In 2019, astronomers released the first image of a black hole, a feat that required the use of a Earth-sized virtual telescope.
Now they have released a new picture of that black hole – and this one is even more remarkable than its predecessor.
The first picture of a black hole
A black hole is a place in space and time where gravity is so strong that nothing can escape it, not even light.
The boundary of a black hole – a point to which nothing can return near it – is called the event horizon. While we can’t actually see anything in the black hole, we can see hot gas and dust swirling around this boundary.
Two years ago, astronomers used measurements from the Event Horizon (EHT) telescope, a network of eight radio telescopes scattered across four continents, to create an image of a supermassive black hole at the center of the M87 galaxy, 53 million light-years from Earth.
That first image of a black hole looked like a glowing orange ring with one side a little brighter than the other – it was the side of the black hole closer to Earth.
Now they have gone back through the same EHT data to create a new black hole image that displays it in even more detail.
A new picture of a black hole
To understand what is happening in this new image of a black hole, you need to know a little about the polarization of light.
Light is a wave, and in its natural state it is unpolarized – this means that the wave moves up and down, but also randomly left and right as it travels through space.
Polarized light moves along one plane, oscillating in only two dimensions instead of three.
Light can become polarized if it travels through certain filters, such as those in polarized sunglasses. It is easier to see objects in polarized light – there is less glare – so we wear those sunglasses.
Hot, magnetized areas of space – such as the area around a black hole – can also polarize light.
This new image of a black hole looks sharper because astronomers have focused on the movement of polarized light around the black hole – the lines we see in the image are magnetic field lines.
“It’s like wearing polarized sunglasses on a clear sunny day – all of a sudden you can see what’s going on,” Sheperd Doeleman, director of EHT’s founding, told the New York Times.
“Now we can actually see the patterns of these fields in M87 and start studying how a black hole directs material to its center,” he added. It could tell us more about how black holes form and grow.
EHT researchers have just published two papers on a new image of a black hole, but are already looking for ways to put the photo on top.
“Even now we are designing a next-generation EHT that will allow us to make the first films about black holes,” Doeleman told the Harvard Gazette. “Follow us for a true black hole cinema.”
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