The Discoveries of the James Webb Space Telescope

 by Amelia Cooper

Over the summer holiday, I was fortunate enough to visit the Chichester Planetarium a few times and, although I was slightly apprehensive that the experience had the potential to be a little boring, I was pleasantly surprised as it cemented in my mind how truly fascinating space is.

Although I am far from being an expert, I have found space and particularly the new discoveries of the James Webb Space Telescope fascinating. The $10 billion telescope was launched on Christmas Day 2021 by being folded and placed in the payload bay of an Ariane 5 rocket then remotely unfolded once in space, and marked a huge milestone in our exploration of space, acting as a massive upgrade to the Hubble Space Telescope, launched in April of 1990.

Although Hubble supplied NASA with profound new knowledge and changed our fundamental understanding of the universe, it heavily utilised ultra-violet vision. This ultra-violet vision evidently was extremely effective in advancing our understanding of the world around us; however, investigations into the use of infrared led scientists to believe that utilising more front-facing infrared would lead telescopes to capture more light and so explore a wider range of space. Hence, the James Webb Space Telescope (JWST), named after James E. Webb (the administrator of NASA who led the organisation for seven years, including during the 1969 lunar landing), focuses solely on infrared vision.

As a result of this, JWST has revolutionary components aboard its ISIM (Integrated Science Instrument Module) such as NIRCam (the near-infrared camera, and primary imager, which will cover the infrared wavelength from 0.6 to 5 microns), NIRSpec (a near-infrared, multi-object spectrograph which will allow up to 100 stars, galaxies, and other objects to be seen at once), MIRI (a mid-infrared camera and spectrograph which covers 5 to 27 microns) and FGS/NRISS (a fine guidance sensor which allows the telescope to point precisely and so gain high-quality images).

These four instruments will help JWST see further back in space than we have ever seen before, and will image the “Dark Ages” of space: 150-800 million years after the Big Bang, when the universe was opaque. The primary mirror of JWST, pictured above with a person on the right for scale, captures red and infrared light travelling through space and reflects it to a smaller secondary mirror. The primary mirror is constructed from 18, 6.5-meter diameter, hexagonal, gold plated beryllium segments, and is more than triple the size of Hubble’s. 

On July 12th this year, JWST sent back its first images, nearly seven months after the telescope’s launch. Above is the first image received from the telescope, picturing a galaxy cluster 4 billion light-years from Earth named SMACS 0723. To demonstrate the huge difference that exists between Hubble and JWST, on the right and below are two images of the famous “pillars of creation” (huge plumes of interstellar gas and dust in the Eagle Nebula). The image on the right was taken by Hubble through the use of visible and ultraviolet light and the image below was taken by JWST with infrared light. The use of infrared here can be seen as pivotal in our understanding of the universe, as it unveils so much more of what is hidden in the depths of space. 

One of the most profound advantages of utilising infrared as opposed to ultraviolet is that the cameras have the ability to cut through clouds of dust. This paired with JWST’s ability to see objects nine times fainter than Hubble as a result of its large mirror has resulted in some incredibly impressive images being sent back. New views of objects in space such as Stephan’s Quintet (pictured below left) have helped scientists to understand the merging of galaxies and the creation of black holes, whilst the image second from the left of Jupiter has allowed scientists to clearly see its auroras for the first time.

The apparent red blob pictured below is actually the oldest galaxy ever observed: something that we have only been able to observe clearly as a result of the JWST. Finally, on the right is an image of the first supernova observed by JWST. Whilst this may not seem an incredible achievement as we have already seen images of supernovas, JWST was not actually designed to image them and so the fact that it has been able to capture such a clear image of the supernova has led scientists to have even more faith in the promise that the telescope promotes.

As the JWST continues on its journey orbiting the Sun, at a distance from Earth of over one million miles, many more images will return to NASA and provide scientists with the information they need to discover more about the universe around us, in addition to potentially continuing the search for extraterrestrial life.