The James Webb Space Telescope (JWST), NASA, developed in collaboration with European and Canadian space agencies, uses a 6.5-meter primary mirror to capture the deepest and clearest infrared image yet of the distant universe and the first full-color image since its launch. The image shows galaxy cluster SMACS 0723, which formed 4.6 billion years ago and contains thousands of galaxies. It was taken by JWST’s Near Infrared Camera (NIRCam) and assembled from photos taken at different wavelengths.
The galaxy clusters in the images are so large that they even bend space and time around them, leading to a phenomenon called the “gravitational lensing effect” that magnifies the more distant galaxies behind the cluster. Light from some of these galaxies has traveled 13 billion years to reach the telescope. JWST will not only image the interesting celestial object but also split the light into different wavelengths. This will allow JWST to not only target distant nebulae, galaxy clusters, and even exoplanets, showing us tiny structures we have never seen before, but also help researchers understand the mass, age, history and composition of galaxies.
Unlike telescopes such as Hubble, the JWST is based on infrared imaging, which observes light from a region of the electromagnetic spectrum (the infrared region) that is invisible to the human eye. The four science instruments used are the Near Infrared Spectrometer (NIRSpec), the Mid Infrared Instrument (MIRI), the Near Infrared Camera (NIRCam), the Near Infrared Imager and the Seamless Spectrograph (NIRISS). Hubble has some infrared detection capabilities but is not as good as JWST.
The infrared range observed by JWST is critical to charting the timeline of our universe. As the universe continues to expand, the oldest and rarest stars and the things they illuminate appear to us only as infrared light. Astronomers hope to use the JWST to explore every phase of cosmic history, from the interior of our solar system to the most distant observable galaxies in the early universe and everything in between, to help humanity understand the origin of the universe, the evolution of galaxies, and our position in it. This means that today we can expect to observe the early state of the visible universe. We can see how the first galaxies formed just a few hundred million years after the Big Bang, revolutionizing astrophysics as we know it.
Engineers and scientists have spent the past six months carefully adjusting the mirror portion of the telescope and calibrating the instruments. Now the JWST is finally ready to collect light from distant galaxies for humanity.