What has the flashy new telescope discovered for astronomy, one year after it was launched?
The James Webb Space Telescope was launched on December 25, 2021. It attracted lots of attention from around the world for its capabilities and implications for future astrophysics studies. But what's so special about Webb, anyway?
Let's recap. Prior to Webb, the most famous space telescope was the Hubble Space Telescope (named after Edwin Hubble, who figured out that space was expanding). Hubble has brought us some brilliant images, perhaps "Pillars of Creation" being the most recognizable of the multitude of photos it has taken.
However, Webb is about 50% larger than Hubble, or approximately 20m in length (compared to Hubble's 13.2m). Not only that, it sees an entirely different band of light than Hubble.
James Webb is an infrared telescope, which means it sees lower frequencies beyond the visible light spectrum. Each "band" of light the telescope captures is converted to a certain color in visible light (red to violet), providing you with brilliantly colorized starscapes. Here's Webb's take on the "Pillars of Creation", compared to the Hubble image from 1995:
As you can see, the image is much more vibrant and detailed!
Benefits of Webb
As light travels through space over a long period of time, its wavelength is stretched so that it shifts toward the red part of the light spectrum (ESA). This phenomenon is called "redshift", and is the reason why much of the older light waves in space are in the infrared frequency. By observing infrared light, we can
Another major advantage of infrared light is that it passes through things that visible light cannot, like dust and dense gases. Think of it as infrared being 'thinner' than visible light, which allows it to slip through the gaps between dust particles with less scattering.
This is convenient because there is a lot of dust and gases in space. "Stellar nurseries" like the Pillars of Creation are filled with them, serving as the birthplace and raw material for new stars to form. By using infrared, we can observe more distant objects and phenomena that were previously shrouded in mystery.
Webb's discoveries
So what exactly has Webb found?
Just two days ago for the first time, it confirmed the existence of an exoplanet: LHS 475 b (NPR). Exoplanet discoveries are special because the light of the star(s) they orbit far outshines any light reflecting off their planetary surfaces. Therefore, phenomena like transits and gravitational lensing have to be used to observe exoplanets, and that's exactly what astronomers did with this one! The Transiting Exoplanet Survey Satellite (TESS) data hinted at the planet's existence, and Webb was used to confirm the data.
That's not the only exciting news Webb has brought. In December last year, astrophysicists from a variety of institutions across the world have presented a yet-unreviewed paper that claims they've found the four oldest known galaxies in the universe using Webb (Time). If this report is true, it would mean that Webb has seen galaxies from just 400 million years after the Big Bang (which happened 13.8 billion years ago), according to Time.
If you want to learn more about Webb, NASA's official page for it is a great place to start. In particular, the 3D model of Webb's real-time location is fascinating and helps put the vastness of space in perspective.
That's all I have for you today. I hope you learned something new or interesting, and I'll see you in the next one very soon!
- Taizo
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Bibliography
NASA. (2018). The Pillars of Creation. NASA. Retrieved January 14, 2023, from https://www.nasa.gov/image-feature/the-pillars-of-creation.
NASA. (n.d.). Where is Webb? NASA/Webb. NASA. Retrieved January 14, 2023, from https://webb.nasa.gov/content/webbLaunch/whereIsWebb.html
Adkins, J. (2022, October 18). NASA's Webb takes star-filled portrait of pillars of creation. NASA. Retrieved January 14, 2023, from https://www.nasa.gov/feature/goddard/2022/nasa-s-webb-takes-star-filled-portrait-of-pillars-of-creation
What is 'red shift'? ESA. (n.d.). Retrieved January 14, 2023, from https://www.esa.int/Science_Exploration/Space_Science/What_is_red_shift#:~:text='Red%20shift'%20is%20a%20key,moves%20relative%20to%20an%20observer.
Archie, A. (2023, January 12). NASA's Webb Telescope has discovered its first exoplanet. NPR. Retrieved January 14, 2023, from https://www.npr.org/2023/01/12/1148626359/nasa-webb-telescope-exoplanet
Kluger, J. (2022, December 13). James Webb Discovery helps date birth of very first galaxies. Time. Retrieved January 14, 2023, from https://time.com/6240683/james-webb-telescope-discovers-oldest-galaxies-ever-seen/
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