As Christmas approached last year, astronomers and space enthusiasts around the world gathered to witness the much-anticipated launch of the James Webb Space Telescope. While a remarkable piece of engineering, the telescope hasn’t been without controversies — from going over budget and falling behind schedule to being named after a former NASA administrator who’s been accused of homophobia.
Despite the controversy surrounding the telescope’s naming and date, one thing has become very clear this year – JWST’s science capability is remarkable. Its science operations began in July 2022, and it has already allowed astronomers to gain new perspectives and unravel mysteries on a wide range of space topics.
The most immediate goal of the JWST is one of the most ambitious projects in the modern history of astronomy: to revisit some of the very first galaxies, which formed when the universe was completely new.
Because light takes time to travel from its source to us here on Earth, by looking at extremely distant galaxies, astronomers can, in fact, look back in time to see the oldest galaxies that formed over 13 billion years ago.
Although there has been some debate among astronomers about the accuracy of some of the first detections of early galaxies — the JWST instrument has not been fully calibrated, so there has been some wiggle room over the exact ages of the most distant galaxies — recent discoveries have supported the idea that the JWST has spotted galaxies from the first 350 million year after the Big Bang.
That makes these the oldest galaxies ever observed, and they had some surprises, such as being much brighter than expected. This means there is more to learn about how galaxies formed 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 regions do not contain bright objects like the planets of the solar system and are located far from the center of our galaxy, which allows astronomers to search deep into space to discover these extremely distant objects.
JWST was able to detect carbon dioxide in the atmosphere of an exoplanet for the first time and recently detected a host of other compounds in the atmosphere of WASP-39b as well, including water vapor and sulfur dioxide. Not only does this mean that scientists can 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 created by chemical reactions with light.
Learning about exoplanet atmospheres is crucial if we want to find Earth-like planets and search for life. Previous generation instruments could identify exoplanets and provide basic information such as their mass or diameter and how far they orbit from their star. But to understand what it would be like on one of these planets, we need to know its atmosphere. Using data from the JWST, astronomers will be able to search for habitable planets far beyond our solar system.
It’s not just the distant planets that have captured JWST’s attention. Closer to home, the 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 in the infrared range, the JWST was able to identify features such as Jupiter’s aurora borealis and a clear view of the Great Red Spot. Also, the telescope’s high resolution means it can see small objects even against the brightness of planets, such as showing the rarely seen rings of Jupiter. It also captured the clearest image of Neptune’s rings in more than 30 years.
The other major investigation by JWST this year was on Mars. Mars is the best-studied planet outside Earth, having hosted many rovers, orbiters, and landers over the years. This means that astronomers have a fairly good understanding of the composition of the atmosphere and are beginning to learn about its weather system. Mars is also difficult to study with a sensitive space telescope like JWST because it is so bright and so close. But these factors made it an ideal testing ground to see what the new telescope was capable of.
JWST used both cameras and spectrometers to study Mars, showing the composition of its atmosphere, which corresponds almost exactly to the model expected from the current data, demonstrating how accurate JWST’s tools are for this type of investigation.
Another goal of JWST is to learn about the life cycle of stars, which astronomers currently understand in broad strokes. They know that clouds of dust and gas form knots that collect more material for them and collapse to form protostars, for example, but exactly how this happens needs more research. They also learn about the regions where stars form and why stars tend to form in clusters.
JWST is particularly useful for studying this subject as its infrared instruments allow it to look through clouds of dust to see the inner regions where stars are forming. Recent images show the development of protostars, throwing out clouds, and peering into regions where stars are dense, such as the famous Pillars of Creation in the Eagle Nebula. By imaging these structures at different wavelengths, the JWST instruments can see different features of dust and star formation.
Speaking of pillars of creativity, one of JWST’s biggest legacies in the public mind is the stunning images of space it took. From international excitement at the reveal of the telescope’s first images in July to new views of famous landmarks like the Pillars, Webb’s images have been everywhere this year.
As well as the magnificent Carina Nebula and the First Deep Field, other images worth marveling at in a minute include the star-sculpted shapes of the Tarantula Nebula, the dusty “tree rings” of binary star Wolf-Rayet 140, and the otherworldly glow of Jupiter in infrared.
And the images keep coming: Just last week, a new image was released showing the glowing heart galaxy NGC 7469.
Here’s a year full of amazing discoveries and more to come.