First, it’s the largest telescope ever put into space, with a gold-coated mirror 6.5m in diameter (compared with Hubble’s 2.4m mirror). With size comes complexity, as the entire structure needed to be folded to fit inside the nose cone of an Ariane rocket.

Second, there were two major engineering marvels to accomplish with Webb. For a large telescope to produce the sharpest images possible, the mirror’s surface needs to be aligned along a curve with extreme precision. For Webb this means unfolding and positioning the 18 hexagonal segments of the primary mirror, plus a secondary mirror, to a precision of 25 billionths of a metre.

Also, Webb will be observing infrared light, so it must be kept incredibly cold (roughly -233℃) to maximise its sensitivity. This means it must be kept far away from Earth, which is a source of heat and light. It must also be completely protected from the Sun – achieved by a 20m multilayered reflective sunshield.

All of Webb’s major spacecraft deployments, including the unfurling of the primary mirror and sunshield, were completed on January 8. The entire process involved more than 300 single points of failure (mechanisms that had only once chance to work). The remaining tiny motions will take place over the next few months.

The main mission

Webb’s primary mission will be to witness the birth of the first stars and galaxies in the early Universe. As the light from these very faint galaxies travels across the vast gulf of space, and 13.8 billion years of time, it gets stretched by the overall expansion of the Universe in a process we call “cosmological redshift.”

This stretching means what started out as extremely energetic ultraviolet radiation from young, hot and massive stars will be received by Webb as infrared light. This is why its mirrors are coated in gold: compared with silver or aluminium, gold is a better reflector of infrared light and red light.

Webb will see much farther into the infrared than Hubble could. It’s also up to a million times more sensitive than ground-based telescopes, where the light from distant galaxies is drowned out by the infrared emission of Earth’s own hot atmosphere.

Because of these previous technological limitations, the first billion years of cosmic history has barely been explored. We don’t know when or how the first stars formed. This is a complex question as stars produce heavy elements when they die. These elements pollute the interstellar gas in galaxies and change how this gas behaves and collapses to form later generations of stars.

All current star formation we can observe, such as in the Milky Way, is from enriched interstellar gas. We haven’t yet seen how stars form in pristine gas, which is without any heavy elements – as such a state hasn’t existed for more than 13 billion years.

But we think formation from pristine gas likely had a large effect on the properties of the first stellar populations.

Links

NASA’s James Webb Space Telescope has reached its destination, 1.5 million km from Earth. Here’s what happens next

How Webb took its first picture: https://theconversation.com/the-james-webb-space-telescope-has-taken-its-first-aligned-image-of-a-star-heres-how-it-was-done-178315

The search for the first galaxies: https://theconversation.com/hubble-webb-and-the-search-for-first-light-galaxies-5116

ASTRO 3D

@betadacunha, elisabete.dacunha@uwa.edu.au

Senior Research Fellow
International Centre for Radio Astronomy Research, UWA

Hubble has had an enormous impact in my field of science, extragalactic astronomy, and in culture in general. Hubble took my favourite astronomical image of all time: the Hubble Ultra Deep Field.

This image was taking by pointing Hubble to a dark patch of sky (i.e., with no stars or nearby galaxies), and just collecting photons for about 10 days. The final image is breathtaking: if you observe for long enough, that tiny dark patch of sky reveals

over ten thousand distant galaxies. This completely revolutionized our view of the Universe: there are many more galaxies than we thought there were, and they extend out to larger distances (i.e., earlier times in the Universe) than originally thought.

We have observed as far as we can possibly observe with Hubble, and that’s where the Webb comes in. Thanks to its huge mirror and infrared detectors, we will be able to observe even more distant galaxies than with the Hubble — in fact, we expect to observe the very first galaxies that lit up the Universe!

It’s extremely exciting!

We will also be able to study distant galaxies in more detail than ever before: we will measure the chemical elements they have in their interstellar medium, and we will see through clouds of cosmic dust that are currently blocking our view of stars in distant galaxies.

Piercing through cosmic dust to reveal the stars is the main goal of the JWST Cycle 1 project I am co-principal investigator of. We will be studying some of the most extreme galaxies known, dusty starburst galaxies. These galaxies are known to be forming stars at extreme rates — up to a thousand times the rate of star formation in the Milky Way — yet we still don’t know why and how they can sustain these rates, and how they evolved to be like this.

