It feels like forever ago that the project for the James Webb Space telescope was announced in 1996, shortly after NASA had to run a special Space Shuttle mission to fix the flawed optics of the Hubble Space Telescope. They decided they wanted to build something more powerful, to be able to see even further away - and therefore further into the past!
To do that, a main change was necessary: the telescope needed to see in infrared light where the Hubble doesn'.t That's because some of these galaxies are so far away that their light redshifts into the infrared spectrum (their light had to pass through an immense amount of space that was expanding, essentially stretching out the light waves, changing their wavelength!). Due to this phenomenon, Hubble is physically not able to detect these signals.
As the Webb needs extremely low temperatures to do its work without noise/interference (heat), it was also necessary to place it much further from Earth than the Hubble. The location deemed best for this was the L2 point (Lagrange 2 point), a semi-stable orbit which will allow the telescope to work without being blinded by the Earth, the Sun or the Moon.
This is all well and good, but how do we get a 6.5-meter (21 feet) mirror in orbit? Naturally, in 18 pieces! That is, 18 hexagonal mirrors, all folded on top of each other, only to be robotically unfolded in outer space - in an extreme feat of engineering.
Fast forward to 25 years later, after countless of problems, redesigns, changed management, attempts to cancel and re-vamp the project, on December 25th, 2021, the JWST was finally launched - what a way to celebrate christmas for the over 1200 scientists, engineers and technicians who worked on the telescope in the past quarter of a century!
From that day, the events really sped up! Hundreds of amateur astronomers tracked the trajectory of the space telescope until it became too faint to detect from Earth. The next big news was that a micrometeoroid hit one of the 18 mirrors of the JWST and has left an impact on it - though NASA assured us the performance of the instrument would not be impacted!
After all this excitement, NASA finally gave us a date for the first images to be revealed - July 12th 2022! As the day approached, the space agency just wouldn't stop teasing us.
First, on July 6th they revealed a teaser image taken with the fine guidance sensor of the instrument.
For context, this is like taking a picture through the tiny little finder scope on top of your backyard telescope! Yet, it showed an astonishing amount of detail and amazing quality. This photo got both amateur enthusiasts and professionals even more excited about the first real images to be revealed on the 12th!
Then NASA announced that the very first image would actually be showed by American President Joe Biden a day earlier than the rest.
On July 11th, at 6:30pm, approximately with a one-hour delay - which I am convinced was only to tease the viewers - the very first image of the James Webb Space Telescope was revealed - showing a Deep Field image from a region in the constellation of Volans.
The choice for making this the very first published photo was no accident! Anyone that has been following the activity of the Hubble Space Telescope is familiar with the famous Hubble Deep Field and Hubble Ultra Deep Field images - these were essentially just photos where the telescope was pointed at a seemingly completely empty region of space for days at a time - only to reveal hundreds or thousands of galaxies billions of light-years away. The images of Hubble were already mind-blowing, so NASA's choice to show how much more detail Webb can show was a calculated one to blow our minds even more! This image below is the original Hubble Ultra Deep Field, the best deep field photo taken with the HST.
After seeing that, what more can we possible expect to see? Well as it turns out, a lot more if we just look further away! We have known about the effect of gravitational lensing from Einstein's predictions and then from very simple photographic evidence, but never before has it been possible to just photograph it and show it in a way that any amateur can understand and see it!
All those smudged, bent lines in the above picture? Those are all galaxies whose image is distorted by the SMACS 0723 galaxy cluster in front of them! Every little speck of light in this photo that doesn't have a 6-pronged star diffraction pattern on it is a whole galaxy with billions of stars! Some of them are so far away, they most likely do not even exist anymore as the light that we are detecting now left them some 13 Billion (with a B!) years ago.
For context, also consider that the Hubble Ultra Deep Field image was taken over multiple days, while the James Webb only took half a day to take this picture! After this reveal, my expectations were even higher and was looking forward to today's reveal, but even these were exceeded by the images we were shown today!
First, we saw spectral data of the exoplanet WASP-96b. WASP-96b is a massive planet nearly 1,150 light-years away from Earth. This target was chosen to be one of the few released right now to demonstrate the insane capabilities of the JWST to analyze the atmospheric composition of exoplanets - and hence identify potentially habitable planets and signs of any life present.
What we can see is a series of peaks showing the presence of water - or more specifically, in the case of this very hot planet, water vapor! This is practically proof that there is water - haze & clouds - present in the atmosphere of this very faraway world - and now with JWST we can detect it - but how? This planet orbits its sun very quickly (as it is closer to its star than Mercury is to our Sun) which means, we are lucky enough to see it pass in front of its star quite often! As it eclipses its star, we can detect which wavelengths of light are absorbed by its atmosphere, as shown in the picture below.
A Dying Star
The second photo shown was of the Southern Ring nebula. It is a planetary nebula, so essentially we are looking at the cloud of gas left behind by a dying star. It is also colloquially known as the “Eight-Burst” nebula because it kind of looks like a figure-8 at high magnifications! It is 2,000 light-years away and has a diameter of nearly half a light-year.
This is the highest resolution photo of any planetary nebula ever taken. The picture on the left was taken with Webb's NIRCam (Near InfraRed) & the one on the right taken with MIRI (Mid-Infrared). Both images reveal the structure of the waves of gas being pushed out by the central star in never-before-seen detail. The amazing thing in the MIRI image is that we can see not just one, but two stars! Scientists have known for a long time that this was a double star, but it was not possible to separate them before Webb. In addition, as an "easter egg" that nobody expected, the oblong shape at around 10 o'clock in both images is an edge-on galaxy that we did not know would be there!
A Galactic Dance
The following photo was Stephan’s Quintet. It is a small group of five galaxies closely interacting with one another. It is famous for being one of the first such groups discovered, and it is also a popular target for amateur astronomers and astrophotographers! It is 290 million light-years away, located in the constellation of Pegasus.
The above image is a combination of the Near- and Mid-Infrared cameras, showing this set of galaxies interacting in incredible detail. You can actually resolve individual stars in a galaxy 300 million light-years away, which would never have been possible before Webb!
As if this photo wasn't amazing enough, the MIRI-only image was then shown, removing pretty much all stellar light and revealing all the nebulosity within these galaxies!
The final image was of the Carina Nebula, one of the largest and brightest nebulae in the night sky - only visible in the Southern Hemisphere. It is known if its “stellar nurseries”, regions of intense star formation. It is no accident that they left this photo to be the last one - the details and the depth shown is simply breathtaking!
In addition to the sheer beauty of the details, Webb also revealed emerging stellar nurseries and individual stars in the Carina Nebula that were previously completely obscured by the clouds in front of them. The photo showcases Webb’s cameras’ capabilities to peer through cosmic dust, shedding new light on how stars form. Called the Cosmic Cliffs, Webb’s seemingly three-dimensional picture looks like an artistic representation of mountains on a moonlit evening. In reality, it is the edge of the giant, gaseous cavity within NGC 3324, and the tallest “peaks” in this image are about 7 light-years high.
I'm sure I'm not the only one looking forward to future results of the James Webb Space Telescope. It has already opened absolutely new frontiers in many areas of astronomy in just a few months since its launch. Its incredible performance means, it will be able to answer questions we do not even have yet!