Black hole lies at galaxy’s center

For years, astronomers speculated that a giant, mysterious force lay at the center of the Milky Way, but it wasn’t until four years ago that UCLA astronomer Andrea Ghez definitively showed what it was.

Using new techniques for peering into the dusty heart of the galaxy, Ghez’s observations proved that scores of stars were rapidly orbiting what could only be a black hole. But it wasn’t the kind of garden-variety black hole created when a star explodes and dies; it was hundreds of thousands of times as powerful — a “supermassive” black hole, as they are now known.

Her discoveries, along with the work of scientists studying other galaxies, have in a short time led researchers to the surprising conclusion that most, if not all, of the universe’s hundreds of billions of galaxies have a supermassive black hole at their core. Even more striking, the astronomers have found that the black holes’ mass and nature are closely related to the size and makeup of the surrounding galaxies.

It also appears that these cosmic monsters — which can “eat” stars whole — are key to understanding how galaxies were formed and are still being formed today.

“Many of these discoveries were unexpected,” said Ghez, a self-described “telescope junkie” and rising astronomy star who does much of her galaxy-gazing at the W.M. Keck Observatory in Hawaii, the world’s largest optical telescope. “There’s tremendous interest in this field now because of the potential that it can tell us so much about the dynamics of very basic galaxy creation.”

Black holes appear, for instance, to be both creators and destroyers — swallowing stars or gases that come too close while also spewing out jets of super-high-energy particles and radiation generated by this violent feeding process. The jets, which can be millions of light-years in length, are believed to seed galaxies with the mass and energy that will, in time, become new stars and perhaps even planets.

With many promising areas to research, the supermassives are drawing astronomers and astrophysicists back into black hole research. In 1915, based on purely theoretical calculations, Albert Einstein laid the groundwork for the existence of these bizarre phenomena, which have such strong gravitational pull that not even light can escape them. But research on them languished for decades because there was no way to observe them directly.

The Hubble Space Telescope provided the first real evidence of the existence of supermassive black holes — revealing in 1994 that something was orbiting rapidly around the nuclei of some distant galaxies, suggesting the presence of a huge mass contained in a very small area.

Since then, the Hubble, NASA’s orbiting Chandra X-Ray Observatory, the Keck and other very large, high-resolution ground telescopes have begun to unravel more about these central black holes — which can be as large as the distance from the sun to well past Mars, and as small as New Jersey.

Because nobody knows what happens after a star or gas is swallowed by a black hole, astrophysicists have focused instead on learning and theorizing more about its outer structure. They believe that black holes have an “event horizon” — the point where anything will be inexorably captured by the gravitational pull — and that they have “accretion disks,” a vast, swirling region where matter is funneled into the hole. The process creates intense friction and heat, and as a result energy and matter can get supercharged and shot out in jets.

As supermassive black holes go, the one at the center of the Milky Way (about 27,000 light-years, or 158 trillion miles, away from our exurbanite sun) is dormant and small. It is believed to have the mass of almost 4 million suns and does not appear to be sending out jets of radiation. Some of the larger supermassives are hundreds of millions to many billions times as massive as our sun. (A typical stellar black hole has five to 10 times the mass of the sun, although researchers this week reported discovering an exploded star that was a record two to three times as massive as that.)

To the enormous surprise of those who study the universe, the size of a supermassive black hole appears to have a direct and unusual correlation to the galaxy around it. Researchers calculated a decade ago that the mass of a supermassive black hole appeared to have a constant relation to the mass of the central part of its galaxy, known as its bulge. This relationship supports the notion that the evolution and structure of a galaxy is closely tied to the scale of its black hole.

“Something very profound is going on here, and the formation of black holes and galaxies is related in some way,” said Juna Kollmeier, an astrophysicist and fellow with the Observatories of the Carnegie Institution.

“This is an exciting new wrinkle on the old concept of black holes, and that’s why so many researchers are drawn to it,” she said.

Talk to us

> Give us your news tips.

> Send us a letter to the editor.

