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The past is looking good: JWST reveals first images

The images captured by the James Webb Space Telescope continue to reveal the incredible structures and secrets of our past.

Webb's First Deep Field (NIRCam Image), released July 12, 2022 10:39AM (EDT).

The James Webb Space Telescope (JWST) delivered its first high-definition images on 11 July at an event at the White House. You’ve likely seen these  now shared on social media: the surfaces of faraway planets, new galaxies discovered as distant blobs in the fabric of the universe, and cosmic dust and starlight coalescing into the widely-adored Cosmic Cliffs image.

Motivated entirely by the advancements made by the Hubble telescope, JWST will expand what astronomers know about the universe. Venturing further into space with larger mirrors and a broader range of light, JWST  provides astronomers a view of galactic geology essential to progression in fields of cosmology (the study of galaxy formation).

JWST can detect infrared light, meaning it is sensitive to redshift. This is where light coming from distant objects gets progressively redder as the universe expands. While celestial objects may not have previously emitted infrared light and thus be indetectable, the expansion of the universe means the JWST can now assist astronomers in  not only locating these objects but calculating when the light was emitted.

Observing redshifted light is also essential to the study of dark matter formation. Scientists understand perilously little about the matter, and it can only be observed by examining how it warps light around it. Gravitational lensing, which emerged from Einstein’s theory of general relativity, predicts that dark matter will bend spacetime and any light that it interacts with. As such, if light from distant stars passes through dark matter, it will deflect and create haloes around the dark matter. Investigating dark matter formation means observing distant and therefore redshifted light from the early universe, something land-based satellites have struggled with.

The telescope’s infrared capabilities also allow it to peer through the cosmic dust that litters the universe. The various images peppering your social media feed are a result of the precision offered by JWST’s mirrors. The Cosmic Cliffs are a tapestry of gaseous cavities: hot dust and gas that rushes away from the nebula as a result of the intense radiation that occurs during the birth of a star. Images of distant galaxies prove the telescope’s unparalleled imaging capacity.

The telescope is a feat of engineering, providing uniquely detailed datasets never collected on such a scale. However, USyd Astronomer Geraint Lewis reports that applications to work with JWST are “extremely competitive” and require “major international collaborations” due to the data complexity and size.

Similar to data from the Hubble telescope, raw data is not yet accessible to scientists. At the moment, outreach and early release programs are given priority. The public will be able to request the data when a year passes between observation and release. As a global project, 80% of observing time is available for those submitting proposals, meaning that people from all around the world will be able to use the telescope for their research.

New protocols should also minimise biases that disadvantaged women, in particular. Proposals for time with both Hubble and JWST are now reviewed by a dual anonymous panel after an inquiry in the 2010s revealed stark gender bias in the selection process. Now, proposals don’t include researchers’ names and researchers don’t know who sits on the panel. Projects are judged solely on their scientific merit, rather than the reputations of researchers. This has led to a more equal demographic shift, but was initially unpopular among seasoned researchers as their well-established career was of no influence in the process.

Considering the lifespan of the Hubble, which has been in orbit for over 30 years, JWST will be essential to the next generation of astronomy. 

When asked what he was most excited about, Lewis answered: “the first galaxies forming out of the featureless soup of material that existed after the Big Bang”. These images will surely be a rich source of questions for decades to come.