Scientists have successfully taken first ever picture of the shadow of a black hole providing direct observation of its immediate environment
The super-massive black holes were first predicted by Einstein in 1915 in his General Theory of Relativity when he showed gravity bends light. There have been many developments since then but never any direct evidence. Scientists were only able to detect them indirectly. The first real picture of the shadow of a super massive black hole has now been captured providing first direct evidence of their presence, thanks to ”The Event Horizon Telescope Collaboration”.
The black holes are extremely compressed mass in a very small region. Its gravity is so high that nothing at all escapes if gets too close to its boundary. The Event Horizon is the boundary around the black hole that marks what is inside and what is outside. Once anything crosses this boundary, it gets swallowed and can never come out. Black holes swallow all light therefore they are invisible and cannot be seen or pictured.
The intense gravity of black hole attracts and pulls interstellar gas onto itself faster and faster. This heats up the gas immensely and light radiation is emitted. These emissions are warped into a circular ring by the gravity of the black hole.
A black hole itself is invisible but its shadow against super-heated gas cloud around it could be pictured.
Black hole’s presence couldn’t be directly observed uptill now mainly due to the fact that black holes are extremely small targets for the available radio telescopes which were not capable enough to observe their event horizon. Observing black holes directly needed building an ingenious telescope virtually the size of Earth.
It took about a decade to organise a network of telescopes called the ”Event Horizon Telescope” spanning the face of the Earth which combined eight separate telescopes in Mexico, Arizona, Hawaii, Chile and South Pole. All eight dishes of the telescope needed to be linked and pointed towards the black hole at exactly the same time. The signals received by the telescopes were combined by a correlator (a super computer) to give an image of the event horizon of the black hole.
The success of this experiment is a significant breakthrough in astronomy.
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Credit: Image taken from “EHTC, Akiyama K et al 2019, ‘First M87 Event Horizon Telescope Results. I. The Shadow of the Supermassive Black Hole‘, The Astrophysical Journal Letters, Vol. 875, no. L1.
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Source(s)
1. EHTC, Akiyama K et al 2019. First M87 Event Horizon Telescope Results. I. The Shadow of the Supermassive Black Hole’. The Astrophysical Journal Letters, 875(L1) https://doi.org/10.3847/2041-8213/ab0ec7
2. Max Planck Institute for Radio Astronomy, 2019. First-ever picture of a black hole. Retrieved from https://www.mpg.de/13337404/first-ever-picture-of-black-hole
3. BlackHoleCam, 2019. IMAGING THE EVENT HORIZON OF BLACK HOLES, Retrieved from https://blackholecam.org/
4. European Commission – Press release, 2019. EU-funded scientists unveil first ever image of a black hole. Retrieved from http://europa.eu/rapid/press-release_IP-19-2053_en.htm
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