08 April 2019
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Artist's impression of a supermassive black hole. Image via Pixabay
Event Horizon Telescope observations of Sagittarius A* and M87 will improve astronomers' understanding of blackholes
Astronomers are expected to release the first-ever photograph of a black hole during the event when they announce the results of the Event Horizon Telescope (EHT) project this week.
On Wednesday, the US National Science Foundation will hold a press conference to announce "a ground-breaking result" from the EHT project. Five other press conferences will be held simultaneously in Tokyo, Taipei, Brussels, Shanghai and Santago by EHT team members to release the first data from the project.
According to scientists, black holes form when stars complete their life cycle and finally collapse. Then, they become extremely dense objects, characterised by intense gravitational fields.
No matter, including planets, stars, dust and gas, can escape from a black hole after being sucked in by it.
As black holes don't allow even light to escape, it becomes extremely difficult to directly observe these objects.
EHT is a visionary project that started seven years ago with the aim of directly observing the surroundings of a black hole and to also capture its photograph, if possible.
More than 200 scientists and astronomers are currently part of this project.
To design EHT, astronomers combined a series of observatories across the world to create a huge virtual telescope. In total, eight radio telescopes - in Mexico, Arizona, Hawaii, Chile, Spain, and around the South Pole - were linked.
The massive virtual telescope eventually generated enough magnifying power for astronomers to target black hole environments and to study their characteristics.
The EHT team focused on two black holes: Sagittarius A* and M87.
Sagittarius A* lies the heart of Milky Way galaxy. It is located about 26,000 light years from Earth and has a mass four million times that of the Sun.
M87 sits at centre of the elliptical galaxy. It lies about 54 million light-years away from Earth, with a mass 3.5 billion times that of the Sun. It is also 1,500 times more massive than Sagittarius A*.
While scientists around the world are eagerly waiting to see the first photograph of a black hole, they also want to know if the new findings from the EHT project challenge Einstein's theory of general relativity.
In 2015, scientists announced that they were able to track collision of two black holes with the help of gravitational wave detectors.
"Einstein's theory of general relativity says that this is exactly what should happen," said Paul McNamara, an astrophysicist at the European Space Agency.
However, the black holes tracked by those detectors were 'just' 60 times more massive than the Sun. Scientists say it would be interesting to see if Einstein's theory also holds for supermassive black holes with mass millions of times that of the Sun.
"Maybe the ones that are millions of times more massive are different — we just don't know yet," McNamara added.
