Skip to Content

Scientists have spotted a tiny black hole that may be just 12 miles across

November 1, 2019
Black hole feeding on gaseous material
Black hole feeding on gaseous materialESO/Gravity Consortium/L. Calçada

A black hole only 3.3 times the mass of the sun may have been spotted, according to results published in Science.

What is it? The black hole is located about 10,000 light-years away, in the outer edge of the Milky Way’s main disk. If it is confirmed, this would be the smallest black hole on record, heralding a new class of black holes we never even knew how to look for. It looks to be about 12 miles (19 kilometers) across, according to Christopher Kochanek at Ohio State University, part of the team that made the discovery. More observations are needed to confirm its actual mass, however.

How was it found? When astronomers look for a black hole, what they’re really looking for are the telltale signs of its existence—a massive accretion disk made of gas and dust swirling around the object and being drawn into the ultra-dense center. Larger black holes that orbit other stars tend to strip massive amounts of material from the stars, producing observable effects like x-ray radiation. 

To find this one, the team scanned a catalogue of 100,000 stars within the Apache Point Observatory Galactic Evolution Experiment (APOGEE), an infrared survey of the stars in the inner galaxy. They found a few hundred stellar candidates that seemed to be wobbling because of gravitational effects induced by other nearby objects. The team narrowed their search down to a binary star system called J05215658. They realized that what looked like a binary star was probably a black hole orbiting another star every 83 days. 

Why it matters: When stars reach their grand finale and explode, they usually take one of two paths: small stars morph into neutron stars, and large stars collapse into black holes. But it’s unclear what the mass threshold for this division is. Further study of J05215658 could help us narrow that down and figure out the factors that play into a star’s afterlife. 

If you like space you should read The Airlock, our space newsletter. You can sign up for free here.

Keep Reading

Most Popular

Geoffrey Hinton tells us why he’s now scared of the tech he helped build

“I have suddenly switched my views on whether these things are going to be more intelligent than us.”

Meet the people who use Notion to plan their whole lives

The workplace tool’s appeal extends far beyond organizing work projects. Many users find it’s just as useful for managing their free time.

Learning to code isn’t enough

Historically, learn-to-code efforts have provided opportunities for the few, but new efforts are aiming to be inclusive.

Deep learning pioneer Geoffrey Hinton has quit Google

Hinton will be speaking at EmTech Digital on Wednesday.

Stay connected

Illustration by Rose Wong

Get the latest updates from
MIT Technology Review

Discover special offers, top stories, upcoming events, and more.

Thank you for submitting your email!

Explore more newsletters

It looks like something went wrong.

We’re having trouble saving your preferences. Try refreshing this page and updating them one more time. If you continue to get this message, reach out to us at with a list of newsletters you’d like to receive.