Worlds most powerful space telescope will let researchers look back in time. This Canadian astronomer will be among its first users – Toronto Star

As she woke on a clear, cold March morning in Montreal, Lisa Dang felt the weight of the pandemic bearing down on her.

It had been a long, hard year since the first lockdowns began, there was no end in sight, and she was deeply troubled by the news a few days earlier of six Asian women being shot to death in Atlanta, a symptom of rising anti-Asian sentiment during the pandemic.

Dang, a 28-year-old PhD candidate at McGill University, is an astronomer. She studies exoplanets planets that orbit other stars. For the past year, she had been working at home, locked down, like all her colleagues, because of the pandemic.

On this day, with all that weighing on her mind, she had to get out. She grabbed her coat, said goodbye to her boyfriend and left her downtown apartment to take a walk and clear her head.

An hour later, her phone began to buzz. Her inbox was flooded with emails. And one of the messages she read there would change her life forever.

Across the world that day, at about the same time, thousands of other astronomers were wading through the same torrent of emails.

But only Dang and a select few colleagues would be among the first to scan the universe with the latest, greatest observational tool the world has ever seen.

The James Webb Space Telescope (JWST) is set to launch in late December. The long-delayed, $10-billion multinational project promises to open the universe to scientists as it never has been before.

Itll settle in orbit around the sun 1.5 million kilometres away from Earth, four times further from the planet than the Moon.

The successor to the famed Hubble telescope, the Webb telescope will be 100 times more powerful, thanks primarily to a mirror thats 6.25 times larger in area. Its designed to observe in infrared, which will not only better equip it to see objects in the furthest reaches of the universe but will also allow it to pierce through veils of cosmic dust that often obscure visible light.

Across the globe, astronomers are salivating at the prospect of peering back through time to the near-dawn of the universe, of scrutinizing planets around other stars that just might possess the same building blocks of life as ours, of gazing into the hearts of galaxies hundreds of light-years away to see how stars are born.

In an alleyway in Montreal, a block from her apartment, Dang, disbelieving, read the email over and over again.

I think I was more stunned than happy at that moment, she says.

Immediately, I started FaceTiming my boyfriend. And the first thing that came out when he picked up was just tears, so he was unsure whether or not I was happy, or if it was some kind of mental breakdown.

Of the nearly 1,200 proposals received from 44 countries around the world, only 286 had been selected for time on the JWST, and only 10 of those with Canadians as principal investigators.

Dangs proposal was to study suspected lava planet K2-141b, closely orbiting a star some 200 light-years away. The planets proximity to its star means it is likely to have a molten rock surface and a rock vapour atmosphere the kind of place where it might rain liquid rock and snow rock particles. It was the first proposal shed ever had accepted as a principal investigator.

Even just getting time to use the Hubble Space Telescope is a huge deal for any astronomer, she says. For me, personally, this is a big deal, because for the first time, I felt like an astronomer ... I cant believe that my first proposal is a James Webb Space Telescope proposal.

For a 28-year-old PhD candidate, it was the rough astronomical equivalent of an NHL rookie having a 50-goal season.

Across the country from Dang, in Victoria, B.C., Erik Rosolowsky was waiting at a B&B for his family to get ready to go for a walk along the coast.

Rosolowsky, an associate professor of physics at the University of Alberta, had driven there from Edmonton with his family for March break.

I shouldnt have been checking my email because I was on vacation, he said. But I did ... and I was just flabbergasted.

Rosolowsky had, four months prior, submitted a proposal to use the Webb telescope to photograph the formation of stars in the spiral arms of a distant galaxy. Hed thought at the time his proposal had little chance of being chosen.

He was wrong.

He reread the email, sure that it was a mistake. As a scientist who had been on review panels, receiving proposals like his, he knew how fierce the competition was to even get time on existent telescopes, let alone be among the first to use the JWST.

With his son tarrying inside the B&B, Rosolowsky stepped outside to try and absorb just what was happening to him. He pondered how wildly different his life had become over the span of a few short moments.

This is the kind of thing that changes what youre going to be doing for the next several years, he says now. Were going to have this great opportunity to be the first people to use the Webb. This is where the great discoveries in the next few years in astrophysics are going to come from.

Then he went inside and told his wife. She was happy for him, he says. And then scolded him for checking his email on vacation.

But Dang and Rosolowsky and researchers like them arent celebrating just yet.

Theyre still holding their collective breaths because the telescope on which they have pinned their hopes has not left the ground.

It sits right now at a European Space Agency spaceport in French Guiana having travelled there from California via the Panama Canal awaiting a scheduled launch date of Dec. 22.

When deployed, the JWST will be the largest, most powerful space telescope ever built.

With its extended reach, it will let astronomers probe back in time to an era only a few hundred million years after the Big Bang itself just after what astronomers call the Dark Age when the first stars began to appear, a time of which we know relatively little.

In those distant reaches, light has been travelling toward us for more than 13 billion years. What astronomers see is a snapshot of what the universe looked like when that light started its journey. The more distant objects we can observe, the further back in time we can see.

The JWSTs primary mirror which is primarily responsible for that extended reach is 6.5 metres in diameter, and made up of 18 hexagonal pieces, each made of beryllium thinly coated with gold, and each individually adjustable. That puts the honeycomb-shaped surface area of the mirror at 25 square metres, about six times that of the Hubble telescope.

