Summary Reader Response Draft 4

 

Griggs, in “Why stars look spiky in images from the James Webb Space Telescope” (2022) explains the technology behind the James Webb Space Telescope (JWST) and how it compares to its predecessor, the Hubble Space Telescope with regards to the number of diffraction spikes. The study of outer space is an interesting topic amongst many individuals. With the recent release of the JWST, space enthusiast are astonished at the advancement of the technology used to study the galaxy. From multiple camera instruments to highly engineered mirrors, I feel that the JWST will be a game changing telescope in the air and space industry. The JWST is the latest, most powerful telescope, cruising millions of miles away from earth, developed by NASA. It observes our galaxy by using infrared light and hopes to see the past and give information about how the galaxy has changed from billions of years ago until today. It was launched on the 25^th of December 2021 in Guiana Space Center, Europe.

The article begins by giving a very brief explanation on the working principal of a telescope. It then discusses the differences between the Hubble Telescope and the JWST. The reason why the JWST is becoming popular amongst astronomers, in the opinion of Griggs, is because of its improved design and technology. From where I stand, I did not think it was possible to view what the galaxy looks like about 13 billion years ago. Nonetheless, the articles explaining the technology behind the JWST refutes my opinion. The JWST is a revolutionary telescope because it utilizes hexagonal mirrors and multiple camera instruments which are able to gather and study new information about our solar system that other telescopes are not capable of doing so due to their lack of technology.

The JWST uses hexagonal mirrors primarily instead of a single round mirror used in the Hubble Telescope. Because JWST’s main aim is to see far into the galaxy, approximately 13 billion light years away (Kluger, 2022), a bigger mirror setup is used for the mission. The purpose of primary mirrors in a reflective telescope is to guide the light into the secondary mirror. “The shape of the primary mirror, in particular the number of edges it has, determines the mirror’s diffraction pattern” (Griggs, 2022). This results in an image with six diffractions. The use of a hexagonal shape mirror eliminates gaps between each mirror, obtaining a high filing factor, indicating minimal gaps between mirrors. (NASA, 2021) A hexagonal outline also makes the design additionally symmetrical, making it easier to launch into outer space as the whole telescope would need to be compact during takeoff. (NASA, 2021)

The JWST utilizes multiple camera instruments to view the solar system. The NIRCam (near-infrared light) is the telescope’s main imager. It shows more prominent diffraction spikes because stars are very bright at those wavelengths (0.6 to 5 microns) (NASA, 2021). “NIRCam will detect light from: the earliest stars and galaxies, in the process of formation, the population of stars in nearby galaxies, as well as young stars in the Milky Way and Kuiper Belt objects” (NASA, 2021). The NIRSpec (Near InfraRed Spectograph) is used to distribute the amount light from a certain target into a spectrum. “Analyzing the spectrum of an object can tell us about its physical properties, including temperature, mass and chemical composition” (NASA, 2021). There is also a Mid-Infrared Instrument (MIRI) that consists a camera and a spectrograph. Its main role is to view the light in the mid-infrared area of the electromagnetic spectrum. The wavelength of the MIRI has a range of 5 to 28 microns. In this range, it gives us a visual of the solar system longer than our eyes can ever see (NASA, 2021).

However, the JWST does pose an obvious weakness. Being millions of miles away from earth, it would be nearly impossible to carry out repairs if something were to go wrong. Unfortunately, the JWST was hit by a meteoroid sometime in May of 2022. The meteor strike damaged one of the mirrors and has caused an uncorrectable damage to the telescope. Thankfully, the effect of the damage is insignificant and the telescope is still functioning above expectations (Howell, 2022). Even so, the idea of the telescope running into complications and not being able to correct it directly is concerning. 

The reason behind the making of the JWST is for astronomers to discover further into the galaxies than ever before. The aim is to discover what lies after the Big Bang. Scientist have spent over 30 years developing the JWST, costing approximately $10 billion USD (Amos, 2021). Compared to Hubble, the JWST is bigger and better and can see much further into the universe, making it a revolutionary telescope with its improved mirror and camera technology. For example, the JWST can look further because the mirrors collect much more light energy due to its 6.5-meter diameter mirror while the Hubble’s primary mirror is only 2.5 meters in diameter (Reilly, 2022). Therefore, with JWST’s breakthrough, it allows scientists and astronomers to discover new galaxies and learn about the beginnings of time.

 

References:

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

Howell, E. (2022, July 18). James Webb Space Telescope picture shows noticeable damage from micrometeoroid strike. Space.com. https://www.space.com/james-webb-space-telescope-micrometeoroid-damage

Kluger, J. (2022, July 13). What the 5 Mind-Blowing Webb Telescope Pictures Tell Us. Time.com. https://time.com/6196675/five-james-webb-telescope-images-explained/

Reilly, C. (2022, July 13). James Webb Space Telescope: NASA's First Images Explained. Youtube: CNET. https://www.youtube.com/watch?v=XvfuxtVr7JY&t=1s

NASA (n.d) Webb Key Facts. jwst.nasa.gov. https://jwst.nasa.gov/content/about/faqs/facts.html

NASA (n.d) Webb’s Mirrors. webb.nasa.gov. https://webb.nasa.gov/content/observatory/ote/mirrors/index.html#:~:text=The%20Webb%20Telescope%20team%20also,in%20diameter%2C%20flat%20to%20flat

NASA (n.d) NIRCam. webb.nasa.gov. https://webb.nasa.gov/content/observatory/instruments/nircam.html

Amos, J. (2021, December 14). What is the James Webb Space Telescope and when will it launch? bbc.com.

 https://www.bbc.com/news/science-environment-59419110