Colouring Space - Visualizing the Universe
With a near-to-mid-infrared sensitivity, ultra image resolution and spectroscopic capabilities, the James Webb Space Telescope has already revealed a universe that has been, up until now, hidden to the human eye. Webb has uncovered stars previously masked by dust clouds, water in the atmospheres of celestial landmarks and the deepest view of the universe humans have ever seen.
On Christmas Day 2021, the James Webb Space Telescope (JWST) or Webb, was released from an Ariane 5 rocket upper stage 27 minutes after launch and began the 29-day journey of one million miles to L2, - a point where an intersection of gravitational fields allows the intrepid technology to stay in a constant orbit with minimal fuel burn or manual adjustment. Three times sharper and 100 times more sensitive than the Hubble Telescope, the $10 billion dollar machine reached its destination and began to unfurl, a process involving over 300 individual steps. With any failure rendering the telescope inoperable, and a repair operation to the distant technology an impossibility, the tense procedure went without a hitch.
From deep in space, Webb's positioning allowed for spectacular views of the stars unimpeded by Earth's atmosphere. With Webb's 250,000 micro shutter system, - each shutter measuring 100 by 200 microns to allow for simultaneous high-resolution observation - scientists got to work. Only a month later, the release of the first full-color images was presented by President Joe Biden:
It’s hard to even fathom. It’s astounding. It’s an historic moment for science and technology, for America and all of humanity... This is the oldest documented light in the history of the universe from 13 billion - let me say that again - 13 billion—years ago.... It’s hard to even fathom
NASA's release of these stunning images catches the galactic frontier as it was 13 billion years ago, a small insight into what the most powerful telescope ever launched in to space is capable of. Webb's dreamy vistas reveal the Carina Nebula, the Southern Ring Nebula, a galactic cluster known as Stephan’s Quintet, and the galaxy field SMACS 0723 - home to some of the universe’s oldest galaxies. And as this small selection of images has proven, this new visuality of space promises to reshape our previous understanding of the universe.
The renderings from Webb are based on images - the data that is transmitted back to Earth manifests in the form of visuals that we can analyse and share. But how do these images become a tool we can both admire and extract information from? First, the images are collected with Webb's specialized instruments, NIRCam, MIRI, NIRISS and NIRSpec. Near Infrared-Camera or NIRCam is Webb’s primary near-infrared camera, providing high-resolution imaging and spectroscopy for a wide variety of subjects. NIRCam is the only near-infrared instrument with coronagraphic and time-series imaging capabilities, playing a significant role in the study of exoplanets. Mid-Infrared Instrument (MIRI) provides imaging and spectroscopy capabilities in the mid-infrared spectrum. The only mid-infrared instrument, astronomers rely on MIRI to study relatively cold objects like debris disks and extremely distant galaxies whose light has shifted into the mid-infrared over time.
The Near Infrared Imager and Slitless Spectrograph NIRISS is used to investigate first light detection, exoplanet discovery and characterization, and exoplanet transit spectroscopy. The Near InfraRed Spectrograph (NIRSpec) will operate over a wavelength range of 0.6 to 5 microns. A spectrometer is used to disperse light from an object into a spectrum. Analysing the spectrum of an object can reveal information about its physical properties, including temperature, mass, and composition.
As we've seen over the past few days, the data relayed from the James Webb Space Telescope is a true marriage of science and art. When instrument data is received, a process of refinition, compilation and translation is undertaken down to the pixel. On the day the first images from Webb arrived, Alyssa Pagan, a Science Visuals Developer who works in the Office of Public Outreach at the Space Telescope Science Institute explained that colouring the frontier of space is "a matter of picking and choosing filters and colors that enhance the details and the structure in the image itself..." On choosing the colours for the final images, Pagan stated "you really are trying to show the different details and the processes that are happening in the astronomical images, but at the end of the day you want it to be very compelling, you want it to be very beautiful, because space is beautiful".
The role of managing the image material from the cosmos is no simple task. Stephan’s Quintet, a visual grouping of five galaxies was recently revealed in a new image comprised of over 150 million pixels and is constructed from almost 1,000 separate files. The enormous mosaic is Webb’s largest image to date, and conveys new insights into how galactic interactions may have driven galaxy evolution in the early universe. The image also shows outflows driven by a black hole in Stephan’s Quintet in a level of unprecedented detail. Combined with the most detailed infrared image ever made of Stephan’s Quintet from MIRI and the Near-Infrared Camera (NIRCam), the data from Webb will provide a bounty of valuable, new information regarding the rate at which supermassive black holes expand.
Joe DePasquale, the Senior Data Imaging Developer in the Office of Public Outreach at the Space Telescope Science Institute says that the shortest wavelengths of infrared light are assigned blue colors, and green and then red are paired to longer and longer wavelengths, which mimic our way of seeing. "But there is a lot of aesthetics that are involved" he says "and painstakingly going through and cleaning these images up with an attention to detail, a level of detail like at the pixel level, is in every image". A selection of Webb’s rendered observations are then chosen by a group of representatives from NASA, ESA, CSA, and the Space Telescope Science Institute to be presented to the public.
Webb's images are no doubt crucial to the investigation of our mysterious cosmos. According to NASA, Webb's voyage has already led to the discovery of the "distinct signature of water" on an exoplanet 1,150 light years away. Rigorously rendered in a process that truly melds art and science into a cohesive undertaking never seen before by humankind, we look forward to what the James Webb Telescope will reveal in the future.
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