That bigger mirror means much higher resolution images of the universe, but what also sets JWST apart from the Hubble, is that its designed to see in infrared, that longer-wavelength portion of the light spectrum thats invisible to the human eye.

This has a few advantages. One is that infrared can pierce through the haze of cosmic dust better than visible light, enabling astronomers to gain clearer images of the bowels of the universe. Another is that they are able to study objects that may be too dim to study in visible light a lava planet for example.

A third advantage has to do with the fabric of space itself.

When astronomers are looking at the furthest reaches of the universe, they are looking at light which has been travelling towards them for millions or billions of years. While that light has been travelling, the universe itself has been expanding. And one of the consequences of that expansion is that the very space through which the light has been travelling has been stretched also.

When that happens, wavelengths become longer think of a Slinky being stretched and light becomes red-shifted what started out as visible light moves toward the red end of the spectrum. And that makes an infrared telescope the ideal instrument to probe the extremes of the universe.

By studying the amount that a particular object has red-shifted, astronomers can gain an idea of its distance relative to us. And by gauging its distance, they can tell how far back in time they are looking.

But to properly observe such faint sources, the JWST has to be isolated from other sources, namely the heat from the sun and Earth, which shows up in infrared. Hence its position in orbit around the sun 1.5 million kilometres from Earth.

The telescope will orbit whats called a Lagrange point, an area of space where the gravitational pull of the Earth and sun balance the orbit of the telescope, keeping it in a relatively stable position with respect to the Earth.

When it arrives there, the JWST will spend three months cooling to the ambient temperature of space.

But even that distance and time is not enough.

The Webb has a huge sunshield about the size of a tennis court made of five layers of a lightweight, heat- and cold-resistant material called Kapton, which has a reflective metallic coating. The sunshield acts as a parasol, always oriented between the sun and Earth and the telescope.

Engineers estimate that while temperatures on the sun side of the shield could rise as high as 85 C, the telescope, in the shade, would still remain at -233 C.

But the size of the sunshield and the telescope comes at a price: its too large to fit into any rockets we have, and it has to be folded like a giant metallic origami for its launch from Earth.

James Webb Space Telescope Stats

5 to 10 years

Mission duration

Dec. 22, 2021 07:20 EST

Proposed launch date

Ariane 5 rocket

Launch vehicle

Kourou, French Guiana

Launch site

Total payload mass:

Approx 6200 kg, including observatory, on-orbit consumables and launch vehicle adapter.

Orbit:

1.5 million km from Earth orbiting the L2 Point

Wavelength coverage:

Near- and mid-infrared light

-233.2 C

Operating temperature

25 m

Mirror collecting area

18

Number of primary mirror segments

Primary mirror mass:

20.1 kg for a single beryllium mirror, 39.48 kg for one entire primary mirror segment assembly (PMSA).

Primary mirror material:

beryllium coated with gold

705 kg

Mass of primary mirror

25 m

Clear aperture of primary Mirror

21.2 m 14.6 m

Sunshield dimensions

And that means, immediately after launch, it has to go through an elaborate two-week unfolding and assembly process, one that will have scientists and engineers chewing at their fingernails as it unfurls. And the stakes are, well, astronomical, since, unlike the Hubble, the JWST will be too distant for repairs once its launched.

Its going to be what I call the 14 days of terror, says Ren Doyon, whos the scientific director of the JWST in Canada. Doyon, a professor at the Universit de Montral, will be in French Guiana for the launch. Hes been working toward that moment for the past 20 years.

This is arguably the most complex machine that humanity has ever built. And were going to send it 1.5 million kilometres from Earth.

Canada has contributed two instruments to the JWST: a Fine Guidance Sensor (FGS) and the Near-Infrared Imager and Slitless Spectrograph (NIRISS).

The FGS targets a series of stars as a reference points and, measuring their positions 16 times per second, uses them to keep the telescope pointed at its target. Its so accurate, says Doyon, that it can detect the telescope being off target by the equivalent of the width of a human hair at a distance of a kilometre.

The NIRISS, which observes infrared wavelengths, also includes a spectrograph, which allows astronomers to look at the atmospheres of planets, to determine whether there are traces of gases such as oxygen, carbon dioxide or methane which might indicate the possibility that life might exist on those planets.

Both of those instruments, a labour of years for Doyon and the Canadian Space Agency, fit into a compact cuboid which belies its importance.

Its the greatest team effort ever ... to build this incredible machine, says Doyon. Its not much bigger than a washing machine, but what a heck of a washing machine.

For now, that washing machine, and its associated telescope are at rest at a spaceport just north of the equator in South America.

If it launches on schedule, after its one-month journey, after its deployment and calibration, it will be about six months before the first JWST research images arrive on Earth.

And that is what researchers are holding their breath for.

The celebration will be actually seeing the science come through, says Rosolowsky.

Were nerds, right? So when those first images end up getting delivered and we see the first view of these galaxies using Webb thats the treat.

Nobody has seen this before. And having that moment where you have an answer that you get to share with the world ... thats really exciting.

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Worlds most powerful space telescope will let researchers look back in time. This Canadian astronomer will be among its first users - Toronto Star