The problem is that most (if not all) we can see of these galaxies right now is the glowing interstellar dust that is being heated by star formation, but we can’t see their stars directly. Webb is the first ever telescope that will be able to piece through their copious amounts of dust to obtain direct images of the stars in these galaxies.

Just like Hubble surprised us with its new observations, I expect Webb to also show us new things that we can’t even predict yet — that unexpected element is what is most exciting! Every time we access a new way to observe the Universe (a bigger telescope, a different wavelength range, etc), it reveals new surprises to us. I just can’t wait to see what Webb will teach us about the Universe, and ultimately, our place in it!

Dr Nicha Leethochawalit, University of Melbourne/ ASTRO 3D,

ASTRO 3D Postdoc Researcher On First Galaxies

nicha.leethochawalit@unimelb.edu.au

What you hope to discover with the Webb?

Webb gives us a depth and the resolution that we did not have before. I hope to discover something that we didn’t know before.

The predictable science will be to better understanding how galaxies re-ionize the universe in the early days (million years) of the universe. First, we will for the first time observe many ‘mediocre’ galaxies at that time.

Previously we have only seen the brightest ones, while in fact there are a lot more low-mass galaxies than massive and bright ones. The distribution of mass (or light) among galaxies is like the wealth distribution. If one wants to study human behaviour, one can’t just observe the richest ones. Moreover, we will see them in many wavelengths or even obtain their spectra. These are crucial information to infer their physical properties: how many stars, what kind of stars they have, and how gas-rich they are.

Dr. Kathryn Grasha, ANU/ASTRO 3D

kathryn.grasha@anu.edu.au, DECRA Fellow & ASTRO 3D Fellow, ANU

The James Webb Space Telescope matters to me because with the first light of JWST, we will have an unparalleled opportunity to view the birth of stars within the hearts of the densest, dust-enshrouded cores of molecular clouds. The technological advancements of JWST will build a revolutionary data set to the astronomical community, spur major scientific advances, and build on recent legacy programs of the Hubble Space Telescope that revolutionised our knowledge of the cosmos. The “unknown unknowns” are the most exciting prospect over the next 5-10 years; we will be discovering unexpected surprises and answering problems we haven’t even imagined yet. The breathtaking views of the Universe are guaranteed to ignite the excitement and imagination of the public and inspire the next generation of astronomers.

Professor Peter Tuthill, University of Sydney

peter.tuthill@sydney.edu.au

University of Sydney Institute for Astronomy, University of Sydney School of Physics

With colleagues from University of Montreal and the Space Telescope Science Institute in Baltimore,Tuthill designed a key component of one of the four scientific instruments onboard the James Webb Space Telescope. His work has led to the development of one of the operational modes of the telescope’s Near-Infrared Imager and Slitless Spectrograph (NIRISS).

a. Why the Webb matters to you

As the only Australian scientist who has built a piece of hardware now flying on the Webb, this is a day I have been looking forward to for a big part of my career.

Because everything about the Webb is so over-the-top audacious – from the titanic articulated mirror down to its orbit out in the cold voids of interplanetary space –

somehow the entire thing aways seemed beyond the boundaries of the possible. So the most amazing part of the journey so far for me was the news I did not hear.

This entire huge, complicated machine flew out and everything seems to have unfolded and deployed like clockwork: this was definitely a time when routine news was good news.

Now that it is out in its science orbit and my experiment has been checked out and passed by NASA engineers, I am super excited to see the first data downlinked.

b. What you hope to discover with the Webb

My particular experiment is designed to home in on very subtle signals – faint whispers and motes of light that betray the presence of material nestled up against the overwhelming glare of the host star in the system. If you think about trying to see our solar system looking back from a vantage point out at a distant star, it turns out to be a truly forbidding technical challenge. Even large planets like Jupiter are incredibly faint compared to the Sun, and all of them would appear to nestle incredibly close when viewed across the interstellar gulf. Webb just might be the first technology humans have built that can really crack that problem, opening the door onto distant worlds we can only guess at today.

c. The impact of Hubble on you and/or science and/or culture.

I was still a student when Hubble was first launched, and it is quite remarkable to see the old warhorse still delivering outstanding science today.

