Einstein and the Event Horizon Telescope

Black Holes are both awe inspiring and endlessly fascinating. Who can fail to be interested in a place where time and light die? They are places of unimaginable power, where the laws of nature as we understand them break down.

And what intrigues me more than anything about black holes is that all we know about them is purely man made. What do I mean; after all, surely, there is nothing less man made than such exotic beasts? Yet all we know about them comes from the human mind and imagination because we have never actually seen one let alone probed or examined one.

Black Holes are the creation of Albert Einstein’s General Theory of Relativity (GTR). Without the theory it would be impossible to have created the concept of the black hole. The GTR predicts that if mass is sufficiently compacted it can deform space-time and create black holes. So what are the features of black holes? A brief summary goes like this:

  • The pulling force of a black hole is so great that not even light can escape – hence the term – black hole. It consumes everything within its gravity. There is no escape.
  • Such enormous gravity is caused by matter being squeezed into a tiny space, such as when stars die and collapse in on themselves
  • There are a whole range of sizes, from the small primordial black holes that are thought to have formed when the universe was formed, to super massive black holes at the centre of galaxies, which have the mass of more than a million times our sun in a space the size of the solar system.
  • The black hole at the centre of our galaxy is called Sagittarius A.
  • We have not seen a black hole – yet, we know of their existence by theory and through stars orbiting close to one producing high-energy light, which we can observe.

However, for the first time it is proposed that we will be able to observe a black hole and take a picture. It is some picture though and it will be taken by the Event Horizon Telescope (EHT).

The EHT is not one stand alone telescope. It is a network of radio telescopes dotted around the globe and it is about to go operational. It plans to focus on the super massive black hole Sagittarius A at the centre of our Galaxy, which is 25000 light years away. The nine telescopes create a virtual telescope the size of the earth by combining data from them all and is capable of seeing a grapefruit on the moon.

What will be seen? Well if GTR is correct a crescent of clouds of dust and gas which blazes with energy. Indeed, the picture will be a validation test for GTR. If the picture sees a ring, then there is something incorrect in the GTR, it predicts a crescent.

All I can say is that every validation so far has proved the theory correct, so I look forward to success. And imagine the excitement of seeing a picture of a black hole!

The EHT is a true Einstein machine. An earth wide network designed to see what the GTR predicted and which will further validate the theory.

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