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CosmosUp | August 15, 2022

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Astronomers Build Telescope As Big As Earth To See Milky Way Black Hole In Detail

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Astronomers Build Telescope As Big As Earth To See Milky Way Black Hole In Detail

Scientists across the globe are planning to bulid a virtual telescope as big as earth by connecting a planet-wide system of telescopes across our planet thus to take detailed pictures of the black hole at the center of our Milky Way galaxy.

This giant telescope will be named the Event Horizon Telescope (EHT) and it’ll be the first instrument ever capable of photographing the event horizon of the supermassive black hole known as Sagittarius A-star.

Even though the Milky Way’s supermassive black hole is 4 million time more massive than our sun, its too far — almost 26000 ly away — to study its event horizon in detail, studying its is equivalent to seeing a grapefruit on the Moon for someone standing on Earth.

But the EHT will make it possible to observe new details of ‘event horizons‘ with its unprecedented resolution, more than 1,000 times clearer than the Hubble Telescope.

The goals of the EHT are to test Einstein’s theory of general relativity, understand how black holes eat and generate relativistic outflows, and to prove the existence of the event horizon, or ‘edge,’ of a black hole.

Says Dan Marrone, an assistant professor in the University of Arizona.

For those who are not aware about the EHT, its an array of radio telescopes spread out across the globe and connected using a technique known as Very Long Baseline Interferometry, or VLBI. With larger telescopes we could make sharper observations, and interferometry allows multiple telescopes to act like a single telescope as large as the separation — or “baseline” — between them.

Now that the technique has been extended to the South Pole Telescope, the Event Horizon Telescope spans the entire Earth, from the Submillimeter Telescope on Mount Graham in Arizona, to California, Hawaii, Chile, Mexico, Spain and the South Pole.

The baselines to SPT give us two to three times more resolution than our past arrays, which is absolutely crucial to the goals of the EHT.

Said Marrone, who leads the effort.


To verify the existence of an event horizon, the ‘edge’ of a black hole, and more generally to test Einstein’s theory of general relativity, we need a very detailed picture of a black hole. With the full EHT, we should be able to do this.

EHT is expected to see the swirling gas on its final plunge over the event horizon — the ‘edge’ of a black hole — and more generally to test Einstein’s theory. If Einstein’s theory is correct, the black hole itself will be invisible because not even light can escape its huge gravity. However, it might still be seen as a silhouette against the background.

I cannot wait to see what we can learn from a telescope 10,000 miles across.

Said Junhan Kim, a doctoral student at the UA.

The science, which addresses fundamental questions of space and time, is as exciting to us as peering back to the beginning of the universe.



  • Press release:


  1. Speaker

    NASA can’t even provide a proper picture of the earth, let alone the Sagittarius A-star.

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