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How the James Webb Space Telescope changed astronomy in its first year

How the James Webb Space Telescope changed astronomy in its first year
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As Christmas approached last year, astronomers and space fans around the world gathered to see eagerly awaited launch of the James Webb Space Telescope. Although the telescope was a wondrous piece of engineering, it was not without its challenges controversies — from well over budget and behind schedule to being named after a former NASA administrator who has been accused homophobia.

Despite debates over the telescope’s naming and history, one thing has become abundantly clear this year — the scientific capabilities of the JWST are remarkable. Beginning its scientific operations in July 2022, it has already enabled astronomers to gain new views and uncover mysteries on a variety of space issues.

JWST’s primary goal is one of the most ambitious projects in the recent history of astronomy: to look back at some of the first galaxies that formed when the universe was very new.

Thousands of galaxies abound in this near-infrared image of galaxy cluster SMACS 0723

Because light takes time to travel from its source to us here on Earth, by looking at extremely distant galaxies, astronomers can actually look back in time to see the earliest galaxies, which formed more than 13 billion years ago .

Although there was some debates among astronomers about the accuracy of some of the early discoveries of early galaxies – JWST’s instrument had not been fully calibrated, so there was some leeway as to how accurate the age of the most distant galaxies was – more recent evidence has supported the idea that JWST it has discovered galaxies from the first 350 million years after the big bang.

This makes them some of the earliest galaxies ever observed, and they had a few surprises in store, including being much brighter than expected. This means we still have more to learn about how galaxies form in the early Universe.

These early galaxies are identified using surveys and Deep field images, which Webb uses to look at large patches of sky that might appear empty at first glance. These areas lack bright objects like Solar System planets and are off the center of our galaxy, allowing astronomers to peer deep into space to spot these extremely distant objects.

JWST has detected carbon dioxide in the atmosphere of an exoplanet for the first time and recently discovered a variety of other connections also in the atmosphere of planet WASP-39b, including water vapor and sulfur dioxide. This means that not only can scientists see the composition of the planet’s atmosphere, but they can also see how the atmosphere interacts with light from the planet’s host star, as sulfur dioxide is formed through chemical reactions with light.

Learning the atmosphere of exoplanets is crucial if we are ever to find Earth-like planets and search for life. Previous generation tools can identify exoplanets and determine basic information such as their mass or diameter and the distance they orbit from their star. But to understand what it would be like to be on one of these planets, we need to know something about their atmosphere. With data from JWST, astronomers can search for habitable planets far beyond our solar system.

Jupiter's rings as seen by the space telescope.

Jupiter’s rings as seen by the space telescope.
Image: NASA

It’s not just distant planets that have caught JWST’s attention. Closer to home, JWST has been used to study planets in our solar system, including Neptune and Jupiter, and will soon be used to study Uranus as well. By looking into the infrared, JWST was able to identify features such as Jupiter’s auroras and a clear view of its Great Red Spot. And the telescope’s high accuracy meant it could see small objects even against the brightness of the planets, such as the rarely seen rings of Jupiter. It also took the clearest picture of Neptune’s rings in more than 30 years.

Another major survey JWST conducted this year involved Mars. Mars is the most studied planet outside of Earth and has hosted numerous rovers, orbiters and landers over the years. This means that astronomers are beginning to understand its atmospheric composition fairly well and are beginning to learn about its weather system. Mars is also particularly difficult to study for a sensitive space-based telescope like the JWST because it is so bright and so close. But these factors made it the perfect proving ground to see what the new telescope was capable of.

JWST used both its cameras and its spectrographs to study Mars and show the composition of its atmosphere, which matched almost perfectly the expected model from current data, showing how accurate JWST’s instruments are for this type of study.

Another goal of JWST is to learn about the life cycle of stars, which astronomers currently have a broad understanding of. They know that dust and gas clouds form knots that accumulate more material and collapse to form protostars, for example, but exactly how this happens remains to be understood. You will also learn about the regions where stars form and why stars tend to form in groups.

JWST is particularly useful for studying this topic because its infrared instruments allow it to peer through dust clouds to see into star-forming regions. Current pictures show the evolution of protostars and the clouds they shed, looking into regions of intense star formation, like the famous one pillars of creation in the Eagle Nebula. By mapping these structures in different wavelengthsJWST instruments can detect various features of dust and star formation.

This image shows a spiral galaxy dominated by a bright central region.  The galaxy has blue-purple hues with orange-red regions filled with stars.  Also visible is a large diffractive peak that appears as a star pattern over the galaxy's central region.  Many stars and galaxies fill the background scene

NGC 7469
ESA/Webb, NASA & CSA, L Armus,

Speaking of Pillars of Creation, one of JWST’s greatest legacies in the public mind is the stunning images of space it has captured. From the international excitement at the unveiling of the first images of the telescope in July it new views of iconic landmarks Like the Pillars, Webb pictures were all over the place this year.

As well as the splendor Carina Nebula and first deep fieldother images worth taking a minute to ponder are the star-shaped shapes of the Tarantula Nebulathe dusty “tree rings” of Double star Wolf-Rayet 140and the otherworldly glow of Jupiter in the infrared.

And the pictures keep coming: Just last week a new picture was published showing the bright shining heart of the galaxy NGC 7469.

Here’s to a year of incredible discoveries and many more to come.

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