> More Herald contact information.

More in Local News

A Mukilteo Speedway sign hangs at an intersection along the road on Sunday, April 21, 2024, in Mukilteo, Washington. (Ryan Berry / The Herald)
Long live the Speedway! Mukilteo’s main drag won’t be renamed

The public shot down the mayor’s idea to change the name: 77% voted ‘No’ in an online survey, with 95% opposed on Facebook.

Motorcyclist dies in crash on East Marine View Drive in Everett

Around 8 p.m. Tuesday, a motorcycle and a vehicle crashed into each other at the intersection of 11th street and East Marine View Drive.

Logo for news use featuring the municipality of Darrington in Snohomish County, Washington. 220118
Motorcyclist dies in crash on Highway 530

Jeremy Doyle, 46, was riding east near Darrington when he crashed into the side of a car that was turning left.

The Marysville School District office on Thursday, Aug. 31, 2023 in Marysville, Washington. (Olivia Vanni / The Herald)
‘Financially insolvent’ Marysville schools to get unprecedented oversight

Superintendent Chris Reykdal will convene a first-of-its-kind Financial Oversight Committee, he wrote in a letter Tuesday.

Woodside Elementary Principal Betty Cobbs on Monday, June 17, 2024 in Bothell, Washington. (Olivia Vanni / The Herald)
Everett’s first Black principal retires after 51 years

In her office, Betty Cobbs kept a black-and-white photo of herself at age 5: “I am right there, with dreams of becoming an educator.”

Junelle Lewis, right, daughter Tamara Grigsby and son Jayden Hill sing “Lift Every Voice and Sing” during Monroe’s Juneteenth celebration on Saturday, June 18, 2022. (Olivia Vanni / The Herald)
On Juneteenth: ‘We can always say that there is hope’

The Snohomish County NAACP is co-sponsoring a celebration Saturday near Snohomish, with speakers, music and food.

Granite Falls
Man, 35, dies from heart attack while hiking Lake 22

The man suffered a heart attack about 1½ miles into the 6-mile hike east of Granite Falls on Friday, authorities said.

36 hours after final show, Everett radio host Charlye Parker, 80, dies

When Parker got into radio, she was a rarity: a woman in a DJ booth. For the past 12 years, she hosted weekend country music shows at KXA.

Homeowners Jim and Chris Hall stand beneath their new heat pump, at right, inside their Whidbey Island home on Thursday, Sep. 7, 2023, near Langley, Washington. The couple, who are from Alaska, have decreased their use of their wood burning stove to reduce their carbon footprint. (Ryan Berry / The Herald)
Snohomish County to start ‘kicking gas’ in push for all-electric homes

Last year, 118 Whidbey Island homes installed energy-efficient heat pumps. A new campaign aims to make the case for induction stoves now, too.

Dr. Scott Macfee and Dr. Daniel Goodman outside of the Community Health Center on Wednesday, June 12, 2024 in Everett, Washington. (Olivia Vanni / The Herald)
Everett CHC doctors, feeling like ‘commodities,’ speak up on ailing system

At the Community Health Center of Snohomish County, doctors say they feel like “rats getting off a sinking ship.” They want it to get better.

Logo for news use featuring the municipality of Mountlake Terrace in Snohomish County, Washington. 220118
Man charged with shooting at ex-girlfriend, child in Mountlake Terrace

The man, 21, showed up to his ex-girlfriend’s apartment and opened fire through the door, new court records say.

People walk along Olympic Avenue past Lifeway Cafe and Olympic Theater that currently hosts Lifeway Church on Friday, July 7, 2023 in Arlington, Washington. (Olivia Vanni / The Herald)
Arlington churches waged covert ‘battle’ against Pride event, records show

Sermons, emails and interviews reveal how an LGBTQ+ nonprofit became the target of a covert campaign by local evangelical leaders.

Support local journalism

If you value local news, make a gift now to support the trusted journalism you get in The Daily Herald. Donations processed in this system are not tax deductible.