Scientists are expected to unveil the first-ever photograph of a black hole, a breakthrough in astrophysics providing insight into celestial monsters with gravitational fields so intense no matter or light can escape.
The US National Science Foundation has scheduled a news conference on Wednesday to announce a "groundbreaking result from the Event Horizon Telescope (EHT) project".
Simultaneous news conferences are scheduled in Brussels, Santiago, Shanghai, Taipei and Tokyo.
The EHT is an international partnership formed in 2012 to try to directly observe the immediate environment of a black hole.
A black hole's event horizon, one of the most violent places in the universe, is the point of no return beyond which anything - stars, planets, gas, dust, all forms of electromagnetic radiation including light - gets sucked in irretrievably.
While scientists involved in the research declined to disclose the findings ahead of the formal announcement, they are clear about their goals.
"It's a visionary project to take the first photograph of a black hole. We are a collaboration of over 200 people internationally," EHT director Sheperd Doeleman said in March.
The research will test physicist Albert Einstein's theory of general relativity, according to EHT project scientist Dimitrios Psaltis.
That theory, put forward in 1915, was intended to explain the laws of gravity and their relation to other natural forces.
The researchers targeted two supermassive black holes.
The first - called Sagittarius A* - is situated at the centre of our own Milky Way galaxy, possessing 4 million times the mass of our sun and located 26,000 light years from Earth.
The second - called M87 - resides at the centre of the neighbouring Virgo A galaxy, boasting a mass 3.5 billion times that of the sun and located 54 million light-years away from Earth.
Black holes, coming in a variety of sizes, are extraordinarily dense entities formed when very massive stars collapse at the end of their life cycle.
Supermassive black holes are the largest kind, devouring matter and radiation and perhaps merging with other black holes.
The scientists also will be trying to detect for the first time the dynamics near the black hole as matter orbits at near light speeds before being swallowed into oblivion.
The fact that black holes do not allow light to escape makes viewing them difficult.
The scientists will be looking for a ring of light - radiation and matter circling at tremendous speed at the edge of the event horizon - around a region of darkness representing the actual black hole. This is known as the black hole's shadow or silhouette.
