The Hubble Space Telescope just snapped photos of the biggest black hole we've ever observed
Chloe Olewitz,Digital Trends 12 hours ago
A new photograph of galaxy NGC 4889 may look
peaceful from such a great distance, but it’s actually home to one of
the biggest black holes that astronomers have ever identified. The Hubble Space Telescope allowed scientists to capture photos of the galaxy,
located in the Coma Cluster about 300 million light-years away. The
supermassive black hole hidden away in NGC 4889 breaks all kinds of
records, even though it is currently classified as dormant.
So how big is it, exactly? Well, according to our
best estimates, the supermassive black hole is roughly 21 billion times
the size of the Sun, and its event horizon (an area so dense and
powerful that light can’t escape its gravity) measures 130 billion
kilometers in diameter. That’s about 15 times the diameter of Neptune’s
orbit around the Sun, according to scientists at the Hubble Space
Telescope. At one point, the black hole was fueling itself on a process
called hot accretion. Space stuff like gases, dust, and galactic debris
fell towards the black hole and created an accretion disk.
Then that spinning disk of space junk, accelerated by the strong
gravitational pull of the largest known black hole, emitted huge jets of
energy out into the galaxy.
During that
active period, NGC 4889 would have classified as a quasar (quasi-stellar
radio source) thanks to the black hole’s emissions of up to a thousand
times more energy than our Milky Way galaxy. But the black hole is now
in dormant mode because there isn’t any more sustenance stored in the
orbiting accretion disk. “The accretion disk sustained the supermassive
black hole’s appetite until the nearby supply of galactic material was
exhausted. Now, napping quietly as it waits for its next celestial
snack, the supermassive black hole is dormant”, says the Hubble Space
Telescope website.
Of course, the announcement posted with new photos of
the NGC 4889 galaxy is quick to point out that the pictures don’t
exactly capture the likeness of the supermassive black hole. It is
impossible to observe a black hole directly, but scientists have been
able to identify the implied presence of a black hole by analyzing the
way celestial objects interact with some invisible force. For this
particular black hole in the NGC 4889 galaxy, scientists used
instruments on the Keck II Observatory and the Gemini North Telescope to
measure the velocity of stars moving around the center point of the
galaxy. The stars’ specific velocities re what allowed scientists to
calculate the incredible size of NGC 4889’s black hole.
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