telescope, revealed the first actual image of a black hole. The event horizon is the point of no return after which light cannot escape the gravitational pull of the black hole.
Shep described the work that was done to add atomic clocks to synchronize the various stations. Scientists waited for just the right weather in Hawaii, Germany and Antarctica. They flew petabytes of data on planes because the internet couldn’t handle it being sent. So much data was collected that it had to be shipped on half a ton of hard drives.
The data they collected had imperfection from the instruments and the atmosphere so it was filtered and downsized to terabytes. Researchers spent time analyzing the data. Four different teams used different imaging algorithms to produce their images before collaborating to see how similar they were to each other and the theoretical computer model.
The black hole they imaged is massive, almost the size of our whole galaxy. Doeleman said that they were thrilled because the team had uncovered part of the universe that had previously been off limits to humans.
Even though black holes are invisible, the first direct visual evidence was collected by mathematicians, astronomers, physicists, and engineers who achieved something that was once thought impossible. Black holes are large sink holes in the fabric of space and time which help mold the shape of galaxies.
While scientist have helped us learn a bit more about space, much is still a mystery. The vastness of the universe is so far beyond human comprehension that even the most powerful computer models cannot begin to approach its full scope. Humans on a tiny blue planet in this solar system cannot comprehend the vastness of this galaxy let alone the universe. The Milky Way occupies an immense amount of space but is only one of 100 billion galaxies.
Kristi McCracken, author of two children’s books and a long time teacher in the South Valley, can be reached at firstname.lastname@example.org.