Introduction
JWST images have achieved resounding success worldwide. A frequent question with the general public concerns how such images are made, triggered especially by the fact that JWST observes in the infrared. This curiosity can, in turn, be used to explore the topic of digital color image processing, promoting computational thinking and data literacy “through the backdoor”. This is also a fertile area for art-science collaborations and an engaging subject for projects co-creating scientific knowledge with marginalized communities.
An evergreen question: How are astronomical images created?
In today’s image-dominated digital landscape, astronomical images enjoy a very fortunate reputation thanks to the fascination enticed by the cosmic subjects they depict. For science visualization purposes, astronomical images are processed via a layering technique that allows multiple data sets to be combined into a color image (Rector et al., 2007). This is however not readily known by the non-expert public, often eliciting questions on how such images are created, for example during public talks, in online forums and on social media. A wide range of multimedia content has been produced to address this question, a classic for Hubble Space Telescope (HST) imagery that was revamped since the JWST Early Release Observations (Pontoppidan et al., 2022) in July 2022.
Online news outlets have covered the topic with in-depth articles and interviews to mission experts, featuring headlines such as: “How the James Webb Space Telescope's first color images were made”,[1] “The Colors in the James Webb Space Telescope Photos Are Fake. And that’s OK”,[2] “Yes, NASA Did Manipulate The Webb Telescope’s First Color Images Last Week—But Don’t Call Them ‘Fake’”,[3] “The James Webb Space Telescope images aren’t what your eyes would see. But that makes them science, not faked”,[4] “What color are the stars? The story behind the James Webb telescope images”,[5] “Are the Colors in Webb Telescope Images ‘Fake’? Humans can't see infrared light, so what makes Webb Space Telescope images so dazzling?”,[6] “The art behind NASA’s scientific space photos. Welcome to the aesthetics of space photography”,[7] “How is color added to the JWST images? An astronomer explains”.[8]
The abundance of content on the topic, which was still popular even several months after the first JWST images were released, indicates a genuine curiosity by the general and interested public to understand science at a deeper level. After all, as the mission was rightfully presented as an infrared observatory, catching light humans cannot see, the question of how these beautiful images were made arose quite naturally. Whereas some of the headlines may contain the word “fake”, suggesting possible disbelief around the images and their scientific truthfulness (this might be linked to the unfortunate expression “false-color” from photography jargon, the use of which is discouraged by the astronomical community), the headlines themselves, and the articles in greater detail, do a pretty good job explaining the process of creating such scientific visualizations from the observatory data.
Opportunities for public engagement
Such a widespread expression of interest is an opportunity for public engagement, not just to delve into the physical processes behind the astronomical objects depicted in the images, but even further, to explain how digital images are made, thus promoting data literacy “through the backdoor” and practicing computational thinking, a vital skill in the current digital age (Wing, 2006). An example of an online tool to explore the topic in the classroom is the Rubin Observatory’s investigation “Coloring the universe”[9] which lets users practice with ordinary color digital images before moving to astronomical image processing. This is also a fertile area for science-art collaborations. An example is the lenticular print of the famous HST Pillars of Creation image created by artist Melanie King in 2017: the choice to use this printing technique, which makes use of a zig-zag texture to feature two images at once, wishes to highlight the levels of mediation that an astronomical image goes through when produced for public consumption.[10]
Another way to explore the extra dimension offered by multi-wavelength astronomical observations is through sonification: transforming the data into sounds rather than images. This approach can be used to make data accessible to visually impaired people as well as providing an additional, multi-sensory layer for people with clear vision. A wide range of astronomical sonifications have been produced, but there is still not a common “grammar” as the one used for image processing. Nevertheless, as sound offers many more parameters to map a data cube rather than images, there is great potential for both public engagement and research. One of the most used conventions is to map wavelength onto pitch, intensity onto volume, and position through a stereo surround system, but research is ongoing to investigate which astronomical parameters are best mapped onto which sound parameters (Zanella et al. 2022). A platform for astronomical sonifications is Chandra’s “A Universe of Sound”,[11] which features some of the JWST ERO images as part of their collection. There is also the option to let users “play” images in real time. An example is the freely available Herakoi[12] software, a motion-sensing sonification experiment that uses machine learning for hand recognition to track in real time the position of the user’s hand in the scene observed by a webcam connected to a computer screen, converting into sounds the visual properties of the "touched" pixels (Guiotto Nai Fovino et al. 2023). An exhibit based on this software to explore the JWST image of the Carina Nebula is also part of the “Time Machines” exhibition, created and produced by INAF at Palazzo Esposizioni Roma.[13]
Exploring the raw data underlying astronomical images in an interdisciplinary way can also be an empowering tool to practice science with marginalized communities. This is being done as part of “Closer to the Sky”,[14] an IAU-OAD funded project run by astronomers and community organizers to co-create scientific knowledge in the Cantagalo Pavão Pavãozinho (PPG) favela complex of Rio de Janeiro (Cortesi et al. 2024). Figure 1 shows a cooperative student work created at Ninho das Águias, the local library that hosts the project, during a workshop led by Prof. Denise R. Gonçalves, an Afro Brazilian woman astronomer at Valongo Observatory of Federal University of Rio de Janeiro, sharing her research on planetary nebulae, which also includes JWST observations of the NGC 3132 nebula (De Marco et al. 2022). This is an example of a public outreach project engaging a marginalized and fragile community, meeting the community where they are, presenting scientist role models in which they can identify themselves and co-designing the project according to the community needs.
