Cygnus Black Hole Confirmed by Harvard-Smithsonian Center for Astrophysics

Astronomers at the Harvard-Smithsonian Center for Astrophysics confirm the presence of a black hole in the constellation Cygnus.

The idea that objects exist whose gravity is so powerful that light cannot escape them has been around for centuries. But it was not until instruments aboard a rocket detected x-rays from an unseen source in the constellation Cygnus in 1964 that researchers considered the possibility that they had in fact discovered a black hole, an object from which nothing, including light, can escape. Seven years later, astronomers discovered a star in Cygnus orbiting something that could not be seen. “The dark object’s gravity seemed to be tearing gas from its bright companion,” says author and astronomer Ken Croswell, Ph.D. ’90, “and as the gas took the final plunge [see illustration], it became so hot it emitted x-rays.” But not everyone believed a black hole was the cause; in 1974, Stephen Hawking even bet another physicist that it wasn’t. Now the controversy (which Hawking conceded long ago, based on indirect measurements) has been definitively put to rest by Mark Reid and colleagues at the Harvard-Smithsonian Center for Astrophysics, who were able to calculate an accurate distance to Cygnus X-1, making possible an inference of its mass. Furthermore, they calculated that the gas closest to the dark object orbits it almost 670 times per second—a phenomenal rate that is half the speed of light—clear evidence of an object whose gravitational pull is so strong that it could only be a black hole. 

Read more articles by Jonathan Shaw
Related topics

You might also like

Rachel Ruysch’s Lush (Still) Life

Now on display at the Museum of Fine Arts, a Dutch painter’s art proved a treasure trove for scientists.

What Happens When Infections Stop Responding to Antibiotics?

Harvard Medical School experts discuss the growing threat of antimicrobial resistance.

Green AI: Hype or Hope?

An expert panel explores AI’s climate impact, from emissions to water use.

Most popular

What Trump Means for John Roberts’s Legacy

Executive power is on the docket at the Supreme Court.

Three Harvardians Win Macarthur Fellowships

A mathematician, a political scientist, and an astrophysicist are honored with “genius” grants for their work.

This Harvard Scientist Is Changing the Future of Genetic Diseases

David Liu has pioneered breakthroughs in gene editing, creating new therapies that may lead to cures.

Explore More From Current Issue

Man splashing water on his face at outdoor fountain beside woman holding cup near stone building.

Why Heat Waves Make You Miserable

Scientists are studying how much heat and humidity the human body can take.

Book cover of "Black Moses" by Caleb Gayle with subtitle about ambition and the fight for a Black state.

Civil Rights In the American West

A new book chronicles one man’s quest for a Black state.

Student walking under bright stage lights shaped like smartphones displaying social media apps.

Two Years of Doxxing at Harvard

What happens when students are publicly named and shamed for their views?