The evolution of infrared astronomy, from Spitzer to WISE and JWST. Credit: Andras Gaspar
The scientific and astronomical communities are eagerly awaiting his arrival on Tuesday 12 July. This is the day NASA promises to release the first images taken by the James Webb Space Telescope (JWST)! According to a previous NASA statement, these images will include the deepest views of the Universe ever taken, as well as spectra obtained from an exoplanet atmosphere. In another statement at a recent press conference, it was stated that the images were so beautiful that they almost made Thomas Zarbuchen, associate administrator of NASA’s Scientific Mission Management (SMD) cry!
The James Webb Space Telescope is the most powerful and complex observatory ever deployed, not to mention the most expensive, with $ 10 billion! Due to its complex system of mirrors and its advanced sunscreen, the telescope had to be designed so that it could be folded (origami style) to fit inside a payload fairing and then unfolded once it arrived. in space. To ensure that everything worked, the telescope had to be rigorously tested, a process that caused numerous delays and extra costs (a situation made worse by the COVID pandemic).
Well-focused star engineering images in the field of view of each instrument show that the telescope is fully aligned and focused. Credit: NASA / STScI
Since its launch on Christmas Day 2021, the observatory has been successfully deployed, commissioned its scientific instruments and has reached the L2 Lagrange point, where it will remain throughout its mission. He also successfully aligned the 18 segmented mirrors, which are arranged in a honeycomb configuration measuring 6.5 meters (more than 21 feet) in diameter, nearly three times the size of Hubble’s main mirror. Earlier, NASA released test images that the JWST made of a star 2,000 light-years from Earth in the direction of the constellation Ursa Major (HD 84406).
According to Zurbuchen, who saw the images during a briefing on Wednesday with other NASA officials, the first-light images he has taken provide a “new worldview” of the cosmos. Addressing what it was like to see the first-light footage at Wednesday’s press conference, Zarbuchen said:
“The images are being made right now. There’s already an amazing science in the can, and more are yet to be taken as we move forward. We’re in the midst of downloading history data. It’s very difficult. not to look at the Universe with a new light and not just have a moment that is deeply personal. It is an emotional moment when you see nature suddenly releasing some of its secrets, and I would like you to imagine it and wait for it. “
During the press conference, NASA officials said the images and other data would include the deepest field image of the Universe ever taken. The previous holder of the record was the image acquired as part of Hubble’s Ultra Deep Field, which included 10,000 galaxies of various ages, colors, and distances toward the constellation Fornax. The 100 oldest galaxies in the image (shown below) appear deep red in color and were dated only 800 million years after the Big Bang, making them the most distant and oldest ever seen.
This view of about 10,000 galaxies is called Hubble’s Ultra Deep Field. Credits: NASA, ESA and S. Beckwith (STScI) and the HUDF team
James Webb’s images look even further into the cosmos and reveal what galaxies were like just a few hundred million years after the Big Bang. These early galaxies were instrumental in dispelling the “Cosmic Dark Age,” a period when the Universe was impregnated with neutral hydrogen atoms and therefore invisible to modern instruments. Astronomers know what the Universe was like just before this period, thanks to the relic radiation from the Big Bang, which is visible to our instruments: the cosmic microwave background (CMB).
As a result, astronomers have not been able to see what the earliest galaxies were like since their formation coincided with the Dark Ages. But thanks to its advanced infrared imaging capabilities, James Webb can pierce the veil of “darkness” and see what galaxies were like initially. This will allow scientists to model and simulate the evolution of cosmic structures with much greater accuracy, which could also provide a new insight into the role of dark matter and dark energy in cosmic evolution.
Another image will offer the audience something they had never seen before (which James Webb is ideal to offer). This image will include an exoplanet, as well as spectral data from its atmosphere obtained by its advanced set of spectrographs. These instruments allow astronomers to observe the chemical signatures of an exoplanet by observing how light (and wavelengths) is absorbed into its atmosphere. These signatures will reveal the composition of the atmosphere, which could include oxygen gas, nitrogen, and carbon dioxide, the same things we associate with “habitability”.
Even more exciting, these same observations could reveal traces of methane gas, ammonia, and other chemicals indicative of biological processes we associate with life (also known as “biosignatures”). Last but not least, the presence of chemicals such as chlorofluorocarbons and others that we associate with industrial processes would be seen as indications of advanced life (also known as “technosignatures”). In short, James Webb’s images will allow astronomers to model the evolution of the cosmos, place stricter restrictions on which exoplanets are “habitable,” and could even reveal that humanity is not alone in the Universe.
There are many other things that James Webb will study during his primary scientific operations (which will last until 2028) and his ten-year mission (which is expected to expand to 20 years). This will include the dust and gas that make up the interstellar medium (ISM), debris disks around young stars, planetary systems in the process of formation, colder objects such as M-type stars (red dwarfs) and brown dwarfs, and the center of the Milky Way.
And it all starts with these “first light” images, which NASA says it plans to release on July 12, starting at 10:30 a.m. EDT (8:30 p.m. PDT). According to NASA Deputy Administrator Pam Melroy, those first images were also emotionally overwhelming for her. “What I saw moved me, as a scientist, as an engineer, and as a human being,” he said. While the rest of us will have to wait another eight days, the teasers that have treated us suggest that years of delays, re-testing, and extra costs will be worth it!
You can view the images by going to the NASA JWST mission page.
Originally published in Universe Today.