Tool Shows Just How Stunning Webb's Space Image Is Compared to Older Ones

An online tool now allows users to compare the recent James Webb Space Telescope image with older cosmic images—showing just how powerful NASA's new telescope really is.

On Monday NASA released one of the first proper images taken by Webb, ending months of anticipation while the telescope—launched last December—calibrated itself in space.

Already, the telescope has pushed the boundaries of just how far scientists can peer into space. The new image, called Webb's First Deep Field, represents the deepest infrared image of the universe ever taken.

It shows a galaxy cluster known as SMACS 0723, located over 5 billion light years away from Earth.

WorldWide Telescope tool
A screenshot from the American Astronomical Society's WorldWide Telescope tool that allows users to compare the new James Webb Space Telescope image to older images of the cosmos. American Astronomical Society/WorldWide Telescope

To some, the image might look no different than other pictures of deep space, such as the famous Hubble Deep Field images that also show countless galaxies unfathomably far away.

The key difference between Webb and Hubble is that while the Hubble telescope views the universe in optical light, Webb sees in infrared light, which is ideal for peering as far back as possible into the cosmos.

"Hubble produced many wonderful discoveries, including the Hubble Deep Field's imaging of the peak era of galaxy formation, at a redshift of about 2, when the universe was just a third of its current age," Michael Barlow, emeritus professor of physics and astronomy at University College London in the U.K., told Newsweek.

"But Hubble is primarily an optical telescope while Webb is an infrared telescope. At higher and higher redshifts, where we look back to when the universe was just a fraction of its current age, the ultraviolet and optical emission from the earliest galaxies gets more and more shifted into the infrared, to wavelengths that Hubble cannot see but which Webb is ideally suited to measure. So Webb can detect and study the first galaxies that formed after the Big Bang."

To further show just how advanced Webb is and why infrared light is useful, experts at the American Astronomical Society's (AAS) WorldWide Telescope (WWT) project have put together an online tool that places Webb's First Deep Field against other images of the universe taken by older telescopes.

Alyssa Goodman, astronomy professor at Harvard, demonstrated how the tool works in a tweet below.

"The really important thing to appreciate it how much better this is than previous images," Goodman said.

The WWT tool allows users to zoom in and out of the tiny patch of sky that Webb focussed on when it captured its recent image. It also allows users to choose which old telescope image they would like to use as a benchmark.

Then, using a slider tool, users can fade in the Webb deep field over the old telescope images to see just how much detail Webb has brought out over a patch of sky that, previously, looked blurry and unassuming.

The WWT tool can be accessed on the AAS website here.

Webb's First Deep Field
A cropped version of Webb's First Deep Field photo, released by NASA on July 11, 2022. The image shows countless galaxies billions of light years away. NASA/ESA/CSA/STScl