Gazing Deep Into the Past: What Has the JWST Learned One Year on?
On the 25th December, 2021, at 12:20 GMT, the James Webb Space Telescope (JWST) launched from French Guiana to search deep into the early universe. Now, almost a year from its launch, what has the JWST discovered?
Credits: NASA, ESA, CSA, and STScI. A look at some of the earliest galaxies in the Universe.
The JWST was designed to supersede the now decaying Hubble space telescope, launched over 30 years ago. The JWST uses a much larger mirror and is capable of looking further into the infrared range of light, allowing it to see the Universe more clearly than ever before. Already, it has discovered some of the furthest galaxies ever seen, and they’re challenging our models of galaxy formation.
For the first few months after its launch, the JWST was mostly in a configuration stage, setting its orbit and aligning its 18 gold-coated mirror segments; but on the 11th July, 2021, President Biden revealed the first image taken by the space telescope (see above). In it, we see the SMACS 0723 galaxy cluster as it looked 4.6 billion years ago. Light takes time to travel, so the further we look out into the Universe, the further back in time we can see.
It’s a beautiful picture, but what’s particularly impressive about it is the power of the technology it shows off. The image was compiled from an infrared camera in just 12.5 hours, whereas Hubble’s deep fields took weeks. It was an exciting taste of what was to come.
A slew of other images also came forth, showing the cosmos as never seen before. Some revealed new sections of the heavens, whilst others revisited old favourites from the Hubble telescope in unparalleled clarity. Its infrared camera allows the Webb telescope to see beyond the clouds of dust that make up nebulae and find many stars that were previously hidden.
Credit: NASA, ESA, CSA, and STScI. JWST is able to peer through the Carina nebula to see stars at the beginning of their lives.
But beyond these stunning images, astrophysicists are making new discoveries from distant exoplanets. Described as a “hot Saturn”, WASP-39b is located 700 million light-years away from the Earth. Although observed before, the Webb telescope has uncovered sulphur dioxide in its atmosphere. This can only be produced via a process called photochemistry, which is seen in the creation of the Earth’s ozone layer, and is the very first evidence of such a process on an exoplanet. However, with a surface temperature of over 800°C, the distant world is “not believed to be habitable”. Nevertheless, it does present the very real possibility that JWST could detect an ozone layer on another more Earth-like planet.
Credit: NASA, ESA, CSA, STScI; Joseph DePasquale (STScI), Anton M. Koekemoer (STScI), Alyssa Pagan (STScI). The iconic Pillars of Creation, first made famous by the Hubble telescope (left), have now been rendered in remarkable new detail by the JWST (right).
We are still very much in the early days of the JWST mission. NASA estimated the mission length to be 5-10 years, although they have now since increased that estimate to “significantly more than a 10-year science lifetime”. In that time, astrophysicists will be keeping a keen eye on the data that pours in. They hope to improve their understanding of the early formation of stars and galaxies, and search for the possibility of life on exoplanetary systems.
One year on, the James Webb Space Telescope is living up to its mission of being the “premier observatory of the next decade”. The future, thanks to this telescope, may now hold the secrets to the past.