WASHINGTON: Using a global network of telescopes to see “the unseeable”, an international scientific team on Wednesday announced a milestone in astrophysics — the first photo of a black hole — in an achievement that validated a pillar of science put forward by Albert Einstein more than a century ago.

Black holes are monstrous celestial entities exerting gravitational fields so vicious that no matter or light can escape. The photo of the black hole at the centre of Messier 87, or M87, a massive galaxy in the relatively nearby Virgo galaxy cluster, shows a glowing ring of red, yellow and white surrounding a dark centre.

The research was conducted by the Event Horizon Telescope (EHT) project, an international collaboration begun in 2012 to try to directly observe the immediate environment of a black hole using a network of Earth-based telescopes. The announcement was made in simultaneous news conferences in Washington, Brussels, Santiago, Shanghai, Taipei and Tokyo.

The team’s observations strongly validated the theory of general relativity proposed in 1915 by Einstein to explain the laws of gravity and their relation to other natural forces. “We have achieved something presumed to be impossible just a generation ago,” said astrophysicist Sheperd Doeleman, director of the Event Horizon Telescope at the Centre for Astrophysics, Harvard & Smithsonian. He said the research “verifies Einstein’s theory of gravity in this most extreme laboratory”.

Black holes, phenomenally dense celestial entities, are extraordinarily difficult to observe by their very nature despite their great mass. A black hole’s event horizon is the point of no return beyond which anything — stars, planets, gas, dust and all forms of electromagnetic radiation — gets swallowed into oblivion. The black hole observed by the scientific team resides about 54 million light-years from Earth. A light-year is the distance light travels in a year, 9.5 trillion kilometres. This black hole is an almost-unimaginable 6.5 billion times the mass of the Sun.

“This is a huge day in astrophysics,” said US National Science Foundation Director France Crdova. “We’re seeing the unseeable.” “It did bring tears to my eyes,” Crdova added.

The project’s researchers obtained the first data in April 2017 using radio telescopes in the US states of Arizona and Hawaii as well as in Mexico, Chile, Spain and Antarctica. Since then, telescopes in France and Greenland have been added to the global network. The global network has essentially created a planet-sized observational dish.

Published in Dawn, April 11th, 2019