The Cartwheel Galaxy is the latest cosmic snapshot from the Webb telescope

Scientists on Tuesday released the latest images from NASA’s triumphant James Webb Space Telescope. The latest publication documents the Cartwheel Galaxy, located about 500 million light-years from our planet and aptly named for its wheel-like appearance, complete with a central hub, tire and even wavy, fluorescent spokes. The Webb also recorded two smaller companion galaxies in addition to Cartwheel.

The new images follow NASA’s July 12 unveiling of five initial scenes captured by the Webb Telescope, the most powerful space observatory built to date. Since launching on Dec. 25, the Webb’s 18 hexagonal gold mirrors have aligned to capture other targets in space, although all images have not yet been released. Snapshots included the Southern Ring Nebula, which resembles a soap bubble spreading from a dead star, and the prominent Carina Nebula, composed of swirling dust resembling jagged cliffs.

Astronomers have been studying the Cartwheel Galaxy for decades. It was originally inspected from two ground-based observatories in Australia, first by the British Schmidt telescope and later by the Anglo-Australian telescope. It is best known, however, from the Hubble Space Telescope, which produced images with more detail of the galaxy’s composition in the 1990s. And just as the Webb in July revealed the presence of even more distant galaxies hiding from our view, his photos of Cartwheel magnified the detailed formation of stars within the galaxy’s rings and the dozens of other star systems beyond.

Cartwheel’s appearance dates back to a collision between two galaxies that occurred hundreds of millions of years ago. “We suspect that initially the cartwheel probably looked something like the Milky Way, and then this other galaxy moved through it,” said Marcia Rieke, principal investigator of the near-infrared camera, or NIRCam, one of the Webb telescope’s science instruments. However, the smaller galaxy did not get stuck in the large spiral it entered, but continued on its way, moving away from the larger one. It is not visible in the image released by NASA.

Galactic collisions are not uncommon in space, although they rarely result in such a perfect shape that piques human curiosity. Kirk Borne, who was the principal investigator for the Hubble observation of the cartwheel but was not involved with Webb, said the galaxy’s odd shape, which happened to have formed during the merger, has motivated astronomers to study it for decades.

Because a smaller galaxy collided into a larger one – and right through its center – this disrupted the shape of each galaxy less, and both were able to relatively preserve their individuality. “What changed the shape of the cartwheel was the influence of this other galaxy’s gravitational field, which changed the orbits of the stars in the original cartwheel galaxy,” said Dr. Rieke.

dr Borne, who has studied other galaxy collisions, described the smaller galaxy as a bullet blasting through the larger one. After observing the cosmic object in the 1990s, scientists noticed a trail of left behind hydrogen gas following the smaller galaxy that Dr. Borne dubbed the “smoking gun,” indicating it had moved on after Cartwheel’s new formation formed.

Already 1.5 times the size of the Milky Way, Cartwheel is still expanding, and new stars are being formed both within its outer ring and around its rim. However, there is no concrete answer as to how big Cartwheel will get, when it will stop growing, or what shape it will take.

Cartwheel’s images were in hand as early as July 12, although they were only released to the public this week. They have been filtered to make them more visually accessible, emphasizing vibrant blue-hued young stars and red-hued molecules from older stars and space dust suspended between the rings. While colorful, Joseph DePasquale, senior science visuals developer at the Space Telescope Science Institute, which manages the Webb and Hubble spacecraft, emphasized that the stars and dust are actually detected as infrared light, not colors.

The new technology to see this light in such detail distinguishes Webb’s images from those made by Hubble and the Anglo-Australian telescope. While Hubble had some ways of recording light in the infrared spectrum, Webb’s are more advanced and produce more vivid images. For example, the NIRCam, which about 25 people together with Dr. Rieke, which was built in 11 years, distinguishes the infrared colors of the stars, which are invisible to the human eye.

When Hubble captured Cartwheel in the 1990s, the galaxy’s “spokes” were obscured by clouds of gas that scattered light, making it difficult to see the thousands of stars that were forming within. Because the Webb can probe wavelengths of light in the mid- and near-infrared, it is now able to filter space dust. This is helping to confirm some of the theories about Cartwheel’s structure that have been advanced using Hubble’s technology and uncover new information, such as the lack of star formation in some regions between the wheel’s spokes.

“I think that the combination of the two telescopes, far from making either of them obsolete, just increases the benefits and power of Hubble because we can now do these comparisons,” said Dr. born.

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