Could NASA’s James Webb telescope images help shape the future?

Here on our little blue rock in the outer suburbs of the Milky Way galaxy, we can now stare into the deepest heart of the cosmos. Not just deep in space, but deep in time, when the first stars were burning through the fog that forged the universe. Their light has taken more than 13 billion years to reach us, stretched beyond the visible spectrum into infrared as the universe has expanded.

To see it, we need a time machine of sorts – a giant telescope powerful enough to catch the heat of infrared light in the cold darkness of space, but light enough to be carried by a rocket more than a million kilometres away from Earth; a machine that can unfurl and assemble itself to precision measurements smaller than the width of a virus, with a sun shield as big as a tennis court on its back.

This is the James Webb Space Telescope, one of the most complex machines ever built. Late in 2021, after more than four decades of work (and billions of dollars), NASA shot it into space. “It could have just blown up on the launch pad,” says University of Queensland’s Dr Benjamin Pope, one of the Australian astronomers who will be using Webb. “There were hundreds of failure points” where a tiny malfunction could have turned the whole mission to space junk. “But everything’s running even better than expected. It’s surreal.”

This landscape of “mountains” and “valleys” speckled with glittering stars is actually the edge of a nearby, young, star-forming region in the Carina Nebula, as captured by the James Webb telescope.

This landscape of “mountains” and “valleys” speckled with glittering stars is actually the edge of a nearby, young, star-forming region in the Carina Nebula, as captured by the James Webb telescope.Credit:NASA

Webb’s first images are now beaming back to Earth, released by NASA in what US President Joe Biden called an historic moment not just for science but for all of humanity. (“And it’s going to remind the world that America can do big things,” he said.)

The first image – the deepest glimpse of the universe ever recorded – represents just a sliver of the night sky, smaller than a grain of sand held at arm’s length. Yet within it, Webb has found whole galaxies twinkling and scientists say the expanded view could help solve all kinds of enduring questions – from whether we’re alone in the universe to how it all began.

So, how did we pull off what has been called “the most expensive astronomical gamble in history”? And what might Webb tell us about the universe – and ourselves?

How can we see that far back in space?

For 10 days in 1995, the Hubble telescope, the precursor to Webb, stared at an empty patch of sky – empty to the naked eye, at least. To Hubble, it was packed with galaxies. The telescope, first launched in 1990, had peered further into the universe than ever before. But there was still no sign of the “dark ages”, that black edge scientists expect to find marking the time before the stars formed in the first hundred million years of the universe. Hubble, they realised, couldn’t see nearly that far.

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Light particles (known as photons) travel in waves, their length determining which colour we see. Light travels faster than anything in the universe (299,792 kilometres per second) since photons have no mass to slow them down. But in a universe this vast, even light speed takes time. The sun’s light, for example, takes roughly eight minutes to reach us on Earth, so when we look up at the sky we’re seeing our star on a time delay.

Light waves from the oldest stars, meanwhile, have also been warped by the expanding universe around them. When they set out, space wasn’t just older, it was much, much smaller and condensed, explains ANU astronomer Dr Brad Tucker, who will be using Webb to hunt for supernovas (dying stars). This stretching out of older light into infrared waves is called “redshift”.

“It’s lived fast, and it’s going to die young. It’s been giving off these giant explosions before it goes supernova.”

Infrared light is actually heat radiation. “You need something more like a soldier’s thermal camera” than a telescope to see it, Pope says. Anything warm, even your telescope, will glow with its own infrared light, clouding the image, so you need to go deep into space, where the temperatures drop well below freezing to get a clear view.

But infrared light also cuts through the “lanes of dust” usually shrouding much of the universe from the eye of telescopes such as Hubble, which see in visible light. “The universe’s a dusty place,” Pope laughs. “You can probably see it at night, out bush: a dark stripe of dust in the middle of the Milky Way.”

In a particularly striking early image from Webb, “cosmic cliffs” within the distant Carina nebula show how the telescope can peer through this dust to study how stars are born – and how they die. “From that wild world of dust, planets form,” says Pope. But in this particular stellar nursery, some stars are in their death throes too, including Eta Carina, likely the brightest star in the Milky Way. “It’s lived fast, and it’s going to die young. It’s been giving off these giant explosions before it goes supernova.”

How does the James Webb telescope work?

Webb isn’t just seeing in infrared – it’s about six times bigger and 100 times more powerful than Hubble (which is already renowned for taking beautiful images of deep space). NASA says Webb is so sensitive it’s like spotting a bee on Earth from the moon. Tucker compares it to going from a 1080p video to 8k (with more than 16 times more pixels). And unlike Hubble, it looks nothing like a telescope.

“It’s like we’re at the intermission of an enormously expensive debut night musical and nothing’s gone wrong.”

Professor Peter Tuthill at the University of Sydney calls it a jewel – a towering gold-plated honeycomb. To see farther in space, you need to capture and concentrate more light with a bigger mirror – but one that fits in a rocket. Webb’s unique geometric design allows multiple small mirrors to open up into one in space, using precision motors to guide it into a near-perfectly flat wall. And gold, it turns out, is much better than silver at picking up infrared, says Tuthill, who designed a key telescope instrument that can further sharpen the image, making him the only Australian with hardware on Webb.

With its back to the sun and the Earth, a massive sun shield spread behind the telescope like a parachute will also chill its instruments to minus 233 degrees, so it can hunt for leftover heat from faraway galaxies without interference. And it’s sitting in a special spot in the solar system where nearby gravity from Earth and the moon will keep it in place with minimal effort from its thrusters, adds Tucker.

