The Event Horizon Telescope project, the group that took the first-ever image of a black hole, has made another historic breakthrough, making the highest-ever resolution observations of space taken from the Earth’s surface. The project uses facilities around the globe to turn the Earth itself into a giant observatory, which is capable of taking highly precise measurements of distant galaxies.
The latest observations made use of the Atacama Large Millimeter/submillimeter Array (ALMA), a large array of radio telescopes located in Chile, as well as other facilities in Spain, France, and Hawaii. To get higher-resolution images than previous observations, scientists weren’t able to make the telescope bigger — as it was already the size of the Earth — so they observed at a higher frequency instead.
The new setup allowed the researchers to detect light at a wavelength equivalent to 0.87 mm, which should make future images of black holes 50% more detailed — especially the area immediately around the boundary of a black hole.
“To understand why this is a breakthrough, consider the burst of extra detail you get when going from black and white photos to color,” said Sheperd Doeleman, founding director of the EHT. “This new ‘color vision’ allows us to tease apart the effects of Einstein’s gravity from the hot gas and magnetic fields that feed the black holes and launch powerful jets that stream over galactic distances.”
This new ability should enable future images of black holes to be sharper, helping to see the cloud of dust and gas around the edges of a black hole that can help explain how black holes feed and grow, as well as learning about the jets of matter that they can send out at extreme speeds when feeding.
“With the EHT, we saw the first images of black holes using the 1.3-mm wavelength observations, but the bright ring we saw, formed by light bending in the black hole’s gravity, still looked blurry because we were at the absolute limits of how sharp we could make the images,” said fellow researcher Alexander Raymond. “At 0.87 mm, our images will be sharper and more detailed, which in turn will likely reveal new properties, both those that were previously predicted and maybe some that weren’t.”
The research is published in The Astronomical Journal.