Scientists have revealed the first image ever made of a black hole.
Astronomers revealed the picture on Wednesday in Washington. They assembled data gathered by eight radio telescopes around the world to show the violent neighborhood near a supermassive black hole.
The image looks like a glowing eye. Co-discoverer Jessica Dempsey says it is a vivid ring of light that reminds her of the powerful flaming Eye of Sauron from the Lord of the Rings trilogy.
Nothing, not even light, escapes from supermassive black holes. They are the light-sucking monsters of the universe theorized by Einstein more than a century ago and confirmed by observations for decades. The event horizon is the point of no return around them.
The results are being published in the Astrophysical Journal Letters.
Scientists expected to release landmark image of black hole
An international scientific team is expected on Wednesday to unveil a landmark achievement in astrophysics - the first photo of a black hole - in a feat that will put to the test a pillar of science: Albert Einstein's theory of general relativity.
Black holes are phenomenally dense celestial entities with gravitational fields so powerful no matter or light can escape, making them extraordinarily difficult to observe despite their great mass.
News conferences are set in Washington, Brussels, Santiago, Shanghai, Taipei and Tokyo to disclose a "groundbreaking result" from the Event Horizon Telescope (EHT) project, begun in 2012 to directly observe the immediate environment of a black hole using a global network of telescopes.
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 project targeted two supermassive black holes residing at the center of different galaxies.
The Washington news conference convened by the U.S. National Science Foundation is scheduled for 9 a.m. (1300 GMT) on Wednesday. Among those due to speak are astrophysicist Sheperd Doeleman, director of the Event Horizon Telescope at the Center for Astrophysics, Harvard & Smithsonian.
The research will test the theory of general relativity put forward in 1915 by Einstein, the famed theoretical physicist, to explain the laws of gravity and their relation to other natural forces.
Einstein's theory allows for a prediction of the size and shape of a black hole. If the prediction turns out to be off the mark, the theory may need rethinking.
This is separate from another key component of Einstein's broader theory of relativity: his 1905 theory of special relativity, part of the basis of modern physics. The theory of special relativity explaining the relationship between space and time.
One of the black holes - Sagittarius A* - is situated at the center of our own Milky Way galaxy, possessing 4 million times the mass of our sun and located 26,000 light years from Earth. A light year is the distance light travels in a year, 5.9 trillion miles (9.5 trillion km).
The second one - M87 - inhabits the center of the neighboring Virgo A galaxy, boasting a mass 3.5 billion times that of the sun and located 54 million light-years away from Earth. Streaming away from M87 at nearly the speed of light is a humongous jet of subatomic particles.
Black holes, which come in different sizes, are formed when very massive stars collapse at the end of their life cycle. Supermassive black holes are the largest kind, growing in mass as they devour matter and radiation and perhaps merging with other black holes.
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 - disrupted matter and radiation 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.
The scientists said the shape of the shadow would be almost a perfect circle in Einstein's theory of general relativity, and if it turns out that it is not, there is something wrong with the theory.
The project's researchers obtained the first data in April 2017 using telescopes in the U.S. states of Arizona and Hawaii as well as Mexico, Chile, Spain and Antarctica. Since then, telescopes in France and Greenland have been added to the global network. The global network of telescopes has essentially created a planet-sized observational dish.
Scientists set to unveil first picture of a black hole
The world, it seems, is soon to see the first picture of a black hole.
On Wednesday, astronomers across the globe will hold "six major press conferences" simultaneously to announce the first results of the Event Horizon Telescope (EHT), which was designed precisely for that purpose.
It has been a long wait.
Of all the forces or objects in the Universe that we cannot see - including dark energy and dark matter - none has frustrated human curiosity so much as the invisible maws that shred and swallow stars like so many specks of dust.
Astronomers began speculating about these omnivorous "dark stars" in the 1700s, and since then indirect evidence has slowly accumulated.
"More than 50 years ago, scientists saw that there was something very bright at the centre of our galaxy," Paul McNamara, an astrophysicist at the European Space Agency and an expert on black holes, told AFP.
"It has a gravitational pull strong enough to make stars orbit around it very quickly - as fast as 20 years."
To put that in perspective, our Solar System takes about 230 million years to circle the centre of the Milky Way.
Eventually, astronomers speculated that these bright spots were in fact "black holes" - a term coined by American physicist John Archibald Wheeler in the mid-1960s - surrounded by a swirling band of white-hot gas and plasma.
At the inner edge of these luminous accretion disks, things abruptly go dark.
"The event horizon" - a.k.a. the point-of-no-return - "is not a physical barrier, you couldn't stand on it," McNamara explained.
"If you're on the inside of it, you can't escape because you would need infinite energy. And if you are on the other side, you can - in principle."
A golf ball on the moon
At its centre, the mass of a black hole is compressed into a single, zero-dimensional point.
The distance between this so-called "singularity" and the event horizon is the radius, or half the width, of a black hole.
The EHT that collected the data for the first-ever image is unlike any ever devised.
"Instead of constructing a giant telescope - which would collapse under its own weight - we combined several observatories as if they were fragments of a giant mirror," Michael Bremer, an astronomer at the Institute for Millimetric Radio Astronomy in Grenoble, told AFP.
In April 2017, eight such radio telescopes scattered across the globe - in Hawaii, Arizona, Spain, Mexico, Chile, and the South Pole - were trained on two black holes in very different corners of the Universe to collect data.
Studies that could be unveiled next week are likely to zoom in on one or the other.
Oddsmakers favour Sagittarius A*, the black hole at the centre of our own elliptical galaxy that first caught the eye of astronomers.
Sag A* has four million times the mass of our sun, which means that the black hole is generates is about 44 million kilometres across.
That may sound like a big target, but for the telescope array on Earth some 26,000 light-years (or 245 trillion kilometres) away, it's like trying to photograph a golf ball on the Moon.
The other candidate is a monster black hole - 1,500 times more massive even than Sag A* - in an elliptical galaxy known as M87.
It's also a lot farther from Earth, but distance and size balance out, making it roughly as easy (or difficult) to pinpoint.
One reason this dark horse might be the one revealed next week is light smog within the Milky Way.
"We are sitting in the plain of our galaxy - you have to look through all the stars and dust to get to the centre," said McNamara.
The data collected by the far-flung telescope array still had to be collected and collated.
"The imaging algorithms we developed fill the gaps of data we are missing in order to reconstruct a picture of a black hole," the team said on their website.
Astrophysicists not involved in the project, including McNamara, are eagerly - perhaps anxiously - waiting to see if the findings challenge Einstein's theory of general relativity, which has never been tested on this scale.
Breakthrough observations in 2015 that earned the scientists involved a Nobel Prize used gravitational wave detectors to track two black holes smashing together.
As they merged, ripples in the curvatures of time-space creating a unique, and detectable, signature.
"Einstein's theory of general relativity says that this is exactly what should happen," said McNamara.
But those were tiny black holes - only 60 times more massive than the Sun - compared to either of the ones under the gaze of the EHT.
"Maybe the ones that are millions of times more massive are different - we just don't know yet."