The James Webb Space Telescope has become one of the most noteworthy scientific instruments of our time. First launched on December 25, 2021, the telescope, named after NASA’s administrator from 1961 to 1968, was designed to peer into galaxies as distant as can be, identify and locate the first formed galaxies and objects after the Big Bang, analyze the chemical properties of exoplanets to discern their surfaces, and observe the early stages of the first star formations and black holes. To complete this exhaustive list of duties, the JWST comes equipped with four instruments: the NIRCam (Near Infrared Camera), the NIRSpec (Near Infrared Spectrograph), the MIRI (Mid Infrared Instrument), and FGS/NIRISS (Fine Guidance Sensors/Near Infrared Imager and Slitless Spectrograph).
You may have noticed that the word “infrared” gets mentioned a lot when speaking of the JWST. That’s because the telescope does not capture visible light like an optical telescope does; it instead observes the sky using infrared radiation. With wavelengths of 760 nanometers to 1 micrometer in length, infrared waves have longer wavelengths than visible light. In comparison, visible light only has wavelengths from 380 to 750 nanometers long. Because of this, infrared waves are able to pass through opaque gases and dust more easily, which means that objects covered in said materials will be more clearly seen by the JWST than an optical telescope, hence why the telescope was built to observe infrared light.
For example, say an astronomical object like a star or planet is covered by dust. Because an optical telescope relies on visible light, it would be unable to view the object, whereas the JWST, dependent instead on infrared, would be able to complete the task at hand because dust is transparent to infrared radiation thanks to infrared’s longer wavelengths. This is ultimately why the JWST is such a valuable tool for astronomers; it would allow them to view celestial bodies and objects with more clarity than ever before.
As of the time this article is being written, NASA has released the first photos taken by the JWST, and when put side-by-side with photos of the same nebulas and galaxies taken by the Hubble Space Telescope, the JWST photos are undeniably of higher resolution.
Lastly, it is important to note that the JWST does not orbit the Earth like the Hubble Space Telescope does. In fact, it’s about 1.5 million kilometers away from the Earth, orbiting the L2 point. The L2 point is one of five Lagrange points, which is defined as a point in space where the gravitational pulls of two bodies balance out.
Sources:
https://webb.nasa.gov/content/about/faqs/facts.html
https://www.nature.com/articles/d41586-022-01906-6
https://www.space.com/james-webb-space-telescope-mission-explained
Photo:
https://www.asc-csa.gc.ca/images/satellites/jwst/jwst-og.jpg
