Pōwehi: The First Photographed Black Hole
The first image of a black hole gets a Hawaiian name from UH Hilo’s own Larry Kimura
Staff Writer Clara Scheidle
Photo Courtesy of Event Horizon Telescope
Astronomers have done what seemed like the impossible: photographing a cosmic entity from which no light escapes.
A black hole, which is a celestial body with a gravitational pull so extreme that nothing—from the smallest particles to radiation—can escape it. The name in Hawaiian, “lolelipo,” literally translates to “to turn the darkness inside out.” They’re massive and all-consuming beasts, which are formed mainly when larger stars are no longer able to continue fusion, at which point the star’s temperature can’t keep the star from collapsing under its own weight. Supermassive black holes, which are at the center of many galaxies, including our own Milky Way, are likely the result of several ancient black holes combining.
Astronomers reached out to Larry Kimura , associate professor of the Hawaiian language and Hawaiian studies at UH Hilo, to name this object. The name he gave it, Pōwehi, has ties in both Hawaiʻi’s language and culture. The name is sourced from the Kumulipo, the sacred chant of creation from the aliʻi, Hawaiʻi’s chiefs. Pō is the powerful, creative darkness referred to in the chant. Wehi is the embellished adornment that would crown and aliʻi—similar to the bright ring of orange that surrounds the black hole. Therefore, Pōwehi stands for the creative darkness which is embellished with a crown.
According to Kimura, the astronomers that had consulted him for a name in late March did not show him the photograph, rather described the photo to him. “They were trying to keep it a secret,” he says.
Kimura says that using Hawaiian conventions of naming is a vital connection of the present to the past. It also puts an emphasis on the Hawaiian language. “We’ve come away from knowing and understanding not only naming but our culture,” he says. “Knowing the language makes that connection.”
Pōwehi resides roughly 53 million light years away from Earth at the center of the galaxy Messier 87, one of the most massive galaxies in the universe. Pōwehi itself is close to 6.5 billion times the mass of the Sun. They chose this particular black hole because it’s immense size has the largest angular diameter in our sky when compared with others—again, followed by the one at the center of our own galaxy.
But how do you photograph something that not even light can escape? The answer: use a radio! Several radio telescopes, from around the world.
Radio telescopes take photos by amplifying signals from radio waves into something that a computer can output as an image. The Event Horizon Telescope, which took the photo of Pōwehi, is actually composed of eight radio telescopes from the northern and southern hemispheres alike. Two of the radio telescopes used reside on Maunakea: the James Clerk Maxwell Telescope and the Submillimeter Array. Using a series of telescopes rather than just one was necessary to photograph Pōwehi, which though it is the largest in our sky, it still needs a telescope with a large diameter to detect.
As they say in astronomy: bigger is better. By connecting eight telescopes from around the world, astronomers were essentially able to create a diameter for a radio telescope that spans across the globe. About 200 researchers have been working on this project, which started collecting data around 2006.
The final photo of Pōwehi was released on April 10. It features the slightly oblong black circle surrounded by a ring of bright orange that places exactly where the event horizon of the black hole takes place.
It’s a spectacular feat with a satisfying conclusion. The image is striking, and has already confirmed Albert Einstein’s general theory of relativity. Pōwehi’s contributions go even further than science, however.
Kimura quotes an astronomer and colleague from JCMT, Doug, who says to think of Pōwehi and its “one name as something to connect to, but as a doorway to something more than just a name.” Kimura also believes that by giving the black hole a proper name is incredibly humanizing. The name Pōwehi can generate curiosity and something to connect to on top of representing Hawaiian culture. He believes that giving celestial bodies names, while not always possible because there are millions out there, is a great way to involve the public in the astronomical field.
Kimura continues by saying that naming this object and future objects “goes hand in hand with restoring our language and culture from where we left off and gives us a place where we can begin from.”