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After several years of planning and trials, NASA’s James Webb Space Telescope sent its first images and data to earth. These pictures were released on July 12 2022, during a televised broadcast by NASA’s Goddard Space Flight Center in Greenbelt, Maryland. However, scientists had modified them slightly before release. This raises the question; why would you do that?
Image Credits: NASA
NASA scientists have clarified that they were real but not exactly what Webb captured. They need to manipulate them for some scientific reasons.
What is James Webb Space Telescope?
James Webb Space Telescope is a space observatory launched on December 25 2021, from ESA’s (European Space Agency) site in French Guiana. It is NASA’s most powerful and largest space telescope-worth $10 billion, designed in collaboration with ESA, which was launched to understand the mystery of the universe, from planet formation to black holes.
According to NASA, the telescope was designed to explore these four areas; galaxies assembly in the universe, formation of stars and protoplanetary systems, the first light in the universe, and the origin of life on planets. Further, it was sent to take pictures of celestial objects like asteroids, meteorites, etc.
What images did Webb capture?
While planning for Webb’s launch, scientists were looking for objects which have a clear and observable structure to determine the limit of the telescope. As the launch was delayed multiple times, engineers selected 70 targets that could demonstrate Webb’s breadth of reach in space. It captured its first images of exoplanet WASP-96b (a planet outside the solar system), Stephan’s Quintet (five galaxies in the Pegasus constellation), and the Carina Nebula, the Southern Ring Nebula and the galaxy cluster SMACS 0723. However, these images were manipulated before releasing in the media.
Why does NASA have to modify the images?
As the Webb Space Telescope detects infrared light, it sees everything in red, the farthest light spectrum in the universe not visible to human eyes. Therefore, scientists had to colour the images to make them visible to normal humans. Webb uses filters or masking techniques to perceive light from distant objects and detect them. This light is a kind of heat radiation and lies in another part of the electromagnetic spectrum (range of frequencies and wavelengths of electromagnetic radiation), invisible to human eyes.
To make Webb’s photos visible, scientists changed the electromagnetic spectrum to a part visible to humans from an invisible portion. They took monochromatic pictures from Webb using different filters, where each filter identifies different wavelengths of infrared light. They assigned each filter to transform invisible infrared light wavelengths into visible light and form a composite image.
It is a complex process to convert raw data into a fully-coloured image. It may take a few weeks to make a beautiful and colourful photo from a bunch of white and grey spots. Though the process sounds difficult, scientists will continue to explore space more, and we can expect more interesting images of the cosmos in the future.
