James Webb image of Pandora’s Cluster has left scientists star-struck

16 Feb 2023

Image: NASA (processed by Alyssa Pagan)

Showing the cluster in much greater detail than Hubble, the latest James Webb image is proof that we are now in a ‘new era of astronomy’.

A new deep field image from NASA’s James Webb Space Telescope has captured yet another distant region of space known as Pandora’s Cluster in unprecedented detail, exceeding scientists’ expectations.

While only the central core of Pandora has been previously studied in detail by Webb’s predecessor, Hubble, the latest image displays much more distant galaxies in the early universe to be observed by using the cluster like a ‘magnifying glass’.

Three clusters of massive galaxies can be seen coming together to form a megacluster. The combined mass of the galaxy clusters creates a powerful gravitational lens, a natural magnification effect of gravity, which allows scientists to see the other galaxies.

“When the images of Pandora’s Cluster first came in from Webb, we were honestly a little star-struck,” said astronomer Rachel Bezanson of the University of Pittsburgh in Pennsylvania, who is the co-principal investigator on the UNCOVER programme to study the region.

“There was so much detail in the foreground cluster and so many distant lensed galaxies, I found myself getting lost in the image. Webb exceeded our expectations,” she added.

“The ancient myth of Pandora is about human curiosity and discoveries that delineate the past from the future, which I think is a fitting connection to the new realms of the universe Webb is opening up, including this deep-field image of Pandora’s Cluster.”

‘New era of astronomy’

The latest James Webb view of Pandora stitches four snapshots together into one panoramic image, displaying an estimated 50,000 sources of near-infrared light.

Distant galaxies in the image appear distorted relative to the ones in the foreground because of gravitational lensing caused by the enormity of the galaxy cluster which warps the fabric of space itself. This is enough for light from distant galaxies passing through to also take on a warped appearance.

“Pandora’s Cluster, as imaged by Webb, shows us a stronger, wider, deeper, better lens than we have ever seen before,” said astronomer Ivo Labbe of the Swinburne University of Technology in Melbourne, who is also a co-principal investigator on the UNCOVER programme.

“My first reaction to the image was that it was so beautiful, it looked like a galaxy formation simulation. We had to remind ourselves that this was real data, and we are working in a new era of astronomy now.”

Just last month, the James Webb discovered its first exoplanet 41 light-years away in the Octans constellation. Almost the same size as Earth, scientists are now trying to determine if the planet has an atmosphere, with more exoplanet discoveries expected for the future.

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Vish Gain is a journalist with Silicon Republic