World / Science & Health

Albert Einstein was right: Takeaways from first image of massive black hole

AP, Kyodo, JIJI

Black holes are cosmic prisons, where nothing escapes, not even light. But lots did come out of Wednesday’s first image of the shadowy edge of a supermassive black hole. Here are four things we learned:

Seeing is believing

Scientists have known for decades that black holes exist, but only indirectly. Three years ago, they essentially heard the sound of two smaller black holes crashing together to form a gravitational wave.

The image revealed Wednesday for the first time showed the edges of the black hole — the point of no return, called the event horizon.

There actually were a few academic holdouts who denied black holes existed, but now they can’t, said Boston University astronomer Alan Marscher, who was on one of four imaging teams.

While much of the matter around a black hole falls into a death spiral and is never to be seen again, the new image captures “lucky gas and dust” circling at just far enough to be safe and seen millions of years later on Earth, said Jessica Dempsey, a co-discoverer and deputy director of the East Asian Observatory in Hawaii.

The new image shows a flaming orange, yellow and black ring that was obviously a black hole and its surroundings, said Harvard’s Sheperd Doeleman, director of the Event Horizon Telescope team.

“We saw something so true,” Doeleman said. “We saw something that really had a ring to it, if you can use that phrase.”

He said the team “uncovered part of the universe that was off-limits to us.”

Dempsey said the ring reminded her of the powerful flaming Eye of Sauron from the “Lord of the Rings” trilogy.

“It’s circular, but on one side the light is brighter,” Dempsey said, because that light is approaching Earth.

The measurements are taken at a wavelength the human eye cannot see, so the astronomers added color to the image. They chose “exquisite gold because this light is so hot,” Dempsey said. “Making it these warm gold and oranges makes sense.”

Unlike smaller black holes that form from collapsed giant stars, supermassive black holes are mysterious in origin. They are situated at the center of most galaxies, including ours, and the size of galaxies and their central black holes are somehow related.

The black hole was one of the two the scientists had targeted, including Sagittarius A* (pronounced “A-star”), the supermassive monster at the center of the Milky Way, 26,000 light-years away from Earth. It has a mass of about 4 million suns and currently is unusually quiet, subsisting on a diet of occasional clouds of gas.

The image the telescope produced was a task as difficult as looking for a tennis ball on the moon with a naked eye.

The international team was able to show the black hole by casting its silhouette against the bright light emitted by the hot gas and dust swirling on the edge of the event horizon.

“This is the first image of a black hole that we’ve seen,” Mareki Honma from the National Astronomical Observatory of Japan said at a news conference in Tokyo. “It’s just one image, but it’s something that has immense meaning.”

Yoshiaki Taniguchi from the Open University of Japan said: “We have visual evidence of something that had never been seen before and on which research and theories were based. This can definitely be considered as worthy of a Nobel Prize.”

Einstein proved right again

Each major astrophysics discovery of the last few decades tends to confirm Albert Einstein’s general theory of relativity, the comprehensive explanation of gravity that the former patent clerk thought of in 1915.

On Wednesday, Einstein’s predictions about the shape and glow of a big black hole proved right, and astronomer after astronomer paid homage to the master.

“Today general relativity passed another crucial test,” said University of Waterloo astronomer Avery Broderick, a co-discoverer. “The Einstein equations are beautiful. So often in my experience, nature wants to be beautiful.”

It sounds strange to keep saying Einstein is right, but every time his general relativity theory is confirmed, “we kill a cloud of alternative theories” and gain better understanding how to create an even more comprehensive theory of physics, said Ethan Vishniac of Johns Hopkins University, who wasn’t part of the discovery team.

A German astronomer, Karl Schwarzschild, in 1916 predicted the theoretical possibility of black holes, based on Einstein’s general relativity, though he did not believe they could actually exist.

Gravity is powerful

The black hole that scientists took a picture of is 55 million light-years away at the center of a massive galaxy called M87 in the nearby Virgo galaxy cluster, and it is far bigger than anything in the Milky Way. Its mass — the chief measurement of a black hole — is 6.5 billion times more than our sun’s. The event horizon stretches about the breadth of our solar system.

“M87’s huge black hole mass makes it really a monster even by supermassive black hole standards,” said Sera Markoff, a discovery team member at the University of Amsterdam.

Some black holes are inactive, but not this one, she said. And that means it converts nearby gas and matter into energy with 100 times more efficiency than the nuclear fusion that powers the stars.

Black holes like these “temporarily become the most powerful engines in the universe,” Markoff said.

Working together works

The project succeeded because of international cooperation among 20 countries and about 200 scientists at a cost of $50 million to $60 million, according to the National Science Foundation.

To get an image of a faraway black hole, scientists had to get eight radio telescopes on several continents, including Antarctica, to look at the same place at the same time. In getting the instruments connected, they essentially created one Earth-size connected telescope.

The amount of data generated was so massive that it could not be transmitted over the internet, so it was flown to data centers by jet.

The data collected was equivalent to a lifetime collection of selfies from 40,000 people, said discovery team member Daniel Marrone of the University of Arizona.

And just to start to take pictures, the weather had to be good at all eight telescopes on the same days in April 2017. The scientists had only 10 days to look; they got four perfect weather days, three of them at the start.

It then took more than a year for that data to be processed into the first glimpse of images that scientists saw in the summer of 2018.

Those images were so good that scientists at first worried that it was just too good to be true, Boston University’s Marscher said.

The telescopes used in the project included the ALMA and APEX telescopes in Chile, the IRAM 30-meter telescope in Spain, the James Clerk Maxwell Telescope in Hawaii, the Large Millimeter Telescope Alfonso Serrano in Mexico, the Submillimeter Array in Hawaii, the Submillimeter Telescope in Arizona and the South Pole Telescope in Antarctica.

From Japan, institutions, including the National Astronomical Observatory of Japan, Tohoku University and Hiroshima University, participated in the EHT project.

While scientists around the world have observed phenomena, such as X-rays released from a disc of gas and other matter around black holes, efforts to observe black holes had been unsuccessful due to insufficient sensitivity and resolution.

There is a myth that says a black hole would rip you apart, but the one pictured is so big, someone could fall into it and not be torn to pieces. But the person would never be seen from again.