It is hard to overstate the impact of this one observatory. Although it has been an overwhelming scientific triumph just about any way you might care to measure it,

even more than that it has given us a vision of the cosmos with crystal clarity and exquisite detail that speaks to all of us. All the spinning galaxies and titanic

shocks and explosions that Astronomers like me study with our instruments – they are just popping out of the images, sometimes hardly seeming to need a caption

to convey the essence of what we are witness to.

Dr Benjamin Pope, University of Queensland

b.pope@uq.edu.au

Why Webb matters to you

The Hubble Space Telescope was launched four months before I was born. There have been many brilliant, but specialized, space telescopes since then, like the Kepler and TESS missions I have used to search for exoplanets. But Webb is the first true successor to Hubble, with general purpose capabilities across a huge chunk of the spectrum of light and with a versatile selection of cameras and other instruments. I am so excited to be part of such a major project.

What you hope to discover with Webb

We will be using the only Australian-designed hardware on Webb – the Aperture Masking Instrument, a device for taking extra-sharp images – to look at newborn planets right as they form out of disks of gas and dust. We hope to see this process directly as an analogue to how our own Earth and planets were born around the Sun.

The impact of Hubble on you and/or science and/or culture.

Hubble images are used everywhere from science-fiction films to galaxy-print clothing – but to astronomers, HST is the hardest telescope to be awarded time to use, and the most rewarding.

My Honours project was using Hubble data to observe brown dwarfs, which are intermediate between stars and planets in mass, to try and see whether they formed more like stars or planets. Now, we will be repeating these observations but for much smaller objects than could ever be observed by Hubble!

Professor James Miller-Jones, Curtin University

Director, Science | Curtin Institute for Radio Astronomy
Director, Science (Curtin) | International Centre for Radio Astronomy Research
james.miller-jones@curtin.edu.au

Why the Webb matters to you

As with any new instrument, the revolutionary new capabilities provided by the Webb will lead to amazing progress in our understanding of the Universe. It will undoubtedly make major advances in the many high-profile science areas for which it was specifically designed. However,

I am most excited by the unforeseen breakthroughs that will be made by the Webb. The new areas of parameter space opened up by this powerful new telescope, when coupled with the creativity of the scientists who use it, will lead to new discoveries that we had not even imagined. Hubble was a perfect example of this, and I am looking forward to what the Webb will achieve.

The impact of Hubble on you and/or science and/or culture.

My team is hoping to use the Webb to find out how feeding black holes launch powerful beams of outflowing matter and energy known as jets. These jets play an important role in transporting energy from the black hole out to enormous distances. Jets from the most massive black holes can affect the evolution of entire galaxies. However, by studying small black holes (just a few times the mass of our Sun), we can watch their jets change in real time, in response to variations in the inflowing gas that feeds them.

Our team will use the Webb to look at how both the brightness and the colours of light from the jets change on timescales as short as a fraction of a second. This will tell us how close to the black hole the jets are first accelerated, how fast they are travelling, and how much energy they carry away with them. The sensitivity of the Webb in a hitherto poorly-probed region of the infrared part of the spectrum is critical in enabling these studies of black hole jets. Coupled with sophisticated computer simulations of processes close to a black hole, this will help us unravel the mystery of how black holes launch these powerful jets.

The amazing images from Hubble helped inspire me to get involved in astronomy.

As a teenager, I remember being awed by its powerful images of the cosmos, and wanted to learn more. I was lucky enough to be able to pursue that passion for science, and moved into astrophysics research. The day I received the first Hubble data for one of my own science programs was extremely exciting, given the part that iconic telescope had played in stimulating my own interest in science when I was growing up. I hope that the Webb will similarly inspire the next generation of scientists in Australia and around the world.

Dr Christophe Pinte, Monash University, Melbourne

christophe.pinte@monash.edu, @c_pinte

The James Webb telescope will be critical for our science because it will open high spatial resolution imaging in the mid-infrared wavelength regime.

Are baby planets born hot?

We hope that JWST will help us to find forming planets. Planets are forming in a disc of gas and dust that surrounds young stars. The disc is opaque in the visible and near-infrared, hiding any potential planets. But in the wavelength range that JWST observes at (which is not accessible from the ground or with HST), the disc becomes transparent, so our goal is to try to get images of these newly born planets. This will tell us if these baby planets are born hot (a few thousands degrees) or cold (less than 1000 degrees), which is the main parameter to pinpoint the main physical processes that lead to the formation of planet.

