On Christmas Day 2021, astronomers and scientists around the world got the best Christmas present they could have hoped for – the successful launch of the James Webb space telescope. The cost of the telescope was way over budget and had been delayed more times than one could count. Finally, it was in space and ready to start the next phase where the giant telescope performed a series of manoeuvers to unfold itself. The procedure involved hundreds of actuators to move the parts of the telescope into position, many of which were single points of failure. Had any one of these failed the telescope may have been rendered useless. There was also the matter of unfolding the tennis court sized sunshield that was vital for keeping James Webb’s instruments shielded from the heat of the Sun. There are many layers of very thin material in the sunshield and one of the biggest challenges in testing was getting it to unfold without snagging and ripping it. The entire process took many weeks and this was followed by a period of cooling where the telescope reached its operating temperature. Once cooled, the alignment and calibration of the mirrors and instruments began. In total the process took about 6 months.
During the commissioning phase a few test images were released and despite the fact they were only test/calibration images, it was clear that James Webb would be worth the wait. The first science image was revealed on Monday, July 12th 2022, by President Joe Biden and was followed by a press conference on Thursday where another four images were released. The images were designed to show the capabilities of the new telescope.
SMACS 0723
The first image is of a galaxy cluster called SMACS 0723. The first thing that stands out about this picture is the stunning detail in it. It’s only when you compare it to the same picture taken by Hubble that you begin to realise how powerful James Webb is. The white galaxies in the picture are all part of the cluster and are located about 5.1 billion light years from us. The rest, most of which are red in colour due to their distance are much further away. Some of them are up to 13 billion lightyears away so they are some of the earliest galaxies in the universe. You may notice that some are stretched into a curve. This is due the gravity from the galaxies in front bending the light and acting as a magnifying glass. The level of detail in the image is stunning and sheer amount of galaxies is breathtaking, especially when you consider that the picture only covers a part of the sky about the size of a grain of rice held at arms length!
WASP-96b
Although the Webb deep field is stunningly beautiful, I am particularly fascinated by spectra produced of the Exoplanet WASP-96b. This may just look like a squiggly line but it tells us so much about a planet 1,150 light years away. To produce the spectra, the telescope watches as the planet passes in front of its parent star. As it does so, the light passes through the planet’s atmosphere and this is what the telescope is measuring. By recording the spectra and comparing it to the star itself, we can tell what the atmosphere is made up of. In this case astronomers were able to detect water in the atmosphere. Although water was detected, the planet is very hot and close to its star (sun) so it is unlikely to be suitable for life. However, James Webb will give us the ability to categorise the atmospheres of many of the exoplanets discovered and if there is life elsewhere in the galaxy. In fact, spectra like this could be the first way we detect it. If you take a distant astronomer looking back at Earth using this method, they would be able to see the oxygen we breath, and the pollution we produce such as methane and CO2.
Stephan’s Quintet
This stunning image is a visual grouping of galaxies called Stephen’s Quintet. This one is a mosaic and is made up of about 1000 data frames. It covers an area the size of about one fifth of the full moon and contains 150,000 pixels. This image is stunningly beautiful but also contains a lot more detail than ever before seen in these galaxies. This will allow astronomers study the interaction of galaxies and the role this plays in the evolution of the universe.
Southern Ring Nebula
This next image is the Southern Ring Nebula. It is a planetary nebula and was created by the death of star. It is located about 2,500 lightyears away. The image produced by James Webb contains much more detail than previous images. One of the questions the James Webb hopes answer about planetary nebula is the distribution of molecules throughout the gas cloud.
Carina Nebula
Last but not least is the image of the Carina Nebula. The Carina Nebula is a huge star forming region. The “cliffs” of gas in the image are about 7 lightyears high! Yet again, the detail in this image is superior to anything we have seen to date and should help astronomers to study the formation of stars in these regions of nebulosity.
It seemed at times that James Webb may never fly and maybe NASA had bitten off more than it could chew. In the end, when it did launch, given its track record to that point it felt inevitable that something would go wrong. We were proven wrong though and so far everything has gone smoothly and in typical NASA fashion the telescope is surpassing expectations. It has opened a new chapter in the exploration of space.
Paul Smith 