Since 2019, when the first-ever image of a supermassive black hole at the centre of the
distant galaxy M87 was released, many have been waiting to see if a similar image of
the supermassive black hole at the centre of our galaxy could be captured.
Well, that time has come, because astronomers have finally pierced through the veil of darkness
and dust that shrouds the core of the Milky way and captured the so-called "gentle giant"
that dwells within it.
Located about 26,000 light-years away, this is Sagittarius a*, the supermassive black
hole at the very heart of the Milky Way galaxy.
It is the first-ever direct visual evidence of the elusive object, as before now, scientists
had only seen stars orbiting around something invisible.
As this timelapse shows.
Because the black hole is so far away from Earth, it appears to us to be about the same
size in the sky as a doughnut on the Moon.
But in reality, it is roughly the size of Mercury's orbit around our star.
That's about 60 million km, or about 40 million miles, across.
To image it, the team created the powerful Event horizon telescope or EHT, which linked
together eight existing radio observatories across the planet to form a single “Earth-sized”
virtual telescope.
The EHT observed Sgr A* on multiple nights, collecting data for many hours in a row, similar
to using a long exposure time on a camera.
Adding to the difficulty was the fact that Earth is situated towards the edge of the
Milky Way, so the researchers had to deal with the light from all of the stars, dust
and gas between Earth and Sgr A*.
Although we cannot see the black hole itself, glowing gas around it reveals a dark central
region, called a “shadow”, which is surrounded by a bright ring-like structure.
The new view also captures light bent by the powerful gravity of the black hole, which
is four million times more massive than our Sun.
The super-heated, excited gas in the ring is travelling around the black hole at extreme
speeds, 300,000 km per second, or about 190,000 miles per second.
The brighter regions are likely places where the material is moving towards us and where
its light emission is being energised as a consequence.
At the very centre of the ring, within the dark shadow, is where the black hole resides.
However, because of the ultra-dense nature of black holes, nothing can escape their enormous
gravity, not even light, making them invisible.
The region where light disappears from view, the inside edge of the ring, is Sagittarius
A*'s event horizon.
The point of no return.
The threshold around the black hole where the escape velocity surpasses the speed of
light.
Soon, the new James Webb space telescope will also turn its eye on Sgr A*.
The $10 billion observatory won't have the resolution to directly image the black hole,
however, but it will bring new capability to the study of the environment around it
with its incredibly sensitive infrared instruments.
Even more exciting is the news that three more telescopes have been added to the EHT
network, which means future images of these colossal cosmic monsters should be sharper
and illuminate subtle details in the areas around the black holes.
And soon, we may even be able to see a video of how Sagittarius A* changes over time.
This extraordinary image is the first-ever look at the supermassive black hole at the
centre of our galaxy.
An object that has fascinated astronomers for so long, can now be seen in all its colossal
glory.
What do you think of this stunning image?
Let me know in the comment section below.
If you would like to find out more about these bizarre objects, then why not check out this
video where you can listen to the sound of a supermassive black million of light-years
away.
Thank you all so much for watching.
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And I'll see you all next time.