![]() Different weather, atmospheric and telescope conditions at each site will require meticulous calibration of the data so that scientists can be sure any features they find in the final images are not artefacts. The data recorded at each station in the network will be shipped to a central processing facility where a supercomputer will carefully combine all the data. What’s at stake?Īlthough the practice of connecting many telescopes in this way is well known, particular challenges lie ahead for the Event Horizon Telescope. But by connecting many telescopes, the Event Horizon Telescope will be about to achieve a resolution of 15-20 microarcsecond (0,000015 arcseconds), corresponding to being able to spy a grape at the distance of the moon. This is comparable to the resolution of the unaided human eye and about a sixtieth of the apparent diameter of the full moon. The resolution of a single radio telescope (typically with an aperture of 100 metres) is roughly about 60 arc seconds. For any telescope, the bigger its aperture, the smaller the detail that can be resolved. ![]() The angular size of the moon as seen from the Earth is about half a degree, or 1800 arc seconds. The resolution of any kind of telescope – the finest detail that can be discerned and measured – is usually quoted as a small angle corresponding to the ratio of an object’s size to its distance. However, telescopes with sufficient resolution and operating at longer, radio millimetre wavelengths can peer through this cosmic fog. The black hole is a compact source on the sky – its view at optical wavelengths (light that we can see) is completely blocked by large quantities of dust and gas. The Atacama Large Millimeter submillimeter Array ALMA by night under the Magellanic Clouds. ![]() It’s rather like putting on spectacles and suddenly being able to see both headlights from an oncoming car rather than a single blur of light. But the addition of sensitive new arrays of telescopes – including the Atacama Large Millimeter Array in Chile and the South Pole Telescope – will give the network a much-needed boost in power. However, these tests initially revealed a limited sensitivity and an angular resolution that was insufficient to probe down to the scales needed to reach the black hole. The “virtual telescope” has been in development for many years and the technology has been tested. The array connects nine stations spanning the globe – some individual telescopes, others collections of telescopes – in Antarctica, Chile, Hawaii, Spain, Mexico and Arizona. And they may even see the shadow of the black hole’s event horizon against the backdrop of this brightly shining swirling material. The tell-tale signature astronomers hope to see with the Event Horizon Telescope is a bright crescent shape rather than a disk. Its brightness and colour are also expected to be altered in predictable ways. The path the light from this material takes will be distorted in the gravitational field of the black hole. NASA/wikipediaĪstronomers know there is a disk of dust and gas orbiting around the black hole. This image was taken with NASA’s Chandra X-Ray Observatory. ![]() Last year, the LIGO experiment provided even more proof by famously detecting ripples in space-time caused by two medium-mass black holes that merged millions of years ago.īut while we now know that black holes exist, questions regarding their origin, evolution and influence in the universe remain at the forefront of modern astronomy. When overfed with material from the surrounding galactic environment, they also eject detectable plumes or jets of plasma to speeds close to that of light. That’s because they can see the gravitational pull they have on stars orbiting around the galactic centre. Their existence was predicted mathematically by Karl Schwarzchild in 1915, as a solution to equations posed in Albert Einstein’s theory of general relativity.Īstronomers have had circumstantial evidence for many decades that supermassive black holes – a million to a billion times more massive than our sun – lie at the hearts of massive galaxies. But this could now be about to change as an international team of astronomers is connecting a number of telescopes on Earth in the hope of making the first ever image of a black hole.īlack holes are regions of space inside which the pull of gravity is so strong that nothing – not even light – can escape. Perhaps part of the allure is that these enigmatic objects have never actually been “seen”. Ever since first mentioned by Jon Michell in a letter to the Royal Society in 1783, black holes have captured the imagination of scientists, writers, filmmakers and other artists. ![]()
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