The James Webb Telescope
If you like stars and the universe as much as I do, you might have heard about the James Webb Space Telescope. The James Webb Space Telescope (short: JWST or Webb) is NASA's newest infrared observatory that will continue the work of the legendary, but aged, Hubble Space Telescope.
But how does the Webb work, and how can it see stars and planets in other star systems, or even in distant galaxies? At its center is a huge mirror, with 18 hexagonal mirror segments, measuring 1.32m in diameter. The mirror enables NASA to focus light from distant stars. Webb's main component is Beryllium, but it is coated with Gold, allowing for the reflection of infrared light into the sensors. In comparison to its predecessor - the Hubble Space Telescope - Webb is a lot more precise and has a higher resolution. It can detect galaxies extremely far away, and show astronomers what galaxies, which were created 200 million years after the big bang, look like. This helps scientists estimate the beginning of the universe. The James Webb Space Telescope is also a lot better at spectroscopy, which is a process where light is broken down into wavelengths to reveal the composition of an object. Webb, therefore, can tell astronomers what distant objects are made of, or even if oxygen or water is present on planets, or in their atmospheres. This is groundbreaking.
Now you might ask yourself, how do you get a telescope that size into space without damaging it? This was probably the biggest problem for engineers working on it, and one of the reasons it took over 30 years to develop. The idea was to fold up the mirror and sun shield to fit the three-story high telescope inside the compartment of the Ariane 5 ECA. It was launched on December 25, 2021, and when it was over 1.5 million kilometers away from the earth and found its orbit around the sun, it started unfolding. It took an entire year to cool down to its operating temperature of about -183 degrees Celsius. It can reach these temperatures because of its tennis-court-sized sun shield and a special electrically powered cryocooler. These temperatures are necessary, as the Webb is supposed to detect infrared light emitted from stars and planets to see them in distant galaxies and behind dust clouds. However, warm objects like Webb’s electronics also emit infrared light, which could affect the telescope's measurements. To prevent these effects, the instruments are cooled, and the space telescope faces away from the sun.
However, despite all these efforts, the mission duration of the Webb is only estimated to be 5 – 10 years, meaning it will be shorter-lived than the Hubble Space Telescope mission. This is mainly because the Webb is too far away to be repaired or enhanced, unlike the Hubble, which orbits around the earth. The Webb has a lot of new missions that astronomers hope to fulfill by the end of these ten years. The first one is to look back in time and look back at the early universe. The second one is to watch the assembly of galaxies and to help understand how galaxies change from small assemblies of stars to grand spirals over billions of years. The third is to more closely watch how stars and planets form, as Webb can see through the dust clouds in which these stellar objects form. Finally, it is supposed to look at exo-planets and possibly find the building blocks of life on other plants. Let's hope the James Webb Space Telescope will be as successful and eye-opening as the Hubble Space Telescope and tell us as much as possible about the mysteries of the universe.
Sources:
YouTube, YouTube, 17 July 2021, https://www.youtube.com/watch?v=tnbSIbsF4t4. Accessed 27 Mar. 2023.
YouTube, YouTube, 8 Sept. 2022, https://www.youtube.com/watch?v=YAeLjJx6lOI. Accessed 27 Mar. 2023.
“What Is the James Webb Space Telescope?” NASA, NASA, 4 Jan. 2022, https://spaceplace.nasa.gov/james-webb-space-telescope/en/.
2022, Science and Technology·27th October, and Emily Hudson. “Introducing the James Webb Space Telescope.” The Oxford Student, 27 Oct. 2022, https://www.oxfordstudent.com/2022/10/27/introducing-the-james-webb-space-telescope/.
“Explained: What Is James Webb Telescope and Why Do People Want to Rename It.” IndiaTimes, 16 July 2022, https://www.indiatimes.com/explainers/news/what-is-james-webb-telescope-and-why-do-people-want-to-rename-it-574922.html.
“What Is the James Webb Space Telescope?” NASA, NASA, 4 Jan. 2022, https://spaceplace.nasa.gov/james-webb-space-telescope/en/.
Greicius, Tony. “Webb Telescope's Coldest Instrument Reaches Operating Temperature.” NASA, NASA, 12 Apr. 2022, https://www.nasa.gov/feature/jpl/webb-telescope-s-coldest-instrument-reaches-operating-temperature.
Karl Glazebrook ARC Laureate Fellow & Distinguished Professor, and Simon Driver Professor of Astrophysics at the International Centre for Radio Astronomy Research. “Two Experts Break down the James Webb Space Telescope's First Images, and Explain What We've Already Learnt.” The Conversation, 21 Dec. 2022, https://theconversation.com/two-experts-break-down-the-james-webb-space-telescopes-first-images-and-explain-what-weve-already-learnt-186738.
