NASA animation zooms in on the largest black holes in the universe

A new NASA animation highlights the “super” in supermassive black holes. These monsters lie at the centers of most large galaxies, including our own Milky Way, and contain between 100,000 and tens of billions of times more mass than our Sun.

“Direct measurements, made with the help of the Hubble Space Telescope, confirm the existence of more than 100 supermassive black holes,” said Jeremy Schnittman, a theorist at NASA’s Goddard Space Flight Center in Greenbelt, Maryland. “How does it get so big? When galaxies collide, their central black holes may eventually merge together, too.”

In 2019 and 2022, a network of planet-spanning radio observatories called the Event Horizon Telescope, respectively, produced the first images of giant black holes at the centers of M87 and the Milky Way. They revealed a bright ring of hot gas orbiting a circular region of darkness.

Any light that crosses the event horizon—the black hole’s point of no return—becomes trapped forever, and any light that passes near it is redirected by the black hole’s intense gravity. Together, these effects produce a “shadow” twice the size of the black hole’s actual event horizon.

A new NASA animation shows 10 supermassive black holes taking center stage in their host galaxies, including the Milky Way and M87, measured by the sizes of their shadows. Starting near the sun, the camera steadily backs away to compare larger black holes with different structures in our solar system.

The first of these is 1601+3113, a dwarf galaxy containing a black hole filled with the mass of 100,000 suns. Matter is so compact that the black hole’s shadow is smaller than our sun.

The black hole at the heart of our galaxy, called Sagittarius A* (pronounced ay-star), boasts the weight of 4.3 million suns based on long-term tracking of stars in orbit around it. Its shadow is about half the diameter of Mercury’s orbit in our solar system.

The animation shows two monstrous black holes in the galaxy known as NGC 7727. Located about 1,600 light-years away, one weighs 6 million solar masses and the other more than 150 million suns. Astronomers say the pair will merge within the next 250 million years.

“Since 2015, gravitational-wave observatories on Earth have detected mergers of black holes of a few dozen solar masses thanks to the small ripples in space-time that these events produce,” said astrophysicist Ira Goddard. “The merger of supermassive black holes will produce waves of much lower frequencies that can be detected with space observatories millions of times larger than their counterparts on Earth.”

That’s why NASA is collaborating with the European Space Agency (ESA) to develop their LISA mission, the Laser Interferometer Space Antenna, expected to launch sometime in the next decade. LISA will consist of a constellation of three spacecraft in a triangle firing laser beams back and forth over millions of miles to precisely measure their spacing. This will enable the detection of transient gravitational waves from mergers of black holes with masses of up to a few hundred million suns. Astronomers are exploring other detection techniques for larger mergers.

On the larger scale of the animation lies the black hole of M87, with an updated mass of 5.4 billion suns. Its shadow is so large that even a ray of light — traveling at 670 million miles per hour (1 billion kilometers per hour) — would take about two and a half days to cross it.

The movie ends with TON 618, one of a handful of extremely distant supermassive black holes of which astronomers have direct measurements. This behemoth contains more than 60 billion solar masses, and boasts shadows so large that a ray of light could take weeks to traverse it.