The James Webb Space Telescope has been operating for less than a year, but already it’s causing astronomers to rethink some long-held beliefs about the early universe. A team from the University of Texas has used NASA’s new space telescope to take a peek at some extremely distant, and therefore ancient, galaxies. Webb’s extraordinary clarity revealed these galaxies have structures known as bars, which astronomers didn’t believe would have existed when the universe was a mere 25% of its current age.
Spiral galaxies are common throughout the universe (our Milky Way is one), and many of them are so-called barred galaxies. At least today they are. These structures appear to develop as spiral galaxies “mature,” drawing gas from the periphery in toward the center, where it fuels star formation at a vastly accelerated rate. Looking back in time, astronomers have spotted fewer bars in spiral galaxies, and that led to wide speculation that they had not formed in the early eons of existence.
Now, we have not one but two examples of barred spiral galaxies in the early universe. Webb focused on a galaxy known as EGS-23205, which appears as it did 11 billion years ago. Hubble images of EGS-23205 just show a round blob, but Webb’s massive mirror resolves the details of a barred spiral. Above, you can see Hubble’s view of EGS-23205 on the left and Webb’s on the right. The team went on to spot EGS-24268, another ancient barred spiral about the same age as EGS-23205. The study, published in The Astrophysical Journal Letters, includes four more barred spirals, though all of those are a few billion years younger.
Hubble had observed all of these galaxies in the past, but even as powerful as it is compared with ground telescopes, it was not able to make out the details. Webb has several advantages over Hubble, including its large primary mirror, which has more than five times the surface area for collecting light. It also operates in the infrared spectrum, allowing it to see beyond layers of dust and gas the obscure parts of the universe from Hubble.
The discovery that barred spirals were common between 8 and 11 billion years ago challenges current models of galactic evolution. The team plans to test different models in future studies, but the implications for the early universe are notable. For example, ancient galaxies may have been much more active in star formation than expected due to the presence of bars. These structures can also channel matter into the supermassive black holes lurking in the center of large galaxies, increasing their mass at a greater rate than previously known.
Now read:
- NASA Could Open Up Access to Future Webb Telescope Observations
- Hubble Telescope Captures a Surreal Galaxy Merger Resulting in a ‘Colossal Ring’
- Webb Telescope Captures Breathtaking Image of the Pillars of Creation
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