– [image: The Event Horizon Telescope provided the first ever photograph of a black hole and its fiery halo (AFP Photo/-)] – [image: The Event Horizon Telescope — a network of eight radio telescopes across the globe — gathered data to generate the first image of a black hole some 50 million lightyears from Earth (AFP Photo/Sophie RAMIS)] – [image: Coined in the mid-60s by American physicist John Archibald Wheeler, the term “black hole” refers to a point in space where matter is so compressed as to create a gravity field from which even light cannot escape (AFP Photo/Alain BOMMENEL)]
link#
Paris – Astronomers on Wednesday unveiled the first photo of a black hole,one of the star-devouring monsters scattered throughout the Universe andobscured by impenetrable shields of gravity.
The image of a dark core encircled by a flame-orange halo of white-hotplasma looks like any number of artists’ renderings over the last 30 years.
But this time, it’s the real deal.
“The history of science will be divided into the time before the image, andthe time after the image,” said Michael Kramer, director at the Max PlanckInstitute for Radio Astronomy.
Carlos Moedas, European Commissioner for Research, Science and Innovationcalled the feat a “huge breakthrough for humanity.”
The supermassive black hole immortalised by a far-flung network of radiotelescopes is 50 million lightyears away at the centre of a galaxy known asM87.
“It’s a distance that we could have barely imagined,” Frederic Gueth, anastronomer at France’s National Centre for Scientific Research (CNRS) andco-author of studies detailing the findings, told AFP.
Most speculation had centred on the other candidate targeted by the EventHorizon Telescope: Sagittarius A*, a closer but smaller black hole at thecentre of our own galaxy, the Milky Way.
Locking down an image of M87’s supermassive black hole at such distance iscomparable to photographing a pebble on the Moon, the scientists said.
It was also very much a team effort.
“Instead of constructing a giant telescope that would collapse under itsown weight, we combined many observatories,” Michael Bremer, an astronomerat the Institute for Millimetric Radio Astronomy (IRAM) in Grenoble, toldAFP.
– Earth in a thimble –
Over several days in April 2017, eight radio telescopes in Hawaii, Arizona,Spain, Mexico, Chile, and the South Pole zeroed in on Sag A* and M87.
Knitted together, they formed a virtual observatory some 12,000 kilometresacross — roughly the diameter of Earth.
“The data is like an incomplete puzzle set,” said team member MonikaMoscibrodzka, an astronomer at Radboud University. “We only see pieces ofthe real true image, and then we have to fill in the gaps of the missingpieces.”
In the end, M87 was more photogenic. Like a fidgety child, Sag A* was too”active” to capture a clear picture, the scientists said.
“What we see in the image is the shadow of the black hole’s rim — known asthe event horizon, or the point of no return — set against the luminousaccretion disk,” Gueth told AFP.
The unprecedented image — so often imagined in science and science fiction— has been analysed in six studies co-authored by 200 experts from 60-oddinstitutions and published Wednesday in Astrophysical Journal Letters.
Read Top Stories
“I never thought that I would see a real one in my lifetime,” said CNRSastrophysicist Jean-Pierre Luminet, author in 1979 of the first digitalsimulation of a black hole.
Coined in the mid-60s by US physicist John Archibald Wheeler, the term”black hole” refers to a point in space where matter is so compressed as tocreate a gravity field from which even light cannot escape.
The more mass, the bigger the hole. At the same scale of compression, Earthwould fit inside a thimble.
A successful outcome depended in part on the vagaries of weather during theApril 2017 observation period.
“For everything to work, we needed to have clear visibility at every(telescope) location worldwide”, said IRAM scientist Pablo Torne, recallingcollective tension, fatigue and, finally, relief.
– ‘Hell of a Christmas present’ –
Torne was at the controls of the Pico Veleta telescope in Spain’s SierraMadre mountains.
After that, is was eight months of nail-biting while scientists at MITHaystack Observatory in Massachusetts and the Max Planck Institute forRadio Astronomy in Bonn crunched the data.
The Universe is filled with electromagnetic “noise”, and there was noguarantee M87’s faint signals could be extracted from a mountain of data sovoluminous it could not be delivered via the Internet.
There was at least one glitch.
“We were desperately waiting for the data from the South Pole Telescope,which — due to extreme weather conditions during the southern hemispherewinter — didn’t arrive until six months later,” recalled Helger Rottmannfrom the Max Planck Institute.
It arrived, to be precise, on December 23, 2017.
“When, a few hours later, we saw that everything was there, it was one hellof a Christmas present,” Rottmann said.
It would take another year, however, to piece together the data into animage.
“To be absolutely sure, we did the work four times with four differentteams,” said Gueth.
Team scientists presenting the findings at a news conference in Brusselswere visibly moved.
“We are looking at a region we have never looked at before, that we cannotreally imagine being there,” said Heino Falcke, chair of the EHT ScienceCouncil.
“It feels like looking at the gates of hell, at the end of space and time–- the event horizon, the point of no return.” – APP/AFP