From its launch at French Guiana near the equator – the Canadian and European space agencies worked with NASA – to its first six months of nervy mirror alignments, “so many things could have gone wrong that didn’t,” says Pope. The sun shield, made of gossamer-thin fabric could have snagged. Even a tiny dent in one of the mirrors, thanks to a collision with a mini-meteorite, didn’t throw off the telescope beam. In fact, Webb managed to conserve more fuel than expected after launch, putting its mission life closer to 20 years than the decade planned.

“It’s this almost anti-climax because everything’s exactly as rehearsed,” says Pope. “It’s like we’re at the intermission of an enormously expensive debut night musical and nothing’s gone wrong.”

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If Webb does run into trouble, its components can be recalibrated from Earth, he says. “The real risks have been retired, as the engineers say. We certainly won’t have to go a rescue mission like for Hubble”. (It suffered a major mirror flaw when it launched in the ’90s and had to be refitted by the NASA shuttle with a “contact lens” of sorts.)

Tuthill’s team now has the all-clear to start work on their Webb experiments. “What lies next for me is a lot of late nights making sure I hold up my part of the mission,” he says.

Pope, who has been simulating the kinds of images Webb was expected to produce admits he has had to pinch himself to remember the pictures just released are the real thing. “They’re just so beautiful.”

NASA technicians work on the James Webb telescope mirror in 2017.

NASA technicians work on the James Webb telescope mirror in 2017.Credit:NASA

What are scientists using Webb to look for?

About a decade ago, a perhaps less well-known telescope – Kepler – dramatically improved the odds of finding life outside Earth. Its survey revealed there are more planets than suns in the universe – ​an estimated 100 billion. One in five of these “exoplanets” is thought to be Earth-sized and orbiting within their suns’ so-called Goldilocks, or habitable, zone where the conditions are neither too hot nor too cold for life. Webb will allow astronomers to more accurately (and speedily) assess the atmosphere of these distant worlds, watching the starlight passing behind them for tell-tale signs of familiar chemicals such as water, carbon dioxide and – the really exciting one – oxygen.

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“Webb just might be the first technology humans have built that can really crack that problem,” says Tuthill, who will be studying these exoplanets using his sharpened camera instrument on Webb.

Already NASA says Webb has picked up a clear signature of water vapour in the atmosphere of one exoplanet, a “hot, puffy Jupiter” 1150 light years away known as WASP-96 b, in the southern-sky constellation of Phoenix.

But this is just the tip of the iceberg – Webb will be turning its eye all over the cosmos, including to look at nearby planets in our own solar system as well as far-flung phenomena.

If the stars glimpsed further back in spacetime, near the cosmic dawn, turn out to be very bright, it could help settle debate over whether the first stars were like those we see today or much, much bigger, Tucker says. In the early, and largely empty universe, stars may have ballooned in size with only hydrogen and helium to fuel them, up to 10,000 times the mass of our own sun –and that could change how they behave.

“Where do these galaxies get the fuel needed to make so many stars, and why are they forming stars so fast? They’re like fireworks in space.”

“We’ve found older stars lacking some of the usual ingredients or metals we see in stars today and their physics are already a bit different,” adds Pope. “So if we keep looking back, will we find stars without those elements altogether? They might have a very different structure.”

The bigger a star, the bigger and faster its death. So, might we, Tucker wonders, also find galaxy-ending supernovas – death throe explosions bigger than would be possible from today’s smaller stars?

Meanwhile, Dr Elisabete da Cunha, an astrophysicist at the University of Western Australia, is part of a team using Webb to hunt for “productive” galaxies, which churn out a lot of stars at once. “Our Milky Way galaxy produces around one star a year on average, while these are producing up to 1000 a year,” she says. “Where do these galaxies get the fuel needed to make so many stars, and why are they forming stars so fast? They’re like fireworks in space.”

Could we end up seeing the start of the universe?

Of course, if we stop seeing stars at all, that means we’ve finally hit that black edge of the universe – the cosmically narrow window before the stars formed, which could help us understand how everything began. “It seems strange to say it, but we’re hoping for blackness now,” says Tucker. “We just want to keep pushing further back until we hit that limit.”

As Hubble did before it, scientists expect Webb will usher in a new age of astronomy. “Everything in the past 30 years has involved Hubble in some way, even Kepler, so many [discoveries] and Nobel prizes,” says Tucker. “How many Nobels will come from Webb? It’s like at the end of Avengers Endgame when there are a thousand people mentioned in the credits. So much of the [scientific] community has come together to build this, and so much of the community is going to benefit from it.”

There is one off-note beneath the buzz. The telescope takes its name from a public servant, not a scientist – James Webb was administrator of NASA during the renowned Apollo missions but his name has now been embroiled in controversy over a connection to the US public service’s dark history of expelling gay staff in the 1950s. More than a thousand astronomers have signed a petition asking for the telescope to be renamed.

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Tucker says he understands why NASA considered naming it Webb, but agrees the subsequent revelations and then failure of NASA to investigate them have left a bad taste.

“And we talk about the skies being for everyone. If people can be so excited by this instrument but there are people who feel that ‘had I been an astronomer 40 years ago, I wouldn’t be able to use it’, that’s not what we want. It’s so easy to change it. And it’s not like we have a shortage of scientific heroes.”

Hubble was named after Edwin Hubble, who discovered the universe was expanding. “And that telescope was later used to discover it wasn’t just growing but accelerating,” says Tucker. “What’s next?”

With Stuart Layt

Images from NASA’s James Webb Telescope.Credit:NASA

https://www.smh.com.au/technology/james-webb-has-seen-billions-of-years-into-the-past-how-could-it-shape-the-future-20220712-p5b0x8.html?ref=rss&utm_medium=rss&utm_source=rss_technology Could NASA’s James Webb telescope images help shape the future?

Chris Barrese

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