Figure 1: Cooperative student work comparing life phases of stars and humans. Credits: Closer to the Sky
References
Cortesi, A., et al. 2024. Proceedings IAU Symposium No. 384.
De Marco, O., et al. 2022. Nature Astronomy, 6, 1421-1432.
Guiotto Nai Fovino, L., et al. 2023. Proceedings of “The 28th International Conference on Auditory Display (ICAD 2023) – Special Session on Astronomical Data Sonification”.
Pontoppidan, K., et al. 2022. Astrophysical Journal Letters, 936, L14.
Rector, T.A., et al. 2007. Astrophysical Journal, 133, 598, Y611.
Wing, J.M. 2006. Communications of the ACM, 49(3):33–35.
Zanella, A., et al. 2022, Nature Astronomy, 6, 1241–1248.
[1] By Will Gater, New Scientist, July 11, 2022 https://www.newscientist.com/article/2327954-how-the-james-webb-space-telescopes-first-colour-images-were-made/ (last retrieved on 10 March 2024)
[2] https://slate.com/technology/2022/07/james-webb-space-telescope-photos-colors-infrared.html By Sarah Braner, Slate, July 15, 2022 (last retrieved on 10 March 2024)
[3] By Jamie Carter, Forbes, July 18, 2022 https://www.forbes.com/sites/jamiecartereurope/2022/07/18/yes-nasa-did-manipulate-the-webb-telescopes-first-color-images-last-week/ (last retrieved on 10 March 2024)
[4] https://qz.com/2188123/the-james-webb-space-telescope-images-arent-faked-theyre-designed By Tim Fernholz, Quartz, July 19, 2022 (last retrieved on 10 March 2024)
[5] Translated from Italian: “Di che colore sono le stelle? La storia dietro le immagini del telescopio James Webb” by Matteo Marini, Repubblica.it, July 20, 2022 https://www.repubblica.it/tecnologia/2022/07/20/news/ecco_come_nascono_i_colori_del_james_webb-358387567/ (last retrieved on 10 March 2024)
[6] https://gizmodo.com/webb-space-telescope-image-colorization-1849320633 By Isaac Schultz, Gizmodo, August 6, 2022 (last retrieved on 10 March 2024)
[7] By Jay Castello, The Verge, October 10, 2022 https://www.theverge.com/2022/10/10/23393194/nasa-image-processing-jwst-astrophotography (last retrieved on 10 March 2024)
[8] Dr Alastair Gunn, BBC Science Focus, February 15, 2023 https://www.sciencefocus.com/space/how-is-colour-added-to-the-jwst-images-an-astronomer-explains (last retrieved on 10 March 2024)
[9] https://investigations.rubinobservatory.org/coloring-the-universe (last retrieved on 10 March 2024)
[10] https://www.melaniek.co.uk/pillars-of-creation (last retrieved on 10 March 2024)
[11] https://chandra.si.edu/sound/ (last retrieved on 10 March 2024)
[12] https://github.com/herakoi/herakoi (last retrieved on 10 March 2024)
[13] https://macchinedeltempo.inaf.it/index.php/en/home/ (last retrieved on 10 March 2024)
[14] https://www.astro4dev.org/closer-to-the-sky-co-creating-astronomical-knowledge-in-the-favela-complex-of-cantagalo-pavao-pavaozinho-ppg-in-rio-de-janeiro/ (last retrieved on 10 March 2024)