All About Space

Unfurling the JWST

For the first time ever, scientists have seen a glow from behind one of these high-gravity objects

- Reported by Daisy Dobrijevic

Generation Space Telescope (NGST) was born.

Over the next six years, various refinement­s were made to its design, including a change of name in 2002 to honour the man who had been at the forefront of the iconic Apollo missions. Designed and overseen in cooperatio­n with the European Space Agency (ESA), Canadian Space Agency (CSA) and the Space Telescope Science Institute (STScI), constructi­on of the JWST began in earnest in 2004. To make NASA’s ambitious plans for the JWST possible, the agency and its partners have brought together some of the most innovative technologi­es currently available in the industry. The craft will have a colossal ‘backpane’ that will serve as the spine for the craft, holding the giant 6.5-metre (21.3-foot) segmented mirror and ensuring the whole vehicle remains motionless while its mirrors and lenses work together to capture each stunning image. This section of the craft will also provide a vital means of regulating the craft’s temperatur­e – an important factor when you consider it will be operating at around -225 degrees Celsius (-370 degrees Fahrenheit).

Those mirrors form the most essential part of the JWST – in order to see the remains of the universe’s birth, over a staggering 13 billion light years away, the mirror in question would have to be big enough to collect every last drop of light. However, a huge mirror means considerab­le weight, so the JWST teams have created one from 18 hexagonal segments, with each one crafted from beryllium and

“Those mirrors form the most essential part of the JWST”

coated in gold to improve its reflection of infrared light. Each individual segment weighs as little as 20 kilograms, and they all fit together to create one giant instrument.

So what does the future hold for the JWST? It’s already shaping up to be a big year for the craft in the run-up to its planned November launch. Currently, almost every element of the telescope has been assembled, including the huge gold and beryllium mirrors and the large ‘backplane’ that forms the spine of the craft. The first of its mirrors was installed at the end of November 2015. With a team of over 1,000 people from over 17 countries involved in its creation, the JWST has been a long time coming, but its mission to capture the first light of the universe has galvanised those involved, setting the stage for one of the most anticipate­d developmen­ts in modern space engineerin­g.

Black holes are regions in space-time where gravity’s pull is so powerful that not even light can escape its grasp. However, while light cannot escape a black hole, the extreme gravity warps the space around it, which allows light to ‘echo’, bending around the back of the object. Thanks to this strange phenomenon, for the first time astronomer­s have observed the light from behind a black hole.

In a new study, researcher­s led by Dan Wilkins, an astrophysi­cist at Stanford University in California, used the European Space Agency’s XMM-Newton and NASA’s Nuclear Spectrosco­pic Telescope Array (NuSTAR) to observe the light from behind a black hole that’s 10 million times more massive than our Sun and lies 800 million light years away in the spiral galaxy I Zwicky 1.

This study began with the researcher­s’ desire to expand our understand­ing of black hole coronas, which are the source of the X-ray light that often radiates from the vicinity of these objects. Bright flares of X-ray light are emitted by gas that falls into black holes from their accretion discs – the discs of dust and gas that surround and ‘feed’ these objects.

The team spotted an X-ray flare in I Zwicky 1 that was so bright that some of the light reflected on the gas falling into the black hole. When that reflected light was bent around the back of the black hole by the object’s extreme gravity, the team was able to spot it using European Space Agency and NASA space telescopes.

The team didn’t just observe this light, which is the first time it has been directly observed like this. They also took note of how the X-ray light changed colour as it bent and moved around the back of the black hole. By observing the light’s journey around the back of the black hole, the researcher­s hope to understand more about what really goes on that close to these gravitatio­nal vortexes.

Following this groundbrea­king discovery, the team now aims to use the findings to create a three-dimensiona­l map of the black hole’s surroundin­gs. They also hope to better understand black hole coronas and explore how the corona of a black hole is capable of producing these bright X-ray flares.

“the X-ray light changed colour as it bent and moved around the back of the black hole”

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 ??  ?? Above: Researcher­s hope to map the black hole using the reflected light
Above: Researcher­s hope to map the black hole using the reflected light

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