NGC 4889 has been asleep for millions of years creating a mostly peaceful environment within the galaxy. But deep within its core lurks a monster – one of the most massive black holes ever discovered.
In this new image from NASA/ ESA’s Hubble Space Telescope, the huge elliptical galaxy NGC 4889 is shown about 300 million light years away in the Coma galaxy cluster. Its central black hole is estimated to be about 21 billion times the mass of the Sun. It dwarfs our Milky Way’s black hole, which has a mass of only 4 million solar masses.
The black holes mass was uncovered by measuring the velocity of stars moving around it using the Keck II Observatory and Gemini North Telescope in Hawaii. The velocities of the stars are dependent on the mass of the object they orbit, so once they knew that, astronomers we able to infer the mass of the immense supermassive black hole.
Amazingly, the black hole has an event horizon (the area around a black hole where even light can’t escape) with a diameter of about 130 billion kilometers – that’s about 30 times the distance Neptune is from the Sun.
Its immense mass hints to the glory days where it would have gorged on large amounts of dust and gas, creating a massive accretion disk shrouding the galactic core. Scientists say during its active period NGC 4889 would have been classified as a quasar, likely emitting up to a thousand times the energy output of the Milky Way.
But you can’t just keep swallowing dust and devouring stars forever – so nowadays NGC 4889’s black hole is resting and dormant, after using up all the surrounding dust and gas. It will likely nap quietly awaiting its next cosmic snack.
Materials provided by ESA/Hubble.