Summary Reader Response Final Draft

October 10, 2022

Summary Reader Response Final Draft

In the article "Why stars look spiky in images from the James Webb Space Telescope", Verge (2022) addressed and explained the functions and features of the James Webb Space Telescope (JWST) that caused the images of stars taken to have a "distinct christmas-ornament-looking spikes". The article explains that the "spikes" which were also known as diffraction spikes are caused by the length between the primary and secondary mirrors of the telescope and the struts that hold the primary mirror and the secondary mirror together. The JWST is a reflecting telescope, whereby a large primary mirror gathers the light and reflects it back to a smaller mirror. The shape of the primary mirror will affect how the light is being reflected onto the secondary mirror where it will lead the light to the near-infrared cameras (NIRCam) and near-infrared spectrographs (NIRSpec) from James Webb Space Telescope (Griggs, 2022). The near-infrared camera (NIRCam) is JWST’s primary imager capable of capturing ‘wavelength range 0.6 to 5 microns’ (NASA, n.d.-C).With this data of wavelength captured, NIRCam can detect light from stars and galaxies in the early process of formation. The NASA NIRCam's captured wavelength will then be analysed by an instrument called the near-infrared spectrographs(NIRSpec) where the evaluated spectrum will show the objects, stars and planets compositions (NASA, n.d.-D). With all the new features, the NIRCAM, NIRSpec, MIRI and the FGS/NIRISS, The JWST takes more detailed images than its predecessor, the Hubble Space Telescope (HST).

With the new features, The James Webb Space telescope (JWST) was able to perceive images of objects further away compared to the Hubble Space Telescope (HST) which results in more detailed images. JWST has 4 instruments, Near Infrared Camera (NIRCam), Near Infrared Spectrograph (NIRSpec), Mid Infrared Instrument (MIRI) and Fine Guidance Sensors/Near Infrared Imager and Slitless Spectrograph (FGS/NIRISS) (NASA, n.d.-F). These will enable it to capture infrared wavelengths of space articles such as stars, planets and galaxies. The NIRCam and the NIRSpec are capturing and processing the wavelength range of ‘0.6 microns to 5 microns’ (NASA, n.d.-E) and the MIRI is able to capture and evaluate the wavelength range of ‘5 to 28 microns’. (NASA, n.d.-B). However, the Hubble Space Telescope instruments capabilities are perceived in ultraviolet and visible parts of the electromagnetic spectrum, from ‘0.1 to 0.8 microns’ and a small part of infrared from '0.8 microns to 2.5 microns' (NASA, n.d.-E). The expansion of the universe includes the space between galaxies and this results in light from the 'first galaxies' to stretch (NASA, n.d.-E). As the light travels further, it shifts to a longer wavelength when it reaches us. These light will stretch and will be in the infrared light spectrum and the JWST was designed to pick up these wavelengths. In comparison with the HST, it is unable to pick these wavelengths as they are only designed to pick up in the visible and ultraviolet spectrum, which are shorter wavelengths than infrared. An example of this was the image taken of the ‘Southern Ring Nebula’ with the HST (NASA, 2008) and the JWST (NASA, 2022). The JWST was able to image galaxies that the HST was not able to. Therefore, the JWST takes more detailed images than the HST.

With the infrared data collected, the JWST will be able to observe more, which results in more details in their images as compared to the HST. With the NIRCam, NIRSpec, MIRI and FGS, which are infrared cameras, the infrared data collected scientists to produce images of stars and planets that were in the midst of forming that are concealed by huge clumps of dust as only infrared light can penetrate through these dust clouds (NASA, n.d.-G). However, these dust clouds do not allow visible light to penetrate. This results in the HBT being unable to image all stars and planets that are concealed in these clouds. An example of this occurrence was when the HST took images of the “Carina Nebula'' with its instruments in the visible and infrared spectrum (NASA, n.d.-E). Therefore, the JWST will be able to observe more objects that are hidden in the infrared view than the HST. This will lead to JWST having more detailed images.

The JWST is more efficient in collecting data which will result in more detailed images as compared to the HST. The HST primary mirror has a diameter of 2.4 metres while the JWST has a diameter of 6.6 metres. Therefore, the area of the collecting area of the JWST is roughly “6.25 times” bigger than the HST (NASA, n.d.-E). This results in the JWST having a bigger field of view to collect data. This directly correlates to JWST being more efficient in collecting data than the HST. Therefore, the JWST is able to produce more detailed images than the HST.

However, the HST is able to be serviced unlike the JWST, which will result in HST having longevity as compared to JWST. Unlike Hubble, which is accessible by the Space Shuttle and orbits about 350 miles above the Earth, the JWST is not made to accommodate servicing as the distance of it from the earth is roughly 1 million miles (NASA, n.d.-A). This means that the JWST is unable to rely on servicing if any problems are to surface. Therefore, JWST has its longevity at the moment to be able to take more detailed images than the HST.

In conclusion, the JWST is able to take more detailed images to the HST with it being able to observe more, further and more efficiently take in data. However, the JWST that launched on 25 December 2021, has to prove it's longevity as the HST can be serviced while the JWST is unable to.

Reference list

Griggs, M.B. (2022, July 16). Why stars look spiky in images from the James Webb Space Telescope. https://www.theverge.com/23220109/james-webb-space-telescope-stars-diffraction-spike.

NASA(n.d.-A). FAQ For Scientists. https://www.jwst.nasa.gov/content/forScientists/faqScientists.html#collectingarea.

NASA(n.d.-B). MIRI. https://webb.nasa.gov/content/observatory/instruments/miri.html.

NASA (2022, July 12). NASA’s Webb Captures Dying Star’s Final ‘Performance’ in Fine Detail. https://www.nasa.gov/image-feature/goddard/2022/nasa-s-webb-captures-dying-star-s-final-performance-in-fine-detail.

NASA(n.d.-C). Near Infrared Camera. https://webb.nasa.gov/content/observatory/instruments/nircam.html.

NASA (n.d.-D). Near Infrared Spectrograph. https://webb.nasa.gov/content/observatory/instruments/nirspec.html.

NASA(2008, March 24). Southern Ring Nebula. https://www.nasa.gov/multimedia/imagegallery/image_feature_443.html.

NASA(n.d.-E). Webb vs Hubble Telescope. https://www.jwst.nasa.gov/content/about/comparisonWebbVsHubble.html

NASA(n.d.-F). Webby Facts. https://webb.nasa.gov/content/about/faqs/facts.html

NASA(n.d.-G). What is the James Webb Space Telescope? https://spaceplace.nasa.gov/james-webb-space-telescope/en/