The first photograph of a black hole and its fiery halo, released on Wednesday by Event Horizon Telescope astronomers, is the “most direct proof of their existence,” one of the project’s
Frederic Gueth, deputy director of the Institute for Millimetric Radio Astronomy (IRAM) in Grenoble, France, talked about the ground-breaking exploit and the science behind it.
How did you do it?
“The Event Horizon Telescope (EHT) marshalled all the millimetric (radio) telescopes on the planet to make the same rigorous observations at exactly the same time.
“By combining the data gathered by all the telescopes – a technique called very long baseline interferometry – we created a virtual antenna the diameter of Earth.
“The millimetric range – measured in thousandths of a metre – turns out to be the best wave length to investigate black holes because the waves pass through the dust clouds that enshroud them. That is not true for infrared.”