Webb Finds That Many Old, Distant Galaxies Look Like Surfboards

While the James Webb Space Telescope has been busy helping scientists solve some of the greatest mysteries of the early Universe, the powerful telescope has also found that many distant galaxies have flattened oval disk and tube-like shapes, unlike the spiral and elliptical structures that are more typically seen in closer galaxies.

“Ready to hit the cosmic ‘waves’ with the James Webb Space Telescope? Like a lifeguard on duty, Webb has scanned the horizon and spotted distant galaxies shaped like volleyballs, frisbees, pool noodles, and surfboards,” writes the Webb Space Telescope team in a recent news release.

Researchers analyzing data from Webb found that surfboard- and pool-shaped galaxies were significantly more common when the Universe was 600 million to six billion years old. This is in stark contrast to nearer galaxies, which are “often clearly defined spirals with star-studded arms.” Continuing the beach day metaphor, the Webb team explains, “Nearby galaxies are often clearly defined spirals with star-studded arms, which also resemble frisbees, or smooth ellipticals, which also look like volleyballs.”

It remains unclear if these unusually shaped galaxies have looked like this throughout their entire existence or if their shapes have been molded by cosmic conditions over the past 13 billion years or so.

“Roughly 50 to 80% of the galaxies we studied appear to be flattened in two dimensions,” explains Viraj Pandya, a NASA Hubble Fellow at Columbia University. “Galaxies that look like pool noodles or surfboards seem to be very common in the early Universe, which is surprising, since they are uncommon nearby.” Pandya is the lead author of a recent study, “Galaxies Going Bananas: Inferring the 3D Geometry of High-Redshift Galaxies with JWST-CEERS.”

Pandya and the rest of the team focused on a vast field of near-infrared images captured by Webb as part of the Cosmic Evolution Early Release Science (CEERS) Survey.

“While most distant galaxies look like surfboards and pool noodles, others are shaped like frisbees and volleyballs. The ‘volleyballs,’ or sphere-shaped galaxies, appear the most compact type on the cosmic ‘ocean’ and were also the least frequently identified. The frisbees were found to be as large as the surfboard- and pool noodle-shaped galaxies along the ‘horizon,’ but become more common closer to ‘shore’ in the nearby Universe,” explains the Webb Space Telescope news release.

What would the Milky Way Galaxy look like if it were possible to turn back time by a few billion years?

“Our best guess is that it might have appeared more like a surfboard,” says co-author Haowen Zhang, a PhD candidate at the University of Arizona in Tucson.

“In the early Universe, galaxies had had far less time to grow,” explains Kartheik Iyer, a co-author and NASA Hubble Fellow also at Columbia University. “Identifying additional categories for early galaxies is exciting — there’s a lot more to analyze now. We can now study how galaxies’ shapes relate to how they look and better project how they formed in much more detail.”

Webb’s exceptional sensitivity and resolution enables scientists to look further back in time than ever before, getting closer to viewing the very beginning of the Universe.

As the Webb team acknowledges, “There are still gaps in our knowledge — researchers not only need an even larger sample size from Webb to further refine the properties and precise locations of distant galaxies, they will also need to spend ample time tweaking and updating their models to better reflect the precise geometries of distant galaxies.”

“There are very early results,” says co-author Elizabeth McGrath, an associate professor at Colby College in Waterville, Maine. “We need to delve more deeply into the data to figure out what’s going on, but we’re very excited about these early trends.”