Working together as one massive “virtual telescope”, Radio observatories around the world produced the first direct images of a black hole located at the center of the Messier 87 Galaxy.
Astronomers working with a network of telescopes across the planet have photographed, for the first time ever, a black hole and its shadow. The Black Hole, which measures a mind-bending 40 billion kilometers across–or nearly three million times the size of our planet– has been described as a cosmic monster’. It is located a little over 50 million light-years from our planet in the Messier 87 galaxy. That may explain why the first image appears so blurry.
The historic feat was achieved by an international network of radio telescopes collectively called the Event Horizon Telescope (EHT). The feat is of unprecedented scale since astronomers basically managed to ‘see’ what we thought was unseeable until not long ago.
The EHT is an international collaboration supported by the National Science Foundation in the US.
“6.5 billion times the mass of our Sun exists… and now we’ve got photographic evidence of one.”
The image captured by the EHT is poised to become one of the most recognized images ever taken. The teams that worked on obtaining this stunning image includes more than 200 astronomers.
“This is an amazing accomplishment by the EHT team,” said Paul Hertz, director of the astrophysics division at NASA Headquarters in Washington.
“Years ago, we thought we would have to build a very large space telescope to image a black hole. By getting radio telescopes around the world to work in concert like one instrument, the EHT team achieved this, decades ahead of time.”
“A new era” in space exploration
The mission to observe and photograph a black hole began in 2015 with seven telescopes that turned towards Messier 87 and the center of the Milky Way, but bad weather made observations impossible.
Then, in April of 2017, a network of eight telescopes synchronized by atomic clocks started observing both black holes off and on for ten days.
Two years later, after gathering so much data it was too large to be shared over the internet, scientists gathered their findings and placed them on hard disks which were flown over to M.I.T.’s Haystack Observatory and the Max Planck Institute for Radio Astronomy.
Data gathered from the observatory in Antarctica arrived in December of 2017.
In 2018, scientists were divided into four groups and were tasked with assembling images from all the data that was gathered.
Then, in April of 2018, another telescope joined the EHT, which gather twice the amount of data that had been gathered in 2017.
“We’ve hitched our wagon to a bandwidth rocket,” explained Dr. Shep Doeleman, an astronomer at the Harvard-Smithsonian Center for Astrophysics.
The observations made in 2018 were not included in the recent study but will help astronomers as they make more observations in the future, as well as to comapre data gathered over a period of two years.
“The plan is to carry out these observations indefinitely,” revealed Dr. Doeleman.
How the images were taken is a fascinating story by itself.
From everything we know about Black Holes, these cosmic monsters are very dense objects from which nothing can escape. Not ever light.
Anything that ends up near a Black Hole’s ‘event horizon’, dubbed ‘the point of no return‘, will be devoured, never to escape. That’s because Black Holes have unimaginably powerful gravity.
Black Holes can’t be seen. However, the disk of materials that surround the black hole gives off light and shines brightly.
Against such an orbiting disk of debris, the black hole cast a shadow.
This was actually predicted for the first time by Albert Einstein in his theory of general relativity. Einstein predicted that if a black hole, was surrounded by light-emitting material such as plasma, some of this material may create a shadow or an outline of the black hole and its boundary, known as the event horizon.
“Einstein must be totally chuffed,” revealed Priyamvada Natarajan, an astrophysicist at Yale. “His theory has just been stress-tested under conditions of extreme gravity and looks to have held up.”
The image also confirmed that the shape of a black hole is circular, just as Einstein’s theory had predicted.
The newly released, first-ever image of a black hole in the center of the Messier 87 Galaxy, shows the shadow of the supermassive black hole. Messier 87 or M87 is an elliptical galaxy some 55 million light-years from Earth. Messier 87 is located in the Virgo Galaxy Cluster.
The Black Hole at its center is humongous; 6.5 billion times the mass of the Sun.
“This black hole is much bigger than the orbit of Neptune, and Neptune takes 200 years to go around the sun,” explained Geoffrey Crew, a research scientist at Haystack Observatory.
“With the M87 black hole being so massive, an orbiting planet would go around it within a week and be traveling at close to the speed of light.”
Photographing the shadow the Black Hole casts was tricky and involved eight ground-based radio telescopes working as one massive telescope the size of Earth.
“People tend to view the sky as something static, that things don’t change in the heavens, or if they do, it’s on timescales that are longer than a human lifetime,” says Vincent Fish, a research scientist at Haystack Observatory.
“But what we find for M87 is, at the very fine detail we have, objects change on the timescale of days. In the future, we can perhaps produce movies of these sources. Today we’re seeing the starting frames.”
“These remarkable new images of the M87 black hole prove that Einstein was right yet again,” says Maria Zuber, MIT’s vice president for research and the E.A. Griswold Professor of Geophysics in the Department of Earth, Atmospheric and Planetary Sciences.
“The discovery was enabled by advances in digital systems at which Haystack engineers have long excelled.”
The EHT project also observed Sagittarius A*, a much smaller and less active supermassive black hole at the center the Milky Way, and the data is still being analyzed by astronomers.
By comparing the black hole at the center of M87 and the one located at the center of our galaxy, astronomers expect to understand more about the nature of black holes, how they rotate and how much they influence their cosmic neighborhood.