$10bn Machine in Search of The End of Darkness

Scientists call it the "dark ages" - the time in the Universe before the first stars ignited. And very shortly, they intend to show us that time, or rather how it ended - how the cosmos ultimately became filled with light.

They'll do it using the biggest telescope ever placed beyond Earth: The James Webb Space Telescope. It's on a mission to look deeper into the Universe - and therefore further back in time - than even the legendary Hubble Space Telescope, which it succeeds.


Equipped with a 6.5m-wide (21ft) mirror (made from beryllium coated in gold) and four super-sensitive instruments, Webb will stare for days at a very narrow spot in the sky to detect light that has been travelling through the immensity of space for more than 13.5 billion years.


"They will be just little red specks," says JWST senior project scientist and Nobel Prize winner John Mather. "We think there should be stars, or galaxies, or black holes maybe beginning at 100 million years after the Big Bang. There won't be many of them to find at that time but the Webb telescope can see them if they're there, and we're lucky," the NASA researcher tells the BBC.


It's an astounding idea that you might still be able to witness such a thing. But that's the consequence of light having a finite speed in a vast and expanding cosmos. If you keep probing deeper and deeper, you should eventually get to retrieve the light from the pioneer stars as they group together into the first galaxies.


For what purpose, though? Why spend 10 years conceiving, and another 20 years building, a $10bn machine to detect some faint, red blobs on the sky? Well, essentially it comes down to the most fundamental of questions: Where do we come from?


JWST ha already been hoisted on to the rocket that will transport it into space - launch is scheduled the day after tomorrow! So, barring yet another delay (last weekend it was pushed back from 22 to 24 December) and assuming the telescope unfurls the way it's meant to, we may soon be peering back more than 13.5 billion years in time to the dawn of the cosmos.

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