This should give us critical answers to understand the origin of our solar system.

Hubble has been instrumental in getting the first images of the discs surrounding young stars, as well as placing in the more general context of star formation within molecular clouds.
I grew up as a teenager with HST images. Many of them motivated to study astronomy. The famous image of the pillars of creation in the Orion nebula is probably the most iconic image for me as it is directly linked to the research I do now. I also used HST images of discs during my PhD, so it has been a key telescope for my own science.

Professor Simon Driver, UWA, Perth

simon.driver@uwa.edu.au

Larissa Wiese of the International Space Centre is organising our activities along with UWA media folk.

Tuesday evening we have a live NASA cross-over during the NASA telecast and possibly an interview. Thursday evening we’re holding a NASA sanctioned Public Lecture https://www.icrar.org/events/jwst-july-22/

a. Why the Webb matters to you

I’ve been involved in Webb since its inception as part of one of the six interdisciplinary scientists teams. We have 112 hours of guaranteed time, three observations now in the bag (although NASA are waiting until the 12th to release them), and will use these data to try to study cosmic ignition.

b. What you hope to discover with the Webb

The very first galaxies and cosmic ignition. Refine our measurements and models of the cosmic radiation incident on Earth from deep space. Compare our models of early galaxy formation and growth to statistical samples built from JWST data. Basically we want to know how stellar mass has formed and evolved, and the energy that is produced during these process from the very first billion years of the timeline of the Universe.

The impact of Hubble on you and/or science and/or culture.

Well we’ve been waiting >25years so lots of anticipation. We’ve built teams, codes, models, and now we just want to be let loose on the data (which will happen from right after the First Light images). We also quietly hope for surprises and unexpected serendipitous discovery’s.

Associate Professor Kim-Vy Tran, Astrophysicist, UNSW

Why the Webb matters to you

I’ve know about JWST since I started as a graduate student decades ago. My PhD supervisor was Prof. Garth Illingworth who has arguably been one of JWST’s biggest advocates. I’ve been able to see the long arc of how a project starts from ideas to delivering a transformative observatory.

Beyond the science discoveries, JWST is a testament to the incredible teams of scientists and engineers from all over our global community to push science into a new frontier. It shows that by working together, we can tackle the biggest challenges as long as we’re able to dream it.

What you hope to discover with the Webb

Of course answering all the many many questions we have about the origins of our Universe, but also to discover the surprising, the unknown, and the simply bizarre!

The impact of Hubble on you and/or science and/or culture.

The Hubble Space Telescope transformed our ability to use gravitational lensing to peer into the very distant Universe. Only with sharp eyes from above the Earth’s atmosphere can we see the incredibly faint cosmic mirages that form when light rays are bent by massive objects. I fully expect JWST to transform astrophysics in equally profound, and at this point completely unknown, ways.

Can you comment on the Webb images on Wednesday morning?

Among the first images will be of the galaxy cluster SMACS 0723, one of the most massive objects in the Universe. This galaxy cluster bends light from objects at the edge of our observable horizon and may reveal how the very first galaxies form.

Gravitational lensing is a topic near & dear to my heart. My team still holds the record for one of the the most distant gravitational lens, and I am currently co-leading an ambitious AGEL survey to find hundreds of new lenses. My hope is that we’ll be able to study some of these new systems with JWST.

Professor Orsola De Marco, Macquarie University

I study stars. I am particularly interested in stars that, being born in pairs, influence each other over their lives, a bit like married couples.

One of the stunning effects of these interactions are planetary nebulae, whose incredible shapes are blueprints of these interaction. The only way to read the blueprint, however, is to paste together multi wavelength imaging and spectroscopic information from every single little bit of the nebula. Only so can we reconstruct the 3D shapes and, eventually, its past history. One of the images that will be released on Wednesday at 12:30AM is that of NGC3132, a planetary nebula with uncanny complexity.

Tidbinbilla (Canberra Deep Space Communication Complex)

Much of the data from JWST flows to back to Earth via Tidbinbilla.

A 34 metre dish named DSS-34 is currently tracking JWST every day for periods ranging from between about 6 to 12 hours depending on the day.

The role that Australia played for Apollo, Voyager and many deep space missions is living on with JWST.