“If I have seen further, it is by standing on the shoulder of giants” - Isaac Newton

The Hubble Space Telescope launched in 1990 and has since been a constant source of valuable information for astronomers across the world. Most of what we know about black holes, other galaxies, and the history of the universe was discovered via the observations of the Hubble telescope. However, nothing is perfect, and neither was this telescope. It was specifically manufactured to capture light that was in the ranges of visible and ultraviolet wavelengths. Yet, visible and ultraviolet light can be interfered with by dense dust clouds in space, meaning there was a limit to how far the Hubble telescope can see. 

Scientists took this opportunity to innovate with the launch of the James Webb Space Telescope (JWST) on Christmas Day 2021. Not only acting as a great Christmas present to astronomers, the JWST improves on the Hubble telescope in every way. With the use of larger and more numerous light-reflecting surfaces and more advanced processing technology targeted at lower wavelengths, the JWST allows us to see farther into the depths of space than ever before.

Mirror Mirror On the Wall

Both the Hubble telescope and JWST are reflecting telescopes, meaning that they use mirrors to reflect and bend light into the telescope to process the images. Each telescope has a primary mirror and a secondary mirror. Light first hits the primary mirror, then is reflected and bent onto the secondary mirror. The secondary mirror finally reflects the light back to the primary mirror, where it is then focused into the telescope. Several instruments within the telescope will process and study the light to produce a clear image. This reflection technique is done to fold the light so that all of the information is compressed enough to process the sight of far-away objects. 

The JWST telescope in particular differentiates itself from the Hubble telescope by having a 6.5 meter sized primary mirror compared to Hubble’s 2.4 meter sized primary mirror. With this, the JWST has a much larger area to collect light and reflect it onto its secondary mirror, meaning that it can receive much more light from celestial objects to create a better image. Additionally, the JWST integrates a third mirror alongside the primary and secondary mirror, which helps to widen its field of view when capturing images. 

Let There Be Infrared Light

In addition to its improvements in reflective technology, the JWST significantly innovates in its processing technology such that it can view objects further away than any telescope previously could. The main advantage of the JWST in this category is the focus on using infrared light instead of visible or ultraviolet light. Infrared light specifically has a lower wavelength than visible light such that it can cut through those dense dust clouds that prevent the Hubble from seeing far away objects. This, along with the mirrors that are wider to capture more light, allows the JWST to see extremely far objects that are moving away from us in our ever-expanding universe. When objects move away from us, the wavelength of the light they emit will become stretched to appear more red, a phenomenon known as redshift. The JWST is significantly better at capturing these redshift lights than the Hubble telescope.

What Have We Found With JWST?

The JWST has so far captured extravagant pictures of star nebulas, exoplanets, and galaxies. The image used for this article was courtesy of the JWST. If you want to see more images captured from the JWST, or just want to know more about the telescope, make sure to visit the Webb Space Telescope website for more information.